Microsurgical Reconstruction for Severe Dento-Alveolar Deficiency in the Mandible and Maxilla

Introduction: Dentoalveolar deficiency may arise from trauma, serious periodontal infections, genetic anomalies such as ectodermal dysplasia or craniofacial clefts, or following excision for tumors. Severe alveolar deficiency over a large part of the mandibular or maxillary alveolar ridge makes rehabilitation of these patients with dental implants impossible, as there is not enough bone height to hold the implants. When a small part of the alveolar ridge is deficient, conventional augmentation methods like sinus lift and non-vascularized bone grafting are often successful. However, when the entire length of the alveolar ridge is deficient these methods invariably fail. The authors have reconstructed such patients using the microvascular fibula transfer to augment the alveolar bone height. Subsequently these patients were rehabilitated by placement of dental implants and implant-mounted prostheses.

Methodology and Material: 12 patients with severe dento-alveolar deficiency due to various causes were reconstructed using the microvascular fibula transfer to augment the alveolar bone height. Subsequently these patients were rehabilitated by placement of dental implants and implant-mounted prostheses. In 3 patients, both maxilla and mandible were augmented, using two separate fibular transfers. The rest had only maxillary augmentation using a single fibula.

The fibula was osteotomized into 3 segments, which were placed over the alveolar region in a curve, and fixed using plates and screws or in some cases only steel wires. A skin island was used in two patients. In the remaining patients, the fibular surface was left open in the oral cavity, and was seen to epithelialize over there to four weeks. The pedicle was brought into the neck and anastomosed with the facial vessels. Six months after all oral wounds had healed and the fibula was covered with healthy mucosa, osseointegrated implants were placed in the fibula, and a dental prosthesis fitted.

Results: Placement of the fibula in the oral cavity, its fixation, and subsequent post-operative monitoring were technically challenging and demanding. There were two failures, necessitating removal of the entire graft. In one patient, with ectodermal dysplasia, the fibular surface, which was left exposed in the oral cavity, failed to epithelialize for over 3 months, and finally had to be skin grafted. In the remaining patients, the fibula was soon covered with healthy mucosa, and the oral cavity healed uneventfully. Placement of osseointegrated implants and rehabilitation with a dental prosthesis was uneventful in patients without dysplasia. Patients with ectodermal dysplasia are extremely difficult to rehabilitate. The fibular surface did not epithelialize, and there was progressive resorption of the fibula in one patient, making subsequent placement of implants not possible.

Donor site healing in the patients with ectodermal dysplasia was a problem as well. Donor sites of skin graft took 6 - 8 weeks to heal.

Conclusions: Dentoalveolar deficiency is a difficult problem to treat. Various modalities are available for treatment, and vascularized bone grafting is reserved only for the most severe cases. Caution must be exercised in patients with ectodermal dysplasia. Wound healing is deficient, and any areas left raw in the oral cavity do not heal at all. Hence, the transferred fibula needs to be covered with mucosa completely, and if this is not possible, as is invariably the case, a small skin island is taken along with the fibula. The donor site in the leg too needs to be treated with care, as skin grafts do not take well, and split skin graft donor sites do not heal. Alternative, less extensive methods such as the use of cultured osteoblasts combined with cancellous bone grafting may be tried. In future, tissue engineering methods using cultured stem cells, osteoblasts, or chemo-modulators may provide simpler answers for a very difficult problem.