Does 360° lumbar spinal fusion improve long-term clinical outcomes after failure of conservative treatment in patients with functionally disabling single-level degenerative lumbar disc disease? Results of 5-year follow-up in 75 postoperative patients.

Background: Surgical treatment of patients with mechanical degenerative disc disease has been controversial, but improvements in clinical outcomes have been shown in properly selected patients with disease-specific diagnoses, with fusion arguably now becoming the "gold standard" for surgical management of these patients. No published study thus far has been designed for prospective enrollment of patients with specific inclusion/exclusion criteria in whom at least 6 months of conservative therapy has failed and who are then offered a standardized surgical procedure and are followed up for 5 years.

Methods: The study group was composed of the patients in the prospective, randomized Food and Drug Administration Investigational Device Exemption trial comparing ProDisc-L (Synthes Spine, West Chester, Pennsylvania) with 360° fusion for the treatment of single-level symptomatic disc degeneration. Of 80 patients randomized to 360° fusion after failure of non-operative care, 75 were treated on protocol with single-level fusions. Follow-up of this treatment cohort was 97% at 2 years and 75% at 5 years and serves as the basis for this report. Patients in the trial were required to have failure of at least 6 months of nonoperative care and in fact had failure of an average of 9 months of nonoperative treatment. The mean Oswestry Disability Index score indicated greater than 60% impairment. The mean entry-level pain score on a visual analog scale was greater than 8 of 10.

Results: After fusion, not only did patients have significant improvements in measurable clinical outcomes such as the Oswestry Disability Index score and pain score on a visual analog scale but there were also substantial improvements in their functional status and quality of life. Specifically, over 80% of patients in this study had improvements in recreational status that was maintained 5 years after index surgery, indicating substantial improvements in life quality that were not afforded by months of conservative care. The percentage of patients using narcotics at the 5-year follow-up visit was less than half the percentage of patients who had used narcotics as part of their prior conservative treatment.

Conclusions: The 5-year results of this post hoc analysis of 75 patients involved in a multicenter, multi-surgeon trial support 360° fusion surgery as a predictable and lasting treatment option to improve pain and function in properly selected patients with mechanical degenerative disc disease. These improvements occurred dramatically immediately after surgery and have been maintained through the scope of this follow-up period, with 98% follow-up at 2 years and 75% of patients available at 5 years.