General Session: Thoraco-Lumbar Degenerative

Presented by: R. Simon - View Audio/Video Presentation (Members Only)

Author(s):

R. Simon(1), S. Grinberg(1), C. Dowe(1), F. Cammisa(2), C. Abjornson(2)

(1) Hospital for Special Surgery, Integrated Spine Research Program, New York, NY, United States
(2) Hospital for Special Surgery, New York, NY, United States

Abstract

Background: To alleviate the symptoms of lumbar spinal stenosis, widely utilized surgical procedures include decompression alone and decompression with fusion but have reported mixed clinical results. As an alternative, microsurgical decompression with interlaminar stabilization (ILS) devices has been shown to be clinically viable. Many publications have reported the efficacy of ILS devices in single level procedures but fewer studies focus on their efficacy in two level procedures.

Purpose: The purpose of this study was to compare microsurgical decompression with instrumented posterolateral fusion to microsurgical decompression and interlaminar stabilization, using coflex® (Paradigm Spine, NY, NY), in patients who require surgical treatment at two levels for lumbar spinal stenosis.

Study Design/Setting: This patient cohort was part of the Investigational Device Exemption (IDE) study which enrolled a total of 322 patients from 21 sites in the United States between 2006 and 2010. It is a prospective, randomized, controlled trial conducted of patients diagnosed with spinal stenosis with up to a Grade 1 spondylolisthesis.

Patient Sample: Of the 322 patients enrolled in this study, 116 patients required surgical treatment at 2-levels. Patients were randomized to treatment groups in a 2:1 ratio. The ILS (coflex®) group consisted of 77 patients and the fusion group consisted of 39 patients.

Outcome Measures: Efficacy was measured using a Composite Clinical Success (CCS). Patients achieve CCS if they achieve all four of the following

Outcomes: ≥ 15 point improvement from baseline Oswestry Disability Index (ODI), no reoperation or epidural injections, no persistent, new, or increasing neurological deficits, and no major device-related complications.

Methods: Data was collected pre-operation, and then at 6 weeks, 3, 6, 12, 18, 24, 36, 48, and 60 months post-operatively. The results of the four assessments were combined to calculate the percentage of patients achieving CCS.

Results: There was a statistically significant difference between groups for the absence of reoperation or epidural injection with 68.8% of ILS patients and only 48.7% of fusion patients meeting this criteria (p=0.044). The number of patients who did not undergo reoperation in the ILS group was 68/77 (88.3%) and the number in the fusion group was 30/39 (76.9%) (p>0.17). The number of patients who did not receive an epidural injection was 60/77 (77.9%) in the ILS group and 25/39 (64.1%) in the fusion group (p>0.12). This influenced the total percentage of patients achieving CCS to be much greater in the ILS group than the fusion group, with 55.1% (38/69) of ILS patients and only 35.3% (12/34) of fusion patients achieving CCS at month 60 (p=0.064). With regards to ODI, there was no significant difference between treatments (p = 1.000). There was also no significant difference between groups for the absence of persistent, new, or increasing neurological deficits (p=1.000).

Conclusions: Although a relatively small sample size, there was a statistically significant difference in the rates of reoperation and epidural injections, and a difference trending toward significance in total CCS, the results of this study indicate interlaminar stabilization using coflex® is more effective than fusion in patients requiring two levels of surgical treatment for spinal stenosis.