计算机辅助导航系统在下颌骨缺损修复重建中的初步应用

INITIAL APPLICATION OF COMPUTER ASSISTED NAVIGATION SYSTEM IN RECONSTRUCTION OF MANDIBULAR DEFECTS

目的 探讨计算机辅助导航系统（computer assisted navigation system,CANS）在下颌骨缺损修复重建中的效果。方法 2012年4月-2014年9月,收治8例下颌骨良性病变切除后一期行修复重建的患者。男5例,女3例;年龄22～50岁,平均34.5岁。造釉细胞瘤4例,牙源性角化囊肿3例,髁状突骨瘤1例。病变切除后缺损部位参照CRABS方法分类：右侧CRAB、左侧RABS、左侧CR、右侧RAB、左侧C、右侧RABS＋左侧S型各1例,右侧AB型2例。术前戴预制的咬合板行颌面部CT及常规供骨区CT检查,应用BrainLab Iplan软件及SurgicaseCMF 5.0软件对颌面部等CT数据分割、三维重建、术前设计及虚拟手术,术中利用模型外科技术切除下颌骨肿瘤,采用BrainLab导航系统实时验证下颌角和髁状突等部位的定位。术后利用Geomagic studio12.0软件通过二维测量和三维色谱偏差分析法进行手术精确度评价;随访观察颜面部对称性、并发症和复发情况。结果 8例患者均顺利完成术前设计、模拟手术和实时导航手术。术后CT复查和三维色谱偏差分析示截骨部位、切除范围、重建外形与术前设计基本一致,下颌角点和髁状突外极点在术前设计复位点与术后CT模型上就位点距离分别相差（1.83±0.19）mm和（1.61±0.24）mm。术后患者均获随访,随访时间2～6个月,平均3.5个月。除肋骨移植患者张口度轻度受限外,余未见明显并发症。患者面部对称性良好,随访期间未见肿瘤复发。结论 CANS可显著提高下颌骨缺损修复重建术的精确性,有效减少并发症,恢复面部对称性,是一种有效的下颌骨缺损修复重建手术的辅助方法。

Objective To evaluate the value of computer assisted navigation system （CANS） in the reconstruction of mandibular defects. Methods Between April 2012 and September 2014, 8 patients with mandibular defects were included in this study. There were 5 males and 3 females with an age range of 22-50 years （mean, 34.5 years）, including 4 cases of ameloblastoma, 3 cases of odontogenic keratocyst, and 1 case of condylar osteoma. According to the CRABS （condyle, ramus, angle, body, symphysis） classification criteria based on the location of mandibular defect, there were 1 case of right CRAB type, 1 case of left RABS type, 1 case of left CR type, 1 case of right RAB type, 1 case of left C type, 1 case of right RABS＋left S type, and 2 cases of right AB type. With the biteplate fixing mandible, maxillofacial CT and the donor site CT scan were done. Computer assisted design was made by using Surgicase CMF5.0 software and BrainLab Iplan software, included delineating the osteotomy lines for resection, ascertaining the normal anatomic structures for defect reconstruction, and determining the reconstructive morphology. With guide plates and the guidance of BrainLab navigation system, an en bloc tumor resection and simultaneous defect reconstruction were performed under the precise localization of mandibular angle and condyle. Preoperative and postoperative CT images were superimposed in Geomagic studio12.0 software system,and both were compared by three-dimensional （3D） objects and 2D slices.The complications and signs of recurrence were observed. Results Under the guidance of navigation, preoperative facial symmetry design, surgery simulation, and simultaneous navigation operation were performed successfully. The postoperative CT and postoperative 3D error analysis showed osteotomy lines and reconstruction contour had good matching with the preoperative planning. The error of important corresponding points （mandibular angle and external pole of condyle） in the reconstruction of mandibular defects were （1.83±0.19） mm and （1.61±0.24） mm. The patients were followed up 2-6 months （mean, 3.5 months）. No complication was observed in the other patients except the patients undergoing rib transplantation who had mild limitation of mouth opening. Good facial symmetry was obtained, and no tumor recurrence was found. Conclusion CANS can effectively increase the surgical precision in the reconstruction of mandibular defects and reduce complications, and recover facial symmetry. It is regarded as a valuable technique in this potentially complicated procedure.