Increasing the Realism of a Laparoscopic Box Trainer: A Simple,Inexpensive Method

Introduction

In recent years, surgical training has gone through fundamental changes, which affect the traditional learning of skills. The operating room was traditionally the place for the trainee surgeon to learn technical, behavioral, and cognitive skills by observing and assisting a more senior surgeon. However, due to the reduction of working hours, time in the operating room has decreased dramatically. ¹ Junior surgeons are thus exposed to fewer patients than in the past. Further, with the pressing need to improve patient safety, the traditional Halstedian approach of “see one, do one, teach one” is no longer regarded as adequate. ² It is vital that supplemental training methods are established. One possible training method, currently attracting large-scale attention, is simulation-based education. According to the chief medical officer in the United Kingdom, simulation-based training will form an important part in bridging the skills gap in the future. ¹ In the United States, simulation is integral to the newly proposed curriculum by the ACS/APDS. ³

Simulations have the potential to address many limitations of traditional training without jeopardizing patient safety. ⁴ Constant technologic improvement means that simulators for educating health care professionals continue to grow with increasing fidelity. ⁵ Such high-fidelity simulations have been shown to be educationally effective. ⁶ Further, skills acquired in simulation also transfer to the real theater setting. ⁷ Studies have also shown that surgeons trained on simulators demonstrate a reduced learning curve, compared to those without such training. ¹

With the advancement of minimally invasive surgery, many three-dimensional (3D) open surgical fields are being replaced by 2D video images. ⁸ Sophisticated virtual reality (VR) simulators can now provide recreations of laparoscopic procedures that are anatomically realistic. The simulators provide inbuilt metrics, which enable technical performance to be recorded, measured, and used for structured feedback. ⁹ Despite providing a high level of realism, VR simulators are expensive and access is thus limited. VR simulators can range from $40,000 to $100,000, depending on the number of modules purchased. Further, this cost does not take into consideration maintenance and upgrade costs. ⁸

Physical bench-top models, such as the box trainer, provide an inexpensive alternative to VR simulators. Traditionally, a black neoprene skin is placed over the open plastic abdomen, in which laparoscopic ports and instruments can be inserted. The trainee can then learn how to manipulate instruments, for instance, by stacking sugar cubes placed in the box. A standard box trainer costs approximately £975 ($1,463) (e.g., VAT). ⁸ Although significantly less expensive than a VR simulator, box trainers lack in visual and tactile realism. For instance, the inside and outside of box trainers are made of either white or grey plastic, thus being far from the actual human color of the abdominal cavity.

This is important, because realism plays an crucial part in simulation and “cannot be overstressed”. ¹⁰ Ideally, surgeons and residents should train with tools that closely emulate surgical reality. Realism could be enhanced by covering a box trainer with surgical drapes and bringing it into context by placing it into a simulated or real operating room. However, due to a lack of resources of simulated facilities, this might not always be possible. An alternative approach would be not to replicate every detail of a clinical environment or procedure, but rather to replicate clinical cues that tap into actual memory. These cues seem to be sufficient to build a realistic representation. ¹¹ In this article, a simple, inexpensive method is described to enhance the visual realism of a box trainer by recreating the visual cues of the human abdomen.

Materials and Methods

A body torso laparoscopic trainer (model BTS300D; Pharmabotics Ltd., Hampshire, UK), commonly known as a “box trainer,” is the shape of a human torso (Fig. 1A). The standard box trainer is white, but is also available in grey and transparent. The box trainer allows both animal and synthetic models to be placed inside the cavity (Fig. 2A). A piece of black-colored neoprene material covers the cavity and allows laparoscopic instruments to be placed through ports inserted into the neoprene material (Fig. 3A).

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FIG. 1.

(A) Standard box trainer. (B) “Modified” box trainer.

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FIG. 2.

(A) Standard box trainer with animal model. (B) “Modified” box trainer with animal model.

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FIG. 3.

(A) Standard box trainer with neoprene skin. (B) “Modified” box trainer with silicone skin.

In an effort to enhance the realism of the abdominal cavity, the standard box trainer was modified from using inexpensive materials. Digital images of the abdominal cavity were captured from the Simbionix^™ LAP Mentor^™ (Simbionix, Cleveland, OH) during a laparoscopic cholecystectomy procedure. The “management” mode of the LAP Mentor was used so that the images were free from text captions, which assist the trainee by detailing the objectives of the task during training modules. The digital images were transferred and saved onto a memory stick. The images were then taken to a nonspecialized printing company, which modified the images to remove the simulated shadows that give the impression of the curvilinear shape of the abdominal cavity. The images were copied and pasted next to one another in order to obtain the required size. The images were then printed onto a laminated card (approximately 0.5 mm thick). In order to omit any reflections created by the light source of the laparoscopic camera, the laminated card was printed with a matte finish. Two laminated sheets of card, of sizes A0 (841 × 1189 mm) and A3 (297 × 420 mm), lined the bottom and sides of the box-trainer cavity. The total cost of printing was £90 (approximately $135). The flexible nature of the laminated card allows the card to be carefully placed in a curvilinear manner akin to the abdominal wall (see Fig. 1B. The card was attached to the box trainer by using nonspecialized double-sided tape. Like the standard box trainer, the laminated surface of the card allows animal and synthetic models to be placed inside the cavity without damaging the card, thus making the card reusable (Fig. 2B). Further, the laminated surface of the card allows the images to be wiped clean with a damp cloth, if soiled when using animal or synthetic models.

To further enhance the visual realism of the box trainer, the black-colored neoprene, which simulates the skin of the torso, was replaced with a low-cost silicone model (Fig. 3B). Like the black-colored neoprene, the silicone skin covers the abdominal cavity and allows surgical instruments to be placed through ports inserted into the skin (Fig. 4B). The silicone skin is visually realistic and is attached to the body torso laparoscopic trainer by using Velcro tape. The silicone skin costs approximately £300 ($450) and was designed and produced by a prosthetic designer. Again, however, it can be reused on multiple occasions. The total cost for increasing the realism of the body torso, using the methods described above, was approximately £390 ($585).

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FIG. 4.

(A) Standard box trainer, draped. (B) “Modified” box trainer, draped.

Results

Discussion

The use of simulation in surgical education, training, and assessment is rapidly increasing. The chief medical officer in the UK has envisaged that simulation-based training will form a fundamental role in bridging the skills gap in the future. ¹ Realism is an important element in creating an optimal training environment. A simple, inexpensive, yet effective, method to enhance the visual realism of a box trainer was described above.

The method discussed in this article is not intended to replace the use of VR simulators in surgical training. However, due to the considerable cost gap between VR simulators and physical trainers, the use of VR simulators in surgical training is limited to a relatively small number of centers. Widely available, physical trainers offer a low-cost alternative to VR simulators, yet they often lack visual realism. Realism is an important element in creating an effective training setting. ¹¹ Thus, the goal should be to enhance the level of realism in simulation (i.e., minimize the gaps between the simulated and clinical environment) to a level that ensures that there are not too many gaps that are wide from reality. ¹¹ Although there have been other examples in the literature of novel box trainers or home trainers,^12,13 these rely upon developing a box trainer from the very beginning. This may require significant time and may not be the most economic approach. Conversely, the method described in this article can be used as an adjunct to increase the realism of box trainers that already exist—making this technique highly adaptable and less resource intensive. Further, not only did this method minimize the visual gap between a standard box trainer and real laparoscopic surgery, it was also found to be extremely effective by end-users.

The method described above is not without limitations. To replicate the method described, access to a VR simulator is required. However, we suggest that this limitation can be overcome by capturing digital images during a real surgical procedure. Also, although we only described the technique for a laparoscopic cholecystectomy, it can potentially be used to increase the realism of any intra-abdominal procedure. This technique could be incorporated into any surgical skills training course, such as the Basic Surgical Skills course in the UK or the Fundamentals of Laparoscopic Surgery (FLS) training program in the United States. Doing so would help create a more realistic environment that closely emulates surgical reality. This may facilitate the suspension of disbelief in a manner that maximizes simulation engagement and provides optimal learning outcomes.

Conclusions

A simple, inexpensive, yet effective, method of enhancing the visual realism of the widely accessible box trainer was developed. The model was evaluated from using both quantitative and qualitative methodologies. Results suggest that the method described above enhances the visual realism of the box trainer. It would thus be beneficial to incorporate this method in the training of laparoscopic skills.