Accuracy of a CAD/CAM surgical template for mandibular distraction: a preliminary study

We have assessed the accuracy and clinical validation of virtual planning using a surgical template in 16 patients with hemifacial microsomia being treated by mandibular distraction osteogenesis. Virtual planning and simulation were first done on three-dimensional models. Distraction was simulated on the virtual model and the new morphology of the mandible was previewed. Both the position and direction of the distractor were calculated to achieve the optimal morphology. The templates were designed based on the virtual planning, and manufactured using a 3-dimensional printing technique. The template was designed to assist the surgeon to make the osteotomy and predrill the screw-holes to guide the distractor into position. The outcome was evaluated by comparing planned with postoperative outcomes. The osteotomy was made and the distractor implanted successfully under the guidance of the template in all patients. The linear and angular differences for the distractor were measured and reported using the root mean square deviation. There was no difficulty in using the templates. The largest linear root mean square deviation between the planned and the postoperative distractors was 0.93mm in the anteroposterior direction, and the largest in the horizontal plane was 4.64°. We suggest that the preoperative plan can be transferred accurately to a patient using the template.