Introduction: Distraction osteogenesis is becoming the treatment of choice for the patients with craniosynostosis in Japan. We have treated 14 cases of craniosynostosis with this technique since 2000, and evaluated for further refinement of the technique. Materials and Method: Twelve cases of craniosynostosis treated with the technique of distraction osteogenesis were evaluated in terms of age at surgery, latency and consolidation periods, rate and frequency of distraction, device stability, complications and pre and postoperative changes in the cranial volume, which was calculated using ZedView® software from their CT data. Twelve cases consisted of 6 brachycephaly, 6 Apert syndromes, one scaphocephaly and one plagiocephaly. The mean follow-up period was 3.2 years. They were planned for surgical intervention for intracranial decompression, reshaping of the skull and four out of fourteen underwent LeFort Ⅳdistraction for improving airway problems and severe exophthalmos. Results: Cranial bone distraction (group 1) was performed in ten of twelve cases and craniofacial distraction (LeFort Ⅳ type distraction, group 2) was undergone in the rest of the four. The age at surgery ranged from 1 year and 5 months to 12 years (mean 4 years 6 months). Latency period before starting distraction was 4.7 days (mean) and rate and frequency of distraction were 1 mm/ day, once a day in both groups. The age at surgery ranged from one year and 5 months to 6 years (mean 2.7 years) in group 1, and from one year and four months to 12 years (mean 6.3 years) in group 2. The length of distraction ranged from 13.5 to 30.0 mm (mean 20mm) in group 1 and from 12 to 28 mm (mean 24mm) in group 2. Devices were remove as soon as an ideal length was obtained and bony bridges were confirmed with the CT images between the distracted gaps were formed. No infection was observed throughout the course of treatment. Both groups achieved exact length of distraction as planned, however, one case of group 2 showed iatrogenic deformity at maxillo-zygomatic junction as a result of the distraction forces applied to the zygoma pushing it forward and thus leaving the middle part of the face posterior. Even though, upper airway was expanded and sleep apnea was significantly improved after surgery. Displacement of the device was found in one case of brachycephaly, who underwent reattachment of the device to the skull. Device bent was found in 2 cases as the devices fixed to the skull with screws were not strong enough to conduct distraction force to the bone. Cranial volume increase was measured to be 35.4 ml to 110.0 ml. Conclusion: Although it required a longer treatment period and second operation for the removal of devices, distraction was apparently safer and more effective than conventional cranioplasty as it only required craniotomy and occasionally with craniectomy. It allows not only for surgeons but parents to determine the final shape of the cranium or craniofacial appearance. If distraction is performed under 2 years of age, cranial bone is flexible enough not only to be advanced by distractor but bent creating a smooth curvature of the cranium. Up to date, all cases showed no retrusion of the distracted segment.
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