Perioperative Factors Associated With Unplanned Re-exploration Following Free Flap Reconstruction for Oral and Maxillofacial Malignancies: A Retrospective Case-Control Study

Background: Free flap reconstruction is the standard approach for restoring complex defects following oral and maxillofacial malignancy resection. However, unplanned re-exploration due to postoperative flap vascular compromise remains a major challenge and may adversely affect reconstructive outcomes. This study aimed to evaluate perioperative factors associated with unplanned re-exploration after free flap reconstruction. Methods: A retrospective case-control study was conducted among patients who underwent oral and maxillofacial malignancy resection followed by free flap reconstruction. The study included 139 patients who underwent unplanned re-exploration for postoperative flap vascular compromise as cases and 285 randomly selected patients without unplanned re-exploration from the same eligible study population as controls. Demographic characteristics, treatment history, perioperative hemodynamic variables, laboratory findings, and surgical variables were collected. Variables showing significant associations in univariate logistic regression analyses were further evaluated using covariate-adjusted multivariable logistic regression models. Exploratory subgroup analyses were performed to assess the consistency of these associations. Results: In univariate analyses, prior radiotherapy (OR = 2.29, P = 0.001), preoperative diastolic blood pressure (DBP) (OR = 1.33 per 10-mmHg increase, P = 0.006), preoperative mean arterial pressure (MAP) (OR = 1.27 per 10-mmHg increase, P = 0.014), postoperative DBP (OR = 1.46 per 10-mmHg increase, P = 0.004), postoperative MAP (OR = 1.35 per 10-mmHg increase, P = 0.019), and the number of previous surgical procedures (OR = 1.26 per additional procedure, P = 0.018) were associated with unplanned re-exploration.