Short-term clinical outcomes in single-stage vs. two-stage corrective surgery after pedicle subtraction osteotomy for degenerative deformities in an elderly cohort.

Objective: Corrective spinal surgery involving pedicle subtraction osteotomy is a demanding procedure associated with a high risk of complications, particularly in elderly patients. Staged approaches have been proposed to reduce perioperative risk and patients' burden; nevertheless, evidence in this population is limited. Research question: This study compares single versus two-staged approaches in elderly patients, assessing short-term outcomes and complication severity. Methods: Fifty-one patients who underwent corrective spinal fusion with pedicle subtraction osteotomy between 2014 and 2023 were retrospectively analyzed. Clinical characteristics and complications were compared, with complications classified using the modified Clavien-Dindo-Sink classification. Results: The median age was 70 and 71 years in the single-stage group (1-SG, n = 30) vs. the two-stage group (2-SG, n = 21). Baseline characteristics and the number of instrumented segments (1-SG: 9.7 ± 4.2; 2-SG: 10.6 ± 3.4) were comparable. Cumulative operative time was significantly shorter in 1-SG (431 ± 131 min) compared with 2-SG (653 ± 142 min). However, perioperative parameters, including estimated blood loss, transfusion rate, hospital stay, and discharge modality, showed no significant differences. The incidence and severity of complications within 90 days were also comparable across both groups. Conclusions: This study demonstrates no beneficial effect of staged surgery for corrective spine surgery in elderly patients. The findings suggest that overall surgical invasiveness, rather than timing strategy, is more critical when prolonged operating times and high blood loss are expected.