Effects of delayed ambulation following posterior spinal fusion for adolescent idiopathic scoliosis: a single institutional study

Abstract

Objective: Mobilizing out of bed and ambulation are key components of recovery following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). However, there remains a paucity of studies identifying risk factors associated with delayed ambulation and its impact on postoperative outcomes. The aim of this study was to investigate patient- and surgical-level risk factors associated with delayed ambulation and the ramifications of delayed ambulation on healthcare utilization for patients undergoing PSF for AIS.

Methods: The medical records of 129 adolescent (10-18 years) patients diagnosed with AIS undergoing posterior spinal fusion at a major academic institution between 2013 and 2020 were reviewed. Patients were categorized based on days from surgery to ambulation: early (≤ 1 day), intermediate (2 days), or late (≥ 3 days). Patient demographics, comorbidities, spinal deformity characteristics, intraoperative variables, postoperative complications, LOS, and unplanned readmissions were assessed. The odds ratios for risk-adjusted delayed ambulation and extended LOS were determined via multivariate stepwise logistic regressions.

Results: One Hundred and Twenty Nine patients were included in this study, of which 10.8% (n = 14) were classified as Early ambulators, 41.9% (n = 54) Intermediate ambulators, and 47.3% (n = 61) were Late ambulators. Late ambulators were significantly younger than early and intermediate ambulators (Early: 15.7 ± 1.9 years vs. Intermediate: 14.8 ± 1.7 years vs. Late: 14.1 ± 1.9 years, p = 0.010). The primary and secondary spinal curves were significantly worse among Late ambulators (p < 0.001 and p = 0.002 respectively). Fusion levels (p < 0.01), EBL (p = 0.014), and the rate of RBC transfusions (p < 0.001) increased as time to ambulation increased. Transition time from IV to oral pain medications (Early: 1.6 ± 0.8 days vs. Intermediate: 2.2 ± 0.6 days vs. Late: 2.4 ± 0.6 days, p < 0.001) and total hospital length of stay (Early: 3.9 ± 1.4 days vs. Intermediate: 4.7 ± 0.9 days vs. Late: 5.1 ± 1.2 days, p < 0.001) were longer in Late ambulators. On multivariate analysis, significant predictors of delayed ambulation included primary curve degree ≥ 70° [aOR: 5.67 (1.29‒31.97), p = 0.030] and procedure time [aOR: 1.66 (1.1‒2.59), p = 0.019].

Conclusions: Our study suggests that there may be patient- and surgical-level factors that are independently associated with late ambulation following PSF for AIS, including extent of major curve and length of operative time. Additionally, delayed ambulation has implications to length of hospital stay and postoperative complications.

Keywords: AIS; Complications; Delayed ambulation; LOS; Outcomes; PSF.