Table1_Augmented reality hologram combined with pre-bent distractor enhanced the accuracy of distraction vector transfer in maxillary distraction osteogenesis, a study based on 3D printed phantoms.docx

BackgroundVector control is a significant concern in maxillary distraction osteogenesis (DO). Distraction vector planning on the patient's 3D-printed skull phantom is more intuitive for surgeons and cost-efficient than virtual surgical planning. However, the accuracy of transferring the planned vector to intraoperative (vector transfer) according to the shape of the pre-bent footplate alone is relatively limited. The application of augmented reality (AR) in surgical navigation has been studied for years. However, few studies have focused on its role in maxillary DO vector transfer. This study aimed to evaluate the accuracy of AR surgical navigation combined with the pre-bent distractor in vector transfer by comparing it with the pre-bent distractor alone.
MethodsTen patients with maxillary hypoplasia were enrolled with consent, and three identical 3D-printed skull phantoms were manufactured based on per patient's corresponding pre-operative CT data. Among these, one phantom was for pre-operative planning (n = 10), while and the other two were for the AR+Pre-bending group (n = 10) and the Pre-bending group (n = 10) for the experimental surgery, respectively. In the Pre-bending group, the distraction vector was solely determined by matching the shape of footplates and maxillary surface. In the AR+Pre-bending group, the distractors were first confirmed to have no deformation. Then AR surgical navigation was applied to check and adjust the vector in addition to the steps as in the Pre-bending Group.
ResultsFor the angular deviation of the distraction vector, the AR+Pre-bending group was significantly smaller than the Pre-bending group in spatial (p < 0.001), x-y plane (p = 0.002), and y-z plane (p < 0.001), and there were no significant differences in the x-z plane (p = 0.221). The AR+Pre-bending group was more accurate in deviations of the Euclidean distance (p = 0.004) and the y-axis (p = 0.011). In addition, the AR+Pre-bending group was more accurate for the distraction result.
ConclusionsIn this study based on 3D printed skull phantoms, the AR surgical navigation combined with the pre-bent distractor enhanced the accuracy of vector transfer in maxillary DO, compared with the pre-bending technique alone.

背景：牵张矢量控制是上颌骨牵张成骨（maxillary distraction osteogenesis, DO）领域的核心关注点。相较于虚拟手术规划，基于患者3D打印颅骨模型（3D-printed skull phantom）的牵张矢量规划对术者而言更直观，且更具成本效益。然而，仅依据预弯足板（pre-bent footplate）的形态将规划好的牵张矢量转移至术中（矢量转移，vector transfer）的精度相对有限。增强现实（augmented reality, AR）在手术导航中的应用已被研究多年，但鲜有研究关注其在上颌骨DO牵张矢量转移中的应用价值。本研究旨在对比仅使用预弯牵张器（pre-bent distractor）与联合增强现实手术导航的预弯牵张器两种方案的牵张矢量转移精度，以评估后者的应用效果。方法：本研究纳入10例上颌骨发育不全患者并获取其知情同意，基于每位患者的术前CT数据制作3个完全一致的3D打印颅骨模型。其中1个模型用于术前规划（n=10），剩余2个模型分别用于实验手术的AR联合预弯组（n=10）与单纯预弯组（n=10）。单纯预弯组中，牵张矢量仅通过匹配牵张器足板与上颌骨表面的形态确定。AR联合预弯组中，首先确认牵张器无变形，随后在单纯预弯组操作步骤的基础上，借助增强现实手术导航对牵张矢量进行核查与调整。结果：就牵张矢量的角度偏差而言，AR联合预弯组在空间维度（p<0.001）、x-y平面（p=0.002）与y-z平面（p<0.001）的偏差均显著小于单纯预弯组，而在x-z平面（p=0.221）则无显著组间差异。AR联合预弯组在欧氏距离（Euclidean distance）偏差（p=0.004）与y轴偏差（p=0.011）方面精度更高。此外，AR联合预弯组的牵张效果更优。结论：本项基于3D打印颅骨模型的研究表明，相较于单纯预弯技术，联合增强现实手术导航的预弯牵张器可提升上颌骨DO牵张矢量转移的精度。