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

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.

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.

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.

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.