Decompression and Paraspinous Tension Band

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Accepted Manuscript

Decompression and paraspinous tension band: a novel treatment method for patients

with lumbar spinal stenosis and degenerative spondylolisthesis

J N Alastair Gibson, MD, FRCS, Bart Depreitere, MD, PhD, Robert Pflugmacher, MD,

Klaus J. Schnake, MD, Louis C. Fielding, MS, Todd F. Alamin, MD, Jan Goffin, MD,

PhD

PII: S1529-9430(15)00004-2

DOI: 10.1016/j.spinee.2015.01.003

Reference: SPINEE 56153

To appear in: The Spine Journal

Received Date: 3 October 2014

Revised Date: 29 December 2014

Accepted Date: 2 January 2015

Please cite this article as: Gibson JNA, Depreitere B, Pflugmacher R, Schnake KJ, Fielding LC, Alamin

TF, Goffin J, Decompression and paraspinous tension band: a novel treatment method for patients with

lumbar spinal stenosis and degenerative spondylolisthesis The Spine Journal (2015) doi: 10 1016/
http://dx.doi.org/10.1016/j.spinee.2015.01.003


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Decompression and paraspinous tension band for degenerative spondylolisthesis

1

2

3

4

J N Alastair Gibson, MD, FRCS5

Spinal Unit, Royal Infirmary of Edinburgh and the University of Edinburgh6

Edinburgh, Scotland7

8

Bart Depreitere, MD, PhD9

Department of Neurosciences, Universitaire Ziekenhuizen KU Leuven10

Leuven, Belgium11

12

Robert Pflugmacher, MD13

Klinik und Poliklinik fr Orthopdie und Unfallchirurgie, Universittsklinikum Bonn14

Bonn, Germany15


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ABSTRACT1

BACKGROUND CONTEXT: Prior studies have demonstrated superiority of2

decompression and fusion over decompression alone for treatment of lumbar degenerative3

spondylolisthesis with spinal stenosis. More recent studies have investigated whether non-4

fusion stabilization could provide the durable clinical improvement after decompression and5

fusion.6

PURPOSE: To examine the clinical safety and effectiveness of decompression and7

implantation of a novel flexion restricting paraspinous tension band (PTB) for patients with8

degenerative spondylolisthesis.9

STUDY DESIGN/SETTING: Prospective Clinical Study10

PATIENT SAMPLE: Forty-one patients (7 men and 34 women) aged 45-83 years (68.29.0)11

were recruited with symptomatic spinal stenosis and Meyerding grade 1 or 2 degenerative12

spondylolisthesis at L3/4 (8) or L4/5 (33).13

OUTCOME MEASURES: Self-reported measures included visual-analog scales (VAS) for14

leg, back and hip pain as well as the Oswestry disability index (ODI). Physiologic measures15


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segmental flexion-extension range of motion or translation and no loss of lordosis in the1

patients with the PTB at 2 years follow-up.2

CONCLUSIONS: Patients with degenerative spondylolisthesis and spinal stenosis treated3

with decompression and a PTB demonstrated no progressive instability at 2 years of follow-4

up. Excellent/good outcomes and significant improvements in patient-reported pain and5

disability scores were still observed at 2 years with no evidence of implant failure or6

migration. Further study of this treatment method is warranted to validate these findings.7

8


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INTRODUCTION1

Decompression alone was the standard surgical treatment for lumbar degenerative2

spondylolisthesis with spinal stenosis [1,2] until several landmark articles suggested that3

decompression and fusion was a superior mode of treatment [3-5]. While there has been4

recent pressure to reduce rates of spinal fusion, payers and medical societies consistently5

recommend that fusion be determined medically necessary for lumbar degenerative6

spondylolisthesis with spinal stenosis [6-8], and it remains the dominant procedure for this7

indication in the US shown by a 95% fusion rate in the SPORT study [9]. However, fusion8

is clearly an imperfect treatment due to the short-term morbidity involved in adding a fusion9

to the decompression, as well as the longer term associated risk of adjacent-level10

degeneration and instability [10,11]. To circumvent these problems dynamic stabilization11

systems were introduced [12,13], but the majority are pedicle screw based and associated12

with many of the same problems as instrumented fusion, notably complex implant loading13

[14-18] and facet joint violation during screw placement [19-21]. For this reason simpler14

constructs have been suggested, such as that by Lee et alwho reported a series of 65 patients15

with degenerative spondylolisthesis treated with decompression and posterior tension band16


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demonstrated restoration of the kinematics of a destabilized spinal segment to that of an1

intact segment, with increased flexion stiffness and reduced sagittal translation [26]. The2

device does not bear any axial loads, and therefore the forces transmitted by the PTB to the3

spinal elements are an order of magnitude less compared to pedicle screw-based systems.4

The PTB was designed to be easily implanted after a standard lumbar decompression with5

minimal additional exposure.6

7

We aimed to prospectively assess clinical and radiographic outcomes of patients treated with8

surgical decompression and stabilization with the LimiFlex PTB device over a two year9

follow-up period. We questioned whether these patients would become progressively more10

unstable from a radiographic standpoint over this length of follow-up, and whether their11

clinical improvement in back and leg pain would deteriorate. This study was intended to12

provide initial data to demonstrate the clinical feasibility of this treatment method.13

14

MATERIALS AND METHODS15


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Surgical Intervention1

Decompression2

All patients received a direct surgical decompression of up to three levels from L1-S1 to3

address their spinal stenosis, preserving at least 50% of the spinous processes. All4

decompressions were performed using an operating microscope, undercutting the facet joints5

and decompressing the foraminae as necessary. The structural integrity of the pars6

interarticularis was preserved and resection of the articular surface of the facet joints7

minimized. In some cases the midline supraspinous/ interspinous ligamentous complex was8

preserved and in other cases not according to the preference of the treating surgeon.9

Decompression characteristics are summarized in Table 2.10

Paraspinous Tension Band Implantation11

Following their decompression, all patients were implanted with a PTB at the level of the12

degenerative spondylolisthesis. The PTB comprises a pair of titanium coil springs secured13

to ultra-high molecular weight polyethylene (UHMWPE) straps (Fig. 1). The straps were14

passed around the cranial and caudal spinous processes piercing the interspinous ligament of15


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1

Intraoperative and postoperative complications were noted and compiled, and then attributed2

as either being related or unrelated to the device or the procedure by the study site3

investigator. All serious adverse events (SAEs) were adjudicated by an independent medical4

monitor who was a board certified orthopaedic spine surgeon.5

6

Radiological assessment7

Diagnostic axial imaging studies (CT or MRI) were obtained preoperatively to confirm8

spinal canal stenosis and to evaluate degenerative lumbar pathology. Flexion, extension,9

standing lateral, and anterior/posterior (AP) radiographs were obtained preoperatively, as10

well as at 3, 6, 12, and 24 months postoperatively (Figs. 2,3). Quantitative and qualitative11

radiographic analyses were performed by a radiographic core laboratory using Quantitative12

Motion Analysis (QMA, Medical Metrics, Houston, TX) [32]. Quantitative radiographic13

analysis included:14

Static measurements of disc angle, anterior slip, disc height, and total lumbar (L1-S1)15

angle in flexion, neutral and extension.16

Dynamic measurements of rotation and translation in flexion extension17


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spondylolisthesis [1,3]. These patients represent a relatively high-risk group, with a mean1

Charlson comorbidity index of 3.8 [33].2

3

Operative results including decompression characteristics are summarized in Table 2. All4

forty-one patients received decompressions and were successfully implanted with the PTB5

with a mean implantation time of 28 minutes (range: 10-58 minutes), which included initial6

learning curve procedures. Thirty-four patients with the PTB in situwere available for 24-7

month follow-up evaluation. One died from a traumatic head injury and one patient was lost8

to follow-up. The device was explanted prior to final follow-up in five patients as described9

further below.10

11

Clinical outcomes12

Clinical outcomes are presented for the group of patients with all follow-up data, as well as13

for the sub-group of patients with the PTB in situ at 24 months. Statistically significant14

improvements and clinically important effect sizes were seen for all pain and disability15

measurements. Disability according to ODI was reduced by an average of 25.4 points (59%16

compared to baseline) Maximum leg pain VAS was reduced by an average of 48 1mm17


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Quantitative analysis1

No change in vertebral angulation or olisthesis was noted on device implantation or seen in2

radiographic measurements at 3 months follow-up. Segmental stability and lordosis were3

maintained to 24 months (Table 5). There were no significant increases in anterior slip,4

dynamic sagittal translation, or flexion-extension range of motion (ROM). Three-level5

ROM of the index, supradjacent and subjacent levels was relatively low preoperatively,6

indicating low patient effort in flexion-extension, with a trend towards increased overall7

motion at 24 months follow-up, in comparison to the index level ROM which showed no8

significant change during follow-up. Exemplary images are shown in Figures 2 and 3. Six9

patients with 24-month follow-up and the PTB in situdid not have all radiographic films10

necessary for quantitative analysis.11

Qualitative analysis12

Throughout the follow-up period, at all time-points, there were no x-ray findings of device13

breakage, disassembly, migration or dislocation; bone-implant interface remodeling; or14

exuberant bone formation. There were no findings of resorption at the strap-spinous process15


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the level below her L4/5 treated segment with no evidence of progressive instability or1

recurrent stenosis at L4/5. She was fused from L4 to S1.2

3

Three days after surgery one patient presented with a symptomatic epidural hematoma4

leading to paraparesis. An emergency laminectomy was performed and the device removed.5

One patient developed a proximally migrated disc extrusion at the inferior adjacent segment6

nine months after surgery, and underwent discectomy. The device was removed to allow for7

easier access to the fragment. These complications represent an overall 12% reoperation8

rate.9

10

Explanted devices were sent to independent laboratories for examination (Exponent,11

Philadelphia, PA) and histopathology (Histion, LLC, Everett, WA). Examination of the12

removed implants found no device failures. Histopathology findings were that the implant13

was well integrated with fibrous tissue with no adverse tissue response.14

15

DISCUSSION16


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1

As this work represents a preliminary series from a small cohort without a control group, we2

have evaluated our results in context with published literature for general comparative3

purposes. The 118 minute average surgical time for decompression and PTB implantation4

compares favorably to the 210.5 minutes and 202.7 minutes reported for the randomized and5

non-randomized cohorts of surgical patients with degenerative spondylolisthesis (treated6

with fusion in 95% of cases) in the SPORT study [9]. The in-patient stay reported here at a7

median of 5 days also compares favorably with the 7 to 9.5 day stays reported for8

posterolateral fusion in Europe [34,35]. In the US, decompression and PTB implantation9

would likely be performed as a short-stay procedure (


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This is in contrast to inter-spinous process devices that provide indirect or mechanical neural1

decompression through distraction of the posterior elements. As described previously, the2

device was designed to provide segmental stabilization, thereby optimizing the residual facet3

joint biomechanics through maximizing effective engaged articular surface area, minimizing4

the risk of progressive translation and a poor clinical result. Perhaps of greater importance5

however is that surgical insult from PTB insertion is minimal, making the procedure6

particularly attractive for the elderly and frail who represent a significant proportion of the7

population with this indication [1,3].8

9

There are several limitations of this non-randomized study without a control group. While10

the patients with degenerative spondylolisthesis represented a broad range of instability, the11

number of patients (41) was low with relatively short follow-up (2 years), and the small12

sample size could create unintentional selection bias by the patient or institution. This work13

was sponsored by the manufacturer of the PTB, and institutional research support was14

provided to the centers involved. The authors have also noted that preoperative ROM and15

translation measured in flexion-extension were relatively low. There was however a small16

ROM and translation of adjacent segments and that with the limitations in methodology17


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reported in the literature for patients with this pathology treated with decompression and1

fusion. Our series represents the preliminary clinical feasibility of this treatment for this2

patient population, and further investigation is merited.3

4


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References1

1.

Macnab I. Spondylolisthesis with an intact neural arch; the so-called pseudo-spondylolisthesis. J Bone2

Joint Surg Br 1950;32-B:325-333.3

2. Fitzgerald JAW, Newman PH. Degenerative spondylolisthesis. J Bone Joint Surg Br 1976;58-B:184-4

192.5

3. Herkowitz HN, Kurz LT. Degenerative lumbar spondylolisthesis with spinal stenosis. A prospective6

study comparing decompression with decompression and intertransverse process arthrodesis. J Bone7

Joint Surg Am. 1991;73:802-808.8

4. Fischgrund JS, Mackay M, Herkowitz HN, et al. Volvo Award winner in clinical studies.9

Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study10

comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation.11

Spine 1997;22:2807-2812.12

5. Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical compared with nonoperative treatment for13

lumbar degenerative spondylolisthesis. Four year results in the Spine Patient Outcomes Research14

Trial (SPORT) randomized and observational cohorts. J Bone Joint Surg Am 2009;91:1295-1304.15

6. Blue Shield of California. Medical Policy. Spinal Fusion [Blue Shield of California Website]. March16

5, 2012. Available at:17

https://www.blueshieldca.com/provider/content_assets/documents/download/public/bscpolicy/Spinal_18

Fusion.pdf. Accessed August 5, 2014.19


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15.

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Executive Summary for Zimmer Spines Dynesys Spinal System. Background material provided to the2

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Impliant, Inc. Impliant Restarts Pivotal Clinical Trial for Patented TOPS Spine System. [PR4

Newswire, UBM plc. Website]. 2008. Available at http://www.prnewswire.com/news-5

releases/impliant-restarts-pivotal-clinical-trial-for-patented-topstm-spine-system-57294052.html.6

Accessed 18 January 2014.7

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U.S. Food and Drug Administration. Class 2 Recall CD Horizon Agile dynamic stabilization device8

[FDA Website]. 2008. Available at:9http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfres/res.cfm?id=68075. Accessed January 30,10

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18.

Sjovold SG, Zhu Q, Bowden A, et al. Biomechanical evaluation of the Total Facet Arthroplasty12

System (TFAS): loading as compared to a rigid posterior instrumentation system. Eur Spine J13

2012;21:1660-1673.14

19.

Kosmopoulos V1, Schizas C. Pedicle screw placement accuracy: a meta-analysis. Spine152007;32:E111-E120.16

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Babu R, Park JG, Mehta AI, et al. Comparison of superior-level facet joint violations during open and17

percutaneous pedicle screw placement. Neurosurgery 2012;71:962-970. doi:18

10.1227/NEU.0b013e31826a88c819

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Patel RD, Graziano GP, Vanderhave KL, et al. Facet violation with the placement of percutaneous20


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30.

Odom GL, Finney W, Woodhall B. Cervical disk lesions. J Am Med Assoc 1958;166:23-28.1

31.

Davis R, Auerbach JD, Bae H, Errico TJ. Can low-grade spondylolisthesis be effectively treated by2

either coflex interlaminar stabilization or laminectomy and posterior spinal fusion? Two-year clinical3

and radiographic results from the randomized, prospective, multicenter US investigational device4

exemption trial: clinical article. J Neurosurg Spine 2013;19:174-184. doi:5

10.3171/2013.4.SPINE126366

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Hipp JA, Wharton ND. Quantitative motion analysis (QMA) of motion-preserving and fusion7

technologies for the spine. In: Yue JJ, Bertagnoli R, McAfee PC, An HS, eds.Motion preservation8

surgery of the spine. Advanced techniques and controversies. Philadelphia, PA: Saunders9Elsevier2008:85-96.10

33.

Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic11

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1987;40:37383.13

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Fritzell P, Hgg O, Wessberg P, et al. 2001 Volvo Award Winner in Clinical Studies: Lumbar Fusion14

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Spine 2007;32:1135-1139.20


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Tables1

Table 1 Patient demographics2

Total patients enrolled (male:female) 41 (7:34)

Age, meanSD (range) 68.29.0 (45-83) years

Body Mass Index (BMI), meanSD (range) 28.64.5 (21-40)

Patients with previous spinal procedures, N (%) 3 (7.3%)

Smoking history, N (%): Current smokersFormer smokers 10 (24%)14 (34%)

Patients with relevant concurrent medical conditions, N (%)

Renal/urinary

Cardiovascular

Endocrine

Pulmonary

MusculoskeletalLiver / Gastrointestinal

Other

34 (82.9%)

5

24

10

6

214

20

Charlson comorbidity index, meanSD 3.81.4

3

Table 2 Operative results4


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Table 3 Summary of clinical outcomes (ODI and VAS)1

All patients, all available follow-up data

Baseline

(N=41)

24 months

(N=37)

P(b) Effect(c)

ODI (%) (a) 45.615.4(40.7, 50.4)

20.319.2(13.9, 26.7)


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Composite Clinical Success perDavis et al[Error! Reference

source not found.]

26/39, 66.7% (52%-81%) (d)

(a)

Binomial confidence interval, normal approximation method(b)Patients with PTB in situat 24 months follow-up(c)All patients, all available follow-up data(d)Subjects with evaluable composite clinical success

1

Table 5 Quantitative radiographic results2

Parameter Baseline

(N=38)

3 months

(N=34)

24 months

(N=28)

Pa

Index level ROM 2.9 2.9(1.9, 3.8)

2.6 2.5(1.8, 3.4)

2.8 2.7(1.8, 3.9)

0.66

Index level ROM, as %of three-level ROM(b)

28% 15%(23%, 33%)

24% 29%(13%, 34%)

25% 14%(20%, 30%)

0.39

Three-level ROM ) 10.5 8.9

(7.7, 13.4)

10.4 8.3

(7.7, 13.4)

12.1 8.0

(9.1, 15)

0.20

Anterior slip (mm) 4.7 2.9(3.8, 5.6)

4.8 3.3(3.7, 5.9)

4.7 3.9(3.2, 6.1)

0.36

Translation (mm) c) 0.9 0.9(0.6, 1.2)

0.6 0.6(0.4, 0.8)

0.8 0.7(0.5, 1.0)

0.84

Standing disc angle(lordosis > 0)

7.6 4.5(6.2, 9.1)

7.2 5.1(5.4, 8.9)

8.5 5.4(6.5, 10.5)

0.96


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Figure Legend1

Fig. 1Paraspinous tension band (LimiFlex Spinal Stabilization System, Simpirica Spine, Inc., San Carlos, CA,2

USA)3

4

Fig. 2Patient with L4-L5 Grade 1 degenerative spondylolisthesis and spinal stenosis with translational5

instability and 12.5 of degenerative lumbar scoliosis. Preoperative 4.9mm slip in standing radiographs is6

reduced in the supine MRI and fluid is present in the facet joints. At 24 months postoperatively there is 44%7reduction of translation and no progression of the spondylolisthesis. The landmarks used by the radiographic8

core laboratory are shown on the endplates of the index and adjacent segments.9

10

Fig. 3Patient with L3-L4 degenerative spondylolisthesis (7.2mm) and spinal stenosis as well as bulging11

intervertebral disc. At 24 months postoperatively there is a 39% reduction of dynamic translation and no12

progression of the spondylolisthesis.13

14

Fig. 4 Summary of clinical outcomes (mean and 95% confidence interval)15

16

Fig 5 Summary of clinical and radiographic results for subjects with >2mm translation at preoperative baseline17


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Acknowledgements:

Institutional research support was provided by Simpirica Spine, Inc. (San Carlos, CA, USA). None of the

institutional investigators hold a financial interest in the company or device. The authors would like to

acknowledge Christine Beadle, Dominike Bruyninckx, Sarah Winkelkotte, Rahel Bornemann, MD, and Tom R

Jansen, MD for their contributions to this work.


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Decompression and Paraspinous Tension Band