The ACS NSQIP Surgical Risk Calculator does not accurately predict risk of 30-day complications among patients undergoing microvascular head and neck reconstruction

Abstract Purpose The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) Surgical Risk Calculator (SRC) is a novel universal risk calculator designed to aid in risk stratification for patients undergoing various types of major surgery. The purpose of this study was to assess the validity of ACS NSQIP SRC in predicting postoperative complications among patients undergoing microvascular head and neck reconstruction. Materials and Methods A retrospective cohort study of patients undergoing head and neck microvascular reconstruction with fibular free flaps at a single institution was completed. The NSQIP Surgical Risk Calculator was utilized to compute complication risk estimates and length of stay (LOS) estimates for all patients under study. Associations between complication risk estimates generated by the SRC and the actual rates of observed complications were evaluated using logistic regression models. Logistic regression models were also used to evaluate the SRC estimates for LOS duration relative to the actual observed LOS following surgery. Results In 153 patients under study a total of 46 (30%) experienced a postoperative complication corresponding to those defined by NSQIP SRC. A total of 38 (25%) patients experienced a postoperative complication that is categorized as severe within the parameters of the NSQIP SRC. None of the SRC complication estimates were found to be statistically significantly associated with the corresponding observed rates of complications. The mean LOS predicted by the SRC was found to be 8.0 days (median 7.5; IQR 6.5-9; range 5.0-18.5). The mean observed LOS for the study group was 9.6 days (median 7.0; IQR 6-9; range 5-67). Lin’s concordance correlation coefficient to measure agreement between observed and predicted LOS was 0.10 indicating only slight agreement between the two values. Conclusion The ACS NSQIP Surgical Risk Calculator is not a useful risk stratifying metric among patients undergoing major head and neck reconstruction with microvascular fibular free flaps. The SRC also does not accurately predict length of hospital stay for this same patient cohort.