Radiographic Risk Factors of Reoperation Following Minimally Invasive Decompression for Lumbar Canal Stenosis Associated With Degenerative Scoliosis and Spondylolisthesis

STUDY DESIGN Prospective cohort study. OBJECTIVE Microsurgical bilateral decompression via a unilateral approach (MBDU), a minimally invasive surgical (MIS) decompression method, has been performed for numerous degenerative lumbar diseases, including degenerative lumbar scoliosis (DLS) or degenerative spondylolisthesis (DS), at our institution. In this study, we evaluated the appropriateness of MBDU for DLS or DS patients. METHODS A total of 207 patients treated by MBDU were included (88 women and 119 men; mean age, 70 [40-86] years). Thirty-seven cases were diagnosed as DLS (group A), 51 as DS (group B), and 119 as lumbar canal stenosis (group C). Patient clinical status assessed by JOA score was evaluated preoperatively and 2 years postoperatively. We evaluated the prevalence of cases that required reoperation among the groups and the radiographic risk factors related to reoperation. RESULTS There was no significant difference in recovery ratios of JOA scores among the groups. Reoperation after MBDU was needed in 13 cases (6.3%); the revision rate did not significantly differ among the groups. Reoperation was associated with poor clinical status, low visual analog scale score for low back pain, and low SF-36 mental component summary score. Reoperation was significantly associated with preoperative scoliotic disc wedging with Cobb's angle ≥3° in L4-5 (odds ratio = 9.88) and lateral listhesis (odds ratio = 5.22 [total], 12.9 [L4-5]). CONCLUSIONS When we are careful to indicate decompression for patients with these risk factors related to reoperation, MIS decompression alone can successfully improve DLS patients with a Cobb's angle of ≤20° or DS patients.