Double-step transport distraction osteogenesis in the reconstruction of unilateral large mandibular defects after tumour resection using internal distraction devices.

One-step transport disc distraction osteogenesis (TDDO) is an effective method for the restoration of mandibular defects. This study aimed to investigate the feasibility of double-step TDDO in the reconstruction of unilateral mandibular segmental defects after tumour resection using internal distraction devices. Six patients with unilateral mandibular segmental defects were reconstructed successfully with this technique. In the double-step TDDO procedure, the mandibular body was lengthened first and then the mandibular ramus was restored. The distraction movement was set at a rate of 0.4mm twice per day. Dental rehabilitation followed distractor removal. The maximal amount of lengthening was 55 mm in the mandibular body and 42 mm in the mandibular ramus. The average amount of lengthening was 52 mm in the mandibular body and 34 mm in the mandibular ramus. The aesthetic and functional results were excellent in all patients. The implants were integrated successfully and dental restoration was satisfactory. In this study, double-step TDDO is a reliable method for reconstruction of mandibular defects after tumour resection, especially for large mandibular defects. This technique is an ideal method for dental rehabilitation, despite the long overall treatment time.