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.     

计算机辅助手术的发展状况和展望——参加第17届国际计算机辅助放射学及手术大会（CARS 03）后记

计算机辅助手术和治疗(IGST)是一个新兴的多学科交叉的研究领域,近年来取得了飞速的发展.作为该领域顶级会议之一的国际计算机辅助放射学及手术大会(CARS2003)于2003年6月25至28日在英国伦敦伊丽莎白二世国际会议中心隆重举行了第17届会议.本文将对这次大会作一回顾和总结,内容包括科学论文方面的评论和产品展览方面的情况.     

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。     

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.     

Impact of Mixed Cognitive Intervention Training on Early Onset Dementia

ObjectivesThe aim of this study was to investigate the impact of mixed cognitive intervention training using spaced retrieval training, and errorless learning in participants with early onset dementia. This was based on reality orientation therapy for cognitive function, depression, and occupational performance of patients.MethodsTwo early onset vascular dementia patients (> 65 years) with mild or moderate impairment were enrolled in a pre-test - post-test single-subject research design study. Prior to the study, the caregivers were interviewed about meaningful times, people, places, and areas of interest for the participant. A list of individual training words were selected based upon this information, and the participant was instructed to recall them after a 45-second, 90-second, 6-minute, and 12-minute delay. Baseline (3 sessions), intervention (20 sessions), and a second baseline period (3 sessions) were conducted. Activities of daily living were measured, and cognition was measured using the Consortium to Establish a Registry of Alzheimer’s Disease Korean version, whilst depression was measured using the Korean Form Geriatric Depression Scale, and task performance and satisfaction measured by the Canadian Occupational Performance Measure.ResultsAfter intervention, both participants showed improvements in activities of daily living (ADL), word list memory/recognition, trail making A, occupational performance, and satisfaction improvement, which was clinically significant in 1 participant who also had a reduced score in the scale of depression classifying him as not depressed.ConclusionSpaced retrieval training and errorless learning based on reality orientation therapy is an effective intervention in patients with early onset dementia and mild or moderate impairment.     

Imaging breasts with silicone implants

Over the last two decades, the use of breast implants both for breast augmentation and for breast reconstruction following mastectomy has increased substantially. It is estimated that around two million women have undergone breast augmentation, while hundreds of thousands have had breast reconstruction surgery. Different types of material have been used for breast implants, but silicone gel implants have been the dominating implant type. Many implants can lead to complications, such as hardening and rupture, and may therefore need in vivo evaluation by imaging, particularly if they lead to clinical symptoms. They can also pose problems in the assessment of surrounding breast tissue by conventional mammography. In this respect, imaging modalities such as ultrasound, computed tomography and magnetic resonance imaging offer greater possibilities to assess a failing implant, as well as surrounding breast tissue. Several factors, mainly of a psychological nature, lead to requests for breast implants. In this review article, only the imaging aspects of breasts with silicone gel implants will be dealt with. Each modality is concisely presented with its possibilities and limitations. Received: 5 February 1998; Revision received: 18 May 1998; Accepted: 25 May 1998     

Efficacy of virtual reality exposure therapy to treat driving phobia: a case report

An AB case design was used to examine the efficacy of virtual reality exposure therapy (VRET) in treating driving phobia. After a one week baseline, the patient received three treatment sessions over a ten day period. Treatment included practice of four VR driving scenarios. Peak anxiety decreased within and across sessions. Ratings of anxiety and avoidance declined from pre-treatment and post-treatment, with gains maintained at seven month followup. Phobia-related interference in daily functioning similarly decreased. The results suggest that it would be useful to further evaluate the efficacy of VRET for driving phobia in controlled clinical trials.