Internal Transport Distraction for Reconstructing Segmental Defects of the Mandible

Objective: Extensive mandibular reconstructions using internal distraction devices which we developed for transporting bone are shown.

Methods: The distraction device comprises a bridging reconstruction plate, brackets with miniplates, traction mechanisms, and traction wire. Activation of the traction mechanism pulls the wires connected to the bracket, which then slides and carries the transport disc along a rail. A stereolithographic mandibular model facilitates simulation of osteotomies, adapting and assembling of the distraction device, and transporting the bony disc. The cylinder sleeve of the traction mechanism is passed through the skin in the retrogonial area, and the entire device except for a part of the traction mechanism remains inside the body. Three (59-, 61- and 38-year-old) patients had segmental defects because of tumor removal. Segmental osteotomies were made to provide a 1.5-cm transport disc. The distraction device was fixed to the mandible as simulated. After a 7-day latency period, the device was activated at a rate of 0.5mm twice a day. Transport discs moved with the brackets sliding on the rails 44mm × 2 (bilaterally), 80mm and 51mm in the respective patients. At the end of distraction the traction mechanisms were removed, leaving only the other components during the consolidation period.

Results: Series of panoramic radiograms after the end of distraction showed a segment of regenerated bone with a longitudinal internal canal structure in the distracted zone. The regenerated bone was achieved with trifocal and bifocal distraction osteogenesis in the former one and the latter two patients, respectively.

Conclusion: The segmental defects of the mandible were reconstructed with the bone transport distraction osteogenesis using the internal devices. This method enables extensive mandibular reconstruction without vascularised free bone graft.