Impact of sagittal spinopelvic alignment on clinical outcomes and health-related quality of life after decompression surgery without fusion for lumbar spinal stenosis

OBJECTIVE Patients with lumbar spinal stenosis (LSS) tend to bend forward to relieve neurological symptoms. They therefore have a positive sagittal vertical axis (SVA). The importance of the SVA value is well known in the field of adult spinal deformity; however, little is known about its impact on LSS. The authors sought to investigate the impact of sagittal spinopelvic alignment on clinical outcome and health-related quality of life (HRQOL) after decompression surgery for LSS. METHODS The authors retrospectively reviewed 83 patients who underwent lumbar decompression without fusion between January 2014 and September 2015 with a minimum follow-up of 2 years. Standing whole-spine radiographs were examined preoperatively and at final follow-up. Based on the SVA, patients were allocated to a sagittal balance group (group B; SVA < 50 mm) or a sagittal imbalance group (group I; SVA ≥ 50 mm). The authors compared the groups using Japanese Orthopaedic Association (JOA), Zurich Claudication Questionnaire (ZCQ), Roland-Morris Disability Questionnaire (RMDQ), and the 8-item Short Form Health Survey (SF-8) scores. RESULTS Preoperative groups B (group pre-B) and I (group pre-I) included 58 and 25 patients, respectively. Preoperative sagittal malalignment had negative effects on the JOA score recovery rate, postoperative ZCQ physical function domain score, and numeric rating scale (NRS) score of postoperative low-back pain (LBP), but no significant effects were observed for RMDQ and SF-8 domain scores. Postoperatively, groups B (group post-B) and I (group post-I) included 60 and 23 patients, respectively. Group post-I had a significantly worse JOA score recovery rate, postoperative symptom severity domain score in the ZCQ, and NRS score for postoperative LBP. Similarly, the postoperative RMDQ score and the Physical Component Summary score of the SF-8 were significantly worse in group post-I. CONCLUSIONS Positive SVA had significantly negative effects on clinical outcome and HRQOL in LSS patients after lumbar decompression surgery.