UNASSIGNED: To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap.
UNASSIGNED: Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases.
UNASSIGNED: Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months.
UNASSIGNED: In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.
UNASSIGNED: 探讨在游离腓骨皮瓣修复下颌骨缺损中，使用混合现实技术定位穿支血管的可行性和效果。.
UNASSIGNED: 2020年6月—2023年6月，采用游离腓骨皮瓣修复12例下颌骨缺损患者。男8例，女4例；年龄35～78岁，平均61岁。下颌骨成釉细胞瘤9例，侵犯下颌骨口腔鳞癌3例。病程15 d～2年，中位病程14.2个月。下颌骨缺损长度5～14 cm，平均8.5 cm；软组织缺损范围为5 cm×4 cm～8 cm×6 cm。术前均行颌面部增强CT和下肢CT血管造影检查，将所得数据制成下颌骨、下肢穿支血管三维模型。术中使用混合现实技术将穿支血管三维模型重叠于患者体表，制取游离腓骨皮瓣修复缺损。腓骨切取长度为6～15 cm，平均9.5 cm；皮瓣切取范围6 cm×5 cm～10 cm×8 cm，供区拉拢缝合（7例）或游离植皮修复（5例）。.
UNASSIGNED: 12例患者术前使用混合现实技术定位穿支血管30支，每例平均2.5支；术中测量术前定位穿支血管穿出点与实际穿出点距离为1～4 mm，平均2.8 mm。术后12例腓骨瓣顺利成活；1例皮瓣远端边缘坏死，换药后延期愈合。供区发生感染1例，经抗炎换药治疗后愈合；其余患者切口Ⅰ期愈合，植皮顺利成活。患者均获随访，随访时间8～36个月，中位时间21个月。修复面部外形好，皮瓣无臃肿。3例术后接受放化疗患者中，随访6个月时2例正常骨愈合、1例延迟愈合。.
UNASSIGNED: 在游离腓骨皮瓣修复下颌骨缺损手术中使用混合现实技术，可以实现穿支血管三维可视化，手术操作简便，误差较小。.

OBJECTIVE: To evaluate the feasibility and application value of mixed reality technology (MR) in Primary retroperitoneal tumour (PRT) surgery.
METHODS: From 276 patients who underwent PRT resection at the First Affiliated Hospital of Xi\'an Jiaotong University, we screened 46 patients who underwent MR-assisted retroperitoneal tumour resection and 46 patients who underwent tumour resection without MR assistance. The intraoperative and postoperative recovery of the patients in both groups were compared, and the reliability and validity of the application of MR were further examined using the Likert scale.
RESULTS: There was a significant difference in the mean intraoperative bleeding volume between the two groups, but it was reduced in the MR group. The results of the Likert scale showed higher scores in the MR group than non-MR group.
CONCLUSIONS: MR can be used to assist PRT resection and has great potential to improve the rate of complete retroperitoneal tumour resection.

UNASSIGNED: It is clinically challenging to accurately drill femoral and tibial tunnels to reconstruct the anterior cruciate ligament (ACL). Mixed reality (MR) technology, a further development of virtual reality technology, presents virtual scene information in real time and establishes an interactive feedback information loop among the real world, the virtual world, and the user.
UNASSIGNED: The purpose of this study was to investigate the structural and early clinical outcomes of ACL reconstruction assisted by MR technology. It was hypothesized that MR technology would improve the accuracy of tunnel localization.
UNASSIGNED: Cohort study; Level of evidence, 3.
UNASSIGNED: Included were 44 patients at a single institution who underwent arthroscopic single-bundle ACL reconstruction between June 2020 and March 2022. Reconstruction with the aid of MR technology was performed in 21 patients (MR group), and conventional arthroscopic reconstruction was performed in 23 patients. Postoperatively, the parameters related to the bone tunnel positioning were compared by computed tomography imaging with 3-dimensional (3D) reconstruction, and 12-month postoperative clinical outcomes were assessed with the Lysholm and International Knee Documentation Committee scores.
UNASSIGNED: There was no statistically significant difference in projection angles in the coronal, axial, or sagittal plane between the preoperative virtually created tunnel guide pin and the actual tunnel (P > .05 for all). In the MR group, the center of the femoral tunnel exit was closer to the apex of the lateral femoral condyle along the proximal-distal axis (14.07 ± 4.12 vs 17.49 ± 6.24 mm for the conventional group; P < .05) and the graft bending angle was lower (117.71° ± 8.08° vs 127.81° ± 11.91° for the conventional group; P < .05). The scatterplot of the femoral tunnel location distribution showed that the entrance and exit points in the MR group were more concentrated and closer to the ideal location of the preoperative design than in the conventional group. Patients in both groups had significant preoperative-to-postoperative improvement based on outcome scores (P < .001 for all), with no significant difference between groups.
UNASSIGNED: ACL reconstruction with the aid of MR technology allowed for more accurate positioning and orientation of the femoral tunnel during surgery when compared with conventional reconstruction.

BACKGROUND: Mixed Reality technology may provide many advantages over traditional teaching methods. Despite its potential, the technology has yet to be used for the formal assessment of clinical competency. This study sought to collect validity evidence and assess the feasibility of using the HoloLens 2 mixed reality headset for the conduct and augmentation of Objective Structured Clinical Examinations (OSCEs).
METHODS: A prospective cohort study was conducted to compare the assessment of undergraduate medical students undertaking OSCEs via HoloLens 2 live (HLL) and recorded (HLR), and gold-standard in-person (IP) methods. An augmented mixed reality scenario was also assessed.
RESULTS: Thirteen undergraduate participants completed a total of 65 OSCE stations. Overall inter-modality correlation was 0.81 (p = 0.01), 0.98 (p = 0.01) and 0.82 (p = 0.01) for IP vs. HLL, HLL vs. HLR and IP vs. HLR respectively. Skill based correlations for IP vs. HLR were assessed for history taking (0.82, p = 0.01), clinical examination (0.81, p = 0.01), procedural (0.88, p = 0.01) and clinical skills (0.92, p = 0.01), and assessment of a virtual mixed reality patient (0.74, p = 0.01). The HoloLens device was deemed to be usable and practical (Standard Usability Scale (SUS) score = 51.5), and the technology was thought to deliver greater flexibility and convenience, and have the potential to expand and enhance assessment opportunities.
CONCLUSIONS: HoloLens 2 is comparable to traditional in-person examination of undergraduate medical students for both live and recorded assessments, and therefore is a valid and robust method for objectively assessing performance. The technology is in its infancy, and users need to develop confidence in its usability and reliability as an assessment tool. However, the potential to integrate additional functionality including holographic content, automated tracking and data analysis, and to facilitate remote assessment may allow the technology to enhance, expand and standardise examinations across a range of educational contexts.

BACKGROUND: The COVID-19 pandemic necessitated changes to the traditional medical ward round to protect staff and patients. This study investigated the value and acceptability of using the Microsoft HoloLens 2 mixed reality headset in a COVID-19 renal medicine ward.
METHODS: The HoloLens 2 was used during the height of the COVID-19 pandemic and it was compared with the days prior to its introduction. Staff exposure to COVID-19 and PPE usage were measured, and staff and patients were surveyed on the HoloLens 2 experience.
RESULTS: The average ward round was significantly shorter with the use of the HoloLens 2 (94 minutes vs 137 minutes; p=0.006). With the HoloLens 2, only the consultant was in direct contact with COVID-19 patients compared with up to seven staff members on a normal ward round. Personal protective equipment usage was reduced by over 50%. Both staff and patients were positive about its use but raised some important concerns.
CONCLUSIONS: The HoloLens 2 mixed reality technology is an innovative solution to the challenges posed by COVID-19 to the traditional medical ward round.

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.