Dual Midfacial Distraction Osteogenesis for Crouzon Syndrome: Long-Term Follow-Up Study for Relapse and Growth

Abstract

Rigid external distraction osteogenesis is regarded as a standard treatment for congenital midfacial hypoplasia. However, external distraction for the upper portion of the midface is not as effective and tends to rotate the midfacial segment in a counterclockwise direction. Moreover, patients poorly tolerate it because of the device's bulkiness. To prevent such drawbacks of an external distractor, both external and internal distractors were synchronously applied to patients with Crouzon syndrome. In 6 patients with Crouzon syndrome in whom a dual-distraction technique was applied, distraction of the midfacial region was performed for up to a mean length of 15.3 mm. The external distractor was removed after a 1-month consolidation period, but the internal distractor was maintained for more than 6 months. The degree of advancement of the midface and ossification was measured with lateral cephalometry and 3-dimensional computed tomography imaging, respectively. At long-term follow-up (mean, 4.6 years), the facial contours retained the initial distraction geometry with almost no relapse, showing that the ideal facial contour and occlusion could be obtained. Bone deposition was found to be continually progressing even 6 months postoperatively, and more than 6 months of consolidation was required for complete ossification that mainly occurred in the pterygomaxillary junction and lateral orbital wall. The dual-distraction technique can induce balanced growth without the recurrence of hypoplasia, and it may eventually yield satisfactory outcomes in Crouzon syndrome.