Surgical Simulation System Research Articles

Simulating blood accumulation with improved smoothed particle hydrodynamics in surgical simulation system.

Blood accumulation often occurs during bleeding in surgery. Simulating the blood accumulation in surgical simulation system not only enhances the realism and immersion of surgical training, but also helps researchers better understand the physical properties of blood flow. To realistically simulate the blood accumulation during the bleeding, this paper proposes a novel kernel function with non-negative second derivatives to improve the SPH method. Meanwhile, a simple form of boundary force equation is constructed to impose the solid boundary condition. We simulate the blood accumulation during liver bleeding and vessel bleeding respectively in the surgical simulation system. The simulation results show that there is no occurrence of blood physically penetrating the boundary. Applying the solid boundary condition to the blood by using the method proposed in this paper is not only convenient but can also eliminate compression instability in the blood accumulation simulation.

Clinical application of resection process map as a novel surgical guide in thoracic surgery.

Resection Process Map (RPM) is a surgical simulation system that uses preoperative three-dimensional computed tomography. Unlike the usual static simulation, this system provides surgeons an individualized dynamic deformation of the lung parenchyma and vessels. RPM was first introduced in 2020. Although the intraoperative usefulness of this system has been evaluated experimentally, there have been no reports on its clinical use. Herein, we presented in detail the first experience on RPM during robot-assisted anatomical lung resection in the real clinical setting.

Computer-Aided Surgical Simulation through Digital Dynamic 3D Skeletal Segments for Correcting Torsional Deformities of the Lower Limbs in Children with Cerebral Palsy

Torsional deformities of the lower limb are common in children with cerebral palsy (CP)-determining gait problems. The mechanisms underlying transverse plane gait deviations arise from a combination of dynamic and static factors. The dynamic elements may be due to spasticity, contractures and muscle imbalances, while the static ones may result from excessive femoral anteversion, which decreases the efficiency of the hip abductors by reducing the muscular lever arms. A therapeutic approach has been identified in multi-level functional surgery for the lower limb. Treating the malalignments of the lower limb with femoral or tibial derotation provides optimal results, especially when supported by adequate biomechanical planning. This planning requires an integrated static-dynamic approach of morphological and functional evaluation, based on radiological measurements, physical examination and gait analysis. Instrumented gait analysis has been confirmed as essential in the evaluation and surgical decision making process for children affected by CP with transverse plane deformities. Computational simulations based on musculoskeletal models that integrate patient-specific CT morphological data into gait analysis can be used for the implementation of a surgical simulation system in pre-operative planning to test the possible effects of the different surgical treatment options on the torsional defects of the lower limbs. Recently, a computer-aided simulation process has been implemented in the preoperative planning of complex osteotomies for limb deformities in children. Three-dimensional (3D) digital models were generated from Computed Tomography (CT) scans, using free open-source software. The aim of this study is to integrate the patient-specific CT musculoskeletal model with morphological data and gait analysis data, with the personalized calculation of kinematic and kinetic parameters, which allow us to generate an “avatar” of the patient for a more in-depth evaluation of the gait abnormalities. The computational simulation platform proposed provides a realistic movable musculoskeletal model in a virtual environment, with the possibility of planning and monitoring the effects of virtual three-dimensional surgical corrections.

Application of Computer-Aided Design and Individualized Templates for Bilateral Zygomaticomaxillary Complex Fractures.

Reduction of the bilateral zygomaticomaxillary complex (ZMC) fracture with individualized templates based on computer- aided surgical simulation system. To evaluate the practicality and accuracy of this approach in the treatment of bilateral ZMC fracture. Sixteen patients with bilateral ZMC fractures were collected to create a study model. The authors reconstruct the ZMC on one side via the three-dimensional (3D) model, and then mirrored to the opposite side. Multiple individualized templates were made based on the 3D model, and used as intraoperative guidance to reduce fractures. After surgery, the facial symmetry and the position of zygoma were observed. The mouth opening, pupil level, and sensation of infraorbital nerve were evaluated. Some mark points on zygoma were measured and the postoperative horizontal asymmetry rate (H) was calculated. Besides, orbital height and width were measured. For all patients, the position of bilateral ZMC was basically restored. The patients with restriction of mouth opening all recovered to normal. The H values were less than 3.0% at all mark points. There was almost no difference in bilateral orbital width and height. Meanwhile, there was no significant difference between the preoperative measurements of the ideal virtual 3D model and the postoperative measurements of patients. The study proves that application of computer-aided design and individualized templates can accurately guide the reduction operation of ZMC fracture, restore the ideal shape of ZMC, and obtain good facial symmetry.

Application of a virtual and mixed reality-navigation system using commercially available devices to the lateral temporal bone resection

BackgroundLateral temporal bone resection (LTBR) is performed for stage T1-2 external ear malignant tumors and requires spatial anatomical knowledge of the rare surgical field. ObjectiveThis paper presents a novel virtual reality (VR) based surgical simulation and navigation system using only commercially available display device and an online software, to assist in the understanding of the anatomy pre and intraoperatively. Result and conclusionVR model created by 3D Slicer modules and visualized on head mounted display enabled users to simulate and learn surgical techniques of a rare surgical case. 3D hologram through HoloLens assisted the surgeon in comprehending the spatial relationship between crucial vital structures and the pathological lesion during the operation. This platform does not require the users to possess specific programming skill or knowledge, and is therefore applicable in daily clinical usage.

The Fundamentals of Vaginal Surgery pilot study: developing, validating, and setting proficiency scores for a vaginal surgical skills simulation system

Surgical training in the simulation lab can develop basic skills that translate to the operating room. Standardized, basic skills programs that are supported by validated assessment measures exist for open, laparoscopic, and endoscopic surgery; however, there is yet to be a nationally recognized and widely implemented basic skills program specifically for vaginal surgery. Develop a vaginal surgical simulation system; evaluate robust validity evidence for the simulation system and its related performance measures; and establish a proficiency score that discriminates between novice and experienced vaginal surgeon performance. In this 3-phased study, we developed the Fundamentals of Vaginal Surgery simulation system consisting of (1) the Fundamentals of Vaginal Surgery Trainer, a task trainer; (2) a validated regimen of tasks to be performed on the trainer; and (3) performance measures to determine proficiency. In Phase I, we developed the task trainer and selected surgical tasks by performing a needs assessment and hierarchical task analyses, with review and consensus from an expert panel. In Phase II, we conducted a national survey of vaginal surgeons to collect validity evidence regarding test content, response process, and internal structure relevant to the simulation system. In Phase III, we compared performance of novice (first and second year residents) and experienced (third and fourth year residents, fellows, and faculty) surgeons on the simulation system to evaluate relevant relationships to other variables and consequences. Performance measures were analyzed to set a proficiency score that would discriminate between novice and expert (faculty) vaginal surgical performance. A novel task trainer and 6 basic vaginal surgical skills were developed in Phase I. In Phase II, the survey responses of 48 participants (27 faculty surgeons, 6 fellows, and 14 residents) were evaluated on the dimensions of test content, response process, and internal structure. To support evidence of test content, the participants deemed the task trainer and surgical tasks representative of intended surgical field and supportive of typical surgical actions (mean scores, 3.8-4.4/5). For response process, rater-data analysis revealed high rating variability regarding prototype color. This early evidence confirmed the value of a white prototype. For internal structure, there was high agreement among rater groups (obstetricians and gynecologists generalists vs Female Pelvic Medicine and Reconstructive Surgery specialists: interclass correlation coefficient range, 0.59-0.91; learners vs faculty interclass correlation coefficient range, 0.64-1.0). There were no differences in ratings across institution type, surgeon volume, expertise (P>.14). In Phase III, we analyzed performance from 23 participants (15 [65%] obstetricians and gynecologists residents, 3 [13%] fellows, and 5 [22%] Female Pelvic Medicine and Reconstructive Surgery faculty). Experienced surgeons scored significantly higher than novice surgeons (median, 467.5; interquartile range, [402.5-542.5] vs median, 261.5; interquartile range, [211.5-351.0]; P<.001). Based on these data, setting a proficiency score threshold at 400 results in 0% (0/6) novices attaining the score, with 100% (5/5) experts exceeding it. We present validity evidence relevant to all 5 sources which supports the use of this novel simulation system for basic vaginal surgical skills. To complement the system, a proficiency score of 400 was established to discriminate between novices and experts.

Augmented reality-based visual-haptic modeling for thoracoscopic surgery training systems

BackgroundCompared with traditional thoracotomy, video-assisted thoracoscopic surgery (VATS) has less minor trauma, faster recovery, higher patient compliance, but higher requirements for surgeons. Virtual surgery training simulation systems are important and have been widely used in Europe and America. Augmented reality (AR) in surgical training simulation systems significantly improve the training effect of virtual surgical training, although AR technology is still in its initial stage. Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice. MethodsThis study proposed an immersive AR lobectomy within a thoracoscope surgery training system, using visual and haptic modeling to study the potential benefits of this critical technology. The content included immersive AR visual rendering, based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling. Furthermore, we designed an AR haptic rendering systems, whose model architecture consisted of multi-touch interaction points, including kinesthetic and pressure-sensitive points. Finally, based on the above theoretical research, we developed an AR interactive VATS surgical training platform. ResultsTwenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system. Face, content, and construct validation methods were used to assess the tactile sense, visual sense, scene authenticity, and simulator performance. ConclusionsThe results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time. The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices.

Using Operator Gaze Tracking to Design Wrist Mechanism for Surgical Robots

This article assessed how surgical robot parameters influenced operator viewpoint during a simulated surgical procedure. Surgical robots are useful tools in minimally invasive surgery. However, even with robots, suturing is difficult because the needle is sometimes obscured by tissue or manipulators and is thus not always visible during the procedure. This is especially true in pediatric surgery, where the surgical environment is smaller than in adult surgery. Hence, surgeons must carefully track the instruments and tissues to understand and predict their current and expected situations. In this article, we used gaze-tracking techniques to analyze the location and timing of the gaze of participants while they manipulated a virtual robotic surgical simulation system. To differentiate between the ideal and actual viewpoint trajectories, we conducted experiments with and without obstacles (i.e., simulated tissue and the manipulator arm). In the obstacle condition, we modulated the wrist length of the manipulator to bring it into view. In the no-obstacle condition, the participants mostly watched the suture needle tip. In the with-obstacle condition, the participants spent less time watching the instruments and more time watching the target point. The amount of time spent watching the target point increased as wrist length increased. Given this tradeoff relationship, we examined the proportion of time the participants spent looking at the instruments or target points by wrist length. We calculated the Pareto solutions and clarified the relationship between wrist length and the watching parts.

THE MOST REALISTIC SURGICAL SIMULATION MODEL TO GAIN SKILLS IN LAPAROSCOPIC SURGERY IS THE CADAVERIC MODEL THIEL, ACCORDING TO OPINIONS OF DIFFERENT SPECIALIST SURGEONS

Abstract INTRODUCTION Laparoscopic procedures are still a challenge for the surgeon residents and young surgeon physicians. Different learning systems have been used without achieving a realism faithful to the lived in the operation room. All existing surgical simulation systems should be compared, with the aim of identifying the most realistic of them, for improving the surgical learning. MATERIAL AND METHODS An 18-item survey was sent to different specialized surgeons (general surgeons, gynecologists and urologists) who participated in international postgraduate laparoscopic surgery courses on cadavers embalmed by Thiel method. Participants were asked to the differences and improving skills in each surgical procedure, about the different surgical simulation models that the participants had already used. Surgeons were asked if they would recommend doing it during residency to improve their confidence in the operating room. RESULTS Attendees (n = 104) had a response rate of 92% (96 replies). The 91.8% surgeons recognized that Thiel model was more realistic than others simulation methods. The 97.9 % of respondents believed that had improved their surgical skills. Globally, 96.9% (93) of the participants surveyed recommended the conducting of these courses with Thiel cadavers to different colleagues of other specialties as a reliable simulation measure during the residency period. CONCLUSIONS Participants in the laparoscopic surgery course on the cadaver Thiel recognized that this is more realistic surgical simulation model than conventional models, one of the best ways to gain confidence and improve laparoscopic skills in operation room for inexperienced surgeons.

A new geometric combination of cutting and bleeding modules for surgical simulation systems

Background and objectives: Cutting and bleeding are often independent of each other in the traditional virtual surgery system because of the differences in the calculation of physical models and the lack of internal structure. In order to improve the fidelity of virtual surgery scene and the training value for surgeons, a new geometric combination of cutting and bleeding modules is introduced.Methods: In this paper, we introduce a cutting model based on volume rendering and meshless method. The multidimensional parameters derived from the gray values are presented to participate in the calculation of both physical and geometric models, which distinguishes between different adjacent soft tissues. The bleeding simulation with improved physical properties and rendering algorithms of geometric model is proposed to meet several different bleeding states. After cutting procedures, the tearing parts can be judged through the vision and the tactile sensation. The initial velocity and rendering algorithm of bleeding particles are determined by the multidimensional parameters of the cutting position, which realizes the geometric combination of cutting and bleeding modules.Results and conclusions: Simulation results show that tearing different tissue structures will produce corresponding bleeding states. When the skin and flesh are torn, the blood is slowly generated at the incision, and then diffuses to the surface of soft tissue. When the important blood vessels are ruptured, the blood gushes from the laceration. Compared with the conventional virtual surgery system, both visual effect and interactivity of the cutting and bleeding modules are improved in the proposed geometric combination.

Bleeding Simulation With Improved Visual Effects for Surgical Simulation Systems

In surgical simulation, the Navier–Stokes (N–S) equation is commonly employed to imitate the physical characteristics of bleeding and the smooth particle hydrodynamics (SPHs) algorithm is applied to solve the numerical solution of the N–S equation. However, blood is viscous, incompressible and non-Newtonian fluid whose physical properties cannot be fully incorporated by the simple N–S equation, and the kernel approximation of the SPH algorithm may lead to both edge and volume distortions plus high computational cost. In this paper, both the tension force and the effect of platelets on the viscous force of bleeding particles are incorporated into the N–S equation in order to render more realistic visual effect and biological features of bleeding in surgical simulation. Constant core radius of the kernel function of the SPH algorithm is substituted with a function of particle density, avoiding potential edge distortions in simulating bleeding area. A repulsive force between particles is introduced, which effectively prevents volume distortions. Besides, accelerated search for particles based on the cube mesh improves the computational efficiency. The simulation results show that the presented simulation method leads to smooth bleeding surface and improves the visual effects of edge and volume in comparison with existing methods, and relatively high computational efficiency can be achieved as well.

Deformation modeling based on mechanical properties of liver tissue for virtuanormal vectors of trianglesl surgical simulation.

In this paper, a method for rapidly constructing a virtual surgical simulation system is proposed. A deformation model based on the mechanical properties of the liver and a rapid collision detection between the surgical micro-instruments and the liver tissue are included in this method. The purpose of this work is to improve the accuracy and real time of particle model deformation interaction in virtual surgery system. Firstly, a finite element model is established based on the constitutive model parameters of liver tissue. According to the simulation results, a mathematical model of node displacement is established. Secondly, the virtual liver is established based on the fast model reconstruction method, and the virtual manipulator is controlled by Geomagic Touch manipulator. Based on the hybrid bounding box, a rapid collision detection process between the instrument and liver is realized and the proposed deformation method is used to simulate the deformation of liver tissue. The simulation and experiment results show that the proposed deformation model can achieve high deformation interaction accuracy. The collision detection algorithm based on the hybrid bounding boxes can realize the collision between the liver and the instrument, and the established virtual surgical simulation system can simulate the liver tissue deformation in the case of small loading displacement. The effectiveness of the collision detection algorithm and deformation model was verified by an established virtual surgery simulation system. The proposed rapid construction method of virtual surgical simulation is feasible.

Maxillofacial surgical simulation system with haptic feedback

&lt;p style='text-indent:20px;'&gt;Due to the complexity of the maxillofacial surgery, the novice should be sufficiently trained before one is qualified to carry on the surgery. To reduce the training costs and improve the training efficiency, a virtual mandible surgical system with haptic feedback is proposed. This surgical simulation system offers users the haptic feedback while simulating maxillofacial surgery. An integrated model is introduced to optimize the system simulation process, which includes force output to a six-degree-of-freedom haptic device. Based on the anatomy structure of the bone tissue, a two-layer mechanism model is designed to balance the requirement of real-time response and the force feedback accuracy. Collision detection, force rendering, and grinding function are studied to simulate some essential operations: open reduction, osteotomy, and palate fixation. The proposed simulation platform can assist in the training and planning of these oral and maxillofacial surgeries. The fast response feature enables surgeons to design a patient-specific guide plate in real-time. Ten stomatology surgeons evaluated this surgical simulation system from the following four indexes: the level of immersion, user-friendliness, stability, and the effect of surgical training. The evaluation score is eight out of ten.&lt;/p&gt;

Cutting procedures with improved visual effects and haptic interaction for surgical simulation systems

Background and objectives: Surface rendering and physical models with constant parameters are often employed for cutting procedures in conventional surgical simulators. As a consequence, the internal structures of soft tissues cannot be rendered properly and haptic interaction is unrealistic. In order to improve both the visual and force feedback, a new volumetric geometric model is introduced. Methods: In this paper, we introduce a new volumetric geometric model, for which multidimensional parameters are derived from the gray values to map the color and transparency of the 3D soft tissues. In the meantime, the biomechanical properties of soft tissues are described by a meshless physical model and the model parameters are closely correlated to the multidimensional parameters of the developed volumetric geometric model. As a beneficial result, the force feedback changes according to the physical properties of different soft tissue structures, which reflects better the real-life scenarios during the course of cutting procedures. Results and Conclusions: Simulation results show that both the surface and internal structures of soft tissues can be rendered properly and the boundaries between different tissue structures are visually distinct in incision. The curves of feedback force change according to the different structures of soft tissue, improving haptic interaction. Compared with the conventional cutting model, both visual effect and haptic interaction are improved in the proposed volumetric geometric model.

Virtual Surgical Planning and Three-Dimensional Printed Guide for Soft Tissue Correction in Facial Asymmetry.

Fat grafting has become a well-accepted surgical modality to correct soft tissue facial defects and asymmetries with overall good results. Several techniques have been reported over the last few years to assist in improving accurate evaluation of facial defects and in the preoperative planning of the reconstruction. Such techniques include among others, computer tomography, three-dimensional (3D) photogrammetry, high resolution ultrasound, and 3D laser scanning. There are advantages and disadvantages for each technique.With the rapid advance of 3D technologies that have become readily available to clinicians, new clinical applications continually emerge to guide and facilitate reconstructive procedures. The authors explored the possibility of fabricating a 3D printed surgical guide to define volume differences for soft tissue reconstruction in patients with facial asymmetry. The model was developed through the authors' virtual surgical simulation and planning system that consists of computer-assisted design (CAD) and 3D printing (3DP).Three-dimensional volumetric scans of patients' faces were analyzed with computer-aided design to quantify areas of facial asymmetry. Surgical guides with containers defining volumetric differences were fabricated using 3D printing to identify and quantify areas of soft tissue deficiency. The 3D printed patient-specific, guides were sterilized and used by the surgeon intraoperatively to accurately mark the areas of soft deficiency. Thus, facial symmetry was achieved by fat grafting the predetermined volume differences defined in the surgical guides. A postop mask was used by the surgeon at the end of the procedure and during follow-up clinic visit to verify and evaluate accurate fat grafting placement as well as to determine areas where to add volume if needed.This paper details the rational for the authors' approach, outlines the technical planning and fabrication process of these patient-specific custom surgical guides with quantified volumetric containers and their intraoperative use by the surgeon. Despite the authors' limited experience we conclude that the authors' technique offer surgeons a precise means for accurate volumetric reconstruction of facial asymmetry.

The accuracy and stability of the maxillary position after orthognathic surgery using a novel computer-aided surgical simulation system

BackgroundMany reports have been published on orthognathic surgery (OGS) using computer-aided surgical simulation (CASS). The purpose of this study was to evaluate the accuracy of the maxillary repositioning and the stability of the maxilla in patients who underwent OGS using a newly developed CASS program, a customized osteotomy guide, and a customized miniplate.MethodsThirteen patients who underwent OGS from 2015 to 2017 were included. All patients underwent a bimaxillary operation. First, a skull-dentition hybrid 3D image was rendered by merging the cone beam computed tomography (CBCT) images with the dentition scan file. After virtual surgery (VS) using the FaceGide® program, patient-customized osteotomy guides and miniplates were then fabricated and used in the actual operation. To compare the VS with the actual surgery and postoperative skeletal changes, each reference point marked on the image was compared before the operation (T0) and three days (T1), four months (T2), and a year (T3) after the operation, and with the VS (Tv). The differences between ΔTv (Tv-T0) and ΔT1 (T1-T0) were statistically compared using tooth-based reference points. The superimposed images of Tv and T1 were also investigated at eight bone-based reference points. The differences between the reference points of the bone surface were examined to evaluate the stability of the miniplate on the maxilla over time.ResultsNone of the patients experienced complications. There were no significant differences between the reference points based on the cusp tip between ΔTv and ΔT1 (p > 0.01). Additionally, there were no significant differences between the Tv and T1 values of the bone surface (p > 0.01). The mean difference in the bone surface between Tv and T1 was 1.01 ± 0.3 mm. Regarding the stability of the miniplate, there were no significant differences between the groups. The difference in the bone surface between T1 and T3 was − 0.37 ± 0.29 mm.ConclusionsVS was performed using the FaceGide® program, and customized materials produced based on the VS were applied in actual OGS. The maxilla was repositioned in almost the same manner as in the VSP plan, and the maxillary position remained stable for a year.

Surgical navigation technology based on computer vision and VR towards IoT

ABSTRACT The neurotomy is complicated and hard to master, and surgical operation is relatively more difficult, as it requires high on fineness and minimal invasion. Besides, there are not many means for teaching and training of anatomy and operation. The clinical and teaching application of virtual reality technology (VR) has been reported, while the reports on application of augmented reality technology (AR) to application of neurosurgical teaching are seldom. The research attempts to study a surgical operation navigation simulation system in the virtual environment. The critical technologies such as image segmentation, image registration and fusion, three-dimensional reconstruction and virtual cutting, and so on for the virtual surgical navigation simulation system are analyzed. The research on the surgical operation navigation simulation system will be of important significance for precise stereotactic surgery, optimization of operation program, improvement on operational quality and training, etc.

Patient-specific immersive HPB surgery simulation using OsiriX-based 3D printing, virtual reality, augmented reality and mixed reality

Image guided virtual surgical planning 3D technology has improved surgical efficiency and precision. To promote these accuracy and usability, we developed new osirix-based surgical simulation system using virtual reality (VR), augmented reality (AR), and mixed reality (MR) with 3D replicating technology. We developed a spatial surgical simulation system using medical images by interactive superimposing 3D hologram in an actual space. Interactive stereo display was used for the existence of an interaction between the users and stereo images of the patient's anatomy depicted on the display in the form of tracking the useŕs head and hand/arm position. We also developed new technology of bio-texture modeling by multi-material 3D printing. Based on MDCT, regions of interest were segmented using DICOM viewer OsiriX application. After generating an 3D surface, the inkjet 3D printer created a 3D multi-material organ replica. Our system is integrated to 3D organ replication and surgical guidance, obtained augmented tangibility in surgical simulation and navigation. It could manipulate the spatial attributes of the virtual and real printed organs, which can enhance spatial reasoning and augmented tangibility. Permitting the physician to manipulate virtual organs also allowed for the creation of a sense of spatial relations among elements in the display via proprioception. The tangible organ replication with spatial surgical image-guided simulation provided better anatomical reference tool as a tailor-made guidance in laparoscopic surgery, and contribute to medical safety and accuracy, less-invasiveness and improvement of the medical education.

Real-time bone sawing interaction in orthopedic surgical simulation based on the volumetric object

Bone sawing is widely used for mandibular angle reduction. In this paper, we develop a surgical simulator for mandibular angle reduction with real-time collision detection, bone reconstruction and force haptic. A volume-based model was organized following the CT or MRI image sequence arrangement. The surgical instrument was simplified into two triangles in geometric model. Then, a new volume-based collision detection method was used to meet the real-time requirements of the simulator. Currently, most of the bone sawing operations regarded the swept surface as the real cut surface of bone. Due to the high-speed reciprocating of the bone saw operation, we innovatively used Marching Cubes Method for the real-time reconstruction of the bone internal sawing part and provided the users with a fine cutting surface. In addition, to obtain a well virtual effect, a simplified bone removal and reconstruction method is carried out to implement the real-time topological changing of the mandibular surface. This paper presents a mechanistic model for prediction of the force during bone sawing, and the simulated force is similar to the measured force in real surgery. Eventually, we realized the high quality visual rendering and tactile rendering, the refresh rate of the force reaches 1000 Hz, and visual refresh frequency up to 30 Hz. To validate the effectiveness of the system, some experiments of simulator evaluation based on the patient-specific data was constructed. Results shown that the virtual orthopedic surgical simulation system can provide inexperienced interns and students with a low-cost, repeatable surgical training platform.

SOS – Simulated Ocular Surgery website and applications

SummaryThere is growing interest in simulation training for learning surgery: there are huge benefits to patient safety if trainees can gain essential skills before they attempt surgery on real patients. In ophthalmology, traditional simulation attempts have included practicing simple surgical techniques on animal eyes, or perhaps cadaveric human tissue. These approaches, whilst undoubtedly useful, have some disadvantages e.g inability to practice in a completely realistic surgical environment, which would ideally be the trainee surgeon's own operating theatre, also, cadaveric human tissue, whilst excellent, is expensive to obtain, and store. In the last few years, advances in virtual reality, and plastics technology have stimulated widespread interest in more realistic, and less expensive surgical simulation systems, many of which, especially plastic eyes, allow the surgeon to practice in their own operating theatre, in the office using table‐top binocular microscopes, or even practice at home using loupes. I present our experiences with the ‘Simulated ocular surgery’ (SOS) system, across the full range of ocular surgery, with supporting videos of trainees using this system. For further information: simulatedocularsurgery.com.