No abstract

Patients with Treacher Collins syndrome have severe middle ear malformations that render operation difficult. We have evaluated 43 patients with Treacher Collins syndrome, on whom only 11 were operated. Computed tomography, the single most important study done preoperatively, routinely showed an underdeveloped temporal bone with islands of bone marrow and absent mastoid pneumatization. The middle ear space was often underdeveloped. Ossicular dysjunction was often noted in which the fused malleus/incus remnant was found 3 to 4 mm distant to the stapes. A common finding was severe dysplasia of the stapes-facial nerve complex that often made the middle ear malformation uncorrectable. Hearing results were much less predictable than in patients with isolated atresia/stenosis of the ear.

No abstract

Distraction osteogenesis of the mandible has found an application in the treatment of patients with a variety of different mandibular deformities. Compared with the relatively simple unidirectional distraction of long bones as described by Ilizarov, the three-dimensional distraction of the mandible is extremely complex. Whereas experience with orthognathic surgery clearly demonstrates that careful presurgical planning is necessary to achieve predictable outcomes, there are few reported methods for the planning of mandibular distraction. The authors have developed a method for planning distraction osteogenesis of the mandible that involves the use of three-dimensional modeling and animation to simulate distraction osteogenesis in virtual reality. The first step in the authors' treatment planning process is to obtain a three-dimensional computerized scan of the facial skeleton. From this scan, a three-dimensional wire-mesh model is built using animation software. With the same software, a virtual distractor is built and installed on the wire-mesh model. The osteotomies and the distraction process are then simulated. Finally, a recipe for sequencing the linear and angular changes of the distractor is calculated. The authors have used this planning process in seven patients (age range, 4 to 10 years): four with unilateral mandibular deformities and three with bilateral. The planning process has yielded predictable and reproducible results.