Objective: 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≥50mm 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

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... ssed. 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.