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Background: Early surgical distraction in patients with craniofacial microsomia suffering from obstructive sleep apnea or severe facial dsymorphism is a widely accepted management strategy. However, there remains significant debate regarding treatment of mild cases of unilateral craniofacial microsomia. This investigation looks at outcomes of patients with mild unilateral craniofacial microsomia undergoing early distraction osteogensis with long longitudinal term follow up to determine factors contributing to superior long term results.
Methods: A retrospective review of all patients undergoing distraction osteogenesis for unilateral craniofacial microsomia by a single surgeon between May 1989 and August 2010 was conducted. Patients with long term longitudinal follow up and Pruzansky I or IIa mandibles were included for analysis. Those with Pruzansky IIB or III mandibles and skeletal immaturity at the time of analysis were excluded. Patients were then divided into two cohorts; those with superior results based on clinical, cephalometric, and facial aesthtics outcomes and those with average results. Clinical variables explored included soft tissue deficiency, device vector, postoperative complications, need for secondary surgery, distraction apparatus utilzed, length of distraction, utilization of postoperative orthodonics, degree of over correction assessed by chin point deviation, oral commisure position, reversal of occlusal cant, gonial angle, total transverse distraction, and percentage of overcorrection. Cohorts were then compared using student’s t-test and Fisher’s exact test.
Results: Nineteen patients, eight females and eleven males, undergoing twenty-one distractions met inclusion criteria for analysis. Their average age at distraction was 69.8 months and average age at long-term follow up was 19.3 years. Six (31.6%) patients had Pruzansky I mandibles while thirteen (68.4%) had Pruzansky IIA . Twelve (63.2%) patients were evaluated to have superior outcomes based on the above outcomes measures, while seven (36.8%) had some degree of undercorrection. Comparing the two cohorts patients with superior outcomes were found to have undergone distraction at an earlier age 56.4 months versus 87.4months (p =0.056), a greater percentage of initial overcorrection 39% versus 4% (p =0.003) and be male patients 75% versus 28.4% (p=0.04). Soft tissue deficiency, pruzansky classification, length of distraction, postoperative orthodontic treatment, complications, and vector used during distraction were similar in both cohorts. The two patients requiring two distractions showed failed growth of the distracted mandible despite overcorrection and orthodonic therapy.
Conclusion: Early distraction of mild unilateral craniofacial microsomia with significantly greater initial overcorrection in male patients yields superior long-term outcomes.