Badiali Giovanni, Ferrari Vincenzo, Cutolo Fabrizio, Freschi Cinzia, Caramella Davide, Bianchi Alberto, Marchetti Claudio
PhD School in Surgical Sciences (Head: Prof. Andrea Stella, MD), University of Bologna, Italy.
EndoCAS Center (Head: Prof. Mauro Ferrari, MD), University of Pisa, Italy.
J Craniomaxillofac Surg. 2014 Dec;42(8):1970-6. doi: 10.1016/j.jcms.2014.09.001. Epub 2014 Sep 11.
We 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.
Our 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.
The 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.
We 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.
我们展示了一种新设计的、无需定位器的头戴式系统，该系统具有增强现实功能，可辅助颌面骨手术，并通过进行可行性研究和验证来评估该设备的潜在效用。
我们开发的头戴式可穿戴增强手术系统是一种独立的、基于视频的透视设备，其视觉特征经过调整以方便颌面骨手术。我们实施了一种策略，旨在向手术医生呈现增强现实信息。选择LeFort1截骨术作为测试程序。该系统旨在展示覆盖真实患者细节的虚拟规划。我们实现了一种方法，可在无导板的情况下进行增强现实辅助的骨重新定位。在人类头骨的物理复制品上进行了体外测试，并使用增强现实系统进行LeFort1上颌骨重新定位。借助光学导航系统测量手术精度，该系统记录了重新定位的上颌骨上三个参考点（位于前、右后和左后位置）的坐标。将结果与在三维环境中预期可实现的结果进行比较。数据来自三个复杂度不断增加的手术规划级别，并针对九名手术技能水平不同的操作员。
平均误差为1.70±0.51毫米。矢状轴上的轴向误差为0.89±0.54毫米，额轴上为0.60±0.20毫米，颅尾轴上为1.06±0.40毫米。与更复杂的规划（中等：1.82±0.71毫米；困难：1.70±0.45毫米）相比，最简单的规划平均误差略低（1.58±0.37毫米）。前参考点的平均误差低于右后（1.72±0.24毫米）和左后点（2.05±0.47毫米）。尽管手术经验不同，但操作员之间在误差方面未发现显著差异。外科医生的反馈是可以接受的；所有测试均在15分钟内完成，并且该工具在实际操作中被认为既舒适又可用。
我们使用了一种新的无需定位器的头戴式、可穿戴、立体、视频透视显示器，开发了一种有用的策略，使外科医生能够获取增强现实信息。我们的设备在用于辅助无导板上颌骨重新定位时似乎是准确的。我们的结果表明，该方法可能潜在地扩展用于面部骨骼的许多手术程序。此外，我们的积极结果表明，进行体内测试以评估实际临床条件下的手术精度是合适的。
