Glutathione Peroxidase Revisited—Simulation of the Catalytic Cycle by Computer-Assisted Molecular Modelling

Glutathione peroxidase, the first example of selenoproteins identified in mammals, was subjected to force field calculations and molecular dynamics in order to enable a clearer comprehension of enzymatic selenium catalysis. Starting from the established X-ray structure of bovine GPX, all kinetically defined intermediates and enzyme substrate complexes were modelled. The models thus obtained support the hypothesis that the essential steps of the catalysis are three distinct redox changes of the active site selenium which, in the ground state, presents itself at the surface of selenoperoxidases as the center of a characteristic triad built by selenocysteine, glutarnine and tryptophan. In GPX, four arginine residues and a lysine residue provide an electrostatic architecture which, in each reductive step, directs the donor substrate GSH towards the catalytic center in such a way that 1ts sulfhydryl group must react with the selenium moiety. To this end, different equally efficient modes of substrate binding appear possible. The models are consistent with substrate specificity data, kinetic pattern and other functional characteristics of the enzyme. Comparison of molecular models of GPX with those of other members of the GPX superfamily reveals that the cosubstrate binding mechanisrns are unique for the classical type of cytosolic glutathione peroxidases but cannot operate e. g. in plasma GPX and phospholipid hydroperoxide GPX. The structural differences between the selenoperoxidases, shown to be relevant to their specificities, are discussed in terms of functional diversification within the GPX superfamily

Orthopaedic education in the era of surgical simulation: Still at the crawling stage

Surgical skills education is in the process of a crucial transformation from a master-apprenticeship model to simulation-based training. Orthopaedic surgery is one of the surgical specialties where simulation-based skills training needs to be integrated into the curriculum efficiently and urgently. The reason for this strong and pressing need is that orthopaedic surgery covers broad human anatomy and pathologies and requires learning enormously diverse surgical procedures including basic and advanced skills. Although the need for a simulationbased curriculum in orthopaedic surgery is clear, several obstacles need to be overcome for a smooth transformation. The main issues to be addressed can be summarized as defining the skills and procedures so that simulation-based training will be most effective; choosing the right time period during the course of orthopaedic training for exposure to simulators; the right amount of such exposure; using objective, valid and reliable metrics to measure the impact of simulation-based training on the development and progress of surgical skills; and standardization of the simulation-based curriculum nationwide and internationally. In the new era of surgical education, successful integration of simulation-based surgical skills training into the orthopaedic curriculum will depend on efficacious solutions to these obstacles in moving forward.

Exploring the use of virtual reality in surgical education

Virtual reality(VR)technologies have rapidly developed in the past few years.The most common application of the technology,apart from gaming,is for educational purposes.In the field of healthcare,VR technologies have been applied in several areas.Among them is surgical education.With the use of VR,surgical pathways along with the training of surgical skills can be explored safely,in a cost-effective manner.The aim of this mini-review was to explore the use of VR in surgical education and in the 3D reconstruction of internal organs and viable surgical pathways.Finally,based on the outcomes of the included studies,an ecosystem for the implementation of surgical training was proposed.

Application Experience of Eyesi Operation Simulation Training System in the Teaching of Cataract Surgery for Ophthalmology Masters

Objective:To explore the application effect of the Eyesi surgical simulator in the teaching of cataract surgery for professional ophthalmology postgraduate students.Methods:The professional postgraduate students who were trained in the third year of ophthalmology at the First Affiliated Hospital of Xi’an Medical University were selected as the research objects.After passing the theoretical examination,they were randomly divided into the pig eyeball group,Eyesi group,and pig eye+Eyesi group,with 5 students in each group.The pig eyeball,Eyesi surgery simulator,and pig eye+Eyesi surgery simulator were used for microscopic technique operation and cataract surgery steps training,respectively.After the training,the overall training effects of the three groups of postgraduates were scored,and questionnaires were used to objectively evaluate the three training methods.Results:The scores of the students in the pig eye+Eyesi group were better than those in the Eyesi group,and the students in the Eyesi group were better than those in the pig eyeball group.Conclusion:The Eyesi surgical simulation training system can evaluate the microsurgical skills of professional masters and improve their surgical skills.This system is of great significance for the training of the cataract surgery skills of professional masters.

A virtual reality based surgical skills training simulator for catheter ablation with real-time and robust interaction

Background Atrial fibrillation(AF)is the most common sustained cardiac arrhythmia that can cause severe heart problems.Catheter ablation is one of the most ideal procedures for the treatment of AF.Physicians qualified to perform this procedure need to be highly skilled in manipulating the relevant surgical devices.This study proposes an interactive surgical simulator with high fidelity to facilitate efficient training and low-cost medical education.Methods We used a shared centerline model to simulate the interaction between multiple surgical devices.An improved adaptive deviation-feedback approach is proposed to accelerate the convergence of each iteration.The periodical beating of the human heart was also simulated in real time using the position-based dynamics(PBD)framework to achieve higher fidelity.We then present a novel method for handling the interaction between the devices and the beating heart mesh model.Experiments were conducted in a homemade simulator prototype to evaluate the robustness,performance,and flexibility of the proposed method.Preliminary evaluation of the simulator was performed by medical students,residents,and surgeons.Results The interaction between surgical devices,static vascular meshes,and beating heart mesh was stably simulated in a frame rate suitable for interaction.Conclusion Our simulator is capable of simulating the procedure of catheter ablation with high fidelity and provides immersive visual experiences and haptic feedback.

Clinical application of improved 2D computer-assisted fluoroscopic navigation through simulating a 3D vertebrae image to guide pedicle screw internal fixation

Objective To study the effect of using improved 2D computer-assisted fluoroscopic navigation through simulating 3D vertebrae image to guide pedicle screw internal fixation.Methods Posterior pedicle screw internal fixation,distraction

Understanding the effects of structured self-assessment in directed,self-regulated simulation-based training of mastoidectomy:A mixed methods study

Objective:Self-directed training represents a challenge in simulation-based training as low cognitive effort can occur when learners overrate their own level of performance.This study aims to explore the mechanisms underlying the positive effects of a structured self-assessment intervention during simulation-based training of mastoidectomy.Methods:A prospective,educational cohort study of a novice training program consisting of directed,self-regulated learning with distributed practice(5x3 procedures)in a virtual reality temporal bone simulator.The intervention consisted of structured self-assessment after each procedure using a rating form supported by small videos.Semi-structured telephone interviews upon completion of training were conducted with 13 out of 15 participants.Interviews were analysed using directed content analysis and triangulated with quantitative data on secondary task reaction time for cognitive load estimation and participants’self-assessment scores.Results:Six major themes were identified in the interviews:goal-directed behaviour,use of learning supports for scaffolding of the training,cognitive engagement,motivation from self-assessment,selfassessment bias,and feedback on self-assessment(validation).Participants seemed to self-regulate their learning by forming individual sub-goals and strategies within the overall goal of the procedure.They scaffolded their learning through the available learning supports.Finally,structured self-assessment was reported to increase the participants’cognitive engagement,which was further supported by a quantitative increase in cognitive load.Conclusions:Structured self-assessment in simulation-based surgical training of mastoidectomy seems to promote cognitive engagement and motivation in the learning task and to facilitate self-regulated learning.

Need for simulation in laparoscopic colorectal surgery training

The dissemination of laparoscopic colorectal surgery(LCS) has been slow despite increasing evidence for the clinical benefits, with a prolonged learning curve being one of the main restrictions for a prompt uptake. Performing advanced laparoscopic procedures requires dedicated surgical skills and new simulation methods designed precisely for LCS have been established: These include virtual reality simulators, box trainers, animal andhuman tissue and synthetic materials. Studies have even demonstrated an improvement in trainees' laparoscopic skills in the actual operating room and a staged approach to surgical simulation with a combination of various training methods should be mandatory in every colorectal training program. The learning curve for LCS could be reduced through practice and skills development in a riskfree setting.

Novel computer-assisted method for revision arthroplasty of the knee

AIM: To introduce the navigation system of software and instruments designed specifically for revision total knee arthroplasty(TKA).METHODS: We present an imageless navigation system for revision TKA,with optical point and tracker identification to assess kinematic and anatomical landmarks.The system automatically positions the cutting guides with a motorized cutting unit.The cutting unit is placed on the distal femur with a femoral clamp and acts as a rigid body and the base for all femoral cuts.The surgical technique for using the navigation system for revision TKA is based on the technique used in primary TKA.However,there are some important differences.The most notable are:(1) differences in estimation of the position of the primary implant relative to the bone and the mechanical axes;(2) the specific possibilities the revision navigation software offers in terms of optimal joint level positioning; and(3) the suggested "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are taken into account to find the optimal femoral component position.We assessed the surgical technique,and accompanying software procedural steps,of the system,identifying any advantages or disadvantages that they present.RESULTS: The system aims to visualize critical steps of the procedure and is intended as a tool to support the surgeon in surgical decision-making.Combining a computer-assisted cutting device with navigation makes it possible to carry out precise cuts without pinning.Furthermore,the femoral clamp provides a stable fixation mechanism for the motorized cutting unit.A stable clamp is paramount in the presence of periarticular bony defects.The system allows the position of the primary implant relative to the bone and mechanical axes to be estimated,at which point any malalignments can be corrected.It also offers an optimal joint level position for implantation,and suggests a "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are considered.The surgeon can therefore make decisions intraoperatively to maximise alignment and,hence,outcomes.Based on the intraoperative findings of joint stability,the surgeon can modify the preoperative plan and switch from a constrained condylar system to a hinged version,or vice versa.CONCLUSION: The system is flexible and easy to learn and allows improvements in workflow during TKA.

Computer-Assisted Surgery for Mandibular Reconstruction Using a Patient-Specific Titanium Mesh Tray and Particulate Cancellous Bone and Marrow

Craniomaxillofacial surgery is difficult due to the complexity of the regional anatomy. Computer-assisted surgery is a promising tool aiming to improve the safety and precision of such surgery. A computer-assisted surgical navigation approach for reconstruction of mandibular defects using a patient-specific titanium mesh tray and particulate cancellous bone and marrow (PCBM) harvested from bilateral anterior ilia is proposed. This case report involves a large multicystic ameloblastoma affecting the right mandible of a 31-year-old male patient. Following detailed clinical examination, radiological interpretation, and histopathological diagnosis, computer-assisted surgical simulation with a virtual 3-dimensional (3-D) model was designed using surgical planning software based on the pre-operative computed tomography data. Long-span segmental resection of the mandible was planned, and the defect was analyzed for reconstruction using a patient-specific reconstruction titanium mesh tray mediated with computer-aided design and manufacturing (CAD/CAM) techniques. During the actual surgery, the ultrasonic bone cutting instrument in the surgeon’s hand was connected to the navigation system to touch an anatomical position on the patient. Therefore, osteotomies were performed finely and smoothly according to the navigation images of the cutting bone line by sequentially moving the instrument. Finally, a CAD/CAM-mediated titanium mesh tray condensed by PCBM was adapted to the remaining mandibular fragments. Six months postoperatively, the patient had a good mandibular configuration and facial contour. Integration of different technologies, such as software planning and 3-D surgical simulation, combined with intraoperative navigation and CAD/CAM techniques, provides safe and precise mandibular reconstruction surgery.

A new robot-assisted orthopedic surgery simulation system

The paper proposes a novel desktop virtual surgical simulation system capable of not only surgical training but also operative planning, surgery rehearsal and telesurgery, which is mainly used on the robot-assisted orthopedic surgery system, HIT-RAOS. The paper first introduces the hardware system: HIT-RAOS. Then presents several major characters of the virtual system: developing tools, building schemes and collision detection algorithm. Additionally, virtual reality based telesurgery is implemented. Based on these works, experiments of locking of intramedullary nails are conducted, and results are content.

宫腔镜模拟在妇产科技能培训中的应用

宫腔镜是现阶段妇产科医师需掌握的必备手术技能之一,但鉴于宫腔镜检查和手术的特殊性,使其难以通过对患者进行实际操作来提高手术技能。宫腔镜模拟培训是提高医学生及住培医师宫腔镜技能的重要手段,近年来得到国内外学者的重视。文章以国际上最新的研究结果为基础,结合中南大学湘雅三医院宫腔镜培训的经验,对宫腔镜模拟培训的必要性、现阶段宫腔镜模拟培训内容的设置、宫腔镜模拟培训模型的种类及优缺点、宫腔镜模拟培训采用的不同评价体系进行了总结和分析,提示开展相应的宫腔镜模拟培训可在一定程度上提高住培医师对宫腔镜操作的自信心和兴趣,也可以提高其相应的手眼协调能力和基本手术技能,为宫腔镜模拟培训的开展提供一定的参考依据。

肺穿刺活检手术的术前演练系统研究

为解决CT引导下经皮肺穿刺活检(Percutaneous CT-guided Needle Biopsy,PCNB)对操作者要求高、术后并发症风险高等问题,设计了一个肺穿刺活检手术的术前演练系统。首先根据8位肺肿块患者CT图像分割出胸部重要器官,并基于分割结果建立病人各异的三维模型。在此基础上采用基于网格形变的方法实现穿刺过程中肺部软组织的形变模拟,并以Geomagic Touch X为基础,搭建了带有触觉反馈的肺穿刺活检术前演练环境。临床医生在行肺穿刺前使用本系统对这8位患者进行肺穿刺演练,探索合适的穿刺路径。将术前演练结果与临床实际穿刺结果对比发现两者有较好的一致性。主观问卷调查结果表明系统具有较高的真实性和易操作性。系统可用于医生进行术前演练,辅助确定合适的手术方案,提高穿刺效率和手术成功率。

脊柱微创手术患者的围手术期快速康复外科理念护理干预作用

目的探讨脊柱微创手术患者行围手术期快速康复外科护理的效果。方法研究时间2022年1月至2023年1月,研究对象为开展脊柱微创手术的患者80例,以随机数字表法分为两组,观察组40例,对照组40例。对照组行常规护理,观察组行快速康复外科护理。观察两组住院时间、视觉模拟评分(VAS)、Fugl-Meyer运动功能评分(FMA)、日常生活能力评分(BI)、脊柱功能评分(SFI)及功能障碍评分(ODI)情况。结果护理后观察组住院时间比对照组短,且VAS评分比对照组低(P<0.05);护理后观察组FMA评分比对照组高(P<0.05);护理后观察组BI评分比对照组高(P<0.05);护理后观察组SFI评分比对照组高,且ODI评分比对照组低(P<0.05)。结论快速康复外科理念用于脊柱微创手术患者围手术期护理中的效果较好,可使患者的脊柱功能得到恢复,疼痛有所缓解,并且有效缩短了住院时间,具有应用价值。

一种鼓膜穿刺模型及其在耳鼻咽喉科教学实践中的应用

目的设计一种鼓膜穿刺模型,并将该模型应用到教学中,探讨其在鼓膜穿刺术培训中的价值。方法利用简易装置设计一种鼓膜穿刺模型,将该模型应用于鼓膜穿刺术培训。选取的培训对象为海军军医大学2019级八年制无军籍学员37人,将学员随机分入实验教学组和常规教学组,其中实验教学组18人,常规教学组19人。两组同时进行常规理论授课,理论授课结束后进行临床见习;临床见习结束后,实验教学组进行鼓膜穿刺模型实践操作4学时,常规教学组观看鼓膜穿刺教学视频4学时。课程结束后,分别对两组行综合能力自我评估和手术操作考核评估。结果教学效果评价显示,实验教学组综合能力自我评估得分显著高于常规教学组[(88.22±3.04)分比(77.95±2.87)分,P<0.01],实验教学组专业学习兴趣、实践操作能力显著高于常规教学组(均P<0.01);实验教学组手术操作考核评估得分显著高于常规教学组[(73.72±3.30)分比(65.68±2.95)分,P<0.01],实验教学组在解剖结构熟悉情况、操作熟练程度均显著高于常规教学组(均P<0.01)。结论该鼓膜穿刺模型,设计简便,将其应用于临床教学中,可显著提高鼓膜穿刺术成功率,降低不良事件发生率,提高教学效果。

Stable Real-Time Surgical Cutting Simulation of Deformable Objects Embedded with Arbitrary Triangular Meshes

Surgical simulators need to simulate deformation and cutting of deformable objects. Adaptive octree mesh based cutting methods embed the deformable objects into octree meshes that are recursively refined near the cutting tool trajectory. Deformation is only applied to the octree meshes; thus the deformation instability problem caused by degenerated elements is avoided. Biological tissues and organs usually contain complex internal structures that are ignored by previous work. In this paper the deformable objects are modeled as voxels connected by links and embedded inside adaptive octree meshes. Links swept by the cutting tool are disconnected and object surface meshes are reconstructed from disconnected links. Two novel methods for embedding triangular meshes as internal structures are proposed. The surface mesh embedding method is applicable to arbitrary triangular meshes, but these meshes have no physical properties. The material sub-region embedding method associates the interiors enclosed by the triangular meshes with physical properties, but requires that these meshes are watertight, and have no self-intersections, and their smallest features are larger than a voxel. Some local features are constructed in a pre-calculation stage to increase simulation performance. Simulation tests show that our methods can cut embedded structures in a way consistent with the cutting of the deformable objects. Cut fragments can also deform correctly along with the deformable objects.

The status of surgical simulation

ultiple academic organizations, administrative _authorities, and some commercial bodies in medicine have accepted the fact that simulation has become crucial and brought tremendous changes in surgical education and training] When integrated into surgical education and training system, simulation not only improves the quality of surgical service by upgrading surgeons＇ skills and decreasing time to the mastery of various critical techniques, but also secures the safety of patients.

交互式外科护理学虚拟仿真教学实践及应用效果分析

目的 探讨人机交互式外科护理学虚拟仿真教学实践及应用效果分析。方法 于2020年下半学年选取南方医科大学2018级护理学本科4个班级共180人作为研究对象,1班、2班共90人为试验组,3班、4班共90人为对照组。试验组90名护生结合虚拟仿真教学平台进行外科护理学虚拟仿真教学;对照组90名护生采用传统的集中讲授方法教学。8周后通过发放问卷调查(沉浸体验、学习感受、理论掌握、实践能力)及操作考核,分析比较两组学生学习体验与考核成绩。结果 试验组护生在沉浸体验、学习感受、实践能力3个维度上得分显著高于对照组(P=0.001、0.014、0.032);在理论掌握维度上得分差异无统计学意义(P>0.05);试验组护生操作考核得分[(85.91±4.09)分]显著高于对照组[(83.21±3.86)分],差异具有统计学意义(P<0.001)。结论 人机交互虚拟仿真教学模式有助于促进学生将知识技能内化吸收,提高外科临床护理操作水平,提高外科护理学教学效果。

年轻眼科医师基于手术模拟器的小切口白内障囊外摘除手术培训的有效性评估

目的:探讨基于手术模拟器操作训练在眼科年轻医师小切口白内障囊外摘除手术培训的有效性评估。方法:前瞻性对照研究。选取2020/2022年在沈阳何氏眼科医院已完成至少3a住院医师规范化培训的眼科专业住院医师或刚取得主治证书的眼科主治医师共48名为研究对象,通过小切口白内障囊外摘除手术相关理论培训及考核后,随机分为模拟器手术操作训练组(试验组)和实体动物眼手术操作训练组(对照组),每组各24名。试验组和对照组医师分别使用手术模拟器和猪眼进行训练。训练结束后使用手术模拟器和实体猪眼操作对两组研究对象进行考核评分,并对两组医师的总体培训效果进行有效性评估。结果:手术模拟器考核评分及用时比较,试验组研究对象在各步骤考核用时均低于对照组(均P<0.05)。试验组研究对象在角膜穿刺注入黏弹剂、娩核及水密角膜穿刺口操作评分与对照组比较均无差异(P>0.05),其余步骤评分,试验组均高于对照组(均P<0.05)。实体动物眼考核评分,试验组研究对象各步骤考核评分均高于对照组(均P<0.05)。试验组研究对象在巩膜切口、角巩膜隧道、连续环形撕囊、水分离及转核至前房、娩核步骤手术模拟器与实体动物眼考核评分比较均无差异(P=0.068、0.126、0.960、0.520、0.206);在穿刺注入黏弹剂、隧道穿刺进入前房及水密角膜穿刺口考核中,模拟器评分均低于实体动物眼(P=0.007、0.014、<0.01);在皮质吸除、人工晶状体植入操作考核时模拟器评分要高于实体动物眼操作评分(P=0.035、<0.01)。结论:将手术模拟器操作训练应用于眼科年轻医师小切口白内障囊外摘除手术技能培训,可以显著提升医师的白内障显微手术操作技能,为建立眼科年轻医师规范化的白内障手术培训提供了新的模式及思路。

外科住院医师规范化培训结业考试单中心成绩分析

目的分析外科住院医师规范化培训(简称住培)结业考试成绩,阐明外科住培结业考试通过率的一般规律,找出提升外科住培结业考试通过率的有效方法。方法首都医科大学附属北京友谊医院外科专业基地2017年至2021年共有252名住院医师参加北京市外科住培结业考试,考试科目有理论、临床技能两项,均合格才能通过结业考试。2020年和2021年,外科专业基地强化过程教学,严格模拟手术训练课程的实施,注重提高住培教学质量的内涵。收集252名住院医师在外科专业基地结业当年直至结业3内参加北京市外科住培结业考试两个科目的全部成绩。结果252名住院医师第1次考试理论通过率为97.6%,第2次考试理论累计通过率即达到100.0%;第1次考试技能通过率为91.7%,至第5次考试技能累计通过率才达到100.0%。经过严格过程教学的年份首考通过率(95.3%~98.2%)明显高于未经过严格过程教学年份的通过率(84.2%~87.7%)。结论结业考核对外科住培的实施具有良好的指导和检验作用,多数住院医师能够在两次以内通过住培结业考试,技能考试的难度高于理论考试,外科专业基地过程教学的严格管理有助于提高首考通过率。