Bilateral Mandibular Distraction Osteogenesis to Correct Post-ankylotic Deformity

Objectives: To formulate a proper protocol for correction of post-ankylotic deformity by distraction osteogenesis of the mandible. Methods: 41 cases (22 females and 19 males). The age ranged from 2 to 40 years, (23 asymmetrical and 18 symmetrical deformities), staged distraction was attempted in asymmetrical deformities till midline shift was corrected. This was followed by bilateral distraction till proper forward position of the mandible was established. In the first 10 cases the distractor was left for 2 months till consolidation was complete. Rigid internal fixation was applied in the last day of distraction simultaneously with the removal of the distractor devices. Release of ankylosis was performed 6 months post-distraction except in the first two cases. Fiber-optic endoscopy for intubation was performed in all cases. Results: In the mandible the amount of bone gained was up to 30 mm. Respiratory compromise occurred in the first two cases when release of ankylosis preceded distraction. Follow-up showed variable degrees of relapse in the first 10 cases. In the remaining cases with rigid fixation, no relapse was seen. Conclusion: In the mandible, distraction should precede the release of ankylosis to avoid respiratory embarrassment. Staged distraction is recommended in asymmetrical mandibular deformity. Rigid fixation is effective in preventing relapse. Fiber-optic endoscopy is a must to ensure safe and proper intubation of these patients.