Predictors for the restoration of the sagittal spinal malalignment in patients with lumbar stenosis after short-segment decompression and fusion surgery

Abstract

Abstract Background To explore the predictors for the restoration of the sagittal spinal malalignment in the elderly patients with lumbar spinal stenosis (LSS) after short-segment decompression and fusion surgery. Methods We retrospectively reviewed 82 LSS patients with sagittal malalignment (SVA ≥ 50 mm or PT ≥ 20° or PI-LL ≥ 20°) who underwent short-segment decompression and fusion surgery between January 2019 and March 2021. Patients’ characteristic, radiographic and paravertebral muscle parameters were assessed. The patients were divided into group A (postoperative malalignment) and B (postoperative alignment) according to whether the postoperative restoration of the sagittal alignment was achieved. Results There existed more males in group B than in group A (p = 0.002). The age of group A (73.36 ± 8.02) was greater than that of group B (69.08 ± 6.07, p = 0.009). Preoperative PT in group A (27.40 ± 5.82) was greater than that in group B (19.30 ± 7.32, p < 0.001). The functional cross-sectional area (fCSA) in group A (28.73 ± 4.23) was lower than that in group B (36.94 ± 7.81, p < 0.001). And the fatty infiltration rate (FI) of group A (27.16% ± 5.58%) was higher than that of group B (22.61% ± 5.81%, p = 0.001). The fCSA was negatively correlated with the postoperative PT and PTr (p < 0.05). Conclusion Stronger lumbar paravertebral muscles, smaller preoperative PI, PT or PI-LL, male and younger age are the predictors for the restoration of the sagittal spinal malalignment in the elderly LSS patients after short-segment decompression and fusion surgery.