计算机辅助导航技术在口腔颌面外科的应用—104例病例分析

目的:探讨计算机辅助导航技术在口腔颌面外科的应用,并评价其效果。方法:选择104例需进行口腔颌面手术的患者,包括陈旧性颧-上颌-眶周骨折34例,颞下颌关节骨性强直27例,骨纤维异常增殖症29例,下颌角肥大畸形9例,颌面部软骨、骨肿瘤3例,面部异物2例。定位钉植入后,拍摄颌面部CT,进行术前设计及模拟,利用镜像技术确定患侧截骨部位、截骨量、骨折复位位置及重建外形。导航辅助下进行手术操作。术后复查CT,与术前设计图像融合,进行手术准确度及导航误差评价。结果:经过点配准和(或)面配准后,所有患者顺利完成导航手术。手术器械实现空间定位,术者能够明确其与解剖结构的位置关系,精确度高,系统误差小于1 mm。术后CT检查示截骨部位、截骨量、骨折复位与术前设计基本一致,平均误差(1.46±0.24)mm。104例患者术后愈合良好,无严重并发症,面部不对称畸形患者术后面形显著改善。结论:计算机辅助导航外科可以实现术前设计、手术模拟及术后预测,有助于提高颌面部手术的精确性,减少创伤,恢复面部对称性,是一种较为理想的颌面部手术辅助方法。     

导航手术在颅颌面外科的应用及误差控制

导航手术越来越多地应用于颅颌面种植修复、损伤、面部整复、正颌外科、放疗及射频热凝治疗。精确性是导航手术的关键,误差的控制贯穿于影像获取、配准、实时跟踪及导航手术操作的各个步骤中。本文就颅颌面外科的导航手术应用及误差控制作一综述。     

计算机辅助导航系统在颌面部陈旧性骨折治疗中的应用

目的：研究计算机辅助导航系统（computer assisted navigation system,CANS）在颌面部陈旧性骨折治疗中的应用及其效果评价。方法：5例单侧面中部陈旧性骨折患者,定位钉植入后行面部CT扫描。在CANS上行术前设计及三维手术模拟骨折复位,计算机辅助导航下行颌面部陈旧性骨折的切开复位内固定术。术后CT复查,并与术前设计比较,检验骨折复位情况。结果：患者解剖结构与面部三维重建模型完全吻合,术中实现实时导航。手术器械实现空间定位,术者能够明确其与解剖结构的位置关系,精确度高,系统误差小于1mm。术后CT检查示骨折复位与术前设计基本一致,复位最大偏差小于2mm。复视、眼球下陷、运动受限症状消失,畸形明显改善,面部对称。结论：计算机辅助导航外科有助于提高颅颌面陈旧性骨折的复位精度,是一种较为理想有效的治疗颌面部复杂骨折的辅助方法。     

计算机辅助动态导航技术在种植手术中的临床精度评价

目的 本研究利用计算机辅助动态导航系统进行种植外科手术,探索动态导航技术在种植手术中的应用精度,为实现精准、微创、高效的种植外科手术提供理论依据。方法 选取2017年6月至2019年12月期间在烟台市口腔医院接受计算机辅助动态导航种植外科手术的51例患者,共66枚种植体。术前佩戴合适的U型管拍摄CBCT,制取数字化印模,利用计算机辅助动态导航软件完成术前种植方案规划。在动态导航引导下完成种植体植入,术后拍摄CBCT获取种植体三维位置,测量每枚种植体的颈部距离误差、根方距离误差及轴向角度误差。结果 51枚种植体颈部距离误差为（0.61±0.17）mm(0.35～0.98mm),根方距离误差为（0.73±0.15）mm(0.50～0.99 mm),轴向角度误差为（3.32±1.55）°（0.43°～6.66°）。结论 计算机辅助动态导航系统引导的种植外科手术存在误差,各项误差在可允许的范围内,计算机辅助动态导航系统引导下的种植外科手术可广泛应用于术前流程规划、术中手术引导、术后精度分析等各个方面。     

高精度光学导航辅助颅颌面骨畸形整复的技术方法建立与应用

目的：通过自主建立用于颅颌面手术的高精度计算机导航软硬件系统,模拟和精确设计手术方案,实现术中实时可视化手术导航。方法：（1）创建颅颌面整复手术规划及导航软件（TBNAVIS—CMFS）。（2）建立基于Polaris光学定位仪的导航工作站。（3）临床上对50例复杂颅颌面畸形患者实施导航辅助矫治与修复重建手术。结果：TBNAVIS—CMFS以清晰的界面和简洁的操作．实现了高精度数字化手术规划;导航辅助的颅颌面骨畸形整复术取得了精确可靠的手术效果,减少了手术创伤。结论：计算机导航技术结合颅颌面整复外科,将有利于从疾病诊断、术前模拟、术中导航等方面推动颅颌面外科趋于精确和微创。     

数字化技术在提高颅颌面畸形整复手术精度中的效果评价

目的 ：探讨数字化外科辅助颅颌面畸形手术相对于传统手术的优势并评价其远期效果。方法 ：本研究是一项前瞻性队列研究,纳入因肿瘤、感染、先天发育等原因需要进行颅颌面畸形整复的患者,进行数字化辅助手术或传统经验性手术。纳入研究后按计划随访,收集基线期、治疗期及术后随访期的手术相关资料、CT数据,使用Mimics软件色谱误差分析分别计算2组患者术后实际下颌骨与理想下颌骨之间的差异。采用SPSS 21.0软件包对数据进行统计学分析。结果：建立了72例颅颌面畸形队列,数字化外科组和对照组各36例。色谱误差分析显示,数字化组手术前、后偏差为（1.06±0.06）mm,对照组为（1.23±0.06）mm;多因素线性回归分析显示,数字化外科与较好的下颌骨修复精度显著相关（P<0.05）,2组并发症发生率相同,无严重不良事件发生。结论：数字化外科技术辅助颅颌面畸形整复手术较传统经验性手术精度显著提高,未增加手术并发症,安全、可靠,远期效果稳定。     

数字化技术辅助颌骨截骨及颌面修复的临床应用

目的:将系列数字化导板用于上下颌骨截骨及修复,实现上、下颌骨缺损的个体化精确修复。方法:15例上颌骨次全切除及下颌骨节段性截骨的患者,男性9例,女性6例,均行术前规划,并3D打印数字化导板,术中分别应用即刻赝复体修复上颌骨缺损,同期血管化腓骨瓣移植修复下颌骨缺损。术中使用导航验证截骨范围,术后利用图像融合技术评价术后效果。结果:导板术中就位顺利,截骨范围与术前设计基本一致。即刻赝复体能顺利戴入,重建钛板及髁突位置准确,面型及咬合关系恢复良好。术后图像融合显示,15例上/下颌骨截骨实际手术与虚拟手术平均偏差,平均为(0.43±0.10) mm。结论:数字化系列导板能够在术中准确还原术前设计,减少手术时间;其与手术导航相辅相成,能实现颌骨个体化、精确化的截骨及颌面缺损修复。     

3 D-DIC技术颌面外科导航的体外初步研究

目的通过体外头颅模型试验,测量基于三维图像关联技术(3D-DIC)搭建的导航系统定位精度及跟踪精度。方法通过3D-DIC导航系统在3D打印头颅模型上选取不同分布模式的标记点进行注册,测量定位误差,比较注册点分布不同对于注册精度的影响,于3D打印头颅模型上模拟Lefort I型截骨线进行截骨,机械臂把持牙槽突骨段在三维空间内作任意移动,3D-DIC系统测量其运动轨迹,并与机械臂末端记录相对比,测量跟踪精度。采用独立样本t检验比较不同运动方向的跟踪精度。结果3D-DIC导航精度为(0.694±0.017)mm。3D-DIC跟踪精度为(0.174±0.089)mm,跟踪精确性良好。结论 3D-DIC导航系统拥有良好的定位精度及跟踪精度。     

导航辅助射频温控热凝术中注册标记系统的改良

目的：改进导航辅助射频温控热凝术中的注册标记系统,使其更加无创,同时达到导航系统的精确要求。方法：采用热塑型塑料面罩,依照人体面部特征加热塑型,表面双侧颞部、眉弓中点和颧骨最高点安置6个塑料标记点．内部随意安置6个标记点。CT扫描获得影像学数据,输入SurgView—RFT电磁导航系统后,分别选用4个（内外各2个）、6个（内外各3个）和8个（内外各4个）标记点进行注册和配准,每组设置5种组合,每点读取3次坐标值,取平均值代入配准误差公式。采用SAS6．12软件包对数据进行t检验。结果：取4个标记点时．系统误差为f1．58_±0．25）mm;取6个标记点时,系统误差为（1．28±0．21）mm;当标记点数量达到8个时,导航系统的配准精度达（1．06±0．10）mm。4点组与6点组间有显著差异（P=0．0149）,6点组与8点组间无显著差异（P=0.1402）。结论：热塑型塑料面罩表面放置标记点可避免患者创伤,配准精度完全符合导航系统的要求和卯圆孔穿刺的特定要求,在应用中至少应有6个标记点。     

应用计算机辅助手术导航系统经口内径路复位颧弓M型骨折临床观察

目的    探讨应用计算机辅助手术导航系统经口内径路复位颧弓M型骨折的技巧及经验。方法    2012年1月至2014年12月武汉大学口腔医学院47例颧弓M型骨折分为非导航组（26例）和导航组（21例）。非导航组患者20例经口内径路,6例经颞部小切口,26例中低年资医师开展3例。导航组患者均应用计算机辅助手术导航系统经口内径路进行开放复位,其中7例由低年资医师完成。术后随访3 ~ 6个月。 结果    非导航组1例经口内径路复位效果不佳,另1例术后复查X线片显示颧弓骨段塌陷,其他病例以及导航组全部病例均复位效果满意。结论    应用计算机辅助手术导航系统经口内径路复位颧弓M型骨折是一种安全、高效、易于掌握的方法,尤其有利于低年资医师快速掌握手术技巧。     

基于虚拟现实技术的正颌手术模拟预测方法的建立

目的:探索建立基于虚拟现实技术的正颌手术模拟研究方法.方法:将颌面畸形患者CT断层图像利用Simplant软件行颅颌面骨组织三维重建,截骨,构建颅颌面骨树状结构模型.在虚拟环境碰撞模型上行上颌骨Le Fort Ⅰ型截骨、双侧下颌支矢状劈开及颏成形的手术模拟.结果:该系统形成的三维立体虚拟影像,可从任意视角观察,清晰逼真.运用系统工具进行骨组织的旋转、平移等手术模拟操作,实现了操作者与模型的交互作用,图像及触觉感知实时反馈,沉浸感强.应用该方法实现了正颌手术设计、虚拟操作及术后效果预测.结论:颅面三维虚拟正颌手术系统可以行正颌手术模拟及手术操作训练,在虚拟环境下实现图像反馈和力、触觉感知的手术模拟,具有较高的临床应用价值.     

虚拟手术计划在经口内入路行下颌骨切除及精确重建中的应用：附9例报道

目的 介绍在虚拟手术计划辅助下行经口内入路下颌骨切除和血管化骨重建的经验,评价术后重建效果。方法 对9例下颌骨良性肿瘤患者术前行虚拟手术计划,设计、制作适用于口内操作的预设钉孔的导板。然后经口内入路利用截骨导板行下颌骨切除,预弯钛板及血管化骨瓣的植入和固定。术中实时导航验证新下颌骨的空间位置。术后半年,通过临床及影像学检查评价患者外形和功能;通过术后CT与术前STL模型拟合,评估下颌骨重建的精确性。采用SPSS 15.0软件包对数据进行统计学分析。结果 在虚拟手术计划辅助下,9例患者均顺利完成经口内入路下颌骨切除及血管化下颌骨重建,术中导航证实重建下颌骨位置准确。术后半年复查见患者面部对称,无面瘫及开口受限。患者对手术效果满意。图像拟合显示,截骨线位置精确,误差<1 mm[（0.72±0.15）mm],下颌骨重建位置与术前设计高度一致,误差为（1.76±1.99）mm。结论 在虚拟手术计划辅助下,利用预设钉孔的导板和预弯钛板,可以精确实施口内下颌骨切除及血管化骨重建,避免了口外切口,显著提高了下颌骨重建的精确性。     

Point-to-point registration with mandibulo-maxillary splint in open and closed jaw position. Evaluation of registration accuracy for computer-aided surgery of the mandible

IntroductionComputer navigation plays an increasingly important role in craniomaxillofacial surgery. The difficulties in computer navigation at the craniomaxillofacial site lie in the accurate transmission of the dataset to the operating room. This study investigates the accuracy of the dental-splint registration method for the skull, midface, and mandible.Material and methodsA synthetic human skull model was prepared with landmarks and scanned with cone beam computer tomography (CBCT). Two registration splints fixed the mandible against the viscerocranium in two different positions (closed vs. open). The target registration error was computed in all 278 landmarks spread over the entire skull and mandible in 10 repeated measurements using the VectorVision² (BrainLAB Inc., Feldkirchen, Germany) navigation system.ResultsIf registered in the closed position an average precision of 2.07 mm with a standard deviation (SD) of 0.78 mm was computed for all landmarks distributed over the whole skull. Registration in the open position resulted in an average precision of 1.53 mm (SD = 0.55 mm). For single landmarks the precision decreases linearly with distance from the reference markers. The longer the three-dimensional distance between the registration points, the more precise the computer navigation is, mainly in the most posterior area of the cranium.ConclusionOur findings in the cranium are comparable with those of other studies. Artificial fixation of the lower jaw via splint seems to introduce no additional error. The registration points should be as far apart from each other as possible during navigation with the splint.     

Augmented reality as an aid in maxillofacial surgery: Validation of a wearable system allowing maxillary repositioning

AimWe present a newly designed, localiser-free, head-mounted system featuring augmented reality as an aid to maxillofacial bone surgery, and assess the potential utility of the device by conducting a feasibility study and validation.MethodsOur head-mounted wearable system facilitating augmented surgery was developed as a stand-alone, video-based, see-through device in which the visual features were adapted to facilitate maxillofacial bone surgery. We implement a strategy designed to present augmented reality information to the operating surgeon. LeFort1 osteotomy was chosen as the test procedure. The system is designed to exhibit virtual planning overlaying the details of a real patient. We implemented a method allowing performance of waferless, augmented-reality assisted bone repositioning. In vitro testing was conducted on a physical replica of a human skull, and the augmented reality system was used to perform LeFort1 maxillary repositioning. Surgical accuracy was measured with the aid of an optical navigation system that recorded the coordinates of three reference points (located in anterior, posterior right, and posterior left positions) on the repositioned maxilla. The outcomes were compared with those expected to be achievable in a three-dimensional environment. Data were derived using three levels of surgical planning, of increasing complexity, and for nine different operators with varying levels of surgical skill.ResultsThe mean error was 1.70 ± 0.51 mm. The axial errors were 0.89 ± 0.54 mm on the sagittal axis, 0.60 ± 0.20 mm on the frontal axis, and 1.06 ± 0.40 mm on the craniocaudal axis. The simplest plan was associated with a slightly lower mean error (1.58 ± 0.37 mm) compared with the more complex plans (medium: 1.82 ± 0.71 mm; difficult: 1.70 ± 0.45 mm). The mean error for the anterior reference point was lower (1.33 ± 0.58 mm) than those for both the posterior right (1.72 ± 0.24 mm) and posterior left points (2.05 ± 0.47 mm). No significant difference in terms of error was noticed among operators, despite variations in surgical experience. Feedback from surgeons was acceptable; all tests were completed within 15 min and the tool was considered to be both comfortable and usable in practice.ConclusionWe used a new localiser-free, head-mounted, wearable, stereoscopic, video see-through display to develop a useful strategy affording surgeons access to augmented reality information. Our device appears to be accurate when used to assist in waferless maxillary repositioning. Our results suggest that the method can potentially be extended for use with many surgical procedures on the facial skeleton. Further, our positive results suggest that it would be appropriate to proceed to in vivo testing to assess surgical accuracy under real clinical conditions.     

Efficacy of surgical navigation in zygomaticomaxillary complex fractures: randomized controlled trial

Accurate reduction is of vital importance in the treatment of zygomaticomaxillary complex (ZMC) fractures. Computer-assisted navigation systems (CANS) have been employed in ZMC fractures to improve the accuracy of surgical reduction. However, randomized controlled trials on this subject are rare and the benefits of CANS remain controversial. The aim of this study was to compare reduction errors between navigation-aided and conventional surgical treatment for ZMC fractures. Thirty-eight patients with unilateral type B ZMC fractures were enrolled. Preoperative computed tomography data were imported into ProPlan software for virtual surgical planning. Open reduction and internal fixation was performed with CANS (experimental group) or without CANS (control group). Postoperative computed tomography scans were obtained to examine the difference between surgical planning and the actual postoperative outcome, namely reduction errors. The median translational reduction errors in the X, Y, and Z axes were 0.80 mm, 0.40 mm, and 0.80 mm, respectively, in the experimental group and 0.53 mm, 0.86 mm, and 0.83 mm, respectively, in the control group (P > 0.05). The median rotational reduction errors in pitch, roll, and yaw were 0.92°, 2.47°, and 1.54°, respectively, in the experimental group and 1.45°, 3.68°, and 0.76°, respectively, in the control group (P > 0.05). In conclusion, compared with conventional reduction surgery, navigation-aided surgery showed no significant improvement in reduction accuracy in the treatment of type B ZMC fractures (Chinese Clinical Trial Registry, registration number ChiCTR1800015559).     

The indication and application of computer-assisted navigation in oral and maxillofacial surgery—Shanghai's experience based on 104 cases

ObjectiveTo explore the indication and application of computer-assisted navigation in oral and maxillofacial surgery.Patients and methodsOne hundred and four patients including 34 zygomatic-orbital-maxillary fractures, 27 unilateral TMJ ankylosis, 29 craniofacial fibrous dysplasia, 9 mandibular angle hypertrophia, 3 cartilage/bone tumours of jaw and 2 cases with facial foreign bodies were enrolled in this study.CT scans were performed and data was saved in DICOM (digital imaging and communications in medicine) format. The osteotomy lines, amount and range of resection, the reduction position of bony segments and the reconstruction morphology was determined and displayed by preoperative simulation with mirroring and superimposing procedures. All operations were performed under the guidance of navigation system. The accuracy of navigation was evaluated by comparing the postoperative CT 3-D model with preoperative surgical planning.ResultsThrough registration, an accurate match between the intraoperative anatomy and the CT images was achieved. The systematic error checked by computer was within 1 mm. All operations were performed successfully with the guidance of real-time navigation. The mean error between virtual simulation and surgical results was 1.46 ± 0.24 mm. All patients healed uneventfully and function and profile was improved significantly.ConclusionsWith the opportunity to perform preoperative planning, surgical simulation and postoperative prediction, computer-assisted navigation shows great value in improving the accuracy of maxillofacial surgery, reducing operation risk and postsurgical morbidity, and restoring facial symmetry. It is regarded as a valuable technique in these potentially complicated procedures.     

Biodegradable fixation for craniomaxillofacial surgery: a 10-year experience involving 761 operations and 745 patients

Patient acceptance, safety, and efficacy of poly-l/dl-lactic acid (PLLDL) bone plates and screws in craniomaxillofacial surgery are reported in this article. Included in the sample are 745 patients who underwent 761 separate operations, including more than 1400 surgical procedures (orthognathic surgery (685), bone graft reconstruction (37), trauma (191) and transcranial surgery (20)). The success (no breakage or inflammation requiring additional operating room treatment) was 94%. Failure occurred because of breakage (14) or exuberant inflammation (31). All breakage occurred at mandibular sites and the majority of inflammatory failure occurred in the maxilla or orbit (29), with only two in the mandible. Failures were evenly distributed between the two major vendors. PLLDL 70/30 bone plates and screws may be used successfully in a variety of craniomaxillofacial surgical applications. The advantages include the gradual transference of physiological forces to the healing bone, the reduced need for a second operation to remove the material and its potential to serve as a vehicle to deliver bone-healing proteins to fracture/osteotomy sites. Bone healing was noted at all sites, even where exuberant inflammation required a second surgical intervention.     

Navigation-guided en bloc resection and defect reconstruction of craniomaxillary bony tumours

The aim of this study was to evaluate the validity of navigation-guided en bloc tumour resection and defect reconstruction in the treatment of craniomaxillary bony tumours. Three patients with ossifying fibroma and two patients with fibrous dysplasia were enrolled in this study. After preoperative planning and three-dimensional simulation, the osteotomy lines for resection were delineated and the normal anatomic structures for defect reconstruction were ascertained. With the guidance of an Accu-Navi navigation system, an en bloc tumour resection and simultaneous defect rehabilitation were performed. The system provided continuously updated information on the position and movement of surgical instruments in the operating field in relation to the preoperative imaging data set. The system error measured by the computer did not exceed 1 mm. The osteotomy lines and reconstruction contour were checked by postoperative computed tomography, and good matching with the preoperative planning was achieved. Patients showed no signs of tumour recurrence or prosthesis infection during follow-up (range 12–35 months). Image-guided navigation makes radical bone tumour resection more reliable by implementing preoperative planning, showing the determined safety margins, preserving vital structures and guiding reconstruction.