[Preoperative Virtual Reality Simulation Regarding the Appropriate Port Location for Thoracoscopic Surgery for the Mediastinal or Chest Wall Lesions].

In thoracoscopic surgery for mediastinal or chest wall lesions the suitable position of ports( trocars) are required depending on the position of a target lesion in a particular patient. We have therefore developed a virtual reality (VR) simulation system using the specific data of each individual patient. The model data generation system, PASS-GEN, is customized for thoracic surgery. The chest wall and organs around the tumor are extracted from DICOM image data of computed tomography (CT) scan, and three-dimensional (3D) virtual images are constructed. Rehearsal of ports insertion is carried out by locating the scope and the forceps anywhere on the chest wall on PC monitor. The constructed VR images clearly show three dimensional relationships between the target and surrounding structures. This system also simulates circumstances where on the chest wall a thoracoscope and tools should be inserted for the better view and more comfortable manipulation. Particularly in mediastinal or chest wall surgery VR simulation is more practical because those structures would be less transformed during operation.

How to reduce the risk of organ injuries during surgical instrument insertion in laparoscopic surgery: Pushing/pressing force analysis using forceps with sensors.

INTRODUCTION: In laparoscopic surgery, surgical instruments are inserted from a trocar to the target organ in a blind fashion, which carries a risk of organ injury. To clarify the risks associated with surgical instrument insertion, we measured grip strength and pushing/pressing force during surgical instrument insertion in laparoscopic surgery. METHODS: Using forceps with sensors inside a trocar, 10 urologists performed a laparoscopic procedure in pigs, in which they were asked to touch the abdominal wall. The surgeons closed their eyes during the procedure and stopped moving the forceps when they felt them come into contact with the abdominal wall. They were ordered to grip the forceps strongly or softly and to move them rapidly or slowly during the procedure. Grip strength and the pushing/pressing force when the forceps hit the abdominal wall were measured and analyzed. RESULTS: The mean pushing/pressing force when the surgeons gripped the forceps strongly and moved them rapidly (strong/rapid), strongly/slowly, softly/rapidly, and softly/slowly were 2.8, 2.0, 1.7, and 1.1 N, respectively. The pushing/pressing force was significantly greater when the surgeons gripped the forceps strongly, regardless of the forceps speed (P < .001). The pushing/pressing force was significantly greater when the surgeons moved the forceps rapidly, regardless of grip strength (P < .001). CONCLUSIONS: When surgeons insert laparoscopic instruments through trocars, the instruments should be gripped softly and moved slowly to avoid organ injuries.

Comparison of the performance of experienced and novice surgeons: measurement of gripping force during laparoscopic surgery performed on pigs using forceps with pressure sensors.

BACKGROUND: Laparoscopic surgical techniques are difficult to learn, and developing such skills involves a steep learning curve. To ensure surgeons achieve a high skill level, it is important to be able to measure and assess their skills. Therefore, it is necessary to understand the performance differences between experienced and novice surgeons, as such information could be used to help surgeons learn laparoscopic skills. We examined the differences in gripping and reaction force between experienced and novice surgeons during laparoscopic surgery. METHODS: We measured the gripping force generated during laparoscopic surgery performed on pigs using forceps with pressure sensors. Several sensors, including strain gauges, accelerometers, and a potentiometer, were attached to the forceps. This study included 4 experienced and 4 novice surgeons. Each subject was asked to elevate the kidney in order to approach the renal hilus using the forceps. Throughout the experiment, we measured the gripping force and reaction force generated during the movement of the forceps in real time. RESULTS: The experienced and novice surgeons exhibited similar reaction force levels. Conversely, gripping force differed significantly between the groups. The experienced and novice surgeons exhibited mean gripping force levels of 3.06 and 7.15 N, respectively. The gripping force standard deviation values for the experienced and novice surgeons were 1.43 and 3.54 N, respectively. The mean and standard deviation gripping force values of the experienced surgeons were significantly lower than those of the novice surgeons (P = 0.015 and P = 0.011, respectively). CONCLUSIONS: This study indicated that experienced surgeons generate weaker but more stable gripping force than novice surgeons during laparoscopic procedures.

Measurement of the Physical Properties during Laparoscopic Surgery Performed on Pigs by Using Forceps with Pressure Sensors.

Objectives. Here we developed a unique training system, a patient specific virtual reality simulator, for laparoscopic renal surgery. To develop the simulator, it was important to first identify the physical properties of the organ. Methods. We recorded the force measured during laparoscopic surgery performed on pigs by using forceps with pressure sensors. Several sensors, including strain gauges, accelerometers, and a potentiometer, are attached to the forceps. Results. Throughout the experiment, we measured the reaction force in response to the forceps movement in real time. Conclusions. The experiment showed the possibility of digitizing these physical properties in humans as well.

Dynamic measuring of physical properties for developing a sophisticated preoperative surgical simulator: how much reaction force should a surgical simulator represent to the surgeon?

The acquisition of physical quantities for a living body in surgery is an important and necessary step toward developing a sophisticated preoperative surgical simulator and its validation and navigation. We have developed a multimodal measuring device that minimizes interference with the movements of the surgeon. We conducted nephrectomy surgery using a laboratory animal and successfully acquired physical quantities. From this experiment, we have acquired the following preliminary result. The surgeon feels a gripping force from -3.5 to 4.4N at the handle of the forceps for dissection. We assume that this data is not far from that of a human.

Development of a patient-specific simulator for laparoscopic renal surgery.

OBJECTIVES: To describe the development of a patient-specific simulator for laparoscopic renal surgery. METHODS: Image data of each patient scheduled to undergo laparoscopic renal surgery are captured by the simulator, enabling each patient's organs to be reproduced. The surgeon can carry out a preoperative "rehearsal" of the operation by using a simulator based on patient-specific data. RESULTS: The simulator is programmed to be adapted to both laparoscopic and retroperitoneoscopic surgery. The scope and the trocars can be located anywhere on the skin, and visualized on the monitor of the simulator. Dissection of the renal hilum can be simulated based in the anatomy of each patient. The haptic device of the simulator provides interactive resistance between the organs and surgical tools during the simulation. CONCLUSIONS: This patient-specific simulator has been developed with the purpose of providing surgeons with a practical training tool for laparoscopic renal surgery. Using specific data for each patient, the simulator enables surgeons to carry out a "rehearsal" operation.

A development of surgical simulator for training of operative skills using patient-specific data.

At the Advanced Medical Research Center at Yokohama City University School of Medicine, we have been developing a practical surgical simulator for renal surgery. Unlike already commercialized laparoscopic surgical simulators, our surgical simulator is capable of using patient-specific models for preoperative training and improvement of laparoscopic surgical skills. We have been evaluating the simulator clinically with the aim of using it in renal surgery training at Yokohama City University Hospital. The simulator can be applied to other types of laparoscopic surgery, such as gynecological, thoracic, and gastrointestinal. Here, we report on the technical aspects of the simulator.