Distraction osteogenesis of the ascending ramus for mandibular hypoplasia using extraoral or intraoral devices: A report of 8 cases

Abstract

The primary surgical objective in the treatment of hemifacial microsomia is to establish functional and asthetic facial anatomy that remains stable long-term. Mandibular ramus deficiency is the most conspicuous skeletal feature of this disorder. To early oral and maxillofacial surgeons, lengthening the deficient skeletal unit was the obvious solution, and lengthening osteotomies and grafts were used to replace the deficient skeletal portion. Despite predictable results using these techniques for orthognathic and trauma-related disorders, the results were often disappointing when applied to craniofacial deformities, particularly those involving lengthening the mandibular ramus. Relapse, continued abnormal growth, and temporomandibular joint degeneration are among factors that produced undesirable results. Important insight into the role of the deficient functional matrix associated with hemifacial microsomia was described by Harvold, 1 Harvold EP The theoretical basis for the treatment of hemifacial microsomia. in: Treatment of Hemifacial Microsomia. Liss, New York, NY1983 Google Scholar who incorporated functional appliance therapy before and after skeletal surgery. Combining functional appliance therapy with skeletal surgery improved treatment outcomes, but patients typically remained with variable expressions of the basic phenotype. Although treatment approaches to hemifacial microsomia vary, achieving stable skeletal lengthening remains a primary challenge in all of the current techniques, including distraction osteogenesis.