3D virtual planning in orthognathic surgery and CAD/CAM surgical splints generation in one patient with craniofacial microsomia: a case report

Objective: In this case report, the feasibility and precision of tridimensional (3D) virtual planning in one patient with craniofacial microsomia is tested using Nemoceph 3D-OS software (Software Nemotec SL, Madrid, Spain) to predict postoperative outcomes on hard tissue and produce CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) surgical splints. Methods: The clinical protocol consists of 3D data acquisition of the craniofacial complex by cone-beam computed tomography (CBCT) and surface scanning of the plaster dental casts. The ''virtual patient'' created underwent virtual surgery and a simulation of postoperative results on hard tissues. Surgical splints were manufactured using CAD/CAM technology in order to transfer the virtual surgical plan to the operating room. Intraoperatively, both CAD/CAM and conventional surgical splints are comparable. A second set of 3D images was obtained after surgery to acquire linear measurements and compare them with measurements obtained when predicting postoperative results virtually. Results: It was found a high similarity between both types of surgical splints with equal fitting on the dental arches. The linear measurements presented some discrepancies between the actual surgical outcomes and the predicted results from the 3D virtual simulation, but caution must be taken in the analysis of these results due to several variables. Conclusions: The reported case confirms the clinical feasibility of the described computer-assisted orthognathic surgical protocol. Further progress in the development of technologies for 3D image acquisition and improvements on software programs to simulate postoperative changes on soft tissue are required.

本病例报告旨在借助西班牙马德里Nemotec SL公司研发的Nemoceph 3D-OS软件，评估颅面短小症患者的三维（3D）虚拟规划方案的可行性与精准度，以预测硬组织术后转归，并生成计算机辅助设计/计算机辅助制造（Computer Aided Design/Computer Aided Manufacturing, CAD/CAM）手术夹板。
方法：本临床研究方案通过锥形束计算机断层扫描（cone-beam computed tomography, CBCT）采集颅面部复合体的三维数据，并对石膏牙科模型实施表面扫描。基于上述数据构建的"虚拟患者"将接受虚拟手术，并模拟硬组织术后效果。采用CAD/CAM技术制作手术夹板，以将虚拟手术方案应用于手术室实操环节。术中，CAD/CAM手术夹板与传统手术夹板的临床效果相当。术后获取第二组三维图像以开展线性测量，并将测量结果与三维虚拟模拟得到的术后预测结果进行对比。
结果：结果显示，两类手术夹板在牙弓上的适配性均佳，二者相似度极高。实际手术结局与三维虚拟模拟的预测结果之间存在一定线性测量偏差，但由于受多种变量影响，对该结果的分析需持审慎态度。
结论：本报告病例证实了所述计算机辅助正颌外科手术方案的临床可行性。未来仍需进一步推进三维图像采集技术的研发，并优化用于模拟软组织术后变化的软件程序。