Indications and Techniques for Spinal Instrumentation in Thoracic Disk Surgery

Study Design: Retrospective case series. Objective: To identify the indications, techniques, and outcomes for instrumented fusion during thoracic discectomy. Summary of Background Data: Thoracic discectomy may require extensive bone removal to avoid spinal cord manipulation, but the indications and techniques for instrumented fusion during thoracic discectomy remain poorly delineated. Methods: The authors identified 220 consecutive patients who underwent thoracic discectomy between 1992 and 2012. Clinical and radiographic variables were compared between patients who underwent instrumented fusion and patients without instrumentation, and among surgical approaches utilized for discectomy. Results: Patient age for the entire cohort averaged 49 +/- 13.01 years, and mean clinical follow-up was 45 months (range, 1-218 mo). Patients underwent 226 thoracic discectomy procedures, including 48 thoracotomy, 136 thoracoscopy, and 42 posterolateral approaches. Seventy-eight patients required instrumented fusion and, compared with patients without instrumentation, were more likely to present with myelopathy (P < 0.0001) and harbor giant (P = 0.0012), calcified (P = 0.019), or transdural (P = 0.0004) herniated disks. Surgery with instrumentation resulted in greater blood loss (P < 0.0001), longer hospital stay (P < 0.0001), and a higher complication rate (22% vs. 9.9%), yet patients in both cohorts had similar rates of symptom resolution postoperatively. Of the patients who underwent thoracic discectomy without instrumentation, 3 (2.1%) developed delayed deformity or instability and required subsequent surgery for fixation and fusion at an average 6.3 months postoperatively (range, 4-8 mo). Patients who underwent instrumented fusion exhibited no nonunions or delayed deformity. Conclusions: Thoracic discectomy without fixation is a reasonable clinical option in carefully selected patients, but instrumented fusion is safe and effective in other patients. Indications for fixation and fusion are thus proposed.