The effect of radiation in distraction osteogenesis for reconstruction of mandibular segmental defects.

Distraction osteogenesis is useful in the reconstruction of mandibular segmental defects. The effects of radiotherapy on distracted bone after resection of squamous cell carcinoma of the oral cavity are still unknown. We report the outcome in six patients who had distraction osteogenesis after postoperative radiotherapy. Distraction was by a unidirectional semi-buried device and panoramic radiographs were taken monthly during the distraction and consolidation periods to monitor the progress of the distraction. Follow-up ranged from 15 to 45 months (mean 33). The dose of radiation ranged from 60 to 70Gy. In one patient the bone was completely exposed and all the screws were loosened. There was no calcification and the gap remained radiolucent in the panoramic radiographs. The other five patients had excellent or good quality of bone. We conclude that radiotherapy may not interfere substantially with distraction osteogenesis although larger series the necessary.

Mandibular odontogenic myxoma. Reconstructive considerations by means of the vascularized fibular free flap.

The odontogenic myxoma is a rare entity located in mandible and upper maxilla. Due to its local aggressiveness, wide surgical excision is mandatory. Several surgical techniques have been described for the reconstruction of segmental mandibular defects. In comparison with other free flaps, the vascularized free fibular flap (VFFF) supports the longest amount of bone and, due to the nature of the vascular supply a complete freedom in location of the osteotomy is present. A precise mandibular arc can be performed following bone resection. We suggest the performance of the in situ VFFF technique in order to recreate mandibular contour by means of several osteotomies, while the pedicle is still attached to the leg. Substantial decrease in surgical time is obtained. With the double-barrel technique and subsequent osseointegrated implants, good results are obtained in the reconstruction of dentate patients without maxillary atrophy. We present two new cases of large odontogenic mandibular myxoma. Wide surgical excision by means of hemimandibulectomies and subsequent reconstruction with VFFF were performed.

Internal distraction osteogenesis in mandibular reconstruction: clinical experience in 10 cases.

BACKGROUND: Distraction osteogenesis has been used for reconstruction of bone and soft-tissue defects. The authors present their clinical experience in the reconstruction of mandibular segmental defects by means of internal distraction osteogenesis. METHODS: Ten patients with mandibular defects ranging from 30 to 80 mm in length were treated in the authors' department. Internal distraction devices with transcutaneous activators were placed immediately after complete resection of the affected bone. Distraction was initiated 10 days after surgery at a rate of 0.5 mm/day. The consolidation period ranged from 12 to 22 weeks. Finally, the distractor device was removed. In two patients, an additional iliac crest bone graft was needed to complete bone union. RESULTS: Follow-up ranged from 4 to 47 months after surgery. Partial cutaneous and intraoral exposure was observed in two patients. At the end of the follow-up period, successful distraction osteogenesis was achieved in eight patients. Six patients were alive and free of disease, whereas two patients showed local relapse and required new resective surgery. Complete intraoral exposure with failure of the distraction process was observed in one patient, whereas another patient did not complete distraction because of metastatic disease diagnosed 4 months after surgery. CONCLUSIONS: Good clinical results for reconstruction of mandibular and soft-tissue postablative defects are reported with the use of this technique. The use of semiburied devices provides better aesthetics and acceptable quality of life to the patients. Larger series are required to popularize the use of this procedure.

Modified Le Fort I osteotomy with preservation of the anterior nasal spine position: preliminary report.

We present a modification of the traditional Le Fort I osteotomy by means of which the anterior nasal spine is left intact. The osteotomies advance from the posterior-lateral side of the maxillary bone through the tuberosity to the inferior-lateral wall of the piriform opening. Two other vertical osteotomies from the lateral side of the piriform opening are placed in a 90 degree fashion to connect with another horizontal osteotomy that runs 5 mm below the floor of the nasal cavity and the anterior nasal spine. In a series of 50 patients with Le Fort I osteotomies, we have performed this new technique in 5 patients. We have observed better esthetic results in terms of nasal tip position and a more predictable value for the nasolabial angle. We believe that this technique is more appropriate for larger advancements in which a large gap may occur at the end of the movement.

Internal distraction osteogenesis with a unidirectional device for reconstruction of mandibular segmental defects.

PURPOSE: To present the authors' clinical experience with unidirectional internal distraction devices to reconstruct mandibular defects. PATIENTS AND METHODS: Five patients have been treated with mandibular distraction osteogenesis to reconstruct different acquired segmental defects. These mandibular defects (35 to 80 mm in length) were reconstructed by means of internal distraction devices with a transcutaneous activator. All the patients underwent complete resection of the affected bone and immediate placement of the distraction device on the remaining mandible. RESULTS: The results' analysis was based on clinical observation, postoperative radiographs, histopathologic findings and 3-dimensional computed tomographic scans. Successful distraction osteogenesis was achieved in 3 cases. In 1 case, extensive intraoral exposure of the device was observed, resulting in a failure of the procedure. One patient died of distant metastases 4 months after the resective surgery. CONCLUSION: Because of the limited number of cases, this study is preliminary. However, considering the good experimental and clinical results, this new technique offers an alternative for patients with segmental mandibular defects in which, because of local or general reasons, a more aggressive procedure should be avoided.

Experimental mandibular regeneration by distraction osteogenesis with submerged devices: preliminary results of a canine model.

The authors describe a new technique for reconstruction of mandibular body defects. The feasibility of distraction osteogenesis with submerged (internal) devices for reconstruction of segmental mandibular defects is investigated in an experiment with five adult dogs. A segmental mandibulectomy was performed on the horizontal ramus. The bony defect was regenerated using distraction osteogenesis (bone transport) at a rate of 1 mm daily. The animals were killed after the consolidation period. Complete bone regeneration of the surgically created gap was successful in three of five dogs. Two animals failed to create new bone. In these two cases, the screws did not offer proper stability to the bony fragments, and this caused a lack of ossification. This experimental study demonstrates the possibility to use internal distraction devices to reconstruct segmental mandibular defects in a canine model. Internal devices show enormous advantages in comparison with the external ones. This method with no donor-site morbidity may become a very useful option in human mandibular reconstruction.