Objective: The purpose of this study was to determine the safety and efficacy and evaluate several radiographic parameters after implantation of coflex™ for the primary diagnosis of spinal stenosis (1 or 2 levels) in patients with neurogenic claudication and low back pain between the ages of 40 and 80 years old.

Methods: Retrospective data were gathered on 589 patients from 5 sites with 429 patients having contemporaneous clinical and radiographic follow-up. Clinical analysis was performed on 209 patients with spinal stenosis using VAS and objective examination measures to determine safety and efficacy of the coflex in relieving neurogenic claudication, radiculopathy and back pain. The median follow-up was 20 months (range 6 to 121 months) For the 209 patients, radiographic data was collected for evaluation of spinal segment motion (index and adjacent levels), implant position, migration and bony remodeling at the bone-implant interface. All device complications were recorded and independently reviewed by Medical Metrics, Inc. (Houston, TX) and an independent orthopaedic spinal surgeon (KP).

Results: Moderate to severe low back pain improved in 75% of patients, while leg pain improved in 88% of patients. Claudication improved in 91% of patients and improvement in walking distance occurred in 79% of the patients. These results were achieved at 1 year and did not deteriorate over the long-term. Patient satisfaction was 88%. Complete radiographs with excellent quality were available for 180 implanted coflex devices. Sagittal rotation and translation measurements were essentially the same for all diagnoses, follow-up time points and levels of implantation. No expulsions and only 1 migration (> 5 mm) was observed. Mild and moderate bone-implant interface remodeling was noted in 15.4 %. No broken or permanently deformed implants were noted.

Conclusions: coflex interspinous stabilization after microsurgical decompression for spinal stenosis demonstrates excellent short term and long term results for back pain, neurogenic claudication and patient satisfaction.