Biologic response to autogenous particulate bone graft and shaped titanium mesh in segmental mandibular defect reconstruction.

PURPOSE: This study evaluated the biologic response to titanium mesh and autogenous particulate bone grafts for the reconstruction of segmental mandibular defects in a dog model. MATERIALS AND METHODS: Unilateral 40-mm critical-sized continuity defects of the mandible were made in five beagle dogs. Titanium mesh was shaped and fixed with titanium screws in the defects. Autogenous bone was harvested from the ablated mandible and iliac crest (the ratio of cortical bone:cancellous bone was 3:1) and used to fill the mesh. Two implants were placed into each bone graft. The animals were sacrificed after 6 months. Radiographs, histologic sections, scanning electron microscopy, and energy dispersive spectroscopy were performed to evaluate bone formation and osseointegration of the implants in the reconstructed mandibles. RESULTS: The outline of the reconstructed mandible was satisfactory, and no bone resorption was observed in the defect area. All implants showed excellent osseointegration of the grafted bone. Furthermore, the density of bone formed around the implants was higher than that seen in control samples (intact, ungrafted dog hemimandibles). CONCLUSIONS: Shaped titanium mesh with autogenous particulate bone graft is a predictable method for restoring critical-sized continuity defects of the mandible. Simultaneous implant placement is feasible and the structure of bone formed near implants may be optimal.

Radial forearm free flap for reconstruction of a large defect after radical ablation of carcinoma of the tongue and floor of the mouth: some new modifications.

BACKGROUND: A modified radial forearm free flap was designed to rehabilitate function and to reduce the complications at both donor and recipient sites. METHODS: Between 2003 and 2007, 15 patients with infiltrating squamous cell carcinoma (T(3)-T(4)) of the tongue and/or floor of the mouth underwent hemiglossectomy and resection of the floor of the mouth with microvascular reconstruction using a modified radial forearm flap. The mean size of the forearm flap was 7.5 x 14 cm, and the de-epithelialized area was 7 x 6 cm, requiring no skin graft from the abdomen. Speech intelligibility tests were administered to test postoperative speech and the functional oral intake scale was applied to assess the postoperative swallowing function, and patients reconstructed with pectoralis major myocutaneous flap were used for comparison. RESULTS: All the flaps were successfully transferred. No obvious complications were found in either the oral-maxillofacial or forearm region. The speech intelligibility was better in the modified flap group (p < 0.01). An acceptable swallowing function was also achieved, although the difference was not significant (p > 0.05). CONCLUSIONS: The modified flap used for reconstructing large defects of the tongue and floor of the mouth might be a valid substitute for pectoralis major myocutaneous flap to improve the outcome in individuals with significant oral carcinoma.

[Experimental study of the shaped titanium mesh combined with autogenous particulate bone graft and simultaneous implant for reconstructing segmental mandibular defect].

OBJECTIVE: To observe the healing and bone formation of the autogenous particulate bone graft and osseointegration of the implants in shaped titanium mesh with autogenous particulate bone graft and simultaneous implant for reconstructing segmental mandibular defect in dogs. METHODS: Five Beagle dogs were prepared with unilateral 40 mm segmental mandibular defect. Titanium mesh was shaped according to the mandibular defect and was fixed with titanium screws. The ablated mandibular bone and iliac bone were crashed to approximately 2 mm particulates which then filled the titanium mesh tightly (cortical bone:cancellous bone, 3:1). Two implants were placed in the autogenous particulate bone graft. The dogs were sacrificed after six months. X-ray films, histological sections, Scanning electron microscopy(SEM) and Energy disperse analysis of the reconstructed mandibles were examined to evaluate the bone formation of the bone graft and osseointegration of the implants. RESULTS: The outline of the reconstructed mandible was satisfactory and its function was excellent. The ossific fusion among the particulate bone grafts was fine and no resorption was found. All implants showed excellent osseointegration with the bone graft. The bone near the implant was more compact than the bone away from it. The structure of the bone near implant was optimized because of simultaneous implant in shaped titanium mesh. CONCLUSIONS: The shaped titanium mesh with autogenous particulate bone graft is a good method for reconstructing segmental mandibular defect, and simultaneous implant is feasible in the reconstructed mandible in dogs.