Predictors and Implications of Bony Union of Osseous Free Flaps for Oromandibular Reconstruction.

[BACKGROUND] Optimal contouring of osseous free flaps for mandibulectomy often requires osteotomies. The impact of malunion or nonunion on hardware extrusion is not well-documented. This study assesses postoperative bony union, its correlation with plate extrusion, and related demographic and surgical predictors.

[METHODS] A retrospective study of 127 patients who underwent segmental mandibulectomy and osseous free tissue transfer from 2004 to 2019. Bony union was assessed via computed tomography (CT) scans at 6-9, 9-15, and 15-24 months using a callus scale. Logistic regression analyzed the relationship between bony union, hardware extrusion, and various factors.

[RESULTS] Radiographic nonunion rates at 6-9, 9-15, and 15-24 months were 24.8%, 20.4%, and 13.2%, respectively. Nonunion at 9-15 months (OR = 3.67) and 15-24 months (OR = 1.80) significantly increased hardware extrusion risk. Lower bony union was linked to prior radiation, alcohol use, perioperative complications, and thinner plates.

[CONCLUSIONS] Bone union after oromandibular free-flap reconstruction is affected by radiation, perioperative complications, and smoking. Fibular and scapular transfers had similar outcomes. Further long-term studies are needed to enhance reconstruction techniques.