Pulmonary embolism after radial forearm free flap reconstruction for oral squamous cell carcinoma: a multicenter retrospective cohort study.

Pulmonary embolism (PE) is a potentially life-threatening complication after head and neck reconstructive surgery. Whether PE risk differs according to center-specific perioperative management remains unclear. In this retrospective multicenter cohort study, consecutive adults undergoing oral squamous cell carcinoma (OSCC) resection with immediate radial forearm free flap (RFFF) reconstruction between 2016 and 2023 were analyzed across two centers, with differing donor-site management and perioperative anticoagulation protocols. The primary outcome was PE during the index hospitalization. Multivariable Firth-penalized logistic regression was used to assess the association between treatment center and PE while adjusting for demographic, oncologic, and vascular risk factors. The cohort comprised 187 patients. PE occurred in 16/86 patients (18.6%) at the primary center and in 2/101 patients (2.0%) at the secondary center. In multivariable analysis, treatment at the primary center (OR 4.63; 95% CI 1.19-25.64; p = 0.025) and longer operative time (OR 1.55; 95% CI 1.13-2.20; p = 0.007) were independently associated with PE, whereas age, sex, BMI, tumor stage, nodal status, and vascular risk factors were not. Although the limited number of PE events - particularly at the secondary center - and the resulting wide confidence intervals necessitate cautious interpretation, the findings suggest that differences in perioperative management warrant consideration as a potential contributing factor, and merit prospective evaluation.