Beyond operative duration: unexpected operative-time deviation and discharge pathway divergence after laparoscopic cholecystectomy

Laparoscopic cholecystectomy is commonly performed within standardized recovery pathways, yet postoperative progression may differ even after technically successful, complication-free surgery. We examined whether decomposing operative time into a preoperatively expected component and residual deviation could identify operative-course variation associated with deviation from the expected discharge pathway. This retrospective cohort study included 316 consecutive adults undergoing elective laparoscopic cholecystectomy performed by a single experienced surgeon between 2023 and 2025. Expected operative time was estimated from preoperative characteristics using repeated 5-fold cross-fitting, and unexpected operative deviation was defined as actual minus expected operative time. The primary outcome was prolonged length of stay (LOS ≥ 4 days), representing deviation from the institutional discharge pathway. Associations were evaluated using multivariable logistic regression, restricted cubic splines, robustness analyses, prespecified sensitivity analyses, and full two-stage bootstrap resampling. Prolonged LOS occurred in 76 patients (24.1%). Unexpected operative deviation was associated with prolonged LOS (OR 1.38 per 15-minute increase, 95% CI 1.12–1.70; P = 0.002), with a two-stage bootstrap 95% CI of 1.12–1.83. In a secondary exploratory analysis, patients in the sample-derived upper quartile of deviation had an adjusted risk of prolonged LOS of 37.9% versus 19.3%, an absolute difference of 18.5% points. Restricted cubic spline analysis showed an overall association ( P = 0.018) without evidence of nonlinearity ( P = 0.775). The association persisted in the complication-free cohort and when LOS was modeled continuously. Complication-free surgery does not necessarily imply complexity-free surgery. By distinguishing preoperatively expected duration from residual deviation, this framework extends the interpretation of operative time beyond elapsed duration alone and provides a structured way to examine operative-course variation not reflected in conventional complication measures. Unexpected operative deviation may therefore provide additional context for postoperative pathway divergence despite technically successful surgery.