Automatic Simulation Surgery Process of the 3D Computed Tomographic Data in the Unilateral Orbital Hypoplasia

Computer-assisted medical imaging has shown tremendous improvements in definition of in vivo anatomy of patients with craniofacial anomalies. In accordance with developments of simulation surgery, preoperative surgical simulation can now be performed more accurately and interactively within the environment of computer graphic workstation and can also provide the best solution for surgery by displaying the 3 dimensional simulation images. The interactive surgical simulation approach is based on digitally osteotomized objects which have been translocated manually by an operator who visually determines the amount of movement required until the desired end result is achieved. However, this approach depends upon subjective assessment and may not consistently provide optimal simulation in all directions due to manual movement of the osteotomized object by mouse or trackball. In addition, this procedure is time and labor intensive due to repetitive processing to obtain a satisfactory end result. This study demonstrates a method of surface matching of digitally osteotomized objects, by simulating the deformed orbit to the assumed ideal position of mirror image without manual manipulation of simulation objects. This process can move the osteotomized object to the preset end results-mirror image- automatically by computer module. The single processing of the osteotomized segment changes the position of simulated segments with certainty. This procedure allows more accurate and reliable result of simulation surgery. However, it will be valuable only when one can determine the ideal end results such as mirror image of this article as a normal template.

Effect of Injectable Calcium Sulfate on Early Bony Consolidation in Distraction Osteogenesis of Facial Bone

The purpose of this project was to study the effect of calcium sulfate on early bony consolidation in distraction osteogenesis. In the control group, a total of 17 patients were treated between December 1997 and December 1999. The age of patients ranged from 2 to 45 years. The follow up period was 6 to 24 months(mean 15.3 months). In experimental group, a total of eight patients with craniofacial microsomia were treated between April 2000 and February 2001. The age of patients ranged from two to 40 years old. All patients were male. The follow up period was 3 to 15 months. The operative procedure in adult was based on the Ortiz Monasterio's simultaneous mandibular and maxillary distraction technique. The authors modified the original Ortiz Monasterio's method by using Le Fort I osteotomy with complete separation of both pterygomaxillary junction and mandibular osteotomy to avoid the resistance during distraction. In child, the osteotomy of the mandible was performed to distract. In the control group, in adults, after 5 days of latent period, distraction was performed at a rate of 1 mm per day. After 6 to 8 weeks of consolidation period, intermaxillary fixation and distraction device were removed. In children, the distraction was started at a rate of 1 mm per day without latent period. The consolidation period was 4 to 6 weeks. In the experimental group, after 5 days of latent period, distraction was performed at a rate of 1 mm per day in 2 adults. However, in children distraction was performed at a rate of 1 mm per day in 2 patients and 2 mm per day in 4 patients without latent period. On the completion of distraction, the calcium sulfate mixed with carboxymethyl cellulose was injected into the distracted zone. Radiographs showed bony consolidation in 4 weeks in 1 child, 5 weeks in 1 child with distraction rate of 1 mm per day, in 5 - 7 weeks in 4 children with distraction rate of 2 mm per day and in 5 weeks in 2 adults with distraction rate of 1 mm per day after injection of the calcium sulfate. The consolidation period in adult was statistically significant compared with that of the control group using Mann-Whitney U test.In conclusion, these findings suggested that injectable calcium sulfate is effective for early bony consolidation in distraction osteogenesis in adult.