Straight-segment mandibulectomy: a reproducible porcine mandibular critical-size defect model

Abstract

Porcine mandibular defect models are commonly used for the preclinical evaluation of reconstruction techniques. Existing studies vary in technique, complexity, and postoperative outcomes. The procedures are complex and often described without sufficient detail. We describe in detail a simple and reproducible method for creating a critical-size mandibular defect in a porcine model. Seven hemimandibular critical size defects were created in five male Yorkshire-Landrace pigs, three with unilateral defects and two with bilateral defects. A transverse incision was made over the mandibular body. Periosteum was incised and elevated to expose the mandibular body and a critical-size defect of 30 × 20 mm created using an oscillating saw. The implant was inserted and fixed with a titanium reconstruction plate and bicortical locking screws, and the wound closed in layers with resorbable sutures. Intraoral contamination was avoided. Dentition was retained and the mental nerve and its branches preserved. The marginal mandibular nerve was not encountered during dissection. All pigs retained normal masticatory function, and there were no cases of infection, wound breakdown, haematoma, salivary leak, or implant-related complications. The procedure can be performed bilaterally on both hemimandibles without affecting load-bearing function. All pigs survived until the end point of three months. Postoperative computed tomographic scans and histology showed new bone formation, and a three-point bend test showed the restoration of biomechanical strength. Straight-segment mandibulectomy is a simple and reproducible method for the creation of critical-size mandibular defects in a porcine model, simulating a load-bearing situation.