Mixed Reality Combined with Three‐Dimensional Printing Technology in Total Hip Arthroplasty: An Updated Review with a Preliminary Case Presentation

Three‐dimensional (3D) printing technology, virtual reality, and augmented reality technology have been used to help surgeons to complete complex total hip arthroplasty, while their respective shortcomings limit their further application. With the development of technology, mixed reality (MR) technology has been applied to improve the success rate of complicated hip arthroplasty because of its unique advantages. We presented a case of a 59‐year‐old man with an intertrochanteric fracture in the left femur, who had received a prior left hip fusion. After admission to our hospital, a left total hip arthroplasty was performed on the patient using a combination of MR technology and 3D printing technology. Before surgery, 3D reconstruction of a certain bony landmark exposed in the surgical area was first performed. Then a veneer part was designed according to the bony landmark and connected to a reference registration landmark outside the body through a connecting rod. After that, the series of parts were made into a holistic reference registration instrument using 3D printing technology, and the patient's data for bone and surrounding tissue, along with digital 3D information of the reference registration instrument, were imported into the head‐mounted display (HMD). During the operation, the disinfected reference registration instrument was installed on the selected bony landmark, and then the automatic real‐time registration was realized by HMD through recognizing the registration landmark on the reference registration instrument, whereby the patient's virtual bone and other anatomical structures were quickly and accurately superimposed on the real body of the patient. To the best of our knowledge, this is the first report to use MR combined with 3D printing technology in total hip arthroplasty.     

Application of an augmented reality tool for maxillary positioning in orthognathic surgery – A feasibility study

BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered.     

血管介入仿真模拟器在心血管医生冠状动脉介入技术规范化培训中的作用

目的明确Angiomemor（美国Simbionix公司生产）血管介入仿真模拟器是否有助于冠状动脉造影技术的掌握和提高。方法选取16名无血管放射介入经验的心血管医生，接受相同课时的冠状动脉介入造影理论培训后，按随机表编码随机分为模拟器培训组与非培训组各8名，模拟器培训组8名医生接受Angiomemor血管介入仿真模拟器培训，模拟冠状动脉造影操作，非培训组8名心血管医生未接受仿真模拟器培训。在随后的真实临床环境中操作冠状动脉造影时，评价2组医生冠状动脉造影操作过程中错误的频数、平均造影时间、造影剂使用量及术中放射线剂量。结果相对于非培训组，模拟器培训组医生在冠状动脉造影操作中错误频数减少62．5％、平均造影时间减少44．0％、造影剂使用量减少44．0％，术中平均放射线曝光时间减少了57．7％，平均X线累计曝光剂量减少51．6％，单位面积X线累计曝光剂量减少了52．4％。结论Angiomemor血管介入仿真模拟器有助于医生较快地熟练掌握冠状动脉造影技术，是冠状动脉介入规范化培训的重要辅助手段之一。     

胡塞尔现象学本质直观理论初析

胡塞尔继承了西方哲学史上的本质主义路线，严格区分事实和本质、形式本质和实质本质，提出了他的现象学本质观。本质观使我们对“本质”的了解获得了从柏拉图主义和洛克主义、实在论和唯名论非此即彼之争中挣脱出来的可能。     

虚拟现实互动技术在交叉韧带等长重建计算机辅助设计中的应用

目的 利用虚拟现实技术还原膝关节骨性结构在屈伸运动过程中的三维空间形态，为观测膝关节面交叉韧带附丽区的相对位置变化和进一步研究前、后交叉韧带等长重建最佳等长点提供计算机辅助设计新方法。方法 采用实验与计算机仿真相结合的方法，对新鲜人体膝关节标本进行屈伸运动实验，并通过激光三维扫描方法记录、计算膝关节的空间活动指标，然后重建膝关节计算机三维模型。通过实验中的空间活动指标控制此模型虚拟运动，再现膝关节各屈伸角度下股骨、胫骨和腓骨的空间位置。结果 计算机还原出各运动角度下膝关节骨性结构（股骨、胫骨及关节面）的空间形态，利用软件Geomagic的几何计算功能可分别测量模型中各个运动状态交叉韧带附丽区两点间的三维空间距离。讨论本研究方法可以真实地记录和再现膝关节三维运动过程，从空间结构上更精确、合理地寻找重建等长点，对膝关节交叉韧带手术重建有重要临床意义。     

基于脑-机接口技术的虚拟现实康复训练平台

对神经损伤的瘫痪病人进行功能恢复训练时应强调患者的主动参与。开发了一套基于脑-机接口技术的虚拟现实康复训练平台。该平台采用患者在想象运动时的脑电信号作为虚拟人运动的控制信号,从而把想象运动与运动功能恢复训练结合在一起。由于虚拟现实系统的实时性与沉浸感能给受试者提供较好的训练反馈信息,因此,使用本平台有望改善患者的训练效果。详细介绍了快速在线脑-机接口算法以及虚拟现实的实时交互技术,并提供了三名受试者的实测结果。初步实验证明了该平台设计的可行性。     

The histological changes in transbronchial biopsy after treatment of acute lung rejection in heart-lung transplants

Transbronchial lung biopsies taken during episodes of acute lung rejection in heart-lung transplant patients were examined histologically. When the diagnosis was confirmed by microscopy, the patients were treated with augmented immunosuppression by high-dose corticosteroids. A second biopsy was obtained an average of 23.5 days after commencement of treatment. These biopsies were examined to determine the histological changes caused by treatment. In most cases, there were both quantitative and morphological differences between the infiltrates in acute rejection and in the remaining perivascular infiltrates after treatment. In acute rejection, 26 of 28 biopsies contained perivascular lymphocytic infiltrates, lymphocytes being large and blast-like. Although 20 of 28 follow-up biopsies still contained perivascular infiltrates, they were smaller and the lymphocytes smaller in size. Half the biopsies in rejection contained neutrophils, but less than half contained eosinophils in the perivascular infiltrates. After treatment, all these cells were less numerous. Another feature of treated rejection was the presence of haemosiderin around vessels suggesting earlier acute vascular injury. However, haemosiderin persists long after the cellular infiltrate has disappeared and cannot be considered a reliable feature of recently treated acute lung rejection. The bronchiolar infiltrates showed a similar pattern of responses to the perivascular infiltrates.     

Color Rendering in Medical Extended-Reality Applications

Cross-platform development of medical applications in extended-reality (XR) head-mounted displays (HMDs) often relies on game engines with rendering capabilities currently not standardized in the context of medical visualizations. Many aspects of the visualization pipeline including the characterization of color have yet to be consistently defined across rendering models and platforms. We examined the transfer of color properties from digital objects, through the rendering and image processing steps, to the RGB values sent to the display device. Five rendering pipeline configurations within the Unity engine were evaluated using 24 digital color patches. In the second experiment, the same configurations were evaluated with a tissue slide sample image. Measurements of the change in color associated with each configuration were characterized using the CIE 1976 color difference (ΔE). We found that the distribution of ΔE for the first experiment ranges from zero, as in the case using an Unlit Shader, to 25.97, as in the case using default configurations. The default Unity configuration consistently returned the highest ΔE across all 24 colors and also the largest range of color differences. In the second experiment, ΔEE ranged from 7.49 to 34.18. The Unlit configuration resulted in the highest ΔE in three of four selected pixels in the tissue sample image. Changes in color image properties associated with texture import settings were then evaluated in a third experiment using the TG18-QC test pattern. Differences in pixel values were found in all nine of the investigated texture import settings. The findings provide an initial characterization of color transfer and a basis for future work on standardization, consistency, and optimization of color in medical XR applications.