Study Design. Prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial.
Objective. To evaluate the safety and efficacy of Coflex interlaminar stabilization compared with posterior spinal fusion in the treatment of 1- and 2-level spinal stenosis and degenerative spondylolisthesis.
Summary of Background Data. Long-term untoward sequelae of lumbar fusion for stenosis and degenerative spondylolisthesis have led to the search for motion-preserving, less-invasive alternatives.
Methods. Three hundred twenty-two patients (215 Coflex and 107 fusions) from 21 sites in the United States were enrolled between 2006 and 2010. Subjects were randomized to receive laminectomy and Coflex interlaminar stabilization or laminectomy and posterolateral spinal fusion with spinal instrumentation in a 2:1 ratio. Overall device success required a 15-point reduction in Oswestry Disability Index, no reoperations, no major device-related complications, and no postoperative epidural injections.
Results. Patient follow-up at minimum 2 years was 95.3% and 97.2% in the Coflex and fusion control groups, respectively. Patients taking Coflex experienced significantly shorter operative times (P < 0.0001), blood loss (P < 0.0001), and length of stay (P < 0.0001). There was a trend toward greater improvement in mean Oswestry Disability Index scores in the Coflex cohort (P = 0.075). Both groups demonstrated significant improvement from baseline in all visual analogue scale back and leg parameters. Patients taking Coflex experienced greater improvement in Short-Form 12 physical health outcomes (P = 0.050) and equivalent mental health outcomes. Coflex subjects experienced significant improvement in all Zurich Claudication Questionnaire outcomes measures compared with fusion (symptom severity [P = 0.023]; physical function [P = 0.008]; satisfaction [P = 0.006]). Based on the Food and Drug Administration composite for overall success, 66.2% of Coflex and 57.7% of fusions succeeded (P = 0.999), thus demonstrating noninferiority. The overall adverse event rate was similar between the groups, but Coflex had a higher reoperation rate (10.7% vs. 7.5%, P = 0.426). At 2 years, fusions exhibited increased angulation (P = 0.002) and a trend toward increased translation (P = 0.083) at the superior adjacent level, whereas Coflex maintained normal operative and adjacent level motion.
Conclusion. Coflex interlaminar stabilization is a safe and efficacious alternative, with certain advantages compared with lumbar spinal fusion in the treatment of spinal stenosis and low-grade spondylolisthesis.
Level of Evidence: 1
Compared with instrumented posterolateral spinal fusion, Coflex interlaminar stabilization led to superior perioperative outcomes, significant improvements in multiple clinical outcomes at 2 years, and maintenance of motion at operative and adjacent levels. Coflex interlaminar stabilization is a safe and efficacious alternative, and demonstrates advantages over lumbar spinal fusion with pedicle screw instrumentation.
*Greater Baltimore Neurosurgical Associates, Baltimore, MD
†Department of Orthopaedic Surgery, Hospital for Joint Diseases-NYU, New York, NY
‡The Spine Institute, Santa Monica, CA; and
§Department of Orthopaedics, Bronx-Lebanon Hospital Center, Albert Einstein College of Medicine, Bronx, NY.
Address correspondence and reprint requests to Joshua D. Auerbach, MD, 1650 Grand Concourse, Bronx-Lebanon Hospital Center, Department of Orthopaedics, 7th Flr, Bronx, NY 10457; E-mail: firstname.lastname@example.org
Acknowledgment date: October 15, 2012. First revision date: February 15, 2013. Second revision date: April 24, 2013. Acceptance date: April 29, 2013.
The device(s)/drug(s) that is/are the subject of this manuscript is/are Now FDA-approved and no longer under investigation.
Paradigm Spine, LLC (New York, NY) funds were received in support of this work.
Relevant financial activities outside the submitted work: consultancy, royalties, payment for lecture, payment for manuscript preparation, patents, payment for development of educational presentations.