Novel Laparoscopic Home Trainer Arturo Minor Martinez, PhD and Daniel Lorias Espinoza, MD
Background: Minimum-invasion surgery is performed by means of 2-dimensional visual feedback and without haptic sensitivity. This demands that specialty surgeons adapt to and develop new psychomotor abilities. These abilities can only be learned. developed, and maintained through training. Training technology has been divided into virtual trainers and physical trainers. The former, due to their high cost, have not had the expected academic impact, whereas the latter, although an excellent lowcost alternative, d o not offer the visual handling options for refining the required psychomotor abilities. The purpose of this article is to describe the design of a box trainer which can establish a closer relationship with the visual and functional perspectives of optics during surgery, thus establishing better learning protocols. Methods: A laparoscopic surgery trainer was designed and built based on the shape of the abdominal cavity formed during such surgery. The visual feedback is achieved with a color minicamera whose position and orientation are controlled by means of a magnetic system with 0 and 45-degree optics options. Results: A trainer which allows for changes in visual perspective, for developing abilities and skills, with optics other than those of 0 degrees within a geometric space similar to that of the pneumoperitoneum has been designed. Conclusions: A training system which provides illumination and visual perspective conditions similar to those of real surgery using 0 and 45degree optics has been designed. The training system is portable and easy to connect for training purposes. Its ports allow for various options that help to improve skills and propose new approaches.
Key Words: home trainer, training, laparoscopic surgery, endoscopy
(Surg Laparosc Endosc Percutan Tech 2007;17:300-302)
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inimurn-invasion surgery is performed through twodimensional visual feedback and without sensitivity. This demands that surgeons adapt to and develop new and improved visual-motor skills. These abilities can Received for publication April 1 I, 2006;accepted March 8, 2007. From the Cinvestav IPN (Centro de Investigacion y de Estudios Avanzados del IPN), AV Instituto Politecnico Nacional Col., San Pedro Zacatenco, Mexico, D.F, Mexico. Reprints: Daniel Lorias Espinoza, MD, Cinvestav IPN (Centro de Investigacion y de Estudios Avanzados del IPN), AV Instituto Politecniw Nacional Col., San Pedro Zacatenco, Mexico, D.F, Mexico 07360 (e-mail:
[email protected]). Copyright O 2007 by Lippincott Williams & Wilkins
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only - be learned, developed, and maintained through training.'-3 Training systems for laparoscopy are basically of 2 types: physical and virtuaL4-' Virtual reality trainers take the surgeon through various skill levels, from basic games to specific surgical procedures that are very similar to reality. The high cost of this technology, however, limits its use. On the other hand, physical trainers are an excellent low-cost alternative that allows surgeons to train on physical models in a real world and interact with physical circumstances similar to those of real surgery. Physical trainers, however, offer only a 0-degree optics'option and d o not have mechanisms for dynamic handling of the optics. The availability of virtual trainers for teaching and training is prohibitively expensive in our country. Nevertheless, residents, and surgeons need access to training systems that allow them to learn and train with visual tools that closely emulate surgical real it^.^ It was for this reason that the design of a physical trainer with visual perspective handling options, as well as 0 and 45-degree optics options, was proposed as part of a learning and training program in laparoscopic surgery at the Hospital Federico G b m e z .
MATERIALS AND METHODS Technology The design of the laparoscopy training system was based on normal operating room conditions, .such as a semicylindrical cavity with several entry ports, uniform model illumination, 0 and 45-degree optics options, and temporary modification of the optics position. To reproduce the pneumoperitoneum, the training box was made semicylindrical. The box has 6 entry ports; the viewing system is introduced through one port and the surgical instruments are introduced through the others. The visual recording system (which replaces the laparoscope) is a commercially available 32 mm x 32 m m lowcost mini-color video camera with a 3.7-mm p i n h ~ l elens and an RCA-to-BNC plug connector. This mini-camera with its original optics makes it possible to observe the inside of the trainer and establish the natural 0-degree visual feedback. The image can be viewed by connecting the camera to any commercially available television. The trainer walls are translucent so the surgeon in training must work with the visual feedback from the monitor. The uniform illumination of the model is achieved using a commercially available 8 W cool white light fluorescent lamp, together with the semicylindrical
Surg Laparosc Endosc Percutan Tech Volume 1 7, Number 4, August 2007
Surg Laparosc Endosc Percutan Tech
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Novel Laparoscopic Home Trainer
shape of the trainer and its white interior, as can be observed in Figure 1, applying 0-degree optics. An accessory was designed to achieve 45-degree optics with the same camera. The accessory has a mirror that changes the viewing optics by 45 degrees without loss of focus, as shown in Figure 2. A polar displacement system with a magnetic adjustment was designed to change the camera orientation, as shown in Figure 3. The position of the camera is manipulated manually from outside the trainer. The movements possible are left, right, up, down, in, and out. This mechanism replaces the assistant and maintains, with minimum manual effort, the position and orientation of the optics within the work space. In addition, the system rotates the camera in both directions, which is necessary to handle the 45-degree optics. This system provides an inverted-cone working space, similar to that encountered in real laparoscopic surgery.
Experimental Evaluation Evaluation was done together with technical development. Visual quality was the first item evaluated. The mini-camera used has 480-line resolution. This is the resolution of a good commercially available television in our country, so image sharpness was excellent. The camera resolution can be fully exploited by any commercially available television. The visual workspace was evaluated and adjusted. The evaluation is of the workspace that can be achieved with the polar camera positioning system. Our evaluation showed that the polar system describes an inverted cone 10 cm in diameter and 17 cm in length. Adjustment refers to the focus at which the camera operates. The focus is not evaluated, but rather adjusted to establish its optimum setting. The adjustment method involves manually changing the camera focus in conjunction with a graduated Cartesian system. The camera focus is experimentally adjusted at a distance of IOcm, to achieve a work area of 6cm 2, distally, and 3cm2, proximally, without changing focus, as shown in Figure 4. The focal distance is very important, given that, when moving in or out, there is a 4 to 7cm range in
FIGURE 1. Trainer with animal model; zero-degree optics. 0 2007
Lippincolt Williams & Wilkins
FIGURE 2. A and B, Trainer with animal model; emulation of 45-degree optics. which the surgical instruments do not interfere with the optics and conditions for working on the model are good. The camera focus can be manually adjusted for greater magnification, but this requires a decrease in the focal
FIGURE 3. Magnetic system for positioning and fixing the camera.
Martinez and Espinoza
Surg Loporosc Endosc Percutan Tech
Volume 17, Number 4, August 2007
physical and virtual trainers is a factor that limits the standardization of academic methods for training in this specialty. The cost of virtual trainers has not adequately justified the set of abilities that can be learned solely from physical trainers. For this reason, we believe an attempt should be made to bring together the best of technologies, integrating improved visual capabilities and optics handling, but incorporating physical models to train in the loss of haptic sensitivity and hand-eye adaptability with different optics, at a cost that is affordable for our residents and public hospitals. We believe that providing training tools with a functional similarity to that of surgical scenarios will help residents adapt more quickly to such scenarios.
CONCLUSIONS The trainer designed offers a'shadowless image of the model and good visual resolution. The visual perspective modification system allows for autonomy and establishes the same inverted-cone workspace that exists in specialty surgeries. The system offers various 0-degree optics with all the close-up and rotation options. The trainer weighs 5 kg, which makes it portable and ideal for teaching. The equipment is plug-and-play, so it can be connected to any television for training and technique refinement, both in a hospital and at home. As part of the equipment evaluation process, we have established a learning-training protocol with medical residents at the Hospital Federico Gdmez, to evaluate with this trainer hand-eye adaptability times and the handling of both optics using the Mistels technique. REFERENCES
FIGURE 4. Magnetic system for positioning and fixing the
camera. distance, causing the instruments to interfere with the camera and rendering the trainer useless.
DISCUSSION In recent years, laparoscopic surgery has .diversified into various specialties, supported by new technological developments and state-of-the-art instrumentation. In any of these specialties, however, training is an inescapable step. The technological and cost gap between
1. Torkington J, Smith SGT. Rees B, et al. The role of the Basic Surgical Skills course in the acquisition and retention of laparoscopic skill. Surg Endosc. 200 1;15: 1071-1075. 2. Fried GM, Feldman LS, Vassiliou MC, et al. Proving the value of simulation in laparoscopic surgery. Ann Surg. 2004;3:51E-525. 3. Derossis AM, Fried GM. Abrahamowia M, et al. Development of a model for training and evaluation of laparoscopic skills. Am J Surg. 1998;6:482-487. 4. Dauster B, Steinberg AP, Vassiliou MC, et al. Validity of the MISTELS simulator for laparoscopy training in urology. JEndourol. 2005;5:54 1-545. 5. Munz Y, Kumar BD, Moorthy K, et al. Laparoscopic virtual reality and box trainers-Is one superior to the other? Surg Endosc Other Interventional Techniques. 2004;3:485-494. 6. Youngblood PL, Srivastava S, Curet M, et al. Comparison of training on two laparoscopic simulators and assessment of skills transfer to surgical performance. J Am Coll Surg. 2005;4:546551. 7. Blacker M R . How to build your own laparoscopic trainer. J Endourol. U)05;6:748-752. 8. Korndorffer JR, Stefanidis D, Scott DJ. Laparoscopic skills laboratories: current assessment and a call for resident training standards. Am J Surg. 2006; 1:17-22.
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