Postoperative complications are predicted by surgery duration in the unilateral deep inferior epigastric perforator (DIEP) flap reconstruction: a retrospective cohort study

Abstract Introduction Currently, one published study documented operative time (OT) as a predictor for postoperative outcomes in bilateral deep inferior epigastric perforator (DIEP) flap breast reconstructions. No literature has investigated this in unilateral DIEP flaps. We aimed to determine the relationship between unilateral OT, postoperative complications and length-of-stay (LOS). Methods Electronic hospital data of adult women that underwent elective immediate or delayed unilateral DIEP reconstruction at a tertiary centre in London, between 2021 to 2022, was retrospectively analysed. Patients were divided into four groups depending on OT quartiles to define a critical cut-off period. Data on extensive potential confounders was recorded and used in univariable and multivariable regression models. Further statistical analyses were performed where appropriate. Results The final cohort contained 66 patients. Through quartiles, the risk-adjusted cut-off OT was defined as 515 minutes. After risk-adjustment, operations >515 minutes had a significantly higher overall complication rate than ≤515 minutes (HR: 2.16, p=0.032, 95% CI: 1.067, 4.38). No significant difference in mean ranks of LOS (p=0.16) was noted above the cut-off period. In patients that developed at least one complication type, no significant difference was observed in the unadjusted return-to-theatre rate between the two groups (HR: 0.86, p=0.82, 95% CI: 0.23, 3.24). Conclusion We confirmed OT was an independent predictor for postoperative complications in the DIEP flap and demonstrated this in unilateral reconstructions. Larger multicentre prospective studies are required to ascertain the significance of the OT effects, and to deduce the minimum OT threshold below which detriment to patient outcomes arises.