Can Preoperative Pelvic and Shoulder Balance Predict Post-Operative Ambulation and Hospital Outcomes after Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis?

Introduction: The aim of this study was to determine the associations between preoperative pelvic and shoulder imbalances and time to postoperative ambulation and length of hospital stay (LOS) following PSF for AIS.

Methods: The medical records of 128 adolescent patients diagnosed with AIS undergoing PSF at a major academic institution from 2013–2020 were retrospectively reviewed. Patients were stratified by preoperative pelvic and shoulder balance measurements (Left, Neutral, Right). Patient demographics, deformity characteristics, comorbidities, operative variables, physical therapy (PT) data, adverse events, and postoperative outcomes were assessed. Multivariate logistic regression analyses were performed to identify significant predictors of delayed postoperative ambulation and extended LOS.

Results: Of the 128 study patients, 37 (28.9%) had Left pelvic balance, 36 (28.1%) had Neutral pelvic balance, and 55 (43.0%) had Right pelvic balance. Of the 127 patients with preoperative shoulder balance data, 33 (26.0%) had Left shoulder balance, 27 (21.3%) had Neutral shoulder balance, and 67 (52.8%) had Right shoulder balance. Hospital outcomes were similar across pelvic and shoulder balance cohorts, including mean LOS, discharge disposition, and unplanned 30-day readmissions. On multivariate analysis, variables significantly associated with delayed ambulation included a primary curve ≥70˚ [aOR: 5.67, CI (1.29 ‒ 31.97), p=0.030] and increased procedure time [aOR: 1.66, CI (1.1 ‒ 2.59), p=0.019], while intraoperative neuromonitoring changes were significantly associated with reduced odds of delayed ambulation [aOR: 0.06, CI (0 ‒ 0.64), p=0.046]. Variables significantly associated with extended LOS included increased time to oral pain medications [aOR: 7.1, CI (2.2 ‒ 30.2), p=0.003] and severe pain prior to initial postoperative PT session [aOR: 4.3, CI (1.2 ‒ 18.8), p=0.038], while history of anemia was significantly associated with reduced odds of extended LOS [aOR: 0.2, CI (0.02 ‒ 0.6), p=0.013]. Preoperative shoulder height or pelvic balance differences were not significantly associated with delayed ambulation or extended LOS on multivariate analyses.

Conclusion : Our study found that preoperative pelvic and shoulder imbalances may not significantly impact hospital outcomes following PSF for AIS.