Relationship Between Post‐Operative Complications and Length of Stay in Patients Requiring Free Flap Reconstruction of the Head and Neck

BACKGROUND: Reconstructive with free flap procedures are often required following ablative removal of pathologies from the head and neck. The Clavien-Dindo Classification (CDC) system is widely used to grade complication severity; however, there are limited studies examining the relationship between complications and length of stay (LOS) in this cohort. PURPOSE: To evaluate the association between complication severity and both hospital and intensive care unit (ICU) LOS in patients undergoing head and neck free flap reconstruction. METHODS: This retrospective cohort study included 994 patients treated between 2016 and 2024. Complications were graded using the CDC system. LOS was analysed using generalised linear models with a Gamma distribution and log-link. Kruskal-Wallis tests were used for supplementary analysis. RESULTS: Complications occurred in 54.5% of patients. Higher CDC grades were significantly associated with longer ICU (p < 0.001) and hospital LOS (p < 0.001). CDC Grades II, IIIb and IVa were independently associated with prolonged ICU LOS. All CDC grades were associated with increased hospital LOS. CONCLUSION: This study provides outcome data linking complication severity to ICU and hospital LOS. The CDC, while advantageous, fails to separate significant negative outcomes, such as free flap failure from a more simple return to theatre. Modifications may further improve distinction in complications and effect on overall hospital stay.