Critical Analysis of Radiographic and Patient Reported Outcomes Following Anterior/Posterior Staged vs. Same Day Surgery in Patients Undergoing Identical Corrective Surgery for Adult Spinal Deformity

Study-Design. Retrospective cohort study of a prospectively collected multi-center adult spinal deformity (ASD) database. Objective. To compare staged procedures to same-day interventions and identify the optimal time interval between staged surgeries for treatment of ASD. Background. Surgical intervention for ASD is invasive and complex procedure that surgeons often elect to perform on different days (staging). Yet, there remains a paucity of literature on the timing and effects of the interval between stages. Methods. ASD patients with two-year (2Y) data undergoing an anterior/posterior (A/P) fusion to the ilium were included. Propensity score matching (PSM) was performed for number of levels fused, number of interbody devices, surgical approaches, number of osteotomies/three-column osteotomy (3CO), frailty, Oswestry Disability Index (ODI), Charlson Comorbidity Index (CCI), revisions, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), and UIV to create balanced cohorts of Same-Day and Staged surgical patients. Staged patients were stratified by intervening time-period between surgeries, using quartiles. Results. 176 PSM patients were included. Median interval between A/P staged procedures was 3 days. Staged patients had greater operative time and lower ICU stays postop ( P <0.05). At 2Y, staged compared to same day showed a greater improvement in T1 slope – cervical lordosis (TS-CL), C2 sacral slope (C2SS), and SRS-Schwab SVA ( P <0.05). Staged patients had higher rates of minimal clinically-important difference (MCID) for 1Y SRS-Appearance and 2Y physical component summary (PCS) scores. Assessing different intervals of staging, patients at the 75 th percentile interval showed greater improvement in 1Y SRS Pain and Total postop as well as SRS Activity, Pain, Satisfaction, and Total scores ( P <0.05) compared to patients in lower quartiles. Compared to the 25th percentile, patients reaching the 50th percentile interval were associated with increased odds of improvement in Global Alignment and Proportion (GAP) score proportionality (9.3[1.6-53.2], P =0.01). Conclusions. This investigation is among the first to compare multicenter staged and same day surgery anterior/posterior adult spinal deformity patients fused to ilium using propensity-matching. Staged procedures resulted in significant improvement radiographically, reduced ICU admissions, and superior patient reported outcomes compared to same day procedures. An interval of at least three days between staged procedures is associated with superior outcomes in terms of GAP score proportionality.