To measure the association between drainage use and postoperative complications (POCs) after posttraumatic ear reconstruction (PTER) with Dieffenbach's postauricular flap (DPF) in patients with antithrombotic therapy (ATT).

This was a retrospective double-cohort study of patients undergoing posttraumatic DRF with vs. without drainage in 4 maxillofacial units during a 7-year interval. The primary predictor variable was drainage use, and the main outcome was POCs (i.e., auricular haematoma and infection). Descriptive, bi- and multivariate statistics were computed with P ≤ 0.05 defined as statistically significant.

The sample was composed of 365 unilateral PTER patients (14% POCs, 15.6% ATT, 34.5% females) aged 58.1 ± 19.7 years (range, 18–101). Among subjects with ATT, drainage use significantly reduced POCs (OR, 0.5; 95% CI, 0.3 to 0.8; P = 0.009; absolute risk reduction [ASR], 34.04%; NNT, 3), especially when delayed surgery > 5 h after trauma was evident (forward stepwise logistic modelling: OR, 20.6; 95% CI, 2 to 215.9; P = 0.012). Drainage placement under DPF in ATT patients with smoking habit, concomitant diseases (e.g. diabetes mellitus), ear cartilage loss, or wound contamination almost halved POC rates (ASR, 34.5 ± 12.1%; range, 22.1% to 49%). Patient's age, gender, American Society of Anesthesiologists (ASA) class, alcohol misuse, ATT and antibiotic type, and international normalised ratio (INR) before surgery had no meaningful effect on POCs.

Drainage should be placed under DPF in patients with ATT, regardless of age, gender, ATT and antibiotic type, and preoperative INR.