Mandibular distraction in hemifacial microsomia is not a permanent treatment: a long-term evaluation

Hemifacial microsomia presents with abnormalities including short ramus, absence of condyle, abnormal canting, deviated chin, and facial asymmetry. Many studies about distraction osteogenesis have been published over the last 20 years, but without long-term follow-up. The aim of this study was to evaluate patients with unilateral craniofacial microsomia who were treated with mandible distraction and with follow-up of more than 5 years.

The following retrospective study was evaluated and approved by the Assistance Center for Cleft Lip and Palate. Data were compiled from the charts of 33 patients with hemifacial microsomia who underwent unilateral mandible distraction.

Average age at time of procedure was 7.3 years, with an average degree of distraction of 20 mm. Seventy percent of cases were treated with internal distraction, 30% external. Follow-up varied between 5 and 15 years, with a mean follow-up of 9 years. Ninety percent of the 33 patients in the study had recurrence of their asymmetry. Mean time to postsurgical recurrence was 44 months. Thirty patients were referred for orthognathic surgery. Six patients have already undergone corrective bimaxillary surgery. One patient underwent genioplasty only, and 1 patient underwent genioplasty with orthognathic jaw surgery. Twenty-two patients are awaiting orthognathic surgery, including one with temporomandibular joint ankylosis. Only 3 subjects had good outcomes, without signs of recurrence.

Bone distraction once seemed a promising long-term option for treatment of craniofacial microsomia. However, this has not proven effective for all cases, and most patients needed subsequent orthognathic surgery.