The sagittal spinal profile type: a principal precondition for surgical decision making in patients with lumbar spinal stenosis.

OBJECTIVE Microsurgical decompression (MD) in patients with lumbar spinal stenosis (LSS) shows good clinical results. Nevertheless, 30%-40% of patients do not have a significant benefit after surgery-probably due to different anatomical preconditions. The sagittal profile types (SPTs 1-4) defined by Roussouly based on different spinopelvic parameters have been shown to influence spinal degeneration and surgical results. The aim of this study was to investigate the influence of the SPT on the clinical outcome in patients with LSS who were treated with MD. METHODS The authors retrospectively investigated 100 patients with LSS who received MD. The patients were subdivided into 4 groups depending on their SPT, which was determined from preoperative lateral spinal radiographs. The authors analyzed pre- and postoperative outcome scales, including the visual analog scale (VAS), walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, Odom's criteria, and the 36-Item Short Form Health Survey score. RESULTS Patients with SPT 1 showed a significantly worse clinical outcome concerning their postoperative back pain (VAS _{back-SPT 1} = 5.4 ± 2.8; VAS _{back-SPT 2} = 2.6 ± 1.9; VAS _{back-SPT 3} = 2.9 ± 2.6; VAS _{back-SPT 4} = 1.5 ± 2.5) and back pain-related disability. Only 43% were satisfied with their surgical results, compared with 70%-80% in the other groups. CONCLUSIONS A small pelvic incidence with reduced compensation mechanisms, a distinct lordosis in the lower lumbar spine with a high load on dorsal structures, and a long thoracolumbar kyphosis with a high axial load might lead to worse back pain after MD. Therefore, the indication for MD should be provided carefully, fusion can be considered, and other possible reasons for back pain should be thoroughly evaluated and treated.