4S Proceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

PATIENT SAMPLE: 96 patients who had whole body CT scans for non-

spinal deformity and 87 patients with AIS who had preoperative CT scans

of the spine were reviewed.

OUTCOME MEASURES: Pedicle morphology was categorized accord-

ing toCobb angle, location of the spinal curve, location on the convex or con-

cave side of the curve, location within the periapical region, age-adjusted

weight percentile, and age-adjusted height percentile.

METHODS: Group Awas composed of patients without spinal deformity.

GroupBwas composedofAISpatients. Pediclemorphologywas recorded as

previously described using the CT-based classification system. Pedicle mor-

phology was classified as Type A:O4 mm cancellous channel, Type B: 2–

4 mm channel, Type C: cortical channel, and Type D: non-existent pedicle.

The incidence of abnormal pedicles, and the pedicles’ locationwas recorded.

Incidence of abnormal pedicle on the concave side of the curve was com-

pared to incidence on the convex side of the curve. Pedicles were then sub-

categorized according to location in thoracic, thoracolumbar, and lumbar

curves, Cobb angle and degree of kyphosis. The Chi-squared test was used

to determine significance. A p - value of!0.05 was considered significant.

RESULTS: 6256 pedicles were reviewed, 3298 pedicles in non-deformity

patients and 2958 in patients with AIS. The incidence of abnormal pedicles

in non-deformity patients was 9.8%, and the incidence in AIS patients was

22%. This was a statistically significant difference (p!0.001). In Group A,

77% of abnormal pedicles were type B, 22% were type C, and 1% were

type D. In Group B, 69% were type B, 18% were type C, and 13% were

type D. In spinal deformity patients 96% of abnormal pedicles were lo-

cated in the thoracic spine. The incidence of abnormal pedicles in the tho-

racic spine was 29.6%. Of those, 30.7% were type C or D. The incidence

of abnormal pedicles in male and female AIS patients was significantly

different, with females having a higher incidence of abnormal pedicles.

We found a significantly larger incidence of dysmorphic pedicles on the

concave side of the curve in thoracic curves measuring 40–70� (n5546,

p5!0.0001). In the thoracic spine, three times as many abnormal pedicles

were located on the concave side of the curve than on the convex side of

the curve (148/197) (p!0.001). When incidence in pedicle morphology

was compared by age and gender-matched height and weight percentiles,

patients above the 50th percentile for weight and with thoracic curves

O70� had greater incidence abnormal pedicles (n548, p50.015).

CONCLUSIONS: Our study found significantly higher incidence rates of

abnormal pedicles in AIS patients than non-spinal deformity patients. Of

abnormal pedicles found in patients with AIS, most were located within

the thoracic curve, with a significant proportion found on the concave side

of the curve. Females had significantly more abnormal pedicles than

males, and heavier patients had significantly more abnormal pedicles than

lighter patients for their age and sex. Due to the high proportion of dysmor-

phic pedicles located with the thoracic spine, radiation exposure may be

limited by reducing the number of segments scanned for preoperative eval-

uation in patients with AIS.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.016

Wednesday, October 6, 20101:00–2:00 PM

Concurrent Session 1: Scoliosis

8. Neurological Outcome of Myelopathy Secondary to Severe

Kyphoscoliotic Spinal Deformities Treated with a Posterior-only

Vertebral Resection and Shortening Procedure: A Retrospective

Review

Kshitij Chaudhary, MS (ortho), DNB (ortho)1, Mihir Bapat, MD, MS

(ortho), DNB (ortho)2, Umesh Metkar, MD, MS (Ortho)3, Ashok Rathod,

MD, MS (ortho)1, Vinod Laheri, MD, MS (ortho)1; 1King Edward

All referenced figures and tables will be available at the Annual Mee

Memorial Hospital, Mumbai, Mumbai, India; 2Kokilaben Dhirubai

Ambani Hospital, Mumbai, India; 3BIDMC and Harvard Medical School,

Boston, MA, USA

BACKGROUND CONTEXT: Severe spinal deformities can result in my-

elopathy. Literature has no standard recommendations for treating cord def-

icits due to severe deformity. Traditionally the surgical treatment has been

a staged anterior and posterior approach to the spine.

PURPOSE: 1. Define role of posterior vertebral resection osteotomy in

the setting of myelopathy; 2. Evaluate neurological recovery patterns; 3.

To audit unfavorable results and complications.

STUDY DESIGN/SETTING: Retrospective.

PATIENT SAMPLE: Records of 13 consecutive patients with cord deficits

due to severe angular kyphotic or kyphoscoliotic deformity were analyzed

(2003- 2008) at a single institution.

OUTCOME MEASURES: Frankel Grade, Bladder dysfunction, Post op-

erative complication, Revision surgery, Percentage of scoliosis and kyphosis

correction.

METHODS: One patient had died of unrelated cause and 12 patients were

available for follow up. Therewere 1, 3, 3 and 5 patients classified as Frankel

A, B, C and D respectively. 4 patients had bladder dysfunction. Average du-

ration of neurological deficitwas 4.2months (0.5 to 12months).Out of the 12

patients, 7 patients had an additional scoliotic component. Etiologies were

congenital (5), neurofibromatosis (3) and tuberculous (4). Apex of deformity

was thoracic in 10 and thoracolumbar in 2. Mean preoperative kyphotic de-

formity was 73.6 deg (10 - 135 deg). Average scoliotic deformity was 84.3

deg (52 - 129 deg). Patients were treated with a single stage posterior verte-

bral resection osteotomy. Minimum follow-up was 2 years (2–5 years).

RESULTS: Mean surgical time was 6.5 hours and average blood loss was

958 ml. All patients except one showed neurologic improvement. Neurolog-

ical recovery startedwithin 1week of surgery in 6 patients, within 1month in

4 patients and afterO1month in 1 patient. Completely neurological recovery

was observed in 100%, 66%, 80% of patient with preoperative Frankel of B,

C & D respectively. All had a complete recovery of bladder function. Com-

plications seen in 5 patients (41%), which included brachial plexus (root

lesion) (1), transient cord deficit (2), implant failures (2), revision (1),

pseudo-arthrosis (1). Mean kyphotic deformity correction was 50.4% while

scoliotic corrections averaged 39%.

CONCLUSIONS: Vertebral resection osteotomy is an effective method of

treating complex spinal deformities with neurologic deficits. In addition to

providing a better environment for the stretched cord, this procedure also

serves to correct the deformity, which probably results in a longer lasting

favorable outcome. Although it is technically demanding surgery and in-

volves a significant complication rate, the pattern of neurological recovery

as seen in this study probably makes the surgical procedure rewarding.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.018

9. Meta-analysis of the Safety and Efficacy of Pedicle Screw Spinal

Instrumentation in Pediatric Spinal Deformity: Results of SRS and

POSNA Task Force

David W. Polly, Jr., MD1, Charles G.T. Ledonio, MD1,

Michael G. Vitale, MD, MPH2, B. Stephens Richards, MD3; 1University of

Minnesota, Minneapolis, MN, USA; 2Morgan Stanley Childrens Hospital

of New York - Presbyterian, New York, NY, USA; 3Texas Scottish Rite

Hospital, Dallas, TX, USA

BACKGROUND CONTEXT: Pedicle screws have revolutionized the

surgical treatment of spinal deformity because they allow better biome-

chanical control and greater correction of spinal deformity as well as lower

rates of instrumentation problems and reoperation.

As the result of these perceived advantages, pedicle screws have become

extensively utilized for spinal fixation in both adults and children.

ting and will be included with the post-meeting online content.