Introduction of temporomandibular joint and skull base combined reconstruction by autogenous bone graft.

OBJECTIVE: This study introduces the application of autogenous bone graft for the reconstruction of temporomandibular joint (TMJ) and skull base combined defects. MATERIALS AND METHODS: Patients treated with autogenous bone grafts for reconstruction of the TMJ and skull base were reviewed. All patients underwent virtual surgical design to confirm the osteotomies of the combined lesion and the selections of autogenous bone graft, fabrication of surgical templates to transfer the plan to actual operation, and reconstruction of autogenous bone graft for the TMJ and/or skull base. Surgical outcomes were assessed by clinical examinations and radiological data. RESULTS: Twenty-two patients were involved in this study. Ten patients underwent reconstruction of the skull base by a free iliac or temporal bone graft and preservation of the TMJ. Twelve patients underwent skull base reconstruction by the same methods and total reconstruction of the TMJ by half sternoclavicular joint flap or costochondral bone graft. No severe complications occurred after surgery. The occlusion relationship was stable and similar to that of the preoperative state. The pain and maximal interincisal opening were significantly improved by the 101.2-month follow-up. CONCLUSION: Autogenous bone graft is a good alternative for repairing the TMJ and the skull base structure and function. CLINICAL RELEVANCE: The study introduced the application of autogenous bone graft for the reconstruction of temporomandibular joint and skull base combined defect, which is a good way to repair the defect and restore the function.

Development and Application of Digital Maxillofacial Surgery System Based on Mixed Reality Technology.

OBJECTIVE: To realize the three-dimensional visual output of surgical navigation information by studying the cross-linking of mixed reality display devices and high-precision optical navigators. METHODS: Applying quaternion-based point alignment algorithms to realize the positioning configuration of mixed reality display devices, high-precision optical navigators, real-time patient tracking and calibration technology; based on open source SDK and development tools, developing mixed reality surgery based on visual positioning and tracking system. In this study, four patients were selected for mixed reality-assisted tumor resection and reconstruction and re-examined 1 month after the operation. We reconstructed postoperative CT and use 3DMeshMetric to form the error distribution map, and completed the error analysis and quality control. RESULTS: Realized the cross-linking of mixed reality display equipment and high-precision optical navigator, developed a digital maxillofacial surgery system based on mixed reality technology and successfully implemented mixed reality-assisted tumor resection and reconstruction in 4 cases. CONCLUSIONS: The maxillofacial digital surgery system based on mixed reality technology can superimpose and display three-dimensional navigation information in the surgeon's field of vision. Moreover, it solves the problem of visual conversion and space conversion of the existing navigation system. It improves the work efficiency of digitally assisted surgery, effectively reduces the surgeon's dependence on spatial experience and imagination, and protects important anatomical structures during surgery. It is a significant clinical application value and potential.

Improved accuracy of hemimandibular reconstructions involving the condyle by utilizing hydroformed reconstruction plates rather than hand-bent stock plates.

BACKGROUND: Computer-aided design/computer-aided manufacturing (CAD/CAM) surgical templates allow precise mandibular reconstructive surgery. However, their clinical accuracy is limited by manual plate bending. Digitally hydroformed plates maintain a digital workstream in virtual planning. METHODS: Twelve patients with Brown's class IIc mandibular defects were randomized into two groups: group I (experimental), the reconstruction plate was digitally hydroformed, and group II (control), surgeries were performed CAD/CAM guided with the reconstruction plate manually prebent. The linear and angular deviations of reconstruction outcomes were compared to surgical simulation in both groups. RESULTS: The mean linear and angular deviations of middle and posterior segments were 2.14 ± 0.79 mm, 3.71 ± 0.95 mm, 8.73° ± 1.91°, and 9.06° ± 0.96° in group I and 4.31 ± 0.78 mm, 6.74 ± 1.40 mm, 16.35° ± 0.72°, and 31.48° ± 3.38° in group II, respectively. Measurements in group I were significantly lower than group II (P < .005). CONCLUSION: Digital hydroforming for plate prebent is a reliable method that helps improving the clinical accuracy of CAD/CAM-guided mandibular reconstruction surgery.