Predictors of Operative Duration in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis: A Retrospective Cohort Study.

Abstract

Accurate prediction of operative duration is necessary for efficient operating room scheduling, minimizing cancellations, shortening waitlists, better risk stratification, and effective preoperative counseling. Prolonged operative duration is also associated with negative patient outcomes. Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) is typically a lengthy surgical procedure with variable operative duration. The purpose of this study is to identify patient-, procedure-, and surgeon-specific variables that influence the operative duration in PSF for AIS and determine its impact on early postoperative outcomes. Hospital records of 150 AIS patients who underwent PSF at a single center were retrospectively reviewed. Various patient-, procedure-, and surgeon-specific variables-deemed to be possibly affecting the operative duration-were analyzed. A multivariate regression model was used to identify independent predictors of operative duration. The association between operative duration and early postoperative outcome measures was determined. The final model obtained from the multivariate regression analysis included the following factors: experience of the chief surgeon (β = -0.36), Cobb angle of the major structural curve (β = 0.35), number of screws inserted (β = 0.28), coronal deformity angular ratio (β = 0.20), and apical vertebral rotation (β = -0.21 to 0.03). The model could explain 44% of the variability in the operative duration (R 2 = 0.44). The operative duration had a significant correlation with estimated blood loss, need for perioperative blood transfusion, and length of hospital stay. A set of variables that predict the variability in operative duration during PSF for AIS was identified, with the experience of the chief surgeon and the severity of the curve being the strongest predictors. The results of this study emphasize the need for each hospital and surgical team to identify predictors of operative duration in their setup in order to better anticipate prolonged operative duration.