Primary versus revision surgery in the setting of adult spinal deformity: A nationwide study on 10,912 patients

Study Design. Retrospective review of a prospectively collected database. Objective. This study compares patient demographics, incidence of comorbidities, procedure-related complications, and mortality following primary versus revision adult spinal deformity surgery Summary of Background Data. Although adult spinal deformity (ASD) surgery has been extensively investigated, no previous study has provided nationwide estimates of patient characteristics and procedure-related complications for primary versus revision spinal deformity surgery comparatively. Methods. Nationwide Inpatient Sample data collected between 2001 and 2010 was analyzed. Discharges with procedural codes for anterior and/or posterior thoracic and/or lumbar spinal fusion and refusion were included for patients aged 25+ and 4+ levels fused with any diagnoses specific for scoliosis. Patient demographics, comorbidity, and procedure-related complications incidence were determined for primary versus revision cohorts. Multivariate analysis reported as (OR [95% CI]). Results. Discharges for 9133 primary and 850 revision cases were identified. Patients differed on the basis of demographic and hospital data. Average comorbidity indices for the cohorts were similar (P=0.580), as was in-hospital mortality (P=0.163). The incidence of procedure-related complications was higher for the revision cohort (46.96 % vs. 71.97%, P=0.001). The mean hospital course for the revision cohort was longer (6.37 vs. 7.13 days, P<0.0001). Revisions had an increased risk of complications involving the nervous system (1.34[1.10-1.6]), hematoma/seroma formation (2.31[1.92-2.78]), accidental vessel or nerve puncture (1.44[1.29 - 1.61]), wound dehiscence (2.18[1.48-3.21]), postop infection (3.10[2.50-3.85]), and ARDS complications (1.43[1.28-1.60]). The primary cohort had a decreased risk for GI (0.65[0.55-0.76]) and GU complications (0.71[0.51-0.99]). Conclusion. Relative to primary cases, those undergoing revision correction of spinal deformity have a higher risk of many procedure-related complications with a longer hospital course despite similar baseline comorbidity burden and the in-hospital mortality rate. This study provides clinically useful data for surgeons to educate patients at risk for morbidity and mortality and direct future research to improve outcomes.