Neurologic Complications of Lumbar Pedicle Subtraction Osteotomy

STUDY DESIGN: Clinical, radiographic, and outcomes assessment focusing on neurologic complications in patients undergoing pedicle subtraction osteotomy (PSO). Clinical data were collected prospectively. Radiographic analysis was performed retrospectively. OBJECTIVE: To evaluate intraoperative and postoperative neurologic deficits following lumbar PSOs in order to determine risk factors, treatment strategies, and patient outcome. SUMMARY OF BACKGROUND DATA: Although technically demanding, PSOs have been increasingly used to restore lumbar lordosis and correct sagittal deformity. Although some reports have commented on various complications of the procedure, to our knowledge, there have been no studies focusing on neurologic complications of the osteotomy. METHODS: An analysis of 108 consecutive patients with an average age of 54.8 +/- 14.0 years and treated with a lumbar PSO at 1 institution over a 10-year period (1995-2005) was performed. Medical records, radiographs, and neuromonitoring data were analyzed. Clinical outcome was assessed using the Oswestry Disability Index and the Scoliosis Research Society (SRS)-24 instruments. RESULTS: A total of 108 PSOs were performed. Following surgery, lumbar lordosis increased from -17.1 degrees +/- 19.3 degrees to -49.3 degrees +/- 14.7 degrees (P < 0.000), and sagittal balance improved from 131 +/- 73 mm to 23 +/- 48 mm (P < 0.000). Intraoperative and postoperative deficits (defined as motor loss of 2 grades or more or loss of bowel/bladder control) were seen in 12 patients (11.1%) and were permanent in 3 patients (2.8%). With time motor function improved by 1 grade in 2 patients and all 3 were able to ambulate. Intraoperative neuromonitoring did not detect the deficits. In 9 patients, additional surgical intervention consisted of central enlargement and further decompression. Deficits were thought to be due to a combination of subluxation, residual dorsal impingement, and dural buckling. CONCLUSION: Intraoperative or postoperative neurologic deficits are relatively common following a PSO; however, in a majority of cases, deficits are not likely to be permanent.