Simulation Training System Of Virtual Knee Arthroscopy

Arthroscope technology is a minimally invasive surgery, i.e. transmigrating inside the joint cavity with optical transmission system of miniature camera, and a medical treatment to realize diagnosis of the joint disease and surgical treatment. It has been widely used for clinical diagnosis and treatment of osteal joint disease at china and abroad because of the minimally invasive procedure and fast postoperative rehabilitation for the patients. However, its operation manner is difficult, thus learner is hard to master this technology within a short time. The inexperienced physicians are often difficult to recognize the operating direction, leading to the operation time increased. In the case of not mastering the handling technique, the important structure inside the joint cavity is easy to be damaged, which makes the patients painful, increases the cost of surgery and wastes medical resources. Therefore, research and development of the training system of virtual arthro-endoscope operation is extremely important. The traditional endoscope training courses only limit in operation of simulator and experimentation on animals. However, the former mode is excessively simple and the other mode is so hard to utilize for the restricted human and material resources.In recent years, Virtual Reality (VR) technology has been used widely on splanchnoscopy training. Implement of virtual endoscopy using VR technology can simulate different kinds of arthroscope operative procedures in the clinical, and make the learner get a lot of training and master key handling techniques in a short time. Although there have been lots of virtual arthroscope used in the training for doctors of joint surgery, all the equipments have defects in expensive cost and poor practicability. In addition, almost all the simulation endoscope devices are depended on import. Now there is no independently developed simulation equipment and technology in our country, so the formed training system remains in recognition of surgical simulation and exploratory stage, it often only provides simulation interface so as to simulate and display the condition that maybe occur during the actual arthroscope operation. This kind of system trains the learners'cognitive ability and theoretical knowledge well. However, it can not do any help in the training of the co-ordination of eyes and hands. Therefore, it benefits solving these problems by research and development of simulation equipment with intellectual property rights, training eye-hand operation and used in large-scale training. Besides, from the long-term perspective, this kind of simulation equipment can promote the popularization and development of arthroscope operation.This paper introduces a system achieving the function of training arthroscope using VR technology. It briefly discusses how to establish 3-dimensional (3D) training model of joint cavity from using the computer 3D visualization technology, and explains the work principle of the system and the production method of this software. Finally, simulation of arthroscope surgical procedure is implemented with computer 3D visualization technology. The trainees can experience actual hand feeling during the clinical operation with the similar optical fiber training handle and operating arm. At the same time, this research designs the experiment to validate the effects of this system on arthroscope training, let the trainees experience the training progress, at the same time, and formulates scientific training program, which will make the trainees fully obtain adequate training in the training environment combined with virtual scene and operating arm. These experimental results fully verify the effects of this virtual system on arthroscopic training. The methods and results of this research are introduced as followed:I Establishment of 3D static and dynamic model of human knee joint cavity and related sceneThis paper analyzes the establishment of knee joint cavity model in 3Ds max2010, and elaborates modeling methods and process of related scene.. Many efficient tools and direct modeling approach provided by this application software can be used in establishing joint cavity model, designing dynamic model and constructing relevant disease models. In this chapter, two typical disease are involved, i.e. corpus liberum and meniscus injury. Based on establishment of the two diseases model, we can extrapolate modeling other joint cavity disease, thus which lays a solid foundation for development of modeling a large number of diseases in the; future.Method:it is chosen joint model of domestic production.1:1 with normal body size, and schematic diagram of joint cavity of Chinese normal human. Normal model and disease model of joint cavity are established with 3D max. The related dynamic model is designed with keyframe, and the scene in upper computer software is formed. During the progress of making joint thigh bone and shin bone, we firstly sketch out a rough shape, change constantly to form an accurate contour, and then continue to add details forming a complex shape, finally the corresponding facies articularis ossium is formed after smoothed and endued with materials. During preparing the structure of ligament, meniscus and shears, we use another modeling method:firstly, create an initial geometry similar with the joint, and then this geometry is sunk to editable grid or polygon, continuously changing and subdividing, finally the model result we want is obtained. After finishing modeling the joint, we establish cartoon model combined with keyframe to express shears opening-closing and the disease model in the second scene. As for meniscal model, we make emargination with Boolean calculation; finally the third scene is formed.Results:joint cavity model, two kinds of disease models and shears opening-closing with 3D max modeling technology, and the contents mainly conclude:(1) cartoon modeling technology of shears opening-closing; (2) dynamic breaking model of corpus liberum; (3) plasty of meniscus injury.Conclusion:the results show that 3D scene established with 3D max has obvious advantages. Particularly, it is easier to understand and operate, so it is very suitable for learning and application by business personnel. In addition, more space for imagination and being modified are remained for the user during the modeling progress. The efficiency of polygon modeling is very high, and a large number of models can be established in a short time. After some revision in details, it is easy to construct the relevant disease models. In the further modeling, we will carefully divide more details, and make more materials express the realization of the model.II Development and implementation of virtual joint system softwareThis chapter describes operating environment of 3D Model assembly software, gross structure of the software, functional description of work flow and software.Methods:language used for software development is standard C++, rendering block uses the open-source rendering engine OGRE which is most popular now. The overall structure of the software is divided into three state machines and a management class of state machine. Every state machine is in charge of managing a scene, including loading, updating and destruction of scene resource. Management class of state machine is in charge of managing every state machine, including driving state machines active currently every frame, and adding or deleting a state machine. Input system uses OIS (DirectInput capsulation), the function of input system is to capture the user's input every frame. In this way, users'requests can be fed back to the system. Loading resources system uses Dotscene, and scene document can be analyzed with this system while loading the resources. And then, all the mesh, light, camera animate, and so on are loaded during the scene. The loading results are fed back to the current state machine.Results:three scenes are designed, (1) cartoon modeling technology of shears opening-closing; (2) dynamic breaking model of corpus liberum; (3) plasty of meniscus injury. At the same time, interface with hardware is formed.Conclusion:each function of the software implements modulatity, meanwhile state machine control is added, which supplies convenient function interface for hardware and a high degree of fluency in software debugging, fully proving that this design is simple and feasible.â…¢Prepare endoscope training handle and operating arm as well as related hardware systemsThis chapter concludes transformation and production of endoscope training handle, hardware constitution of the controller of training handls, the overall process of bottom software, and the communication protocol between controller and the upper machine.Method:firstly this article analyzes which signals need to be processed in the whole system, and the signals need to be collected in the training system are divided as followed:analog signals with shears opening-closing (changed into voltage value); digital signal with keying value (switching signal), and pulse value of photoelectric sensor (impulse signal). Universal Serial Bus (USB) interface is used to communicate with the upper machine. All the STM32F103C8 chips are considered as the principal controller. Controller hardware is divided into power pack, pulse potentiometer, photoelectric sensor signal processing, keystroke handling, AD transformation, USB interface, and other parts. Prepare the corresponding drivers, and fully consider anti-jamming capability of hardware and software so as to improve the reliability and stability of the system. In order to strengthen the reliability of data transmission for controller and the upper machine, there is a communication protocols between the control panel and PC. The data are packaged while being sent and the upper machine perform unpacking treatment of the data also based on communication protocol, while receiving the data.Results:(1) A complete hardware system of endoscope training handle is designed. The left hand simulate operating camera, and the right hand simulate operating shears. (2) Data are exchanged for controller by USB interface similar to the upper machine. In this way, when you operate the training handle, the appropriate action can be seen in the upper machine, which realizes the simulation progress of knee joint-endoscope operating.Conclusion:the training handle with the type of ball arm benefits operating the sensor signals with both hands, and the hardware system is sensitive with transduction and reorganization of the signal with strong capacity of resisting disturbance. The entire transforming progress is smooth, suggesting the mechanical equipment is coordinated with hardware configuration.â…£Initial practice of simulation training system of knee joint endoscope operationIn this chapter, we use browse mode with one hand in the virtual systemscan, removal the corpus liberum and perform meniscectomy with both hands. The training effect of virtual joint endoscope system is evaluated by the training for interne compared with the professional joint doctor so as to determine its practicability in arthroscope training. Method:subjects are interne from 3 different kinds of university and joint surgeons from different hospitals. The experimental period is from Mar.1,2009 to Mar.30,2010. In experiment 1, the trained doctors and non-training doctors are compared with the experts with actual clinical operations. In experiment 2, the results of the members in the above three groups are compared, and record the results of each group. The thoughts in the expert group and intern group are evaluated by 28 questions about training system. The first part of the questionnaire concludes first impression for simulation system, design, user interface, and other questions. The subjects answer in a rating scale from 1 (Very poor) to 10 (very useful). The second part of the questionnaire concludes the problems of training capacity about simulation system. The third part of the questionnaire concludes the questions about the willing to accept the system training and the system price. The data are analyzed by SPSS 13.0.Results:during general impression, most numerical value inclines to good (above 7). There is no significant difference between the expert surgeons group and surgical intern group. Training capacity and responsibility:the overall training capacity and a majority of responsibility are evaluated as good, and the mean score is about 8. As for the reaction to representation,81.6% of the subjects consider the system is generally useful in training endoscopic technique for resident physician,72% of the subjects agree simulation system benefits training cooperation ability between hands and eyes.70.8% of all the subjects believe that it is useful for the training inside the hospital, and 62.5% of all the subjects consider simulation system benefits the training at home. About half of the surgeons (50%) point that simulation system can be used in detecting endoscopic technique. In the real clinical operations, the performance obtained by the experts is much better than that received by untrained physician, which has a significant difference. In addition, the performance obtained by trained physician is obviously better than that received by untrained physician, which has a significant difference. During virtual system operation, the results obtained by the experts are not better than that received by untrained physician, which has no significant difference. In addition, the performance obtained by trained physician is obviously better than that received by untrained physician, which also has a significant difference.Conclusion:this training system combines the real endoscope instrument with the software, which provides a more realistic training environment of endoscopic surgery with sense of sight and touch for the learner. It benefits in being familiar with internal structure of the joint cavity, mastering the arthroscopic operation skill, and improving operation level for the learner. Therefore, it should be widely applied in arthroscopic clinical training. In the future development research, we can establish more disease models based on the existing grounding to simulate different kinds of arthroscope surgery. At the same time, this training system can be further developed cross-specialty and applied in the training of the surgery of belly cavity, thoracic cavity, and uterine cavity.