Reconstruction of mandibular defects following tumor ablation by vertical distraction osteogenesis using intraosseous distraction devices.

Objectives: Distraction osteogenesis has recently evolved a challenging technique to overcome major drawbacks of conventional augmentation procedures. We, therefore, report the application of miniaturized intraosseous distraction devices for the rehabilitation of mandibular defects due to ablative tumor surgery.

Methods: In 10 patients who had undergone box-shaped or segmental resections, augmentation of the residual mandibular bone or of full thickness iliac crest grafts was performed by intraosseous implant-shaped distractors. Distraction and reconsolidation was monitored by ultrasonography. Implants were inserted within 1 week after active distraction. Median follow-up after implant insertion was 38 months.

Results: On average, a vertical gain of 7.3 mm was obtained by distraction. Except for one case (local infection), all distraction zones showed complete ossification by radiologic and ultrasonographic evaluation. Overall 28 implants were placed in the distracted bone. Two implants were lost at 2.4 and 22 months after placement. The estimated 4-year implant survival rate in this population was 90%. For the endpoint 'bone loss' (>1.5 mm in the first and >1 mm in following years), the estimated 4-year success rate was 59% with four out of seven events occurring in a single patient (patient No. 1 of this series).

Conclusion: Vertical distraction by means of implant distractors could be performed with reasonable success in tumor patients with box-shaped resection defects or undercontoured bone grafts. Overall morbidity was very low. Even though blood supply is continuously maintained in distraction osteogenesis, bone resorption remains a critical issue for this reconstruction technique too.