Treatment of Midface Hypoplasia using Distraction Device in Apert's Syndrome

ABSTRACT

The current surgical treatment of midface hypoplasia, often associated with exorbitism and malocclusion, is to perform multiple osteotomies, fill the defects with autogenous bone grafts and apply rigid fixation with miniplates and screws. The complications of such procedures are considerable and include donor site morbidity, bone graft infection, resorption of the bone graft, and a skeletal relapse with the development of a malocclusion. Distraction osteogenesis, a technique initially used and described in the correction of lower limb deficiencies and discrepancies, has been recently adapted, at first in animal models and later in the human, to the craniofacial skeleton and has gained popularity as the devices became more sophisticated and the techniques more refined. We experienced a 12-month-old child with Apert's syndrome who had bilateral coronal suture synostosis, severe midface hypoplasia involving the orbits, zygoma, maxilla and associated syndactyly. He underwent a fronto-orbital surgical advancement combined with midface distraction procedure. Bilateral frontal bone flap and supraorbital bar was made and fixed in advanced position. After that, bone lengthening device was applied bilaterally. The anterior segment is attached to the posterior surface of the zygomatic body, and the posterior segment connected to the temporal bone. Distraction began on the 10th day after operation at the rate of 0.5 mm per day and continued for 21 days and then 1.0 mm/day for 8 days. After 13 months of follow-up period, we could find the protruded midface and loss of exorbitism. The lateral cephalogram shows that SNA angle improved from 69 to 80.9 after the operation. The postoperative X-ray and three dimensional CT demonstrate the improved relationship between the midface, mandible, and cranium. Based on our clinical findings, we believe that midface advancement without osteotomies can be achieved in infant patients with syndromic craniosynostosis and midface hypoplasia.