Application of digital guide plate with drill-hole sharing technique in the mandible reconstruction.

Background/purpose: With the development of computer-assisted surgery, digital guide plate was widely used in vascularized bone flap grafts for mandibular reconstruction. The purpose of this study was to design and manufacture a digital guide plate with drill-hole sharing for mandibular reconstruction and assess for surgical accuracy. Materials and methods: 17 patients that required mandibular reconstruction using fibula free flap or iliac crest free flap were included in the study. The computed tomography (CT) data of the patient's mandible and pelvis or fibula were acquired preoperatively. A surgical simulation was then performed using computer-aided surgical simulation (CASS) technology based on above date, which allowed the design of two cutting guide and a repositioning guide for mandibular reconstruction. After surgery, the accuracy of reconstruction was evaluated by superimposing the postoperative image onto the preoperative image of mandible, recording the linear and angular deviation of landmarks, measuring the differences between the planned and actual outcomes. Results: The osteotomy and repositioning of fibula or iliac crest segments were successfully performed as planned using surgical guides. The digital guide plate with drill-hole sharing showed excellent accuracy, When the iliac crest or the fibula free flap were used for mandibular reconstruction, the largest mean differences between the preoperative and postoperative were 1.11 mm and 2.8° or 1.3 mm and 3.87°. Conclusion: The digital guide plate with drill-hole sharing designed preoperatively provides a reliable method of for the mandibular reconstruction. This can assist surgeons in accurately performing osteotomy and repositioning fibula or iliac crest segments during the mandibular reconstruction.

Design and manufacture of dental-supported surgical guide for genioplasty.

BACKGROUND/PURPOSE: Genioplasty were used widely to correct chin deformities. The purpose of this study was to design and manufacture a dental-supported surgical guide for genioplasty surgery and assess for surgical accuracy. MATERIALS AND METHODS: eleven patients with chin deformities were treated in this study. The computed tomography (CT) data of the patient's skull and the digital dental models of stone dental models were acquired preoperatively. For each patient, a virtual three-dimensional (3D) model of the skull was constructed and enhanced with digital dental models. A surgical simulation was then performed using computer-aided surgical simulation (CASS) technology based on clinical examination and 3D cephalometry. The surgery was simulated preoperatively which allowed the design of a cutting guide and a dental-supported repositioning guide for genioplasty, which was then 3D-printed and used during operation after disinfection. After surgery, the outcome was evaluated by superimposing the postoperative CT model onto the preoperative model, recording the linear and angular deviation of landmarks and plane, then measuring the differences between the planned and actual outcomes. RESULTS: The osteotomy and repositioning were successfully performed as planned using surgical guides. No inferior alveolar nerve damage was seen in this study. The dental-supported surgical guide showed excellent accuracy, with the largest differences between the planned and the postoperative chin segment being 0.9 mm and 3.2°. CONCLUSION: The dental-supported surgical guide designed preoperatively provided a reliable method of transfer genioplasty planning. This can assist surgeons in accurately performing osteotomy and repositioning bone segments during a genioplasty.