Iliac crest grafting for mandibular reconstruction.

Mandibular reconstruction poses significant challenges to oral and maxillofacial surgeons. The mandible is a complex three-dimensional structure with great functional and aesthetic importance. Precise anatomic restoration allows maintenance of skeletal and dental relationships and preserves aesthetics and physiologic function. The goals of mandibular reconstruction are to establish bone continuity with adequate anteroposterior and transverse relationships to the maxilla and provide a functional oromandibular complex preserving speech, mastication, and deglutition. Two major types of mandibular defect require reconstruction: marginal and segmental. Marginal defects typically involve the alveolar portion of the bone with an intact inferior or posterior mandibular border, which maintains mandibular continuity, whereas segmental defects are defined by the presence of mandibular discontinuity. When marginal defects are reconstructed, the ultimate goal is to restore the morphology of the alveolar process of the mandible to facilitate placement of osseointegrated dental implants or provide an anatomic foundation for a dental prosthesis. The purpose of reconstruction for segmental defects is to provide mandibular continuity and dentoalveolar reconstruction. Small segmental lateral defects may be well tolerated without reconstruction. When reconstruction is undertaken in a normal host, defects smaller than 5 cm typically can be restored with nonvascularized bone grafting. Defects larger than 5 cm or defects in an irradiated host are typically well suited for microvascular reconstruction. The application of rigid skeletal fixation without bone reconstruction is also appropriate in selected lateral defects in compromised patients with significant comorbidities or a guarded prognosis. Anterior mandibular segmental defects are not well tolerated and often cause significant loss of support for the tongue musculature (glossoptosis), which leads to potential airway compromise if not reconstructed. Several types of bone grafting are available for mandibular reconstruction, including nonvascular autologous, allogenic and xenogenic bone, and vascularized free tissue transfer. Considering nonvascularized grafting options, autologous bone grafting has the ability to transfer osteocompetent cells to the recipient site (transfer osteogenesis) for osteoid formation. Alloplastic, xenogeneic, and alloplastic bone substrates are incapable of transferring osteocompetent cells and rely on the osteoinductive bone formation from the residual osteocompetent cells at the recipient site (periosteum) for new bone formation. It is critically important when considering the application of nonvascularized mandibular bone grafting that meticulous surgical technique is used in preparing the recipient site and during bone graft harvesting. The aim is to transfer as many osteocompetent cells to the recipient site as possible. Although grafts may be stored in isotonic saline, it is the author’s preference to limit this and transfer the normothermic bone graft directly from the donor to recipient site. This approach requires complete preparation of the donor site before bone graft harvest. It is also important to note that to improve bone graft survival, oral contamination should be avoided; most nonvascularized mandibular bone grafting should be performed transcervically. In situations in which inadvertent perforation of the oral mucosa has occurred,