#412 Two-level Coflex® Interlaminar Stabilization Compared to Two-2-level Lumbar Spinal Fusion for the Treatment of Spinal Stenosis with Low-grade Spondylolisthesis

General Session: Lumbar Therapies Motion Preservation

Presented by: J. Auerbach


J.D. Auerbach (1)
S. Leary (2)
F. Kuwamura (3)
J. Field (4)

(1) Bronx-Lebanon Hospital Center, Department of Orthopaedic Surgery, Bronx, NY, USA
(2) Alvarado Hospital Medical Center, San Diego, CA, USA
(3) South Texas Spine Clinic, San Antonio, TX, USA
(4) Desert Institute for Spine Care, Phoenix, AZ, USA


Introduction: Coflex® interlaminar stabilization following decompression for spinal stenosis and low-grade spondylolisthesis at 1-2 levels has recently been shown to be equally or more effective than spinal fusion, with notable improvements in hospital stay, operative times, blood loss, and by affording radiographic protection of the adjacent levels. In the current study, we report the two-year clinical and radiographic results from the US FDA IDE trial focusing only on the cohort of patients with 2-level disease.

Materials and Methods: This was a multicenter, randomized, prospective FDA IDE trial comparing 1- and 2-level patients with spinal stenosis (with low back pain), and up to a stable Grade 1 degenerative spondylolisthesis who had failed at least 6 months of conservative treatment, including at least 1 epidural steroid injection. Patients were randomized 2:1 to receive either decompression with coflex® interlaminar stabilization or decompression and posterolateral spinal fusion. Patients did not receive interbody grafts or bone morphogenetic protein as adjuncts to fusion. Clinical Composite Success (CCS) at 2 years, as determined by the FDA, required a patient to meet the following criteria: 1) at least 15 point improvement in ODI, 2) no reoperations, revisions, or device removals, 3) no neurologic complications, 4) no epidural injections post-operatively. A total of 77 coflex® and 39 fusion patients were enrolled with 2-level disease.

Results: The follow-up rate at 2 years was 96% for coflex® (74/77) and 100% (39/39) for fusion subjects. Using the stringent criteria above, Clinical Composite Success was achieved by 70.3% (52/74) of coflex® and 56.4% (22/39) of fusions (p=0.151) at 2 years. On average, coflex® subjects had shorter operative times by 62 minutes (p< 0.001), less blood loss by 316cc (p< 0.001), and shorter hospital stay by 1.8 days (p< 0.001) compared to fusions. Coflex® subjects experienced an improvement in ODI of 39.7 points, compared to 33.4 for fusions (p=0.72). Similarly, both groups improved significantly from baseline with respect to ZCQ outcomes, with coflex® subjects experiencing significantly greater improvement than fusions in Satisfaction (p=0.009) and a trend towards greater improvement in Physical Function (p=0.056). VAS Back outcomes revealed similar significant improvements from baseline in both groups, with a higher proportion of coflex® patients experiencing VAS Leg (worse) improvement at 24 months (p=0.036). Radiographic analysis at 2 years revealed significantly elevated angulation at the superior adjacent level (p=0.008) and significantly elevated translation at the inferior adjacent level in the fusion cohort (p=0.019) at 2 years compared to coflex®.

Conclusions: This is the first Level 1 study to report exclusively on two-level stenosis with spondylolisthesis treated with either a motion-preserving stabilization device (coflex®) or posterior spinal fusion. Our data suggests that two-level interlaminar stabilization is not only a viable alternative to 2-level fusion, but provides substantial improvements in perioperative outcomes and equal or superior clinical outcomes sustained at 2 years, while fusions exhibited hypermobility at both the superior and inferior adjacent levels.