SPONSOR: Orthopedic Surgical Manufacturers …ryortho.com/Osma_Petition.pdfachieved with posterior screws inserted through the plate into either the cervical pedicles and/or the lateral

Reclassification Petition: Lateral Mass and Pedicle Screws – Cervical Spine Uses

November 18, 2011 Page 1

TITLE: RECLASSIFICATION PETITION:

Lateral Mass and Pedicle Screw Spinal Systems(cervical spine)

SPONSOR: Orthopedic Surgical Manufacturers Association (OSMA)



Table of Contents:SECTION PAGE

1. Background And Regulatory History.............................................................. 4

2. Device Description ........................................................................................... 6

2.1. Attributes Of Generic Device Type........................................................... 6

2.2. Intended Use .............................................................................................. 7

3. Recommended Classification.......................................................................... 7

4. Supplemental Data Sheet................................................................................. 7

5. Classification Questionaire.............................................................................. 7

6. Summary Of Reasons For Reclassification.................................................... 7

7. Effectiveness Benefits Information................................................................. 9

7.1. Published Literature.................................................................................. 97.1.1. Search Methods ..................................................................................... 97.1.2. Results .................................................................................................. 11

8. Risks To Health............................................................................................... 18

8.1. Published Literature................................................................................ 18

8.2. Maude Database Search ......................................................................... 25

9. Regulatory Control Of Risks.......................................................................... 27

9.1. General Controls ..................................................................................... 27

9.2. Special Controls ...................................................................................... 27

9.3. Risk Mitigation ......................................................................................... 29

10. Representative Unfavorable Information .................................................. 30

11. Summary Of New Information.................................................................... 30

12. Copies Of Source Documentation ............................................................. 30

13. Financial Certification................................................................................. 31

Attachment A: Supplemental Data Sheet ............................................................ 32

Attachment B: Classification Questionnaire ....................................................... 36

Attachment C: Abstracts: Study Design/Effectiveness...................................... 39

1. Lateral Mass And Pedicle Screws ............................................................. 39

2. Hooks And/Or Wiring.................................................................................. 72

Attachment D: Abstracts: Safety .......................................................................... 78

Attachment E: Posterior Cervical Procedures: Us Data................................... 112

Attachment F: Bibliography/Articles.................................................................. 115



1. Lateral Mass And Pedicle Screws ........................................................... 115

2. Hooks And/Or Wiring................................................................................ 117

Attachment G: AANS Letter Dated November 29, 2010.................................... 119



1. BACKGROUND AND REGULATORY HISTORY

The Orthopedic Surgical Manufacturer’s Association (OSMA) is a trade organization whose membership consists of manufacturers of orthopedic surgical appliances, implants, instruments, and equipment and orthobiologics. Since its inception in 1954, OSMA has actively participated in standards development, patient education, product labeling guidelines, international activities, and supported multiple reclassification petitions. Cooperation and interaction with FDA and health care professionals on issues that lessen the regulatory burden and improve the application of device law continue to be major objectives. This position goes hand in hand with the least burdensome provisions of the Food and Drug Administration Modernization Act of 1997 (FDAMA).

Based on adequate and valid scientific information, OSMA is filing a reclassification petition to classify unclassified screw use in the lateral masses and pedicles of the cervical spine (Product code NKG) to Class II. OSMA originally filed a Petition for this use in May 2010 as an amendment to its August 2009 reclassification petition for pedicle screws in the thoracic, lumbar and sacral spine as an adjunct to fusion in the treatment of degenerative disc disease and spondylolisthesis other than either severe spondylolisthesis (grade 3 or 4) or degenerative spondylolisthesis with objective evidence of neurologic impairment; and in skeletally immature patients. In response to FDA’s 2011 request, OSMA is re-filing this Petition as a stand-alone document.

Pedicle screw fixation of the lumbar spine originated in Europe in the early 1960’s with Roy-Camille’s application for the treatment of fractures. In the United States (U.S.), Harrington was the first to initiate use of pedicle screws to reduce and stabilize high grade spondylolisthesis in 1969. For pedicle screw use in the cervical spine, in 1985, Roy-Camille described the application, and in 1994, Abumi reported the first clinical use. Lateral mass fixation in the cervical spine was first described by Roy-Camille in 1992.

As pedicle screw systems for various spinal indications were first marketed in the U.S.before the 1976 Medical Device Amendments (MDA), they are preamendment devices. More than 10 years ago in the July 27, 1998 Federal Register (and as amended May 22, 2001), FDA published a final rule classifying certain previously unclassified preamendment pedicle screw spinal systems. FDA classified pedicle screws intended for the treatment of various indications as Class II or Class III, and some indications remained unclassified.

With respect to this Petition, various preamendment uses of pedicle screws were not addressed specifically and remained unclassified (Product code NKG). These included pedicle screw use for cervical spondylolisthesis (all grades and types), cervical spondylolysis, cervical degenerative disc disease, degeneration of the cervical facets accompanied by instability, cervical trauma (fracture and dislocation) and revision of failed previous fusion surgery (pseudarthrosis) of the cervical spine.

For the unclassified product code NKG, 510(k) K062254 was cleared and included spinal screw fixation with posterior pedicle and lateral mass screws for various indications from C2 to T3 (inclusive). A number of 510(k) clearances have included Class II uses (Product code MNI and KWP) for fusion of the cervical spine and occipito-cervico-thoracic junction (occiput -T3). These systems include screws, plates, rods and connectors; screw use is limited to the occiput, as well as the pedicles from T1-T3 only.



As illustrated by the instructional courses taught by major orthopedic and spine societies, lateral mass and pedicle screw use in the cervical spine has become the standard of care when posterior fixation and fusion are indicated. These screws have largely replaced the use of earlier wiring, cable and/or hook approaches. Examples of the courses and workshops on the use of cervical pedicle and/or lateral mass screws follow.

American Academy of Orthopedics Surgeons (AAOS)

Spine Surgery: State-of-the-Art Techniques and Science, September 22 - 24, 2011, Rosemont, IL Posterior Surgical Techniques: Tips, Tricks, Set-up and Complication. Frank J.

Eismont, MD Indications and Techniques for Occipital-Cervical Screw Placement: C1 and C2

Fixation, Lateral Mass, Pedicle, Transarticular and Intra-Laminar Screws. John C. France, MD

C1 Lateral Mass Screw; C2 Laminar Screw Technique for Posterior C1-C2 Fusion. Alpesh A. Patel, MD.

C1 Lateral Mass Screw; C2 Laminar Screw Technique for Posterior C1-C2 Fusion, Open Foraminotomy, Laminoplasty, Laminectomy, Occiput to T5 Instrumentation. Lab Instructors: Drs. Bellabarba, Brodke, Choma, Daubs, Eismont,France, Ghanayem, Hsu, Patel, Sasso, Singh, Tribus, and Youssef

http://www7.aaos.org/education/courses/course_detail.aspx?ProductId=11872

Cervical Spine Research Society Instructional Courses:

16th Course: December 7, 2011, Scottsdale, AZ Posterolateral Transpedicular Approach for Ventral Intradural Lesions.

Christopher P. Ames, MD.

15th Course: December 1, 2010, Charlotte, NC C1 Lateral Mass/C2 Laminar Screw Fixation for Posterior Atlantoaxial Fusion.

Rick C. Sasso, MD.o Cervical Pedicle Screw Fixation. Sang Hun Lee, MD.

14th Course: December 2, 2009, Salt Lake City, UT Subaxial Cervical Pedicle Screw Placement. Kuniyoshi Abumi, MD.

http://www.csrs.org/web/meetings/instructional.htm

This Petition supports reclassification of lateral mass and pedicle screws for cervical use from unclassified to Class II (special controls) due to the ability of the general and special controls to provide a reasonable assurance of safety and effectiveness.



2. DEVICE DESCRIPTION

21 CFR 860.123(a) (1)

2.1.ATTRIBUTES OF GENERIC DEVICE TYPE

This Petition seeks to reclassify a generic type of device, pedicle and lateral mass screw systems. These systems are identical to those systems used for current Class II indications (i.e., Product code MNI and KWP for fusion of the cervical spine and occipito-cervico-thoracic junction (occiput -T3)). According to 21 CFR 860.3(i), a generic type of device means:

“a grouping of devices that do not differ significantly in purpose, design, materials, energy source, function or any other feature related to safety and effectiveness, and for which similar regulatory controls are sufficient to provide reasonable assurance of safety and effectiveness”.

Cervical pedicle and lateral mass screws are part of multi-component occipito-cervico-thoracic (OCT) devices that allow surgeons to construct an implant system to accommodate the patients’ anatomic and physiologic requirements. The multi-component OCT devices consist of an anchor via the screw (i.e., occipital, lateral mass, and pedicle) and optionallongitudinal members (e.g., plates, rods, and/or plate/rod combinations) and transverse connectors. An interconnection mechanism (e.g., offset connector, nuts, screws, sleeves or bolts) may be utilized. The anchors or screws form the bone-implant interface, the longitudinal members connect the anchoring members, and transverse connectors link the longitudinal members.

Various screw features (e.g., variable-angle designs, self-tapping and self-drilling screws, double-thread designs, top-loading, pre-assembled) have been incorporated in these screw systems. These features have been designed to increase stability and rigidity, to enhance ease of use, and to achieve better alignment. Screw designs (e.g., screw cannulation) permit minimally invasive or percutaneous screw placement. Rods in fixed or varying lengths include straight, pre-contoured, and flat designs, as well as various degrees of stiffness. Metallic plates (manufactured from various materials) can be used as cervical fixation devices. These plates are available in a variety of lengths and widths. The plates have round holes or elongated slots for the posterior cervical screws. Posterior spinal fixation is achieved with posterior screws inserted through the plate into either the cervical pedicles and/or the lateral masses. Transverse connectors include fixed or adjustable configurationsto increase rotational stability.

The system components are comprised of various materials including: 316L or 316LVM Stainless Steel (ASTM F-138-08 Standard Specification for

Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants),

Titanium (ASTM F-67-06 Standard Specification for Unalloyed Titanium, for Surgical Implant Applications),

Chromium Alloys (ASTM F-1537-08 Standard Specification for Wrought Cobalt-28Chromium-6Molybdenum Alloys for Surgical Implants),

Titanium Alloys (ASTM F-136-08e1 Standard Specification for Wrought Titanium-6 Aluminum-4 Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications; and ASTM F1295 Standard Specification for Wrought Titanium-6 Aluminum-7 Niobium Alloy for Surgical Implant Applications)



These systems may be provided either sterile or non-sterile (sterilized by third party before use) and are intended for single use only.

2.2. INTENDED USE

With this amendment, the Petition recommends including the following:

Lateral mass and pedicle screw systems are intended to provide immobilization and stabilization of spinal segments as an adjunct to fusion during bone graft healing and fusion mass development and/or to restore the integrity of the spinal column even in the absence of fusion for a prolonged period for the following acute and chronic instabilities of the cervical spine (C1 to T3 inclusive): trauma, including spinal fractures and/or dislocations; instability or deformity; pseudarthrosis or failed previous fusions; and degenerative disease, including intractable radiculopathy and/or myelopathy, neck and/or arm pain of discogenic origin as confirmed by radiographic studies, and degenerative disease of the facets with instability; and tumors. Spinal screw fixation is achieved with posterior pedicle and lateral mass screws implanted from C1 to T3 levels inclusively.

3. RECOMMENDED CLASSIFICATION

21CFR 860.123(a) (2)

This Petition seeks to reclassify pedicle and lateral mass screws for use in the cervical spine (Product code NKG), currently unclassified, to Class II (special controls) due to the ability of the general and special controls to provide a reasonable assurance of safety and effectiveness.

4. SUPPLEMENTAL DATA SHEET

21 CFR 860.123(a) (3)

A Supplemental Data Sheet for cervical pedicle and lateral mass screws has been provided in Attachment A.

5. CLASSIFICATION QUESTIONAIRE

21 CFR 860.123(a) (4)

A Classification Questionnaire for cervical pedicle and lateral mass screws has been provided in Attachment B.

6. SUMMARY OF REASONS FOR RECLASSIFICATION

21 CFR 860.123(a) (5)



The Petition includes evidence that pedicle and lateral mass screws for cervical use conform to the criteria for Class II, defined according to the FDCA as follows.

Section 513(a) (1)(B) of the FDCA defines a Class II medical device as follows:

“(B) CLASS II, SPECIAL CONTROLS.-A device which cannot be classified as a class I device because the general controls by themselves are insufficient to provide reasonable assurance of the safety and effectiveness of the device, and for which there is sufficient information to establish special controls to provide such assurance, including the promulgation of performance standards, postmarket surveillance, patient registries, development and dissemination of guidelines (including guidelines for the submission of clinical data in premarket notification submissions in accordance with section 510(k)), recommendations, and other appropriate actions as the Secretary deems necessary to provide such assurance. For a device that is purported to be for a use in supporting or sustaining human life, the Secretary will examine and identify the special controls, if any, that are necessary to provide assurance of safety and effectiveness and describe how such controls provide such assurance.”

Pedicle and lateral mass screw systems for the cervical spine are intended to provide immobilization and stabilization of spinal segments as an adjunct to fusion during bone graft healing and fusion mass development and/or to restore the integrity of the spinal column even in the absence of fusion for a prolonged period. The device does not support or sustain life. Continued instability, non-unions and pseudarthrosis could lead to continued pain and disability; therefore, pedicle screws may be considered of substantial importance in preventing impairment of human health.

Evidence presented in the Petition for pedicle and lateral screw use in the cervical spine, including 40 years of pedicle screw use in the lumbar spine, more than 15 years of pedicle and lateral mass screw use in the cervical spine and more than 10 years of a Class II designation for other pedicle screw uses, demonstrates that general and special controls provide for reasonable assurance of safety and effectiveness, and that the risks to health are not unreasonable. Section 9 defines how general and special controls may be applied to control the known risks to lateral mass and pedicle screw spinal systems in the cervical spine.

In addition, a Class II designation of pedicle and lateral mass screws for cervical use is consistent with the current regulation of other spinal implants for the same intended use. Various Class II product codes for other posterior and anterior spinal implants for the cervical spine incorporate the same indications for which the Petition recommends a reclassification for lateral mass and pedicle screws. FDA product codes and the classification citation for these Class II spinal implants include:

Posterior Approach

NQW 21 CFR 888.3050 – Plate, Laminoplasty, Spinal Interlaminal FixationThese devices consist of plates and screws, where the plate that is attached to the lamina after a laminoplasty or laminectomy procedure. The screws attach the plates to the bone through the holes within the plates.



KWP 21 CFR 888.3050 - Spinal Interlaminal Fixation OrthosisThese devices consist of various wires, hooks and a posteriorly placed compression distraction rod. The levels of attachment include hook fixation to the lumbar, thoracic or cervical spine, as well as wire fixation across adjacent vertebra. These devices include fixation systems for the occipito-cervico-thoracic junction (occiput -T3) withscrew use in the occiput and pedicles from T1-T3.

JDQ 21 CFR 888.3010 – Bone Fixation CerclageThese devices, made of metal alloys, consist of a metallic ribbon or flat sheet or a wire. The device is wrapped around the long bone, anchored to the bone with wire or clamps, and used in spinal trauma surgery (sublaminar, interspinous, or facet wiring techniques); spinal reconstructive surgery (incorporated into constructs for the purpose of correction of spinal deformities such as scoliosis, kyphosis, spondylolisthesis); and spinal degenerative surgery, as an adjunct to spinal fusions.

Anterior Approach

KWQ 21 CFR 888.3050 – Spinal Intervertebral FixationA spinal intervertebral body fixation orthosis or anterior cervical plate consists of various vertebral plates that are attached to the vertebral bodies with screws.

ODP 21 CFR 888.3080 – intervertebral fusion device with bone graft, cervicalDevice consists of a hollow cylinder or rectangular box made of metal or polymer and is intended to stabilize cervical spinal segment to promote fusion with bone graft, to restrict motion and decrease pain.

Based on this information and further evidence provided in the Petition, a Class II designation is appropriate for pedicle and lateral screws for use in the cervical spine.

7. EFFECTIVENESS BENEFITS INFORMATION

21 CFR 860.123(a) (6)

Literature searches were performed to identify valid scientific evidence for the use of pedicle and lateral screw fixation in the cervical spine. A summary of the search methods and the results are provided below.

7.1.PUBLISHED LITERATURE

7.1.1. SEARCH METHODS

Lateral Mass and Pedicle Screws

To identify published clinical evidence on cervical lateral mass and pedicle screws, PubMed, a service of the National Library of Medicine, was searched for articles published in the past 10 years (January 1, 1999 to May 5, 2011). Further limits included English language and humans only. To result in a search with increased specificity, PubMed’s Medical Subject Headings (Mesh) terms, which is a controlled vocabulary thesaurus for indexing articles,



was applied to the search. From the PubMed search, a listing of article titles and abstracts was obtained. When the published abstract did not include information that would exclude the article, the complete article was obtained and reviewed. In addition, the bibliographies from the relevant articles were also screened to identify additional pertinent articles.

The PubMed search was conducted using the following criteria: Cervical vertebrae [Mesh] AND pedicle AND (arthrodesis [Mesh] OR screw OR bone screw [Mesh]). Articles were included if 15 or more subjects had lateral mass and/or pedicle screw use in cervical spine with reports of safety, performance, and/or effectiveness. Articles were also included when they contained general background information on the use of pedicle and lateral mass screws in the cervical spine.

Articles were excluded for the following reasons: pre-clinical (e.g., bench or cadaver) study, the cervical fixation construct included other screws in addition to lateral mass or

pedicle screws (e.g., included use of transarticular, pars, laminar, or other screws), unclear what instrumentation was used or where it was used, the sample size was less than 15 subjects, unable to differentiate lateral mass or pedicle screw results from other constructs,

data a subset or duplicate or other study (larger or more recent study selected), and

no safety or effectiveness results.

Hooks, Wiring, Cables:

In addition, a PubMed search based on English language literature published between 1999 and 2009 was performed to identify comparative safety and fusion results for cervical fixation methods including cervical cables, hooks and/or wiring methods, which are Class II devices.

Article inclusion criteria were as follows: Studies with a minimum of 1 year clinical and radiological follow-up that reported on

outcomes (fusion rate, revisions, etc.) Patients suffering from degenerative disorders of cervical spine such as spinal

stenosis, DDD or spondylolisthesis; occipitocervical dislocation; tumors; atlanto-axial fracture or instability; and need of revision for a previous spine surgery.

Posterior cervical instrumentation. Validated scores/questionnaires were accepted for effectiveness measures.

Article exclusion criteria were as follows: General descriptions of surgical techniques or providing an overview/perspective

of the technology. No safety or efficacy outcomes, specifically neurological complications, revision rate, or

fusion rate. Not a minimum of 1 year clinical and radiological follow-up that reported on outcomes

unless safety, surgical outcomes (i.e. proper placement) and/or complications are discussed.

Utilization of novel materials in conjunction with instrumentation (such as BMPs) without the presentation of an autograft or allograft cohort.

Patient population < 15 unless complications have been reported.



Preclinical data such as functional animal or in vitro data, mechanical bench or biomechanical testing without clinical data.

Isolated case reports. Duplicate publications and publications re-reporting on the same patient cohort. In cases

of redundant patient cohorts, the literature reporting on the most recent follow-ups and outcomes will be utilized.

Economic analyses related to litigation or work compensation. Studies with more than 20% lost to follow-up. Construct included screws.

7.1.2. RESULTS

From the PubMed search for lateral mass and pedicle screws, a total of 273 titles were listed and reviewed for relevance to the Petition. From this search, as well as additional articles identified in retrieved articles, a total of 59 full text articles were reviewed. A total of 32articles with clinical study results and six general overview articles were selected and included in the Petition.

The PubMed search for hooks, cabling or wiring resulted in identification of 39 titles, review of nine full text articles, and selection of five articles for inclusion.

A summary of results follows. In addition, Attachment C provides a detailed summary of each article characterizing the study design and effectiveness results. For the hook, wiring or cable studies, safety results appear in the summary abstract. For lateral mass and pedicle screw studies, safety results each are abstracted and tabulated in Attachment D.

Background

A description of the evolution of pedicle and lateral mass screw fixation in the cervical spine is provided below. This introduction provides perspective for classification of pedicle and lateral mass screws for cervical spine use as Class II.

In the cervical spine, when spinal fixation and fusion are indicated, a majority of the procedures are performed from an anterior approach. According to PearlDiver’s estimates (http://www.pearldiverinc.com/pdi/spine.jsp) in the U.S. for 2010, of 261,927 cervical fusion procedures 93.4% (244,708) were anterior and 6.6% (17,219) posterior. While the most frequent indication for posterior cervical spine fixation is instability secondary to traumatic injury, posterior stabilization is also utilized in treating non-traumatic causes of instability including congenital (e.g., hypoplasia or aplasia of the odontoid process or os odontoideum), inflammatory conditions resulting in instability (e.g., rheumatoid arthritis, ankylosing spondylitis), tumors, and degenerative conditions (e.g., facet arthropathy, degenerative disc disease, myelopathy with spondylosis) (Liu 2001). The intended outcome of posterior stabilization may be stability with fusion, temporary stabilization, pain control, relief and/or prevention of neurologic deficit. For patients with metastatic tumors, the palliative treatment is intended to improve the patient’s quality of life (Oda 2006).

For approximately 100 years, surgeons have applied various surgical techniques to achieve posterior stabilization of the cervical spine (Liu 2001). Wiring has the longest history of usewith reports as early as the 1890’s. Wiring is relatively easy to implement, carries a low risk



of neurological or vascular injury, and does not require x-ray guidance (Arnold 2005). The Bohlman and Rogers’ methods of spinous process wiring, which requires intact spinous processes, have been described in the literature (Arnold 2005). In addition, the Brooks’ wire/cable construct has been utilized (Sasso 2007). While it is more technically challenging and biomechanically inferior to spinous process wiring, facet wiring may be used when intact spinous processes are not available (Arnold 2005). Halo-vest immobilization is generally prescribed for three months after surgery with wiring (Sasso 2007). With wiring, non-union rates, even with a halo vest, may be as high as 30% (Harms 2001, Stulik 2007). Halo-vest immobilization often results in significant co-morbidities among elderly and fragile patients. Interlaminar clamps have also been utilized (Harms 2001).

First described in 1986, Magerl developed an alternative to wiring with the transarticular screw technique (Harms 2001, Sasso 2007). The technique across the C1-C2 facet joint provided more stability than posterior wiring and eliminated the need for halo-vest use. However, according to Sasso (2007), transarticular screw placement is the most challenging as the C1-C2 articulation must be perfectly reduced, the steep cranial trajectory may be difficult to achieve, kyphosis may preclude placement, and 20% of patients have anatomical anomalies increasing the risk of vertebral artery injury. To maximize stability, posterior wiring has to supplement the procedure. This increases the risk of neural injury by the passage of wires or cables into the spinal canal, and requires an intact arch of C1 and structural bone graft (Harms 2001).

Originally described by Roy-Camille in 1992, lateral mass fixation initially with plates and later with rods gained popularity over the past 10 to 15 years (Arnold 2005). The techniqueinvolves screws fixing plates or rods, which are contoured to the spine’s curvature, to the lateral masses of the cervical spine.

Ludwig (1999) noted that three-column fixation with pedicle screws increased stability and strength. Also, the pedicle offered the strongest point of attachment to the spine. As described by Ludwig (1999), the history of initial efforts with transpedicular instrumentation in the cervical spine follows. In 1985, Roy-Camille described the surgical technique and use of pedicle screws for Hangman’s fractures at C2. In 1991, Panjabi published a three-dimensional anatomic study of the human cervical spine. The capacity of the cervical pedicles to accept transpedicle fixation was shown. In 1994, Kotani demonstrated the biomechanical feasibility. Pedicle screws offered increased stability over conventional anterior and/or posterior constructs when used for 2-column or 3-column instability. In 1994, Abumi (2000) was the first to report transpedicle instrumentation in 13 patients with subaxial cervical trauma. Arnold (2005) noted that pedicle screw use in the cervical spine was initially intended for C2 and C7 due to the poor fixation of lateral mass screws at C2 and the cervical-thoracic junction.

Liu (2001) provides illustrations of the placement of cervical lateral mass and pedicle screws in the figures below.



Figure1. Lateral mass screws - The Magerl technique. The entrance point for screw insertion is located slightly medial and rostral to the midpoint of the lateral mass. The direction of the screw is 25° laterally in the axial plane and parallel to the facet joint in the sagittal plane. Center: The Anderson technique. The entrance point for screw insertion is located 1 mm medial to the midpoint of the lateral mass. The direction of the screw is 10° lateral in the axial plane and 30 to 40° rostral in the sagittal plane. Right: The An technique. The entrance point for screw insertion is located 1 mm medial to the midpoint of the lateral mass. The direction of the screw is 30° lateral in the axial plane and 15° rostral in the sagittal plane. (Reprinted with permission from Liu and Das, 2001)



.Figure 2. Pedicle screws. A: Cervical pedicle screw (left screw) achieves rigid three-column fixation in contrast with lateral mass screw (right screw). B: Placement of cervical pedicle screws requires precision and thorough knowledge of the anatomy to avoid damage to the vertebral artery and neural elements. The angle of the screw insertion can vary from 25 to 45° medial to the midline in the axial plane (modified with permission from Jones EL, et al.) C: In the sagittal plane, the angle of screw insertion should be parallel to the upper endplates for the pedicles of C-5 to C-7 and in a slightly cephalad direction for the pedicles of C-2 to C-4. (Reprinted with permission from Liu and Das, 2001)



Performance and Effectiveness Results

The 32 studies include data on 2,024 subjects with pedicle and lateral screw fixation of the cervical spine: 16 of the studies included 15-49 patients, 12 included 50-99 patients, three (3) included 100-199 patients, and one included 319 subjects. A majority of the studies included an average follow-up of one or more years.

Table 1 provides a distribution of the indications for 1,836 patients included in 30 studies. The indications for an additional 188 patients in three studies were not provided (Djurasovic 2005, Liu 2010, and Ondra 2006). As shown in Table 1, the largest majority of patients were treated for trauma including fractures and dislocation (40.6%). Instability/deformity comprised 30.1% of the patients and included kyphosis, subluxation, congenital (hypoplasia or aplasia of the odontoid process), rheumatoid arthritis, infection, ankylosing spondylitis, Klippel-Feil Syndrome, destructive spondyloarthropathy from long-term dialysis and os odontoideum). Degenerative spinal conditions included 15.6% of the patients. The remaining patients had failed fusion, tumors or other conditions.

Indication Total %

Trauma (fractures/dislocation) 745 40.6%

Instability/Deformity 553 30.1%

Pseudarthrosis/Failed Fusion 20 1.1%

Degenerative 287 15.6%

Tumor 169 9.2%

Other 62 3.4%

Total 1836 100.0%

Table 1. Total Number of Patients by Indication

Screw use included pedicle screws only in 19 of the 32 studies (C1-T3), pedicle and lateral mass screws in 12 studies, and lateral mass screws only in one study (C1-C2). For the 19pedicle screw only studies, six of the studies included C1-C2, nine C1-T3, and four studies did not specify the specific cervical vertebra. Nine of the 12 lateral mass and pedicle screw studies included use of pedicle screws at C2 and/or C7 with lateral mass screws at C1 and/or C3-C6. Rods and/or plates may have been included in the construct.

Screw diameter size was specified in 20 studies and screw length in nine studies. Ten studies used 3.5mm screws, eight 3.5 or 4.0mm screws, one 3.5 or 4.0 or 5.0mm, and one study 2.7 or 2.9mm. With the exception of one study (14-17mm), screw lengths ranged from 20-34mm.

Nineteen studies reported fusion and/or other clinical outcome results (Table 2). Sixteen studies reported fusion outcomes with 13 reporting 100% fusion. The other three studies reported fusion greater than 93%. Many of the patients who receive a posterior fusion have significant instability and seriously compromised neurologic function. Eleven studies noted results for neurologic outcomes, and all reported maintenance or improvement in outcomes. Five studies included results for pain and/or disability, and consistently reported improvement.



Table 2. Summary of Lateral Mass and/or Pedicle Studies with Reports of Fusion Rates and/or Clinical Outcomes

Author/Year NumberSubjects

Fusion Rate

Outcome

Abumi/2000 164 99.4% (163/164)

--

Arnold/2005 48 93.8% (45/48)

0% worse neurologic outcomes12 with complete motor injuries: 4 improved/3

unchanged16 with incomplete motor injuries: 16 improved

Cornefjord/2005 19 -- 1/11 with no pre-op neurologic deficit developed a right arm weakness

2/8 with pre-op neurologic deficits improved; other 7 were stable

ElMiliqui/2010 15 100% (15/15)

VAS Neck Last: 1 (range 0-2)

Goel/202 160 100% (160/160)

Pre-op 140/160 quadraparesis or quadriplegic; all improved

Harms/2001^ 37 100% (37/37)

0% worse neurologic outcomes

Hasegawa/2008^

47 97.9% (46/47)

Presence of nape pain improved from pre-op 66% (38/58) to last follow-up16/5 (10/38)

Neurologic status improvedJian/2010 29 100%

(29/29)Neurologic function (JOA) Pre/Last:

12.9/15.4 improvedImproved clinically: 92.9% (24/29)

Kim/2007 65 -- NDI Pre/Last:38/17

VAS Pre/Last:Neck: 8.2/3.2Arm: 7.1/2.3

Lee/2010 27 96% (26/27) VAS Neck: 96% (26/27) improvedNeurologic/Ambulation Recovery

(Frankel Scale): improvementLi/2008^ 23 100%

(23/23)--

Liu/2009 25 Fused segments

stable

NDI Pre/Last:32.96/16.84

Neurologic Function (JOA) mean improvement: 4.1 Oda/2006^ 32 94.0%

(30/32) stable*

Neurologic/Ambulation Recovery(Frankel Scale):

80% (24/30) with spinal cord lesions improved89% (16/18) not ambulatory pre-op walked

Ogihara/2010 23 100% (23/23)

Neurologic function (JOA) Pre/Last:7.1/11.3 improved

Neurologic deficit (Ranawat):74% (12/23) improved more than one grade

Stulik/2007 28 100% (24/24)

--

Tan/2009 17 100% (17/17)

--

Wang/2010 319 100% (319/319)

--



Table 2. Summary of Lateral Mass and/or Pedicle Studies with Reports of Fusion Rates and/or Clinical Outcomes

Author/Year NumberSubjects

Fusion Rate

Outcome

Yukawa/2009 140 100% (140/140)

96% (135/140) good cervical alignment

Zhuo/2010 48 100% (48/48)

Neurologic Function (ASIA):30 with Grades B-D improved 1-2 grades;

18 Grade A did not improve*metastatic tumor subjects/no bone graft if life expectancy < 1 year. ^no definition provided for “fusion”. All others based on radiographs and/or dynamic CT.

Four of the five articles with results for posterior wiring, cabling or hooks provided fusion rate results as shown in Table 3.

Table 3. Summary of Posterior Wiring or Cable Studies with Reports of Fusion Rates

Author/Year Construct NumberSubjects

Fusion Rate

Bapat/2005 Hartshill rectangle

16 92.6% (14/16)

Epstein/2000 Spinous process wiring

or facet-braided cable

22 100% (22/22)

Reilly/2003 Wiring 38 71% (27/35)Zimmerman/2002 Ransford Loop 20 95% (19/20) stable

Benefits of high fusion rates, and improved/preserved neurologic function for patients treated with pedicle and lateral mass screw fixation of the cervical spine were demonstratedconsistently. Fusion rates with lateral mass and pedicle screws were consistently higher than achieved with the cited studies for hooks, cables and wiring, which are Class II devices.Improvement in pain and function was also noted in several lateral mass and pedicle screw studies.

In conclusion, the literature provides valid scientific evidence of the effectiveness of pedicle and lateral screw devices used alone or in combination with other instrumentation for diseases of the cervical spine. According to 21 CFR 860.7(2), “valid scientific evidence is evidence from well-controlled investigations, partially controlled studies, studies and objective trials without matched controls, well-documented case histories conducted by qualified experts, and report of significant human experience with a marketed device, from which it can fairly and responsibly be concluded by qualified experts that there is reasonable assurance of the safety and effectiveness of a device under its conditions of use.”



8. RISKS TO HEALTH

21 CFR 860.123(a) (6)

Risks to health were identified from the published literature, as well as FDA’s Manufacturer and User Facility Device Experience (MAUDE) database. Comparisons between the safety results for lateral mass and pedicle screws to current Class II cervical fusion devices follow.

8.1.PUBLISHED LITERATURE

With the anatomic variations of the cervical spine between patients and levels, fixation of the screws in the cervical pedicles has historically been criticized for its risks to the neurovascular structures. Use of cervical pedicle screws entails the potential risk of vertebral artery (VA), spinal cord and nerve root injury. Anatomic restrictions for pedicle screws include anomalies of the VA artery, varied and small size pedicles with restricted direction for screw insertion, and bone that precludes placement (Sciubba 2009, Ludwig 1999, Yukawa 2009). Deformity may cause abnormality of the VA, and stenosis or occlusion may exist (Ogihara 2010). Harms (2001) noted that approximately 20% of patients requiring atlanto-axial stabilization show anatomic variations in the path of the VA and in the osseous anatomy, at least on one side, precluding screw placement.

For cervical pedicle screws, Neo (2005) reported that a lateral violation of the transverse foramen is more serious than other directions, and when they deviate, pedicle screws tend to deviate laterally for several reasons. The cortex of the transverse foramen is much thinner than the spinal canal and the pressure of the retracted paravertebral muscle makes horizontal insertion difficult. Neo also noted that medial deviation seldom injures the spinal canal because of the wide space between the cord and the medial wall of the pedicle, and direct nerve root injury can be avoided with fluoroscopy.

Arnold (2005) noted that cervical pedicle screws were originally designed for C2 and C7 as the other cervical levels can easily accept lateral mass screws. Arnold pointed out that the C2 pedicle is bigger than the subaxial cervical pedicles, with a width averaging 8 mm. Ludwig (1999) noted that C7 has an increased height and width when compared with the above levels, (average width, 6.4 mm; minimum value, 4.5 mm). Lee (2007) reported that the complex transitional anatomy of the cervicothoracic junction make pedicle screw insertion challenging. The size and orientation of the cervical and thoracic pedicles change significantly across this junction, and the shoulder girdle hinders use of intra-operative fluoroscopy or radiography (Lee 2007). Arnold (2005) noted that at the cervicothoracic junction, the C7 lateral mass is attenuated making safe passage of a lateral mass problematic, and that the upper thoracic spine is better suited to accept a pedicle screw.

Dissection of the posterior arch for insertion of lateral mass screws at C1-C2 also carries risk of VA injury; the VA runs in a groove on the superior surface of the posterior arch (Sasso 2007). Other potential complications include injury to the internal carotid artery, dura or spinal cord, hypoglassal nerve, and irritation of the dorsal ganglion at C2 (Bransford 2011).

Given these potential procedural risks, a number of studies have been conducted specifically to assess screw placement risk. As displayed in Table 4, 23 studies included a



CT post-op assessment of pedicle and/or lateral mass screw placement, and three other studies examined screw placement following various methods of intra-operative guidance.

For the 23 studies summarized in Table 4, various criteria to assess screw breach or perforation were applied to define satisfactory and unsatisfactory screw placement. In addition, 22 of the 23 studies reported whether screw misplacement resulted in an adverse event. Adverse events included VA injury, bleeding or neurologic injury due to the probe, drill or screw use. The use of intra-operative visualization methods varied, which is noted in the table.

For the 10 studies with screws in C1-C2, the rate of satisfactory placement, including minor or non-critical breach, was greater than 93% in eight studies. Lower satisfactory placement rates were reported for Alosh (2010) and Mueller (2010) with rates of 74.7% and 83.0% respectively. Four of the 10 studies reported no adverse events related to screw placement; five studies included rates ranging from 1.1% to 3.7%. A fifth study with only 15 patients reported one event (6.7%).

For the 13 studies with screws at C2 to the upper thoracic vertebra, the rate of satisfactory placement, including minor or non-critical breach, was greater than 93% in 12 studies. Lower satisfactory rates were reported for Ishikawa (2010) and Neo (2005) with rates of 87.3% (fluoroscopy group), and 86.0%. Seven of the 13 studies reporting adverse eventsreported none. Four included rates ranging from 1.4% to 3.2%. Two studies with fewer than 20 patients reported rates of 5.3% and 5.6%.

Table 5 provides information on each of the adverse events identified in Table 4. VA injuries were resolved intra-operatively with application of bone wax or screw insertion. One patient with a VA occlusion remained free of stroke and transient ischemic injury 18 months after surgery. The neurologic events were transient, or resolved with screw revision.

The placement studies did not demonstrate any consistent trend for screw placement accuracy based on the type of visualization during surgery, including free hand, image intensifier/fluoroscopy and computer assisted surgery. Two additional studies (Lee 2007 and Liu 2010) compared the accuracy of screw placement with various visualization methods. Lee (2007) compared the accuracy of pedicle screw placement at the cervicothoracic junction using the open or freehand method to 2-D and 3-D computer-assisted surgery (CAS) techniques. Pedicle screw placement was at C7, T1 and T2. At C7, the pedicle breach rates were comparable with 30% freehand (18/60), 27% 2-D CAS (8/30) and 29% (sic) 3-D CAS (4/16). No screws required revision in any group. Liu (2010) compared the accuracy of pedicle screw placement in the cervical spine using either fluoroscopy, CT-navigation and 3D-navigation. All three methods had high rates of acceptable placement. There were no differences in the rates of excellent or acceptable placement between CT-navigation (96.9%, 151/159) and 3D-navigation (100%, 140/140); and the accuracy with both these methods was statistically significantly better than fluoroscopy (91.7%, 133/145). No complications were reported.



Table 4. Summary of Studies with a CT Assessment of Lateral Mass and Pedicle Screw PlacementAuthor/Year Number

SubjectsNumber Screws

Visualization During Surgery

Screw Assessment by CT SubjectsSatisfactory Not Satisfactory Adverse Clinical

Event*C1-C2:

Alosh/2010(C2: pedicle)

93 170 Fluoroscopy 74.7% (127/170) 25.3% (43/170) 1.1% (1170)

ElMiliqui/2010(C2: pedicle)

15 30 Image intensifier 93.4% (28/30) 6.6% (2/30) 6.7% (1/15)

Goel/2002(C1-C2:lateral mass)

160 NS Fluoroscopy -- 6 screws 2.5% (4/160)

Harms/2001(C1: lateral mass; C2 pedicle)

37 NS Fluoroscopy 100% 0.0% 0.0%

Mueller/2010(C2: pedicle)

27 47 Fluoroscopy 83.0% (39/47) 17.0% (8/47) 3.7% (1/27)

Ondra/2006(C2: pedicle)

79 150 CAS 94.0% (141/150) satisfactory5.3% (8/150) non-critical

breach

0.7% critical breach(1/150)

2.5% (2/79)

Parker/2009(C1-C3: pedicle)

70 161 Free hand majority; fluoroscopy as

needed

93.2% (150/161) 6.8% (11/161) 1.4% (1/70)

Sciubba/2009(C2: pedicle)

55 100 Free hand 98.0% (98/100) 2.0% (2/100) 0.0%

Stulik/2007(C1: lateral mass)(C2: pedicle)

28 5656

Image intensifier 100% (56/56)94.6% (53/56)

0%5.4% (3/56)

0.0%

Wang/2010(C1: lateral mass)(C2: pedicle)

319 638638

Fluoroscopy 95.5% (609/638)92.8% (592/638)

4.5% (29/638)7.2% (46/638)

0.0%

C2 – Upper Thoracic:

Abumi/2000(C2-C7: pedicle)

180 669 Radiograph 93.3% (624/669) 6.7% (45/669) 1.7% (3/180)

Cornefjord/2005(C2-C7: pedicle)

19 67 Fluoroscopy 94.0% (63/67) 6% (4/67) 5.3% (1/19)

Djurasovic/2005(C3-C6: lateral mass; C7: pedicle)

26 148 None 94.6% (140/148) 5.4% (8/148) NS



Table 4. Summary of Studies with a CT Assessment of Lateral Mass and Pedicle Screw PlacementAuthor/Year Number

SubjectsNumber Screws

Visualization During Surgery

Screw Assessment by CT SubjectsSatisfactory Not Satisfactory Adverse Clinical

Event*Ishikawa/2010(C2-C7: pedicle)

30 126 Fluoroscopy 87.3% (110/126) 12.7% (16/126) 3.2% (2/62)32 150 3D-Fluoroscopy 96.7% (145/150) 3.3% (5/150)

Ito/2008(C2-C7: pedicle)C2-C7: lateral mass)

50 176 3D-Fluoroscopy 97.2% (171/176) 2.8% (5/176)0.0%

50 58 100% (58/58) 0%Kim/2007(C1, C3-C6: lateral mass; C2, C7: pedicle)

65 486 Fluoroscopy 97.5% (474/486) 2.5% (12/486) 1.5% (1/65)

Liu/2009(C3-C7: pedicle)

25 150 Free hand with image intensifier as

needed

96.0% (144/150) 4.0% (6/150) 0.0%

Neo/2005(C2-C6: pedicle)

18 86 Fluoroscopy 86.0% (72/86) 14.0% (12/86)

5.6% (1/18)

Ogihara/2010: pedicle(C2, C7, thoracic)(C3-C6)

23 4147

CAS 100% (41/41)97.9% (46/47)

0%2.1% (1/47)

0.0%

Richter/2005(C3-C7: pedicle)

20 93 Image intensifier 100% (93/93) 0.0% 0.0%32 167 CAS 100% (167/167) 0.0% 0.0%

Yoshimoto/2009(C2-C7: pedicle)

52 280 Fluoroscopy 98.2% (275/280) 1.8% (5/280) 0.0%

Yukawa/2009(C2-T2: pedicle)

144 620 Fluoroscopy 96.1% (596/620) 3.9% (24/620) 1.4% (2/144)

Zhuo/2010(lower-: pedicle) 48 NS Fluoroscopy 100% 0% 0.0%

CAS=computer assisted surgery; *Includes events from probes, drilling and/or screws: vertebral artery injury, bleeding, neurologic



Table 5. Placement Studies from Table 4 with Report of Adverse Event: Event Description/Consequences

Author/Year Adverse Clinical Event

VA Neurologic/Other

C1-C2:Alosh/2010(C2: pedicle)

1.1% (1/93) 1 VA injury; screw used to tamponade bleeding

--

ElMiliqui/2010(C2: pedicle)

6.7% (1/15) 1 VA injury; controlled by screw application

--

Goel/2002(C1-C2:lateral mass)

2.5% (4/160) 4 VA bleeding; bone wax stopped --

Mueller/2010(C2: pedicle)

3.7% (1/27) 1 clinically asymptomatic VA compression

--

Ondra/2006(C2: pedicle)

2.5% (2/79) 1 VA injury resolved with screw placement

1 asymptomatic breach >4mm; revision performed.

Parker/2009(C1-C3: pedicle)

1.4% (1/70) 1 VA occlusion; patient took aspirin and symptom free @ 18

months

--

C2 – Upper Thoracic:

Abumi/2000(C2-C7: pedicle)

1.7% (3/180)

1 VA injury; bleeding stopped with bone wax

2 radiculopathy resolved

Cornefjord/2005(C2-C7: pedicle)

5.3% (1/19) -- 1 right arm weakness resolved after screw removal

Ishikawa/2010(C2-C7: pedicle)

3.2% (2/62) 2 VA injury; bleeding stopped with bone wax

--

Kim/2007(C1, C3-C6: lateral mass; C2, C7: pedicle)

1.5% (1/65) -- 1 shoulder pain; screw removal and reposition

resolved

Neo/2005(C2-C6: pedicle)

5.6% (1/18) 1 blurred vision (symptom of VA injury); subject insisted present

pre-op

--

Yukawa/2009(C2-T2: pedicle)

1.4% (2/144) 1 VA injury; bleeding stopped with bone wax

1 transient radiculopathy

For purposes of comparison of the accuracy of pedicle screw placement in the cervical, thoracic and lumbar spine, Kosmopoulos (2007) conducted a meta-analysis of the published literature (1966-2006). Comparisons were also made with and without CAS navigation. Overall, for 12,299 pedicle screws paced in 32 in vivo patient studies with and without the use of navigation, the mean and median accuracy of placement with and without CAS navigation were 92.4% versus 82.2% and 95.2% versus 90.3% respectively. For studies focusing on specific levels of the spine, the results are displayed in Table 6. Kosmopoulos noted that the overall placement rate accuracy was high with and without navigation for all levels of the spine. Using the geometric mean and median accuracy, the navigation-assisted subgroup had a higher accuracy in the placement of pedicle screws for all but the thoracic subgroup. For all levels of the spine, thorough knowledge of local anatomy, careful pre-op planning and intra-operative visualization or computer guidance, based on the surgeon’s preference, are important.



Table 6. Kosmopoulos (2007) Pedicle Screw Placement AccuracyCharacteristic Number

StudiesNumber Screws

Mean Accuracy

Median Accuracy

Standard Deviation

Without NavigationCervical 5 1089 89.0% 93.3% 11.1%Thoracic 3 343 63.1% 94.3% 39.2%Lumbar 7 1674 81.2% 79.0% 13.0%

With NavigationCervical 5 114 99.4% 99.4% 0.8%Thoracic 3 717 85.1% 82.2% 5.4%Lumbar 7 864 93.0% 96.1% 9.2%

A total of 27 studies included assessment of device events for 1,231 patients and general medical events for 1,423 patients. Abstracts of safety results for each article with the tabulated results appear in Attachment D. Table 7 provides a summary of the reported adverse events by type of event. If the screw mal-position resulted in a symptom (e.g., vertebral artery injury), the table includes a separate tabulation of the specific symptom.Device events are differentiated from general medical events, and the types of events are comparable to other spinal devices. The total of all neurologic events resulted in an overall rate of 1.8% (25/1,423). And, the overall rate of VA injury and bleeding was 1.8% (26/1,423). A low rate of re-operation was reported (1.1%, 15/1,423).

Table 7 includes the adverse events included in Table 5, as well as VA injuries from studies without CT assessment of screw placement. Compared to Table 5, four additional studies reported a VA injury: Hasegawa (2008) reported two events (3.4%) without any event details, Lee (2010) reported one occurrence (3.7%) where no consequence of VA injury resulted, and Tan (2009) reported one occurrence (5.9%) where the bleeding was stopped with gauze tamponade. Stulik (2007) reported no cases of VA or neurovasulcar injury from screw placement; however, six instances of venous plexous bleeding were reported; all resolved with bipolar coagulation, screw insertion and tamponing. Jian (2010) reported a death from a VA injury where the C2 screw breached the pedicle, and entered the transverse foramen with VA stenosis and distal thrombosis.

Neo (2008) noted that VA injury can occur with various cervical spine surgery techniquesincluding anterior cervical discectomy/fusion (ACDF) with reported rates ranging from 0.3% to 0.5%, and transarticular screw use with rates ranging from 0% to 8.2%. Neo noted that the occurrence of VA injuries in lateral mass and pedicle screw surgeries warranted investigation. To assess the occurrence of these injuries, Neo (2008) conducted a survey of 29 general orthopedists and seven spine surgeon groups in Japan to present the incidence and management of VA injuries amongst cervical surgeries performed in the past five years. A total of 5,641 surgeries were reported: 2,190 were anterior cervical decompression/fusion (ACDF) or foraminotomy, 149 Magerl (atlantoaxial transarticular) screws, 204 lateral mass/pedicle screws, nine transarticular screws and 42 tumors (surgery not specified). (Note: In a personal communication, Neo speculated that the remaining 3,047 cases were cervical laminoplasty or laminectomy with little risk of VA injury.) The overall incidence of VAinjuries was very low at 0.14% (8 cases of injury split between anterior and posterior approaches: 3 ACDF, 1 tumor resection, 2 Magerl, 1 foraminotomy, 1 lateral mass screw). No VA injuries were reported for pedicle screw cases.



Total Number Patients: Device Events

Total Number of Patients: All Other Events

Adverse Events Total %

Device:

Lateral mass fracture 2 0.2%

Pedicle fracture 1 0.1%

Malposition screws 13 1.1%

Loss of correction 6 0.5%

Screw loosening/pull out 3 0.2%

Strut/graft displacement 1 0.1%

Screw breakage/dislodgment 10 0.8%

Progressive degenerative change 3 0.2%

Heterotopic ossification 1 0.1%

Pseudarthrosis 2 0.2%

Operative/Post-op

Neurological:

Upper extremity numbness/pain 4 0.3%

Neuropathic pain 1 0.1%

Transient paresis 6 0.4%

Muscle weakness 3 0.2%

Dural lesion/violation 2 0.1%

Radiculopathy 6 0.4%

Wound:

Dehiscence/Debridement 1 0.1%

Delayed wound healing 1 0.1%

Wound hematoma/seroma 2 0.1%

Infection 4 0.3%

Deep wound infection 11 0.8%

CSF leak 15 1.1%

Other:

Neck pain 5 0.4%

Swallowing disturbance 1 0.1%

Blurred vision 1 0.1%

Venous plexus bleeding 6 0.4%

Vertebral artery bleeding 4 0.3%

Vertebral artery injury 16 1.1%

Respiratory issue 2 0.1%

Skin irritation 2 0.1%

Iliac crest pain 1 0.1%

Other General Medical 6 0.4%

Death related to procedure and/or device 1 0.1%

Re-operations 15 1.1%

1423

Table 7. Summary of Adverse Events: Published Literature

1231



Five of the five articles with results for posterior wiring, cabling or hooks provided adverse event results as shown in Table 8. The rate of neurologic events and re-operations was higher in these patients compared to those treated with lateral mass and pedicle screws (i.e., neurologic: 1.8% screws vs 5.8% wiring/cable; and re-operation: 1.1% screws vs 10.3%) wiring/cable).

Table 8. Summary of Posterior Wiring or Cable Studies with Reports of Neurologic or Re-operation Events

Author/Year Construct NumberSubjects

Neurologic Re-operation

Bapat/2005 Hartshill rectangle

16 0% (0/16) 0% (0/16)

Epstein/2000 Spinous process wiring

or facet-braided cable

22 13.6% (3/22) 18.2% (4/22)

Fagerstrom/2002 Hooks/rods 60 6.7% (4/60) 10.0% (6/60)

Reilly/2003 Wiring 38 2.6% (1/38) 15.8% (6/38)Zimmerman/2002 Ransford

Loop20 5.0% (1/20) 0% (0/20)

Total -- 156 5.8% (9/156) 10.3% (10/156)

In summary, placement accuracy rates of lateral mass and pedicle screws in the cervical spine were high, and the results were comparable to screw placement accuracy in the thoracic and lumbar spine. The rate of VA and neurovascular injury was low and, with the exception of one event out of 1,423 surgeries, none resulted in serious long term consequences. The rate of neurologic and re-operation events for lateral mass and pedicle screws was lower than the cited studies for posterior wiring/cabling.

8.2.MAUDE DATABASE SEARCH

To demonstrate that the risks associated with pedicle and lateral mass screws for cervical use do not pose an unreasonable risk of injury or illness and that the types of risks are not different than current Class II cervical devices, MAUDE data for the past five years (January 1, 2006 to December 31, 2010) were reviewed. This period coincides with available data on the number of procedures performed (See Attachment E). A variety of product codes thatpertain to use of spinal devices in the cervical spine were included in the MAUDE review, as shown in Table 9.



Table 9. MAUDE Events by Product Code: 2006 - 2010Cervical Spine Devices

Product Code

Events Comment

Pedicle and lateral mass screws

NKG 0 One cleared device, 2008

PosteriorLaminoplasty plates and screws

NQW 2 Seven devices cleared; first in 2004. Events described below.

Hooks/wire KWP 2,039Not differentiated for cervical spine use

KWP includes devices in the cervical spine (e.g., hooks/wire, occiput-T3 screws, plates), as well as devices for the thoracic and lumbar devices. Not possible to differentiate cervical events from other levels of the spine by product code.

Wire JDQ 93Not differentiated for cervical spine use

JDQ applies not only to wire in the cervical spine, but also to orthopedic use in long bones. Not possible to differentiate cervical events from other levels of the spine by product code.

AnteriorPlates/screws KWQ 1,879

Not differentiated for cervical spineuse

KWQ applies not only to plates/screws in the cervical spine, but also to thoracic and lumbar devices. Not possible to differentiate cervical events from other levels of the spine by product code.

Interbody fusion cages ODP 57 Reclassification from Class III to II in July 2007, and first event reported in 2008. Events described below.

The laminoplasty events included one allergic reaction and one cracked lamina.

The 57 interbody fusion cage events included: 6 broken screw, 16 screw back-out, 12 implant broke, 1 instrument broke, 3 dislodged/migration, 3 malposition, 2 fracture bone, 1 pain, 7 pseudarthrosis, 1 subsidence, 2 wound infection, 1 canal impingement, and 2 unknown events. (Note: MAUDE reports also included 18 replicate events and 1 event that was not cervical.)

In addition to the inability to differentiate cervical versus other spine use for posterior (KWP and JDG) and anterior (KWQ) uses, the number of procedures performed annually for each of the product codes is not available. In the absence of this information, an “orders of magnitude” worst case comparison for 2006 to 2010 of posterior versus anterior cervical MAUDE rates for Class II devices, assuming all events are for the cervical spine, follows. From 2006 to 2010, according to PearlDiver from there were 1,160,456 anterior cervical fusion procedures and 80,579 posterior cervical fusions. With 1,936 anterior and 2,134posterior events, the MAUDE rates for this five year period are 0.12% and 2.65% respectively. The rates of events reported from the published literature for pedicle and lateral mass screws in the cervical spine are comparable to these rates for Class II spinal implants.



9. REGULATORY CONTROL OF RISKS

21 CFR 860.123(a) (6)

The Petition’s review of the published literature and MAUDE data for the pedicle and lateral mass screws in the cervical spine demonstrates that the risk of illness or significant injury is low and the types of events are consistent with other Class II uses in the spine. Class II spinal implants are currently regulated by general and special controls. As described below, these controls are adequate to provide reasonable assurance of safety and effectiveness. Further clinical evidence regarding the safety and effectiveness of lateral mass and pedicle screws is not required.

9.1.GENERAL CONTROLS

General controls include manufacturing establishment registration, Quality System Regulation, provisions regarding adulteration and misbranding, record keeping, and reporting of adverse events.

9.2.SPECIAL CONTROLS

In addition to general controls, this Petition recommends use of special controls to mitigate any risk associated with use of pedicle and lateral mass screws in the cervical spine. These special controls include performance standards (i.e., material, mechanical testing, and biocompatibility), training and other appropriate labeling information. These special controls were implemented with FDA’s Guidance for Industry and FDA Staff: Spinal System 510(k)s (May 3, 2004 which superseded a September 27, 2000 guidance).

Material Standards

The metals used in the manufacture of pedicle and lateral mass screws have a long history of safe use in humans. In addition, material standards provide the chemical, mechanical and metallurgical requirements for these materials, when they are to be used in the manufacture of surgical implants.

ASTM F-138-08 Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for Surgical Implants

ASTM F-67-06 Standard Specification for Unalloyed Titanium, for Surgical Implant Applications

ASTM F-1537-08 Standard Specification for Wrought Cobalt-28Chromium-6Molybdenum Alloys for Surgical Implants

ASTM F-136-08e1 Standard Specification for Wrought Titanium-6 Aluminum-4 Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications

ASTM F1295 Standard Specification for Wrought Titanium-6 Aluminum-7 Niobium Alloy for Surgical Implant Applications

Biocompatibility Standards



Biocompatibility of devices comprised of alternative or new materials can be assured through ISO 10993, Biological Evaluation of Medical Devices and through adherence to existing material standards. Compliance with these standards and/or ISO 10993 will provide reasonable assurance of the safety of material used in devices.

Mechanical Testing Standards

The mechanical performance of pedicle and lateral mass screws is addressed with the following test standards:

ASTM F-1717 (2004) Standard Test Methods for Spinal Implant Constructs in a Vertebrectomy Mode,

ASTM F-1798-97(2008) Standard Guide Evaluating the Static and Fatigue Properties of Interconnection Mechanisms and Subassemblies Used in Spinal Arthrodesis Implants.

ASTM F2706-08 Standard Test Methods for Occipital-Cervical- and Occiptital-Cervical-Thoracic Implant Constructs in a Vertebrectomy Model

These test standards address static and dynamic (fatigue) characteristics. Testing conducted according to this standard ensures that FDA can assess mechanical performance, which may impact the device’s safety and effectiveness.

Training

Training and education is currently offered by the major orthopedic and spinal societies. In addition, product manufacturers can provide training regarding specific product use.

Labeling

The Guidance for Spinal System 510(k)s (May 2004) provides examples of additional labeling specific to spinal implants. Labeling requirements are designed to direct use and inform users to limit risks.

Currently, the Guidance for Spinal System 510(k)s includes the warning and precaution identified below. With this Petition, we recommend elimination of the warning that follows:

``Warning: The safety and effectiveness of pedicle screw spinal systems have been established only for spinal conditions with significant mechanical instability or deformity requiring fusion with instrumentation. These conditions are significant mechanical instability or deformity of the thoracic, lumbar, and sacral spine secondary to severe spondylolisthesis (grades 3 and 4) of the L5-S1 vertebra, degenerative spondylolisthesis with objective evidence of neurologic impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudarthrosis). The safety and effectiveness of these devices for any other conditions are unknown. ``

We recommend inclusion of the precaution statement that follows:

``Precaution: The implantation of cervical lateral mass and pedicle screw spinal systems should be performed only by experienced spinal surgeons with specific training in the use of this pedicle screw spinal system because this is a technically demanding procedure presenting a risk of serious injury to the patient.``



As an additional precaution, we recommend inclusion of the following:

“Precaution: Pre-operative planning for implant of cervical lateral mass and pedicle screw implants should include review of radiographs, CT and/or MRI imaging to evaluate the patient’s anatomy, transverse foramen and the course of the vertebral artery. If any findings would compromise the placement of lateral mass or pedicle screws, other surgical methods should be considered. In addition, use of intra-operative imaging should be considered to guide and/or verify device placement, as necessary”.

In addition, labeling requirements are discussed in various FDA guidance documents including the Device Labeling Guidance (#G91-1 (Blue Book Memo)). This guidance describes the contents of the label including indications, contraindications, precautions and warnings. The labeling for these devices includes the caution: Federal law restricts this device to sale by or on the order of a physician.

9.3.RISK MITIGATION

Table 10 lists the potential risks with lateral mass and pedicle screws in the cervical spine and identifies the regulatory controls that mitigate the risk. The risks and regulatory controls currently apply to anterior and posterior cervical spine implants for Class II indications.

Table 10. Potential Risks and Regulatory ControlsDevice-Specific Adverse Events

Material Standards

Mechanical Testing

Biocompatibility Standards*

Training Labeling QSR General Controls

Malposition -- -- -- Yes Yes --

Implant loosening - Yes Yes Yes Yes --

Device breakage Yes Yes -- Yes Yes YesDisassembly Yes Yes -- Yes Yes --

Malfunction-Device Yes Yes -- Yes Yes YesBone Fracture -- -- -- Yes Yes --

Graft settling/ displacement

-- -- -- Yes Yes --

Loss of correction Yes Yes Yes Yes Yes --

Pseudarthrosis Yes Yes Yes Yes Yes --

Other Adverse Events

Material Standards

Mechanical Testing

Biocompatibility Standards*

Training Labeling QSR General Controls

Bleeding/Vascular Injury

-- -- -- Yes Yes --

Neurologic injury - - - Yes Yes -CSF leak -- -- -- Yes Yes --

Wound - - - Yes Yes -Infection - - - Yes Yes -Skin irritation - - Yes Yes Yes -

Cardiac - - - Yes Yes -Respiratory - - - Yes Yes -

Revision surgery Yes Yes Yes Yes Yes --Death Yes Yes Yes Yes Yes --

*New materials



Class II spinal implants are currently regulated by general and special controls. As described above, these controls are adequate to provide reasonable assurance of safety and effectiveness.

10. REPRESENTATIVE UNFAVORABLE INFORMATION

21 CFR 860.123(a) (7)

Unfavorable information has been included in Section 7 Effectiveness/BenefitsInformation and Section 8 Risks to Health.

11. SUMMARY OF NEW INFORMATION

21 CFR 860.123(a) (8)

All of the information in the Petition is publicly available. FDA is aware of the data presented as required by Section 519 of the FDCA though its MAUDE database. However, the information presented is organized and compiled for the first time for purposes of this Petition.

12. COPIES OF SOURCE DOCUMENTATION

21 CFR 860.123(a) (9)

The Petition includes source documentation as follows: Attachment C: Study Design/Effectiveness Abstracts Attachment D: Safety Abstracts Attachment E: Posterior Cervical Procedures: US Data Attachment F: Bibliography/Articles



13. FINANCIAL CERTIFICATION

21 CFR 860.123(a) (10)

Financial relationships were disclosed for the following:

Cornefjord 2005. Not specified; however, Olerud one of authors, which corresponds to device evaluated.

Harms 2001. Although the author(s) have not received or will receive benefits for personal/professional use from a commercial party related directly or indirectly to the subject of this manuscript, benefits have been or will be received but are directed solely to a research fund, foundation, educational institution or other nonprofit organization which the author(s) have been associated.

Richter 2005. One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript.

Scuibba 2009. One of authors serves as a consultant to Medtronic and receives support from DePuy Spine. Also serves on board of US Spinal Technologies and Spinal Kinetics. (Note: not clear what manufacturer’s screws used.)



ATTACHMENT A: SUPPLEMENTAL DATA SHEET







SUPPLEMENTAL DATA SHEET (Addendum)

4. Indications for use

Lateral mass and pedicle screw systems are intended to provide immobilization and stabilization of spinal segments as an adjunct to fusion during bone graft healing and fusion mass development and/or to restore the integrity of the spinal column even in the absence of fusion for a prolonged period for the following acute and chronic instabilities of the cervical spine (C1 to T3 inclusive): trauma, including spinal fractures and/or dislocations; instability or deformity; pseudarthrosis or failed previous fusions; and degenerative disease, including intractable radiculopathy and/or myelopathy, neck and/or arm pain of discogenic origin as confirmed by radiographic studies, and degenerative disease of the facets with instability; and tumors. Spinal screw fixation is achieved with posterior pedicle and lateral mass screws implanted from C1 to T3 levels inclusively.



ATTACHMENT B: CLASSIFICATION QUESTIONNAIRE







ATTACHMENT C: ABSTRACTS: STUDY DESIGN/EFFECTIVENESS

Complete bibliography and copies of articles provided in Attachment F.

1. LATERAL MASS AND PEDICLE SCREWS

Note: abstracts presented for each of the 32 clinical studies. Abstracts for general overview articles (Bransford 2011, Kosmopoulos 2007, Liu 2001, Ludwig 1999, Neo 2008, and Sasso 2007) are not provided.



Author/Year Abumi 2000

Objective To determine the risks associated with pedicle screw fixation in the cervical spine for 70 spinal injuries and 110 non-traumatic lesions.

Surgery

Devices: Brand Company VSP plates or Isola Rods or CPS plates or rods ( AcroMed); occipitocervical fusion CD rods (Medtronic or rods (Aescurap(sic))

Material Ti alloy or stainless steel

Screw Placement

Occiput As needed (28 patients)

Pedicle C2-C7 (diameter: 3.5, 4.0, 4.5mm; length 20, 22, 24, 28mm)

Graft NS

Other Plates/rods; laminoplasty as necessary (58 cases)

Pre-op planning Plain films, CT and MR; myelography and CT myelography in most patients. Oblique films to measure size of pedicles and to evaluate condition while

kyphosis assessed with lateral films.Visualization during surgery Radiograph

Study Design

Retrospective, single cohort

Period Surgeries Aug 1990-Jan 1997

Number Patients 180

Number Screws 712; 669 assessed (7 patients refused CT and 4 died early post-op stage)

Follow-up 164 with > 2 yrs, excluding deaths (14 tumor/2 NS; none cited as related to procedure or devices)

Indications Number Percent

Trauma (fractures/dislocation) 70 38.9%Instability/Deformity 43 23.9%Degenerative 24 13.3%Tumors 24 13.3%Other 19 10.6%Total 180 100.0%Effectiveness

Screw Placement

Assessment Method CT, lateral/oblique radiograph

Results 169 patients/669 screws

Satisfactory: 93.3% (624/669)

Perforation: If one/both observers determined screw penetrated the wall of the pedicle

Perforation: 6.7% (45/669); perforated medial wall 21, inferior 10, lateral 10 and superior 4. Perforation

highest at C4 then C7.

Clinical Symptoms 1 vertebral artery injury/bleeding stopped by bone was

2 nerve root injury/radiculopathy resolved

Fusion (%) Fusion: homogeneous fusion mass on lateral x-rays and segmental motion < 2 degrees on flex/ext, as well as clear zone around screws.

99.4% (163/164) excluding 16 patients with spinal metastases who did not undergo fusion and two patients died soon after surgery

Comments/Conclusions

Clinically significant complications caused by pedicle screw insertion was low. Complications can be minimized by sufficient pre-op imaging of the pedicles and strict control of screw insertion. Useful procedure for reconstruction of the cervical spine for various disorders. Screw perforation highest at C4 then C7. Pedicle diameter smallest C4, and shoulder girdle often obstructs CTAuthors’ Financial Disclosure

Category 12 (no funds were received in support of this study)



Author/Year Alosh/2010

Objective To identify pre-op radiographic variables associated with likelihood of intra-op breach during C2 pedicle screw placement and to correlate breach rate with surgeon

experience.Surgery

Devices: Brand Company NS

Material and Screw Sizes NS

Screw Placement

Lateral Mass

Pedicles C2Graft NSOther NSPre-op planning CTVisualization during surgery 18 (19.4%) intra-op fluoroscopyStudy Design

Retrospective

Period Surgeries 2002-2008

Number Patients 93

Number Screws 170

Follow-up NS (day following surgery?)


Trauma (fractures/dislocation) 21 22.6%Instability/Deformity 12 12.9%Pseudarthrosis/Failed Fusion 0.0%Degenerative 38 40.9%Tumors 18 19.4%Other 4 4.3%Total 93 100%Effectiveness

Screw Placement

Assessment Method CT

Results: Breach

>10% pedicle screw protruding beyond C2 bony cortex

25.3% (43/170)

Clinical Symptoms 0.5% (1/170) vertebral artery injury, screw placed to tamponade bleeding, neurologically intact

Radiographic: Breach Axial left/right and coronal right pedicle diameters statistically significantly smaller for breach cases.

Learning Curve: Breach Surgeons who had placed 50-100 screws had a breach rate of 21.5% vs surgeons who had placed 10-20 screws with rate of 36.2%. Regression analysis statistical significance.


Although cortical breach was not clinically significant in overwhelming majority of patients, the likelihood of breach detected radio graphically may be associated with pedicle size and surgeon experience. Suggest

careful pre-op evaluation of CT scans and consideration of technical complications. Authors’ Financial Disclosure Not specified



Author/Year Arnold 2005

Objective Report 5-year data in treating posterior cervical trauma with lateral mass and pedicle screw fixation.

Surgery

Devices: Brand Company Variable angled screws (DePuy Spine and Medtronic)

Material Not specified

Screw Placement

Lateral Mass C3-C7 (sizes not specified)

Pedicle C7; long constructs (sizes not specified)

Graft local bone, supplemented with allograft as necessary

Other Rods, connectors

Pre-op planning x-rays followed by CT and/or MRI

Visualization during surgery NS

Study Design

Retrospective, Single cohort

Period Surgeries Jan 2000 - Jan 2004

Number Patients 48

Number Screws NS

Follow-up 48 @ 1-yr; 39 @ 2-yrs


Trauma (fractures/dislocation) 48 100.0%Effectiveness

Fusion (%) Fusion: lateral and flex/ext x-rays with pseudarthrosis defined as motion greater than 2mm at any point within fused segment

94% (45/48) at 1-yr and (92.3%) 36/39 at 2-yrsOutcomes (Neurologic) No patients had worse neurologic outcomes.

Functional 12 with complete motor injuries: 2 regained ability to walk and 2 regained upper extremity strength, other 8 unchanged.

16 with incomplete injuries: 13 improved and ambulated independently and the other 3 improved one ASIA grade.


Excellent fusion rates with good neurologic outcomes and minimal complications demonstrating that lateral mass and pedicle screw fixation is a useful technique in cervical trauma. Instruments easier to use and biomechanically superior to interspinous or facet wiring.Authors’ Financial Disclosure None disclosed



Author/Year Cornefjord 2005

Objective To evaluate pedicle screw use in fracture repair in patients with ankylosing spondylitis. These patients have high risk of

neurological injuries at admission and are more susceptible to develop large epidural hematomas. These fractures are often

highly unstable and invariably span the width of the spine.Decreased bone quality due to osteoporosis gives sub-optimal

anchorage for implants.Surgery

Devices: Brand Company Screws and rods (Olerud Anatomica)

Material NS

Screw Placement

Lateral Mass C3-C6 (some instances) (sizes NS)

Pedicle C2, C7; C3-C6; upper thoracic (sizes NS)

Graft NS

Other Rods, anterior plate ( 3 patients), anterior plate/posterior plate with occiput included (1 patient)

Pre-op planning NSVisualization during surgery Fluoroscopy/C-arm; Computer-assisted (1 patient)Study Design

Retrospective, Single Cohort


Number Patients 19

Number Screws 119 (67 pedicle/52 thoracic); 16 lateral mass screws and 2 transarticular screws used/not included in report

Follow-up 24 months (10-55 months); 5 deaths unrelated causes (3 pneumonia, 1 lung edema, 1 intestinal obstruction/peritonitis)


Trauma (fractures/dislocation) 19 100.0%Effectiveness

Screw Placement


Results Cervical pedicle-misplaced: 6% (4/67)

Thoracic pedicle-misplaced: 8% (4/52)

Also could not probe pedicle in 2 patients.

Clinical Symptoms 1-right arm weakness (resolved after screw extraction)

Outcomes (neurologic) Of 11 with no pre-op neuro deficit, 1 developed right arm weakness. Of 8 with pre-op neuro deficit, 2 improved and others

unchanged.Healing (%) Healed (bone trabeculae bridging fracture): (9/19)

No healing disturbances (10/19)Comments/Conclusions

Fixation with the Olerud or other like systems is suited for treating subaxial fractures in patients with ankylosing spondylitis allowing high healing rates. The complication rate was acceptable

Authors’ Financial Disclosure Not specified. Olerud one of authors.



Author/Year Djurasovic 2005Objective Describe the method of intra-operative EMG monitoring in posterior

cervical fixation with lateral mass and pedicle screws to examine accuracy of technique with CT in assessing screw mal-position.

SurgeryDevices: Brand Company Vertex (Medtronic)

Material Not specifiedScrew Placement Lateral Mass C3-C6 (diameter: 3.5mm) Pedicle C7 (diameter: 3.5mm)Graft NS

Other Rod

Pre-op planning NS

Visualization during surgery None; radiograph post screw placement

Study DesignNS, single cohort

Period Surgeries NSNumber Patients 26Number Screws 148Follow-up Not applicableIndications Number Percent

Not specifiedEffectivenessScrew Placement

Assessment Method CTAcceptable: contained within bone

of lateral mass/pedicleUnacceptable: cortical perforation of

the lateral mass or C7 pedicle, or excessively long extending into soft

tissue anterior

EMG: CT position/threshold

Results 94.6% (140/148 screws) acceptable5.4% (8/148) unacceptable

( total 148 as specified vs 147 noted elsewhere)

>15mA: 124/125 acceptable10-15mA: 13/15 acceptable<10mA: 7/7 unacceptable

Clinical Symptoms Not specifiedComments/ConclusionsA simulation value of < 10mA provided a 100% predictive value that the screw was mal-positioned. Intra-op

EMG monitoring is a valuable tool in posterior instrumentation using lateral mass and pedicle screws.Authors’ Financial Disclosure

Grant from the Fischer-Owen Orthopaedic Fund and Norton Healthcare.



Author/Year ElMiligui/2010

Objective To evaluate the results of C2 transpedicular fixation in Type II TSA.

Surgery

Devices: Brand Company AO Synthes

Material NS

Screw Placement

Pedicles C2 (diameter: 3.5 or 4.0mm; length: NS)Graft NSOther NonePre-op planning Radiographs, Ct and MRI (latter to exclude spinal cord

compression in five cases)Visualization during surgery Image intensificationStudy Design

Prospective consecutive series


Number Patients 15

Number Screws 30

Follow-up 32 (25-56) mos


Trauma (fractures/dislocation) 15 100%Total 15 100%Effectiveness

Fusion Fusion: based on lateral and flex/ext x-rays, evidence of healing across the fracture site, no metal failure and no

evidence of instability on dynamic views.100% (15/15)

VAS Neck Pain Final follow-up: 1 (0-2) with 10 worse score

Function/ROM All regained excellent functional outcome with no limitation on range of motion

Reduction Significant reduction achieved/maintained

Screw Placement


Results: Placement

Adequate 93.4% (28/30)

Minimal intrusion (<2mm) 6.6% (2/30)

Clinical Symptoms 1 severe bleeding (vertebral artery injury) during drilling; promptly controlled by screw application. No neuro deficit or

other symptoms.Comments/Conclusions

Direct pedicle screw fixation appears safe and useful in reduction and stabilization of Hangman’s fracture. Adequate reduction achieved and motion segments were preserved.

Authors’ Financial Disclosure No funds or benefits



Author/Year Goel 2002

Objective To report experience with plate and lateral screws in treatment of 160 patients with atlanto-axial instability

Surgery


Material Metal

Screw Placement

Lateral Mass C1, C2 (diameter: 2.7 or 2.9mm; length 14-17mm length)

Pedicles --Graft Corticocancellous bone or allograftOther PlatePre-op planning Radiography, and CT and/or MRIVisualization during surgery Intra-op fluoroscopyStudy Design

Not specified (retrospective)


Number Patients 160

Number Screws Not specified

Follow-up 42 mos (4mos-14 yrs) (2 patients died of causes related to their condition)


Trauma (fractures/dislocation) 160 100%Effectiveness

Clinical weakness Pre: 97.5% (140/160) quadraparesis,1.2% (2/160) quadriplegia and 2.5% (4/160) no weakness

All improved to some degreeFusion 100% (no dislocation observed on dynamic radiographs 5

mos post op)Screw Placement

Assessment Method Not specified

Results: Placement

Protrusion > 4mm 6 screws

Satisfactory (screw did not protrude more than 4mm beyond the anterior cortex of the lateral mass of the axis and axis)

All remainder satisfactory

Safety

Reported complications Comments made on complications (did not appear to be systematic assessment): 4 patients had significant bleeding during guide hole drilling; bone wax stopped the bleeding.

No symptoms.

1 broken screw at 18 mosComments/Conclusions

The plate/screw method of fixation with intra-articular bone graft in patients with atlanto-axial instability yielded 100% fusion rate with low incidence of complications.


Article has insufficient information for full characterization.



Author/Year Harms and Melcher 2001

Objective Describe a novel technique for atlantoaxial stabilization using fixation of the C1 lateral mass and C2 pedicle with mini polyaxial screws and rods. Describe initial results.

Surgery

Devices: Brand Company Polyaxial pedicle screw (company not specified); custom lateral mass

Screw Placement

Material NS

Lateral Mass C1 (diameter: 3.5mm; length NS)

Pedicle C2 (diameter: 3.5mm; length NS)

Graft local bone and/or autograft

Other Rods

Pre-op planning Radiographs and tomographic angiograms

Visualization during surgery Fluoroscopy; screw position verified by image intensifier

Study Design


Period Surgeries Aug 1997-Oct 2000

Number Patients 37

Number Screws NS

Follow-up 5mos-2 yrs


Trauma (fractures/dislocation) 20 54.1%Instability/Deformity 15 40.5%Degenerative 2 5.4%Total 37 100.0%Effectiveness

Screw Placement


Results Satisfactory placement in all

Clinical Symptoms None

Fusion (%) Fusion: definition not provided100% (37/37)

Outcomes no neurologic deterioration post-surgery or follow-up


Fixation of the atlantoaxial complex using polyaxial screws and rods seems to be a reliable technique and should be considered an efficient alternative to previously reported techniques. No neural or vascular

damage in this series.Authors’ Financial Disclosure

Although the author(s) have not received or will receive benefits for personal/professional use from a commercial party related directly or indirectly to the subject of this manuscript, benefits have been or will be received but are directed solely to a research fund, foundation, educational institution or other nonprofit organization which the author(s) have been associated.



Author/Year Hasegawa 2008

Objective To evaluate clinical results of patients with non-traumatic cervical lesions treated by cervical pedicle screw fixation.

Examined results for patients with kyphosis/destructive lesions and without destructive lesions.

Surgery

Devices: Brand Company Olerud Anatomica, Oasys Stryker

Screw Placement


Pedicle Yes (levels and sizes not specified)

Graft Local bone chips

Other 11 patients with myelopathy (CSM) or ossification posterior longitudinal ligament (OPLL) treated with laminoplasty

Pre-op planning CTVisualization during surgery Radiograph image intensifierStudy Design

NS, likely retrospective

Period Surgeries NS

Number Patients 58; 38 destructive (D) lesions and 20 non destructive (ND)

Number Screws NS

Follow-up D: 42.7 months (18-108 months); 11 died from malignant disease

ND: 59.2 months (24-96)Indications Number Percent

Instability/Deformity 22 37.9%Pseudarthrosis/Failed Fusion 4 6.9%Degenerative 11 19.0%Tumors 16 27.6%Other 5 8.6%Total 58 100.0%Effectiveness

Fusion (%) Fusion: definition not providedD: 100% (27/27; excludes 11 deaths)

ND: 95% (19/20)Combined: 97.9% (46/47)

Outcomes (D vs ND) Neurologic status (Frankel) improved in both groupsPresence of Nape Pain:

D: 78.9% (30/38) pre-op vs 10.5% (4/38) final follow-upND: 40% (8/20) pre-op vs 30% (6/20) final follow-up

Comparison: CSM/OPLL 11 patients treated with pedicle screws and 11 with laminoplasty

Pedicle screw op times longer and blood loss higher. No differences in JOA. Post-op VAS higher in pedicle screw group. Pedicle screw significantly corrected kyphosis and maintained

alignment.Comments/Conclusions

Based on results, pedicle screws indicated for destructive lesions because of high fusion rate and improved nape pain. Neuro complications decreased since began performing screw insertion after decompression.

Although there is limitation given the small numbers, there is no indication for CSM/OPLL if risk of vertebral artery or nerve root injury taken into account compared to laminoplasty as the first option.

Authors’ Financial Disclosure No funds or benefits will be received from a commercial party directly or indirectly related to this project.



Author/Year Ishikawa/2010

Objective To compare the accuracy of cervical pedicle screw placement using 3D fluoroscopy based navigation vs

conventional methods. Surgery


Material NS

Screw Placement

Pedicles C2-C7 (diameter 3.5mm; length NS)Graft Not specifiedOther If pedicles diameter < 3.5mm, used lateral mass screws or

lamina hooksPre-op planning NSVisualization during surgery Lateral Fluoro (conventional technique: CVT) compared to

3D Fluoro Navigation (3D FN)Study Design

Retrospective


Group CVT 3D FN

Number Patients 30 32

Number Screws 126 150

Follow-up 41.7 (13-68) mos 21.2 (14-30) mos

Indications

Trauma (fractures/dislocation) 7 7Instability/Deformity 10 8Pseudarthrosis/Failed Fusion 0 0Degenerative 9 9Tumors 1 2Other 3 6Total 30 32Effectiveness

Fusion rate 93.1% 93.5%

Screw Placement


Results: Perforation

None 73% (92/126) 81.3% (122/150)

Grade 1 (less than 1mm) 9.5% (12/126) 11.3% (17/150)

Grade 2 (> 1mm and < 2mm 4.8% (6/126) 4.0% (6/150)

Grade 3 (> 2mm) 12.7% (16/126) 3.3% (5/150)

Clinical Symptoms No neurologic injuries; no re-operation to remove screws. Two patients had massive arterial bleeding from the entry hole created by the pedicle probe in C2 possibly injury to

vertebral artery; bleeding stopped with bone wax.Comments/Conclusions

If perforation defined as > Gr 1, no differences in the rates between groups. If defined, as > Gr 2, there was a statistically significant lower prevalence of mal-positioning in the 3D FN group. However, severe

malposition that can cause VA or neuro complications can occur even with 3D FN.Authors’ Financial Disclosure No funds or benefits



Author/Year Ito 2008

Objective To assess the accuracy of first 50 cases of 3D fluoroscopy-guided cervical pedicle, lateral mass

and odontoid screw insertion. Surgery


Screw Placement C1-C7


Odontoid C1

Lateral Mass C2-C7( if narrow < 3.5mm pedicles) (screw sizes not specified)

Pedicle C2-C7 (screw sizes not specified)

Graft NS

Other NSVisualization during surgery 3D Fluoro: Siremobil Iso-3D (Siemens) and

StealthStation (Medtronic)Study Design

Prospective, Single cohort

Period Surgeries Jul 2004-Dec 2005

Number Patients 50

Number Screws 239 (176 pedicle, 58 lateral mass, 5 odontoid)

Follow-up NS


Trauma (fractures/dislocation) 35 70.0%Degenerative 12 24.0%Tumors 3 6.0%Total 50 100.0%Effectiveness

Screw Placement

Assessment Method CT: 176 pedicle screws

Results

Grade 1 (threads cut into cortex): 97.2% (171)

Grade 2 (perforation of cortex up to 2mm): 2.8% (5)

Grade 3 (perforation of cortex > 2mm): 0% (0)

None of the 58 lateral mass screws showed evidence of violation.

5 of 5 odontoid screws accurate. Clinical Symptoms No neurovascular injury.


Screws were correctly inserted in the cervical pedicles using the 3D fluoroscopy and navigation system.

Authors’ Financial Disclosure No conflict of interest.



Author/Year Jian 2010

Objective To report results for the treatment of basilar invagination (congenital anomaly) with atlantoaxial dislocation by direct

posterior reduction and fixation with intra-op distraction between occiput and C2 pedicle screws. Basilar invagination is

a prolapse of the cervical spine into the cranial base.Surgery

Devices: Brand Company DePuy Spine pedicle screws, Y-shaped titanium plate, occipital screws, rods (3.0mm)

Material NS

Screw Placement

Occiput Plate fixed with occipital screws (4.5mm with length 6-14mm),

Lateral Mass C3 (3 patients)

Pedicles C2 (3.5mm diameter; length 22-24mm)Graft Not performedOther Rods (Oc and C2)Pre-op planning Radiographs, CT and MRIVisualization during surgery Intra-op fluoroscopyStudy Design

Prospective


Number Patients 29


Follow-up 18 (6-50) mos


Instability/Deformity 29 100%Effectiveness

Atlanto axial dislocation (AAD) Pre-op 82.8% (24/29) irreducible ; Post-op 96.6% (28/29) achieved more than 50% reduction of AAD. 1 partial loss of reduction due to screw head not tightened.

26/29 achieved good reduction without exposure of C1-C2 joints and bone graft implant was not performed.

Fusion Fusion: CT showed bone bridge formation and dynamic x-ray showed stable reduction of the dislocation with implant failure at 3-6 mos

100%JOA Pre-op: 12.9 improved to 6-mos Post-op: 15.4 (p<0.01)

Clinical outcomes 92.9% (26/29) improved clinically; 2 had stable symptoms. 3 patients with respiratory symptoms improved.

Decompression MRI showed good decompression of the spinal cord and medulla oblongata in 100%

Screw Placement

Clinical Symptoms One C2 screw breached the pedicle and entered the transverse foramen with vertebral artery stenosis and distal

thrombosis; patient died.Comments/Conclusions

Surgical technique is effective, simple, fast and safe method for treatment of BI with AAD.




Author/Year Kim 2007

Objective Review clinical experience with the polyaxial screw-rod system in cervical fusion.

Surgery

Devices: Brand Company Vertex Medtronic/Summit DePuy Spine

Screw Placement

Material NS

Lateral Mass C1, C3-C6 (diameter not specified; most length: 14mm)

Pedicle C2, C7; and if extended to thoracic (diameter: 3.5 or 4.0mm; length: 20-24mm)

Graft local bone; allograft long construct

Other Rods, anterior (5 cases) or laminoplasty (2 cases) as needed

Pre-op planning NS

Visualization during surgery FluoroscopyStudy Design

Type NS, single cohort

Period Surgeries July 2003 - March 2006

Number Patients 65

Number Screws 486

Follow-up 8.8 mos (4-40 mos)


Trauma (fractures/dislocation) 14 21.5%Instability/Deformity 2 3.1%Degenerative 31 47.7%Tumors 18 27.7%Total 65 100.0%Effectiveness

Screw Placement


Results Satisfactory:Suboptimal trajectory: 2.5% (12/486)

Clinical Symptoms No vascular sequelae; 2 screws right shoulder pain in one subject resulting in screw removal and reposition resolved

Fusion (%) Fusion: pseudarthrosis motion > 2.0m between laminae at the base of the spinous processes between the upper and lowermost fixed

and fused levels on flex/ext x-raystoo early: although no motion for for first 24 patients at 6-mos and 8

at 4-mos.Outcomes NDI:

Pre: 38+16.4 VAS Pain: Pre: Neck: 8.15+2.3 Arm: 7.1 + 2.3

Last: 17+14.9 Last: Neck: 3.2+3.0 Arm: 2.3+3.1


Suggest cautiously that posterior polyaxial screw-rod systems can be safely used as a primary or additional fusion method in this risky region. Dependent on precise pre-op surgical plan and tactics for safe screw insertion.Authors’ Financial Disclosure

None disclosed



Author/Year Lee 2010

Objective To compare the results in patients who underwent C1 lateral mass-C2 pedicle screw fixation for atlanto axial instability compared to C1-C2 transarticular screws

Surgery

Group: C1-C2 Transarticular Screws C1 LM and C2 Pedicle Screws

Devices: Brand Company Not specified MSD VertexMaterial Transarticular screws Ti

Screw Placement

Transarticular C1-C2 (diameter: 3.5 or 4.0mm ; length NS)

Lateral Mass C1 (diameter: 4.0mm; length 28-34mm)

Pedicles C2 (diameter: 4.0mm; length(24-32mm) Graft Brooks-Jenkins method: 26

Cancellous: 2Autograft: 25

None: 2Other Sublaminar wires RodsPre-op planning Radiographs, CT and MRIVisualization during surgery Intra-op fluoro Intra-op fluoroStudy Design

Retrospective


Number Patients 28 27

Number Screws 55 (total not clear) 54 LM/54 pedicle

Follow-up 60.2 mos 32.8 mos

Indications

Instability/Deformity 28 27Effectiveness

VAS Neck Pain: Pre/Last 6.14/1.8593% (25/28) improved

6.26/1.67 (p> 0.05)96% (26/27) improved

Myelopathy, Frankel Pre Last

D: 6, C: 3, A: 1E: 4, D: 4, C: 1; A: 1

D: 8, C: 2, A: 1E: 5, D: 4, C: 2

Fusion 82.1% (23/28) 96% (26/27) (p> 0.05)

Fusion: x-ray and CT: bony trabecular continuity and <2mm motion between the segments on flexion/extension.

Post-op kyphosis 2/28 0/27

Screw Placement

Assessment Method Not Specified

Results:

Misplaced 4 with 1 passage medially into the spinal canal with no consequence

1 pedicle screw protruded into the vertebral artery; no consequence

Complications*

Hardware failure 10.7% (3/28) 3.7% (1/27)

Occipital neuralgia -- 3.7% (1/27)

Transient neck pain -- 7.4% (2/27)

CSF leak 3.6% (1/28) --

Vertebral artery injury 3.6% (1/28) during screw placement 3.7% (1/27)(result of monopolar cauterization during muscle dissection)


Both methods effective for stabilizing the atlantoaxial complex. Radiologic outcomes slightly better in C1 lateral mass and C2 pedicle screws.




*Article information on complications insufficient/inconsistent

Author/Year Lee 2007

Objective To compare the clinical accuracy of pedicle screw placement at the cervicothoracic junction (CTJ) using the open lamino/foraminotomy

(freehand) or computer assisted techniques (CAS). Surgery

Devices: Brand Company Summit DePuy Spine (freehand group); Summit DePuy Spine and Axis Medtronic (CAS group)

Material TitaniumScrew Placement

Pedicle C7-T2 (diameter: 3.5-4.5mm; length not specified)

Graft Not specified

Other Plates, rodsPre-op planning CT Visualization during surgery Freehand or CASStudy Design

Serial groups

Period Surgeries January 2000 – July 2004

Number Patients 60 (32 freehand; 9 3-D CT CAS and 19 2-D CAS fluoroscopy)

Number Screws 194 (104 C7, 60 T1 and 30 T2)86 freehand; 63 2-D CAS,45 3-D CAS

Follow-up Median 17 months (8-55 months); 1 lost


Trauma (fractures/dislocation) 8 13.3%Instability/Deformity 12 20.0%Degenerative 31 51.7%Tumors 9 15.0%Total 60 100.0%Effectiveness

Screw Placement

Assessment Method CT: Pedicle Breach

Results: any breach Freehand 2-D CAS 3-D CAS

C7 30% (18/60) 27% (8/30) 29% (4/16) sic

T1 25% (5/25) 13% (3/24) 0% (0/14)

T2 33% (2/6) 0% (0/9) 7% (1/15)

Total 29% (25/86) 17% (11/63) 11% (5/45)

By Distance:

< 2mm 4% (3/86) 15% (10/63) 11% (5/45)

2-4mm 23% (20/86) 2% (1/63) 0% (0/45)

>4mm 2% (2/86) 0% (0/63) 0% (0/45)

Clinical Symptoms No neurologic, vascular of visceral complications; no screws required revision in any group.

Construct failure No evidence


Overall breach rate was significantly different between the groups (p=0.04). The pedicle breach rates between spinal levels were not significantly different using the open and 2-D techniques. Pedicle breach rates at C7 quite similar between groups. A majority of the breaches were lateral; 44% freehand group and 100% CAS group. CAS allowed for more accurate placement of pedicle screws in the CTJ. No

screws required revision in any group. Authors’ Financial Disclosure Nothing received



Author/Year Li 2008

Objective To evaluate the feasibility, safety and efficacy of atlas pedicle screw system fixation and fusion for

upper cervical diseases.Surgery

Devices: Brand Company Summit DePuy Spine

Screw Placement


Screw sizes Diameter: 3.5mm; Length: 26-30mm C1, 24-28mm C2

Lateral Mass Lower cervical

Pedicle C1, C2, some lower cervical

Graft Cancellous bone granules of iliac crest or iliac crest bone flaps

Other Rods Pre-op planning Not specified; noted radiographs and CT usefulVisualization during surgery C-armStudy Design

Single cohort

Period Surgeries October 2004 – October 2007

Number Patients 23

Number Screws 96 (Pedicle: 46 C1 and 42 C2; 6 lower cervicalLateral mass: 6)

Follow-up 15 (3-36) months


Trauma (fractures/dislocation) 19 82.6%Instability/Deformity 2 8.7%Tumors 2 8.7%Total 23 100.0%Effectiveness

Fusion (%) Fusion: firm bony fusion; 100% (23/23)


Posterior fixation and fusion with the atlas pedicle screw system as an alternative technique provides immediate rigid fixation and has superior biomechanical properties.

Authors’ Financial Disclosure Not specified



Author/Year Liu 2009

Objective To investigate free hand cervical pedicle screw placement in the management of cervical instability.

Surgery


Screw Placement


Pedicle C3-C7 (diameter: 3.5 or 4.0mm; length: not specified)

Graft Bone graft

Other Laminoplasty; rods Pre-op planning Radiographs, CT and MRIVisualization during surgery Free hand with use of C-arm lateral image intensifier as

needed (two cases)Study Design

Retrospective, Single cohort

Period Surgeries Oct 2004 – Aug 2008

Number Patients 25

Number Screws 150

Follow-up 16.6 (6-30) months


Trauma (fractures/dislocation) 3 12.0%Degenerative 22 88.0%Total 25 100.0%Effectiveness

Screw Placement


Results

Complete perforation (deviation from the pedicle by > half of screw diameter):

4% (6/150)

Perforation: 4% (6/150)


Fusion (%) Fusion: flex/ext x-rays intervertebral angles < 2 deg and distance variations between adjacent spinous processes

< 2mm.At 6-months and last follow up, fused segments stable.

Outcomes JOA mean improvement: 4.1 points*NDI pre/6-months: 32.96/16.84*

*improvements P=0.000Comments/Conclusions

No neurovascular injuries, or instrumentation-related complications, such as failure of implants, screw loosening, or lucent formation. No CSF leakage. Anatomizing the pre-op radiographic data facilitates

precise operative design prior to surgery. Free-hand cervical pedicle screw placement is capable of obtaining satisfying clinical efficacy and safety for cervical instability.




Author/Year Liu 2010

Objective To compare the accuracy of cervical pedicle screw fixation assisted by x-ray fluoro, CT-based navigation or 3-D C-arm navigation.

Surgery

Devices: Brand CompanyNot specifiedMaterial and Screw Sizes

Screw Placement

Lateral Mass

PediclesGraftPre-op planning Radiographs, CT,

MRICT CT

Visualization during surgery: Groups X-ray Fluoro CT-Navigation 3D-navigationStudy Design

Prospective, comparative

Period Surgeries 2001-2002 2002-2005 2005-2009

Number Patients 24 29 29

Number Screws 145 159 140

Follow-up Not specified

Indications

Included trauma, kyphosis, degenerative disease and tumors. Numbers by indication not provided.

Effectiveness

Screw Placement

Assessment Method CT-3-D reconstruction

Results: Placement

Excellent: within pedicle 66.2% (96/145) 88.7% (141/159) 90.7% (127/140)

Acceptable (< 1mm outside pedicle cortex)

25.%% (37/145) 8.8% (14/159) 9.3% (13/140)

Poor (>1mm) 8.3% (12/145) 2.5% (4/159) --

Comparison No differences between CT-navigation and 3D-navigation. The accuracy was statistically significantly better in these two groups

compared to x-ray fluoro. Clinical Symptoms No severe or permanent neurovascular complications associated with

screw insertion.Comments/Conclusions

CT-navigation and 3D-navigation were similarly accurate, and significantly more accurate than C-arm fluoroscopy for guiding pedicle screw fixation in the cervical spine.




Author/Year Mueller 2010

Objective To describe the technique, accuracy and complications of transpedicular C2 screw fixation without cervical navigation.

Surgery

Devices: Brand Company Cannulated screws (Neon Ulrich)Material and Screw Sizes NS

Screw Placement

Pedicles C2Graft NSOther RodsPre-op planning CTVisualization during surgery FluoroscopyStudy Design

Retrospective

Period Surgeries NS

Number Patients 27

Number Screws 47

Follow-up Post-op, 3 mos, 9 mos, 2 yrs


Trauma (fractures/dislocation) 17 63.0%Instability/Deformity 3 11.1%Pseudarthrosis/Failed Fusion

Degenerative 5 18.5%Tumors 2 7.4%Total 27 100%Effectiveness

Screw Placement


Results: Perforation pedicle wall

Perfectly within pedicle 55.3% (26/47)

< 2mm perforation 27.7% (13/47)

2 to < 4mm perforation 10.6% (5/47)

4 to < 6mm perforation 6.3% (3/47)

>6mm perforation 0%

Clinical Symptoms 1 clinically asymptomatic vertebral artery compression

Risk factors C2 fractures and smaller pedicle diameters were significantly more common in perforations > 2mm.


82.9% screws placed accurately. No screw had to be repositioned due to gross misplacement and no screw placement morbidity. In cases of narrow pedicles (<5mm) spinal navigation or an alternate fixation method might be used. Notably all screws that perforated did so laterally (toward vertebral artery canal)

and not medially (toward spinal canal). No hardware failures.However, high rate of misplaced screws when inserted without spinal navigation, despite the fact that no

neurovascular injury occurred, supports use of spinal navigation in C2 pedicle screw insertions.Authors’ Financial Disclosure No funds or benefits



Author/Year Neo 2005

Objective Evaluate the risks of cervical pedicle screw placement.

Surgery

Devices: Brand Company Various (Olerud Nordopedic AB, Synergy Interpore, Ti-mini-VSP DePuy Spine)

Screw Placement

Material Titanium-VSP System

Pedicle C2-C6 (diameter: 4.0mm; length not specified)

Graft NS

Other NS

Pre-op planning CT

Visualization during surgery Fluoroscopy

Study Design

NS, single cohort

Period Surgeries Sept 1998-Dec 2003

Number Patients 18

Number Screws 86

Follow-up NS


Instability/Deformity 10 55.6%Degenerative 6 33.3%Tumors 2 11.1%Total 18 100.0%Effectiveness

Screw Placement

Assessment Method CT/MDCT Angiography

Results


Deviation < 2mm: 15.1% (13/86)

Critical deviation (>2mm) 14.0% (12/86)

Clinical Symptoms 1 blurred vision (common symptom of vertebral artery obstruction; however subject insisted symptom present pre-op)


Deviation rate of screw placement was higher than expected, although no serious complications occurred. Insertion based solely on anatomic landmarks and fluoro control is more risky than previously reported,

and it should no longer be used. Use of computer assisted navigation or other equivalent techniques recommended.

Authors’ Financial Disclosure

No funds were received in support of this work.



Author/Year Oda 2006

Objective Evaluate clinical outcomes of palliative spinal reconstruction in patients with metastatic lesions of the cervical spine using pedicle screws.

Surgery

Devices: Brand Company VSP and CPS DePuy Spine

Screw Placement


Occiput Plate/Rod (Aesculap)

Pedicle all levels (sizes not provided)

Graft autograft if life expectancy > 1 yr (4 or 5 cases)

Other Rods or plates. Anterior column reconstruction if life expectancy > 1 yr

Pre-op planning Not specified

Visualization during surgery Fluoroscopy

Study Design


Period Surgeries from 1991 - ?

Number Patients 32

Number Screws NS

Follow-up 12.2 mos (2 wks-36 mos) post-op survival; all patients died none attributable to surgery


Tumors 32 100.0%Effectiveness

Fusion (%) 2/5 who underwent bone graft; other 3 died before union (fusion not defined)Spinal stability restored in 94%.

Outcomes: Frankel 80% (24/30) with spinal cord lesions improved.

89% (16/18) not ambulatory pre-op, walked

Pain Pain relief achieved all patients (determined by any need or reduction in analgesic dose)


Improvement in spinal stability, pain, neurologic function maintained throughout survival for 94%. For subaxial lesions, posterior decompression followed by pedicle screw fixation provided sufficient neural decompression, and anterior surgery could be avoided in 78%. Consider anterior if survival likely > 2 yrs. Pedicle screws provided excellent stability without the need for external support. For upper cervical lesions, screw fixation provided palliative reconstruction. Only one screw loosening due to tumor.Authors’ Financial Disclosure




Author/Year Ogihara 2010

Objective To evaluate the long-term results of occipito-cervical reconstruction using pedicle screw and usefulness of

computer-assisted navigationSurgery

Devices: Brand Company Nord Opedic Olerud and Stryker Oasis, Robert Leid RSS Loop System

Material NS

Screw Placement

Occiput Occipital

Pedicles C1-T3 (diameter: 3.5mm; length NS)Graft Iliac bone graftOther Occipital plate, rodPre-op planning MRIVisualization during surgery TREON Stealth Station Optoelectronic Stereotactic Image

Guidance System (Medtronic)Study Design

Retrospective


Number Patients 23 (occipitocervical 13, occipitothoracic 10)

Number Screws 88 cervical and upper thoracic

Follow-up 52.9 (24-108) mos (2 patients died of unrelated causes during follow-up)



Ranawat-Neuro Deficit: Pre/Last(I=none to IIIB=quadraparesis)

74% (17/23) improved more than one grade

Pre: II:6, IIIA: 8; IIIB: 9Last by pre-op: pre-op 6 II: II 4, I 2; pre-op 8 IIIA: IIIA 2, II 6; pre-op 9 IIIB: IIIB 3, IIIA 5, II 1

JOA: Pre/last 7.7/11.3 (p=0.005)

Fusion Fusion: bony union based on dynamic x-rays and CT 100% (23/23)

Screw Placement


Results: Perforation C2, C7, Thoracic (wider pedicles)

C3-C6(narrower pedicles)

None 39/41 43/47

Minor 4.9% (2/41) 6.4% (3/47)

Major 0/41 2.1% (1/47)

Clinical Symptoms No vertebral artery, spinal cord or nerve root injury


Screw mal placement rate 1.1% (1/88). The five minor breaches were in C2(2), C4 (1) and C6 (2); one major breach in C4. One occipital screw back out. Occipital cervical reconstruction with pedicle screws and occipital plate-cervical rod systems provided a high fusion rate and maintained alignment without need for

halo vest post-op. In pre-op planning, need to evaluate bone substance of pedicle wall.Authors’ Financial Disclosure No funds or benefits



Author/Year Ondra 2006

Objective Show that an open technique combined with C-arm guidance provides rapid placement of C2 pedicle screws.

Surgery

Devices: Brand Company Axis or Vertex MSD

Screw Placement


Pedicle C2 (3.5 or 4.0mm; length not specified)

Graft local bone

Other Hooks if unilateral (2 patients)

Pre-op planning CT 3D

Visualization during surgery C-arm

Study Design

NS, single cohort

Period Surgeries NS, before 1998

Number Patients 79

Number Screws 150

Follow-up 4.8 yrs (1-12 yrs)


No specified

Effectiveness

Screw Placement


Results


Non-critical breach (< 3mm): 5.3% (8/150)

Critical breach: 0.7% (1/150)

Clinical Symptoms Two: 1 vertebral artery injury/resolved with screw placement; 2nd

with breach > 4mm and while no symptoms, revised.Comments/Conclusions

Pre-operative planning, anatomic knowledge, and lateral C-arm orientation create a low morbidity method for C2 screw placement.Authors’ Financial Disclosure




Author/Year Parker 2009

Objective To compare the clinical experience of pedicle (PS) vs translaminar screws (TLS) for axial (C1-C2 or C1-C3)

and subaxial (C2 and caudal) fusion. Surgery


Screw Placement

Material and Screw Sizes Not specified

Translaminar Axial: bilateral screws; Subaxial: unilateral (16%)

Pedicle Axial: bilateral screws; Subaxial: unilateral (14%)

Graft DBM; < 10% each group BMP

Other NSPre-op planning CT-3DVisualization during surgery Fluoroscopy used in a minority: PS 10% (7 patients) and

TLS 6% (4 patients); all others freehand. Study Design

Retrospective, Comparative


Number Patients PS: 70 TLS: 66

Number Screws PS: 161 TLS: 152

Follow-up 1 year

Indications PS TLS

Trauma (dislocation/fracture) 14 12

Degenerative 45 42

Tumors 9 10

Other 2 2

Total 70 66

Baseline comparability Higher incidence of mechanical pain TLS group (79% vs 51% with P=0.003)

Effectiveness

Screw Placement

Assessment Method CT: breach 20% screw diameter outside C2

lamina or pedicle Results PS TLS

Breach 6.8% (11/161) (P=0.018) 1.3% (2/152)

Clinical Symptoms: Screw revision Neurological/Vertebral artery damage

01

10

Unilateral occlusion VA; patient took aspirin; stroke

and transient ischemic attack free at 18-mos

Screw pull out/pseudarthrosis requiring revision: Subaxial Axial

0% (0) (P<0.05)0% (0)

6.1% (4)0% (0)


The increased incidence of C2 PS breach did not result in increased morbidity. By 1-year post-op, TLS were associated with a higher incidence of revision for pseudarthrosis and screw loosening when used for subaxial fusion. Therefore, TLS might be inferior to PS for subaxial fusions but equally effective for axial

cervical fusions.



Authors’ Financial Disclosure None

Author/Year Richter 2005

Objective To compare cervical pedicle screw placement with conventional method (CM) with an image intensifier vs computer assisted

surgery (CAS) with VectorVision BrainLab. Surgery

Devices: Brand Company Neon Ulrich, cannulated screws

Material Titanium alloy

Screw Placement

Material NS

Pedicle C3-C7 (diameter: 4.0mm), high thoracic as needed (diameter: 5.0mm)

Graft NS

Other RodsPre-op planning CTVisualization during surgery Image intensifier vs CASStudy Design

Prospective, serial periods

Period Surgeries Aug 2000 – Oct 2003

Number Patients CM: 20 CAS: 32

Number Screws CM: 93 CAS: 167

Follow-up CM: 29.6 (22-37) months CAS: 18.6 (7-22) months

Indications CM CAS

Trauma (fractures/dislocation) 1 11

Instability/Deformity 3 6

Pseudarthrosis/Failed Fusion 4 1

Degenerative 10 4

Tumors 2 10

Total 20 32

Effectiveness

Screw Placement

Assessment Method CT:Correct: w/out perforation or perforation < 1mm

Perforation: > 1mm w/out need for revisionPerforation w/revision

Results

Correct 91.4% (85/93) 97% (162/167)

Perforation 8.6% (8/93) 3% (5/167)

Perforation w/revision 0% (0/93) 0% (0)

Clinical Symptoms 0 0


Transpedicular screws were applied safely and with high accuracy with the conventional method. Computer assisted surgery allowed for reduced screw misplacement rates.

Authors’ Financial Disclosure One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript.



Author/Year Sciubba 2009

Objective To describe results from meticulous dissection of C2 and freehand placement of pedicle screws.

Surgery


Material NS

Screw Placement

Lateral Mass C1

Pedicle C2 (diameter: 3.5mm; length: avg 26mm)

Graft NSOther NSPre-op planning Radiographs and CT or MRIVisualization during surgery Free hand; no visualizationStudy Design

Prospective, Single cohort

Period Surgeries NS

Number Patients 55

Number Screws 100 pedicle screws




Screw Placement

Assessment Method CT:Breach magnitude by % screw diameter beyond cortical

edge Results

None Grade I: < 25% Grade II: 26-50% Grade III: 51-75% Grade IV: 76-100%

85% (85/100)10% (10/100)

3% (3/100)1% (1/100)1% (1/100)



Freehand placement of pedicle screws at C2 can be accomplished safely and effectively without the use of fluoroscopy or navigation following careful assessment of anatomy on pre-op images combined with

accurate identification of the C2 pars and pedicle intra-operatively via careful dissection. When breaches did occur, they were overwhelmingly lateral with < 50% of the screw diameter beyond the cortical edge and

were not symptomatic. Authors’ Financial Disclosure One of authors serves as a consultant to Medtronic and

receives support from DePuy Spine. Also serves on board of US Spinal Technologies and Spinal Kinetics. (Note: not clear what manufacturer’s screws used.)



Author/Year Stulik 2007

Objective Evaluate the results of the atlantoaxial fixation using polyaxial screw-rod system with Harms procedure

Surgery

Devices: Brand Company Peak Summit DePuy Spine, Spine System Aesculap, Vertex MSD

Material NS

Screw Placement

Lateral Mass C1 (diameter:3.5mm; length 26-34mm)

Pedicle C2 (diameter: 3.5mm; length 28-34mm)

Graft Autograft bone graft substitute, if required (fusion goal in 24 cases); some cases temporary stabilization

Other RodsPre-op planning Radiographs and CT; MRI as neededVisualization during surgery Image intensifierStudy Design

NS, Single cohort

Period Surgeries Dec 2002-May 2006

Number Patients 28

Number Screws 112

Follow-up 17.1 mos (12-29 mos)


Trauma (fractures/dislocation) 26 92.9%Instability/Deformity 1 3.6%Degenerative 1 3.6%Total 28 100.0%Effectiveness

Screw Placement


Results lateral mass: 94.6% (53/56) correctinto the anterior cortex or atlas without perforation of the

transverse foramenpedicle: 94.6% (53/56) correct

into the anterior cortex or atlas without perforation of the transverse foramen

pedicle: 5.4% (3/56) malpositioned no neuro or VA injury

Separately reported 6 cases of bleeding of venous plexus around greater occipital nerve, resolved with bipolar

coagulation, screw insertion and tamponing. Clinical Symptoms None

Fusion (%) Fusion: bone bridging on lateral x-ray between the posterior arch of the atlas and the arch of the

epistropheus.100% (24/24; other 4 temporary stabilization)


Harms' method is very effective in stabilizing the atlantoaxial complex. Provides possibility of temporary fixation without damage to the atlantoaxial joints and of reduction after the screws/rods have been inserted.

Essential issue in all types of C1-C2 fixation with screws is possible injury of the vertebral artery and the nerve structures. In this series, Harms’ method saved the greater occipital nerve. Three of four patients, who complained of paresthesia in the region innervated by the greater occipital nerve, resolved within 12 weeks; one persisted at 9 months. Bleeding from the venous plexus occurred in six patients were treated



with bipolar coagulation and later by quick screw insertion and tamponing.


Author/Year Tan 2009

Objective To validate the clinical feasibility, safety and value of C1 lateral mass C2 pedicle screw and crosslink compression

fixation in unstable Atlas fractures. Surgery

Devices: Brand Company Summit DePuy Spine

Screw Placement

Material and Screw Sizing NS

Lateral Mass C1

Pedicle C2

Graft Bone graft

Other Rods, Transverse ConnectorPre-op planning Radiographs, CTVisualization during surgery FluoroscopyStudy Design

NS

Period Surgeries Jan 2001 – Dec 2004

Number Patients 17

Number Screws NS



Trauma/fracture/dislocation 17 100.0%Effectiveness

Fusion (%) Fusion: bony union without instability on lateral x-ray100%( 17/17)

Safety

1 VA injury by electric cauterization led to VA rupture; hemorrhage controlled by outward tamponade of

hemostatic guaze and fixation of gauze onto the internal fixation with cement. No intracranial ischemic events

observed. Comments/Conclusions

Osteosynthesis of the atlas by C1 lateral mass screws C2 pedicle screws and crosslink compression fixation is an ideal option for C1 burst fractures with or without rupture of the transverse ligament.

Authors’ Financial Disclosure No funds or benefits.



Author/Year Wang 2010

Objective To evaluate the accuracy of C1 lateral mass screws and C2 pedicle screw placement, compare fusion rates and

vertebral artery injury.Surgery


Material NS

Screw Placement

Lateral Mass C1 (diameter: 3.5mm; length 28-30mm)

Pedicles C2 (diameter: 3.5mm diameter; length 22-26mm)Graft Iliac crest boneOther PlatesPre-op planning NSVisualization during surgery C-arm fluoro guidanceStudy Design

Retrospective

Period Surgeries 2000 – 2008

Number Patients 319

Number Screws 638 lateral mass screws638 pedicle screws

Follow-up Mean 32.4 (6-80) mos


Instability/Deformity 299 93.7%Other 20 6.3%Total 319 100%Effectiveness

Fusion Fusion: radiographs with confirmatory reconstructive CT with obvious osseous union between the C1 posterior arch

and C2 lamina100% (319/319)

Screw Placement


Results: Position Lateral Mass Pedicle Screw

Good 95.5% (609/638) 92.8% (592/638)

Clinical Symptoms No clinically manifested injury and no findings on CT or MRI angiography


Lateral or C-arm guidance efficient and adapts to osseous variations, malformation, and rotation of the atlas. The technique for C1 lateral mass and C2 pedicle screws appears to be safe and effective.




Author/Year Yoshimoto 2009

Objective To report the learning curve of cervical pedicle screw insertion and to evaluate whether this technique could be

utilized by cervical spine surgeons without special instruction.

Surgery

Devices: Brand Company Ti-mini-VSP DePuy Spine; Axon Synthes; Universal Spine System Synthes

Material and Sizing NS (except for VSP titanium)

Screw Placement

Lateral Mass C1 (excluded from analysis)

Pedicles C2-C7Graft NSOther NSPre-op planning NSVisualization during surgery FluoroscopyStudy Design

NS

Period Surgeries May 1998 – current

Number Patients 52

Number Screws 280

Follow-up 53 (6 – 113) months; 3 unrelated deaths (MI, lung cancer, accident)


Trauma (fractures/dislocation) 9 17.3%Instability/Deformity 20 38.5%Pseudarthrosis/Failed Fusion 11 21.2%Degenerative 6 11.5%Tumors 6 11.5%Total 52 100.0%Effectiveness

Screw Placement

Assessment Method CT:


Complete (more than half screw diameter)

1.8% (5/280)

Partial (less than half screw diameter)

5.0% (14/280)

None (did not violate pedicle cortex)

93.2% (261/280)


Learning Curve: Perforations Period E (early): 18 cases/92 screws Period M (mid): 20 cases/100 screws Period L (late): 15 cases/88 screws

12.0% (11/92)7.0% (7/100)1.1% (1/88)


Screw perforations occurred in each period. There were no complications such as infection, neurological deterioration, and neurovascular injury directly related to screw insertion. The learning curve showed a

significant improvement especially in the later period. However, the rates in the earlier and middle periods cannot be underestimated. (Note: the methods of insertion varied slightly between the three periods.)




Author/Year Yukawa 2009

Objective To investigate the efficacy of fluoroscopy-assisted imaging technique in accurately placing pedicle screws to treat unstable cervical injuries, and the clinical outcomes

and complications. Surgery

Devices: Brand Company Olerud, Vertex Medtronic; Oasys Stryker

Material NS

Screw Placement

Pedicle C2-T2 (diameter: 3.5mm; length 20-22mm)

Graft Local bone chips

Other Plates or Rods, anterior reconstruction with iliac bone graft as indicated

Pre-op planning Radiograph, CT and MRI; more recently MR angiography or CT angiography obtained to observe patency of

vertebral arteryVisualization during surgery FluoroscopyStudy Design

NS

Period Surgeries 1995 – 2006

Number Patients 144

Number Screws 620

Follow-up More than 6 months for 140 patients; 4 deaths (1 renal failure, 2 pneumonia, 1 pulmonary embolism)


Trauma/fracture/dislocation 144 100.0%Effectiveness

Screw Placement

Assessment Method CT:

Results: Exposure or Perforation

None: 86.9% (539/620)

Screw exposed: broke the pedicle wall but > 50% screw diameter remained within the pedicle

9.2% (57/620)

Perforation: breached the pedicle wall and 50% screw diameter outside the pedicle

3.9% (24/620)

Of the 81 screws out of position, 69% lateral, 30% medial and 1% infralateral.

Clinical Symptoms One pedicle probe into the vertebral artery (bleeding easily stopped with bone wax) and one transient

radiculopathy.Fusion (%) Fusion: flex/ext bony union

100% (140/140); excludes 4 deaths

Outcomes 96% (135/140) good cervical alignment at final follow-up


Twenty patients (13.9%) needed a pre or post-op tracheotomy, which was easier to perform with posterior cervical fixation than in those treated with anterior cervical surgery or Halo vest fixation. The placement



of cervical pedicle screws using a fluoroscopy-assisted pedicle axis view technique provided good clinical results and a few complications for unstable cervical injuries.


Author/Year Zhuo 2010

Objective To investigate the method and efficacy of the cervical pedicle screw system for fracture-dislocation of the

cervical spineSurgery

Devices: Brand Company Medtronic Vertex

Material and Screw Sizes NS

Screw Placement

Pedicles Lower cervicalGraft If preserved: lamina or if lamina resected, facet joint

cancellous boneOther RodsPre-op planning X-ray. CT and MRIVisualization during surgery X-ray C-armStudy Design

Prospective


Number Patients 48


Follow-up 3, 6, 12 and 24 months; no stats


Trauma (fractures/dislocation) 48 100%Effectiveness

ASIA Pre: 18 Gr A (complete spinal cord injury) AND 15 Gr B, 10 Gr C and 5 Gr D (incomplete spinal cord injury)

30 with grades B-D improved 1-2 grades; 18 with grade A had no improvement in neural function; however, their nerve root symptoms such as pain and numbness were relieved to some extent.

Fusion Fusion: x-ray and CT100% (48/48)

Screw Placement



None (did not penetrate the pedicle)

All

Clinical Symptoms No vertebral artery injury, spinal cord injury or nerve root injury


The cervical pedicle screw system was an effective and reliable method for restoration of cervical stability.




2. HOOKS AND/OR WIRING



Author/Year Bapat 2005

Objective To compare the use of transarticular screws to the standard occipito-cervical fusion in tuberculous

atlanto-axial instability.Surgery

Construct Hartshill rectangle

Levels C1-C2 (some fixation C3)

Graft Strut autograftOther Pre-op planning Radiographs, MRIVisualization during surgery Not specifiedStudy Design

Single cohort


Number Patients 27 (16 Hartshill/11 transarticular screws); results abstracted for the 16

Follow-up Minimum 24 months (2-4 yrs)


Instability (tuberculosis) 16 100%Effectiveness

Fusion Lateral radiographs with facet fusion complete if bridging trabeculae (haziness) seen crossing the joint surface. Lateral mass fusion assessed on open mouth radiographs. Complete fusion included both.92.6% (14/16)

Safety

Neurological event 0%

Vertebral artery injury 0%

Occipital sore 25% (4/16)

Dural puncture 6.3% (1/16)

Delayed wound healing 6.3% (1/16)

Device breakage 6.3% (1/16)

Re-operation None noted


Defining the pattern of erosion of the articular surfaces of the atlas and axis helps to salvage patients for rigid segmental fixation of the atlanto-axial complex. Sparing the occiput improves

the fusion rate, allows early restoration of movement and improves patient satisfaction.Authors’ Financial Disclosure Not specified



Author/Year Epstein 2000

Objective To determine if vertebral fractures and graft extrusion would be prevented if anterior cervical plates were

added to ACF and posterior wiring Surgery

Construct Posterior wiring: spinous process or facet-braided-cable

Levels Average 2.5 levels

Graft Iliac crest autograftOther Anterior corpectomyPre-op planning MRI and CTVisualization during surgery Not specifiedStudy Design

Single cohort

Period Surgeries January 1989-March 1997

Number Patients 22 (22 subsequent patients with plates; results not abstracted)

Follow-up 4 (2-9) yrs


Degenerative, multi level 22 100%Effectiveness

Fusion CT every 1-2 months for as long as 6-mos or until bony bridging with trabeculation and lack of lucency at the graft vertebral body interface. Flexion extension films then used to confirm lack of significant motion (<3.5mm translation, < 20° rotation, and < 2mm displacement).100% (22/22)

Safety

Neurological event 13.6% (3/22) transient root deficit

CSF fistula 4.5% (1/16)

Dysphagia 4.5% (1/16)

Deep venous thrombosis 4.5% (1/16)

Recurrent OPLL 4.5% (1/16) requiring re-op

Vertebral artery injury 0%

Graft extrusion/ Vertebral fracture 13.6% (3/22) leading to re-op

Death 4.5% (1/16) cardiovascular 48-hrs after surgery: co-morbid factors cardiovascular disease and extensive

myelopathyRe-operation 18.2 % (4/22)


Vertebral fractures and graft extrusions have not occurred in subsequent series of patients with plates.




Author/Year Fagerstrom 2002

Objective To investigate the outcome and safety of cervical Cotrel Dubousset (hooks/rods) system.

Surgery

Construct Medtronic CD Hooks/rods

Levels Occiput to T6

Graft 20 tumor patients not fusedOther Bi-lateral claw as needed for dislocations, atlanto-axial

instability; occipital screws used when needed for fixation at this level

Pre-op planning NSVisualization during surgery NSStudy Design

Retrospective Single cohort

Period Surgeries NS

Number Patients 60

Follow-up 41 patients( 9 died before follow-up (7 tumors, 1 post-op neuro deterioration, 1 myocardial infarction), 10

considered that they lived too far away or not in good physical shape to attend)

18 (1-48) mosIndications Number Percent

Trauma (fractures/dislocation) 17 28.3%Instability/Deformity 23 38.3%Tumors 20 33.4%Total 60 100.0%Effectiveness

Fusion Not assessed (20 not fused intentionally)

Safety

Neurological event 6.7% (4/60) two with re-op

Vertebral artery injury 1.7% (1/60) lower extremity thrombosis

Implant failure 3.3% (2/60)

Wound infection 10% (6/60)

Dysphagia 1.7% (1/60)

Hematoma 3.3% (2/60) included in neuro re-op

Hook loosening 1.7% (1/60) re-op

Unstable instrumentation 1.7% (1/60) re-op

Screw loosening-Occiput 1.7% (1/60) no re-op

Pulmonary edema 1.7% (1/60)

Re-operation 10% (6/60)


Cervical hooks/rods can be safely used for external support in severe pathologies of the cervical spine.




Author/Year Reilly 2003

Objective To review the results of patients with atlanto-axial instability who required arthrodesis to compare

posterior wiring to transarticular screwsSurgery

Construct Wiring cabling with modified Gallie or Brooks

Levels C1-C2

Graft autograftOther Pre-op planning Not specifiedVisualization during surgery Not specifiedStudy Design

Retrospective comparative

Period Surgeries 1988-2001 (last five years screws preferred)

Number Patients 38 each group (abstracted only results from wiring group)



Trauma 17 44.7%Instability/deformity 19 50.0%Tumor 2 5.7%Degenerative 38 100%Effectiveness

Fusion Lateral and flex/ext radiographs with fusion solid if evidence of apparent consolidation of the autograft bone at C1 or C2 posterior arches had <2mm motion.71% (27/35)

Safety

Neurological event 2.6% (1/38) worsening myelopathy

Vertebral artery injury -

Wound infection 5.2% (2/38)

Re-operation 15.8% (6/38)


Note: 21% (7/38) developed pin-site infections with one case of osteomyelitis (3%) from the halo vest. Other vest complications can include osetomyelitis, nerve injury, dural penetration, CSF

leak, intracranial abscess, dysphagia, pin-site scar, restriction of respiratory function, and loss of reduction.




Author/Year Zimmerman 2002

Objective To describe experience with Ransford loops in patients with primary or metastatic tumors of the

occipito-cervical junction and the upper cervical spine as a palliative concept.

Surgery

Construct Ransford loops

Levels Occiput-C6

Graft None due to short life expectancyOther sublaminar titanium cable fixationPre-op planning Radiographs, CT and MRIVisualization during surgery Not specifiedStudy Design

Single cohort

Period Surgeries Not specified

Number Patients 20



Tumors 20 100%Effectiveness

Stability 95% (19/20)

Safety

Neurological event 5% (1/20) temporary hemiparesis

Vertebral artery injury None noted

Wound infection 5% (1/20)

pneumonia 5% (1/20)

Re-operation None noted


Immedaite stabilization resulting in pain improvement was achieved.




ATTACHMENT D: ABSTRACTS: SAFETY



ADVERSE EVENT, FUSION, AND RE-OPERATION RATESPedicle and Lateral Mass Screws: AE results by article

1

Author Abumi 2000

Total Number Patients: Device Events 180

Total Number of Patients: All Other Events 180

Adverse Events (% / N)

Device: Lateral mass fracture

Pedicle fracture

Malposition screws 3 1.7%Loss of correction

Screw loosening/pull out

Strut/graft displacement

Screw breakage/dislodgment 2 1.1% Progressive degenerative change 3 1.7% Heterotopic ossification

Pseudoarthrosis 1 0.6%

Operative/Post-op

Neurological:

Upper extremity numbness/pain Neuropathic pain

Transient paresis

Muscle weakness

Dural lesion/violation


Wound: Dehiscence/Debridement

Delayed wound healing 1 0.6% Wound hematoma/seroma

Infection

Deep wound infection 2 1.1% CSF leak/fistula 8 4.4%

Other:

Neck/shoulder pain

Swallowing disturbance Blurred vision

Venous plexus bleeding

Vertebral artery bleeding

Vertebral artery injury 1 0.6% Respiratory issue

Skin irritation 2 1.1% Iliac crest pain

Other

Death related to procedure/device




ADVERSE EVENT, FUSION, AND RE-OPERATION RATES

Pedicle and Lateral Mass Screws: AE results by article

1

Author Abumi 2000





Pedicle fracture

Malposition screws 3 1.7% Loss of correction



Screw breakage/dislodgment 2 1.1% Progressive degenerative change 3 1.7% Heterotopic ossification


Operative/Post-op

Neurological:


Transient paresis

Muscle weakness




Delayed wound healing 1 0.6% Wound hematoma/seroma

Infection


Other:

Neck/shoulder pain





Skin irritation 2 1.1% Iliac crest pain

Other







1

Author Arnold 2005





Pedicle fracture

Malposition screws

Loss of correction



Screw breakage/dislodgment 1 2.1% Progressive degenerative change

Heterotopic ossification

Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness

Dural lesion/violation 1 2.1% Radiculopathy


Delayed wound healing

Wound hematoma/seroma

Infection 2 4.2% Deep wound infection

CSF leak/fistula

Other:

Neck/shoulder pain




Vertebral artery injury

Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorCornefjord

2005





Pedicle fracture




Screw breakage/dislodgment

Progressive degenerative change


Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness 1 5.3% Dural lesion/violation

Radiculopathy




Infection

Deep wound infection 1 5.3% CSF leak/fistula

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other







AuthorDjurasovic

2006

Total Number Patients: Device Events Not reportedTotal Number of Patients: All Other Events Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection

Deep wound infection

CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorElMiligui

2010

Total Number Patients: Device Events 15Total Number of Patients: All Other Events 15



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Goel 2002

Total Number Patients: Device EventsNot

reportedTotal Number of Patients: All Other Events 160



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain



Vertebral artery bleeding 4 2.5% Vertebral artery injury

Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorHarms 2001




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorHasegawa

2008




Pedicle fracture 1 1.7% Malposition screws 2 3.4% Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:

Upper extremity numbness/pain 4 6.9% Neuropathic pain

Transient paresis


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain

Swallowing disturbance 1 1.7% Blurred vision



Vertebral artery injury 2 3.4% Respiratory issue 2 3.4% Skin irritation

Iliac crest pain

Other 5 8.6%Death related to procedure/device

Re-operations





1

AuthorIshikawa

2010


reportedTotal Number of Patients: All Other Events 62



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other


Re-operations





Author Ito 2008


reportedTotal Number of Patients: All Other Events

Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Jian 2010




Pedicle fracture

Malposition screws 1 3.4% Loss of correction 1 3.4% Screw loosening/pull out





Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other

Death related to procedure/device 1 3.4%Re-operations





1

Author Kim 2007



Device: Lateral mass fracture 2 3.1% Pedicle fracture







Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness

Dural lesion/violation 1 1.5% Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain 1 1.5%





Respiratory issue

Skin irritation

Iliac crest pain

Other







1

Author Lee 2007




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis


Radiculopathy



Wound hematoma/seroma 1 1.7% Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Lee 2010




Pedicle fracture








Operative/Post-op

Neurological:

Upper extremity numbness/pain Neuropathic pain 1 3.7% Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:






Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Li 2008




Pedicle fracture

Malposition screws

Loss of correction





Heterotopic ossification 1 4.3% Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





Author Liu 2010



Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorLiu

2009




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorMueller

2010




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy





CSF leak/fistula 1 3.7%

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other 1 3.7%Death related to procedure/device

Re-operations





1

Author Neo 2005




Pedicle fracture






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis 2 11.1% Muscle weakness


Radiculopathy




Infection


Other:

Neck/shoulder pain

Swallowing disturbance Blurred vision 1 5.6% Venous plexus bleeding



Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Oda 2006




Pedicle fracture


Screw loosening/pull out 1 3.1% Strut/graft displacement 1 3.1% Screw breakage/dislodgment



Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness





Wound hematoma/seroma 1 3.1% Infection


Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other







1

AuthorOgihara

2010

Total Number Patients: Device Events 23Total Number of Patients: All Other Events

Not reported



Pedicle fracture

Malposition screws

Loss of correction

Screw loosening/pull out 1 4.3% Strut/graft displacement




Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorOndra 2006




Pedicle fracture


Screw loosening/pull out 1 1.3% Strut/graft displacement



Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection



Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other







1

AuthorParker 2009




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy






Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorRichter

2005




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorSciubba

2009




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness







CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

Author Stulik 2007




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis 4 14.3% Muscle weakness


Radiculopathy

Wound: Dehiscence/Debridement 1 3.6% Delayed wound healing


Infection


CSF leak/fistula

Other:



Venous plexus bleeding 6 21.4% Vertebral artery bleeding


Respiratory issue

Skin irritation

Iliac crest pain 1 3.6% Other


Re-operations





1

Author Tan 2009




Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other


Re-operations





AuthorWang 2011



Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorYoshimoto

2009

Total Number Patients: Device Events 52Total Number of Patients: All Other Events Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations





1

AuthorYukawa

2009




Pedicle fracture

Malposition screws

Loss of correction 5 3.5% Screw loosening/pull out




Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness






Infection


Other:

Neck/shoulder pain





Skin irritation

Iliac crest pain

Other







1

Author Zhuo 2010

Total Number Patients: Device Events 48Total Number of Patients: All Other Events

Not reported



Pedicle fracture

Malposition screws

Loss of correction






Pseudoarthrosis

Operative/Post-op

Neurological:


Transient paresis

Muscle weakness


Radiculopathy




Infection


CSF leak/fistula

Other:

Neck/shoulder pain





Respiratory issue

Skin irritation

Iliac crest pain

Other


Re-operations




Reported Device and/or Other Events 27

Table 7. Summary of Adverse Events: Published Literature



Adverse Events Total %

Device: Lateral mass fracture 2 0.2% Pedicle fracture 1 0.1% Malposition screws 13 1.1% Loss of correction 6 0.5% Screw loosening/pull out 3 0.2% Strut/graft displacement 1 0.1% Screw breakage/dislodgment 10 0.8% Progressive degenerative change 3 0.2% Heterotopic ossification 1 0.1% Pseudarthrosis 2 0.2%

Operative/Post-op

Neurological:

Upper extremity numbness/pain 4 0.3% Neuropathic pain 1 0.1% Transient paresis 6 0.4%Muscle weakness 3 0.2%

Dural lesion/violation 2 0.1% Radiculopathy 6 0.4%

Wound: Dehiscence/Debridement 1 0.1% Delayed wound healing 1 0.1% Wound hematoma/seroma 2 0.1% Infection 4 0.3% Deep wound infection 11 0.8% CSF leak 15 1.1%

Other:

Neck pain 5 0.4%

Swallowing disturbance 1 0.1% Blurred vision 1 0.1% Venous plexus bleeding 6 0.4% Vertebral artery bleeding 4 0.3% Vertebral artery injury 16 1.1% Respiratory issue 2 0.1% Skin irritation 2 0.1% Iliac crest pain 1 0.1% Other General Medical 6 0.4%Death related to procedure and/or device 1 0.1%Re-operations 15 1.1%



ATTACHMENT E: POSTERIOR CERVICAL PROCEDURES: US DATA



About PearlDiver http://www.pearldiverinc.com/pdi/spine.jspAccessed March 26, 2010

PearlDiver is an emerging growth company leader in the life sciences information industry. Its services include search and analysis software and database technologies, consulting services and information based strategic advisory services. PearlDiver’s mission is to improve the ways surgeons, product manufacturers, hospitals and regulators connect with and utilize health care related information.

PearlDiver was founded by Robin R. Young CFA, a former equity research analyst with extensive experience in the life sciences industry and Benjamin B. Young, a nationally recognized leader in database architecture, analysis and simulation modeling.

PearlDiver is building the orthopedic industry’s largest online repository of data and information. More than 650 medical professionals and 20 corporate clients rely on PearlDiver’s fast and intelligent access to massive patient, clinical trial and adverse event databases.

General and Administrative Staff:Robin R. Young, CEO and Co-founderBenjamin B. Young, President and Co-founderRob Young, EVP - Business DevelopmentTom Bishow, Vice President of SalesHeather Truex, Office ManagerPearlDiver Information TechnologiesBenjamin B. YoungPhillip Fielder, Database/Software engineerPearlDiver Analytics and Consulting ServicesRobin R. YoungMatt Menze, Senior Analyst, Spine Products and MarketsDev Joshi, Analyst, Extremities Reconstruction Products and MarketsScott Ellison, Analyst, Large Joint Reconstruction Products and Markets SpineMatt Menze, Senior Analyst, Spine Products and Markets7235 Vicksburg PikeFort Wayne, IN 46804 [email protected]



U.S. Spine Fusion Summary 2006-2012



ATTACHMENT F: BIBLIOGRAPHY/ARTICLES

1. LATERAL MASS AND PEDICLE SCREWS

Abumi K, Shono Y, Ito M, Taneichi H, Kotani Y, Kaneda K. Complications of pedicle screw fixation in reconstructive surgery of the cervical spine, Spine, 2000; 25(8):962-9.

Alosh H, Parker SL, McGirt MJ, Gokaslan ZL, Witham TF, Bydon A, Wolinsky JP, Sciubba DM. Preoperative radiographic factors and surgeon experience are associated with cortical breach of C2 pedicle screws. J Spinal Disord Tech. 2010;23(1):9-14.

Arnold P, Bryniarski M and Mahon J. Posterior stabilization of subaxial cervical spine trauma: indications and techniques, Injury. 2005; 36 Suppl 2:B36-43.

Bransford R, Lee M, Reis A. Review article: posterior fixation of the upper cervical spine: contemporary techniques. JAAOS. 2011; 19: 63-71.

Cornefjord M, Alemany M, Olerud C. Posterior fixation of subaxial cervical spine fractures in patients with ankylosing spondylitis. Eur Spine J. 2005;14(4):401-8.

Djurasovic M, Dimar JR 2nd, Glassman SD, Edmonds HL, Carreon LY. A prospective analysis of intraoperative electromyographic monitoring of posterior cervical screw fixation, J Spinal Disord Tech. 2005;18(6):515-8. Comment in: J Spinal Disord Tech. 2006;19(6):463.

ElMiligui Y, Koptan W, Emran I. Transpedicular screw fixation for type II Hangman's fracture: a motion preserving procedure. Eur Spine J. 2010 Aug;19(8):1299-305. Epub 2010 Apr 17.

Goel A, Desai KI, Muzumdar DP: Atlantoaxial fixation using plate and screw method: A report of 160 treated patients. Neurosurgery 2002;51(6):1351-1357.

Harms J and Melcher R. Posterior C1-C2 fusion with polyaxial screw and rod fixation, Spine, 2001, 26(22): 2467-2471.

Hasegawa K, Hirano T, Shimoda H, Homma T, Morita O. Indications for cervical pedicle screw instrumentation in nontraumatic lesions. Spine. 2008, 33(21):2284-9.

Ishikawa Y, Kanemura T, Yoshida G, Ito Z, Muramoto A, Ohno S. Clinical accuracy of three-dimensional fluoroscopy-based computer-assisted cervical pedicle screw placement: a retrospective comparative study of conventional versus computer-assisted cervical pedicle screw placement. J Neurosurg Spine. 2010; 13(5):606-11.

Ito Y, Sugimoto Y, Tomioka M, Hasegawa Y, Nakago K, Yagata Y. Clinical accuracy of 3D fluoroscopy-assisted cervical pedicle screw insertion. J Neurosurg Spine. 2008; 9(5):450-3.

Jian FZ, Chen Z, Wrede KH, Samii M, Ling F. Direct posterior reduction and fixation for the treatment of basilar invagination with atlantoaxial dislocation. Neurosurgery. 2010; 66(4):678-88.



Kim SH, Shin DA, Yi S, Yoon do H, Kim KN, Shin HC. Early results from posterior cervical fusion with a screw-rod system, Yonsei Med J. 2007;48(3):440-8.

Kosmopoulos V, Schizas C. Pedicle screw placement accuracy: a meta-analysis. Spine 2007; 32(3):E111-20.

Lee SH, Kim ES, Sung JK, Park YM, Eoh W. Clinical and radiological comparison of treatment of atlantoaxial instability by posterior C1-C2 transarticular screw fixation or C1 lateral mass-C2 pedicle screw fixation. J Clin Neurosci. 2010;17(7):886-92.

Lee GY, Massicotte EM, Rampersaud YR. Clinical accuracy of cervicothoracic pedicle screw placement: a comparison of the "open" lamino-foraminotomy and computer-assisted techniques. J Spinal Disord Tech. 2007; 20(1):25-32.

Li L, Zhou FH, Wang H, Cui SQ. Posterior fixation and fusion with atlas pedicle screw system for upper cervical diseases. Chin J Traumatol. 2008; 11(6):323-8.

Liu Y and Das K. Posterior fusion of the subaxial cervical spine: indications and techniques. Neurosurg Focus 2001; 10(4).

Liu Y, Hu JH, Yu KY. Pedicle screw fixation for cervical spine instability: clinical efficacy and safety analysis. Chin Med J (Engl). 2009;122(17):1985-9.

Liu YJ, Tian W, Liu B, Li Q, Hu L, Li ZY, Yuan Q, Lü YW, Sun YZ. Comparison of the clinical accuracy of cervical (C2-C7) pedicle screw insertion assisted by fluoroscopy, computed tomography-based navigation, and intraoperative three-dimensional C-arm navigation. Chin Med J (Engl). 2010; 123(21):2995-8.

Ludwig SC, Kramer DL, Vaccaro AR, Albert TJ. Transpedicle screw fixation of the cervical spine, Clin Orthop Relat Res, 1999; 359:77-88.

Mueller CA, Roesseler L, Podlogar M, Kovacs A, Kristof RA. Accuracy and complications of transpedicular C2 screw placement without the use of spinal navigation. Eur Spine J. 2010;19(5):809-14.

Neo M, Fujibayashi S, Miyata M, Takemoto M, Nakamura T. Vertebral artery injury during cervical spine surgery: a survey of more than 5600 operations, Spine. 2008; 33(7):779-85.

Neo M, Sakamoto T, Fujibayashi S, Nakamura T. The clinical risk of vertebral artery injury from cervical pedicle screws inserted in degenerative vertebrae, Spine, 2005;30(24):2800-5.

Oda I, Abumi K, Ito M, Kotani Y, Oya T, Hasegawa K, Minami A. Palliative spinal reconstruction using cervical pedicle screws for metastatic lesions of the spine: a retrospective analysis of 32 cases, Spine, 2006; 31(13):1439-44.

Ogihara N, Takahashi J, Hirabayashi H, Hashidate H, Kato H. Long-term results of computer-assisted posterior occipitocervical reconstruction. World Neurosurg. 2010;73(6):722-8.

Ondra SL, Marzouk S, Ganju A, Morrison T, Koski T. Safety and efficacy of C2 pedicle screws placed with anatomic and lateral C-arm guidance, Spine, 2006; 31(9):E263-7.



Parker SL, McGirt MJ, Garcés-Ambrossi GL, Mehta VA, Sciubba DM, Witham TF, Gokaslan ZL, Wolinksy JP. Translaminar versus pedicle screw fixation of C2: comparison of surgical morbidity and accuracy of 313 consecutive screws. Neurosurgery. 2009;64 (5 Suppl 2):343-349.

Richter M, Cakir B, Schmidt R. Cervical pedicle screws: conventional versus computer-assisted placement of cannulated screws. Spine. 2005;30(20):2280-7.

Sasso R. C1 lateral screws and C2 pedicle/pars screws. AAOS Instructional Course Lectures 2007; 56: 311-317.

Sciubba DM, Noggle JC, Vellimana AK, Alosh H, McGirt MJ, Gokaslan ZL, Wolinsky JP.Radiographic and clinical evaluation of free-hand placement of C-2 pedicle screws. Clinical article. J Neurosurg Spine. 2009;11(1):15-22.

Stulik J, Vyskocil T, Sebesta P and Kryl J. Atlantoaxial fixation using the polyaxial screw-rod system, Eur Spine J, 2007, 16: 479-484.

Tan J, Li L, Sun G, Qian L, Yang M, Zeng C, Teng H, Jia L C1 lateral mass-C2 pedicle screws and crosslink compression fixation for unstable atlas fracture. Spine. 2009; 34(23):2505-9.

Wang S, Wang C, Wood KB, Yan M, Zhou H. Radiographic evaluation of the technique for C1 lateral mass and C2 pedicle screw fixation in three hundred nineteen cases. Spine. 2010;36(1):3-8.

Yoshimoto H, Sato S, Hyakumachi T, Yanagibashi Y, Kanno T, Masuda T. Clinical accuracy of cervical pedicle screw insertion using lateral fluoroscopy: a radiographic analysis of the learning curve. Eur Spine J. 2009 ;18(9):1326-34.

Yukawa Y, Kato F, Ito K, Horie Y, Hida T, Nakashima H, Machino M. Placement and complications of cervical pedicle screws in 144 cervical trauma patients using pedicle axis view techniques by fluoroscope. Eur Spine J. 2009 ;18(9):1293-9.

Zhou F, Zou J, Gan M, Zhu R, Yang H. Management of fracture-dislocation of the lower cervical spine with the cervical pedicle screw system. Ann R Coll Surg Engl. 2010l; 92(5):406-10.

HOOKS AND/OR WIRING

Bapat MR, Lahiri VJ, Harshavardhan NS. Metkar US, Chaudhary KC. Role of transarticular screw fixation in tuberculous atlanto-axial instability. Eur Spine J. 2007;16(2):187-97.

Epstein NE. The value of anterior cervical plating in preventing vertebral fracture and graft extrusion after multilevel anterior cervical corpectomy with posterior wiring and fusion: indications, results, and complications. J Spinal Disord. 2000; 13(l):9-15.

Fagerstrom T, Hedlund R. Cotrel Dubousset instrumentation in occipito-cervicothoracic fusion. Eur Spine J. 2002; 1(4):364-74.



Reilly TM, Sasso RC, Hall PV. Atlantoaxial stabilization: clinical comparison of posterior cervical wiring technique with transarticular screw fixation. J Spinal Disord Tech. 2003;16(3):248-53.

Zimmermann M, Wolff R, Raabe A, Stolke D, Seifert V. Palliative occipitocervical stabilization in patients with malignant tumors of the occipito-cervical junction and the upper cervical spine. Acta Neurochir(Wien). 2002; 144(8):783-90.



ATTACHMENT G: AANS Letter dated November 29, 2010

The following letter was originally submitted in support of the 513(e) petition for Reclassification: Pedicle Screws (certain uses) AMENDMENT (pedicle and lateral mass screws in the cervical spine) Docket No. FDA – 2009 – M – 0101. Earlier this year, FDA communicated to OSMA that the petition for the reclassification of posterior cervical pedicle screws should be a stand-alone petition as these devices and indications were not included in the original 515i Notification Letters to Industry in April 2009. This document addresses that communication and is now a complete, stand- alone Petition for the reclassification of posterior cervical pedicle screws. Since the attached letter dated November 29, 2010 from the American Association of Neurological Surgeons was submitted in support of the above mentioned AMENDMENT, and is still relevant to the current Petition being filed with the FDA, OSMA has included it in this submission.





Documents

SPONSOR: Orthopedic Surgical Manufacturers …ryortho.com/Osma_Petition.pdfachieved with posterior screws inserted through the plate into either the cervical pedicles and/or the lateral