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Virtual Reality Simulation: The Future of Minimally Invasive Gynecologic Surgical Training

Gregory J. Raff, MD

As minimally invasive surgical techniques are developed and refined, both residents and experienced surgeons are under constant pressure to improve their skills. In many situations, virtual reality simulation (VRS) is proving to be a viable solution.

Over a century ago, Dr William Halstead first proposed what has become the traditional model for surgical education—ie, learning procedures through apprenticeship. With a large volume of surgical cases and time to progress from observer to primary surgeon, this model has served well for open surgical techniques.1 However, improvements in medical management options during the last decade have led to fewer surgical cases for training. Innovative techniques have increased the types of surgeries to be learned, while resident work-hour restrictions have reduced the time available for learning. Economic factors (eg, operating room expenses) and ethical concerns (eg, learning skills on patients) have led educators to reevaluate how resident physicians are trained. Furthermore, the technical advances that allow for minimally invasive surgery (MIS) procedures present unique psychomotor challenges—eg, two-dimensional monocular vision, counterintuitive movements, fixed access points, diminished tactile feedback (haptics). Finally, such technology requires additional training to promote efficient use and understand the limitations. All of these factors have forced educators to reconsider how, when, and where surgical training should occur.2-5

These challenges extend to the practicing physician, who may not have undergone adequate training in MIS prior to graduating residency. There are limited opportunities for these physicians to develop fundamental laparoscopic skills and learn new MIS procedures. Didactic training opportunities include meetings, weekend courses, and industry-sponsored preceptorships emphasizing lectures and telesurgery. “Hands on” training opportunities may include cada-ver anatomic dissection and “pig labs.” All of these methods involve isolated episodes of intensive training, which have been shown to be inferior to multiple episodes of less intense training extended over a longer period of time.6 In an effort to develop a training modality that addresses all of these concerns, educators have stepped out of the real-time operating room and into the virtual reality surgical suite.

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VIRTUAL REALITY SIMULATORS


Surgical simulation offers a safe, relaxed learning environment during which failure does not result in injury to a patient.7 For the novice surgeon, surgical simulation can “train out” the MIS learning curve, allowing the physician to develop proficiency with basic MIS skills before entering the operating room.8 The possibility of using VRS for surgical training was first proposed nearly a decade ago.9 Similar to computer games, VRS allows the surgeon to interact with a computer-generated surgical field on a monitor. If equipped with haptics, the surgeon can also feel the interaction of the simulated surgical instruments with the virtual tissue (Figure 1).

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FIGURE 1. Virtual reality simulation with haptics allow the surgeon to “feel” the instruments in contact with the tissue. Courtesy of Simbionix Ltd.

The three most common simulators are the MIST VR, the LAP Mentor, and the LapSim. They are all capable of teaching fundamental MIS skills, such as camera navigation, utilizing a 0° or 30° laparoscope, instrument navigation, manipulation of objects, clip application, cutting, suturing, and intracorporeal knot tying (Figures 2 and 3). By breaking down complicated MIS procedures into smaller tasks (ie, procedural task modules), LAP Mentor guides the surgeon through the critical stages of the procedure, offering visual signs and instructions on how to perform the procedure. Internal metrics software objectively evaluates the surgeon’s performance and at the completion of the module, provides immediate feedback with a score and instructional aids to improve technique. As the surgeon’s skill improves, the tasks become more difficult, ultimately advancing the surgeon to proficiency in that particular skill set.10

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FIGURE 2. Cutting with virtual reality simulation. Reproduced with permission from Immersion Corporation, copyright 2007 Immersion Corporation. All rights reserved.

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FIGURE 3. Tying knots with virtual reality simulation. Courtesy of Simbionix Ltd.

The LapSim and LAP Mentor also have the capability of full procedural simulation. Lap Mentor has a library of virtual patients with different anatomic variations to make these full procedural modules as “real-life” as possible. Currently, only LapSim has gynecologic modules, including ectopic pregnancy, sterilization, and suturing of a myomectomy bed. However, the Laparoscopy VR platform will soon be introduced to replace LapSim (Figure 4); gynecologic modules will not be included in the initial release but are expected later in 2007, expanding the available procedures to include oophorectomy and laparoscopic hysterectomy. Full procedural gynecologic modules for the LAP Mentor will be released later in 2007 as well.

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FIGURE 4. Laparoscopy VR platform. Reproduced with permission from Immersion Corporation, copyright 2007 Immersion Corporation. All rights reserved.

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ADVANTAGES

Virtual reality simulation has many advantages. It does not require substantial set-up time, whereas traditional box trainers need an educator to set up the trainer prior to each session, evaluate the trainee, and take down the equipment. The VRS trainers allow for immediate, objective assessment of surgical skills; keep track of each surgeon’s scores; offer instantaneous, unbiased feedback; and provide individualized training based on identified deficiencies.6 Surgeons can also change effortlessly from basic surgical-skills modules to full procedural modules.

Do skills learned with VRS translate into the operating room? A double-blind, randomized study utilizing the MIST VR simulator demonstrated that physicians trained with VRS were 29% faster at dissecting the gallbladder, with a 6-fold reduction in error during laparoscopic cholecystectomy. Those who did not receive training on the MIST VR were nine times more likely to have transient failures in progress during surgery.11 Although VRS has proved valuable in reducing error and operating time, further validation studies are needed—especially in gynecology.

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DISADVANTAGES

Virtual reality simulation has several disadvantages. Full procedural VRS equipment is currently quite expensive ($50,000 to $150,000), and it is necessary to purchase upgrade modules as new software is created.12 The number of gynecologic procedural modules is still limited and may cost up to $20,000. Also, VRS does not allow for utilization of the exact instruments used in the operating room.

When comparing LapSim to a traditional box trainer, one study reported no substantial advantage of one system over the other.13 However, a double-blind, randomized trial demonstrated LapSim was superior to traditional box trainers for more complex, two-handed, coordinated tasks. Nonetheless, it remains to be established whether the advantages of VRS outweigh
the expense.14

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CONCLUSION

As technical advances continue to decrease morbidity through MIS, new means of training must be developed as well. Although VRS technology is still in its infancy, it is a realistic training option.15 As processing speeds increase and computer prices decrease, VRS will become more affordable and accessible. The ability to replicate tissue distortion and suture manipulation will become more realistic. More gynecologic procedural modules will be developed, with varied scenarios and graduated degrees of difficulty. The immediate, objective assessment of technical skills, minimal set-up time, and full procedural modules represent true advantages over traditional box trainers (Table). Potential applications are endless. For example, new MIS techniques may be refined using VRS with no risk to a live patient. Conceivably, the digital output from pelvic magnetic resonance imaging or computed tomography may be loaded into a simulator, and an entire procedure performed to judge the suitability of that MIS technique for a particular patient prior to actual surgery. Robot-assisted surgery has its own unique learning curve, and is also well suited to VRS training.

Table not available online

TABLE. Simulator Comparison VRS = virtual reality simulation.

Virtual reality simulation has played an effective role in the training, certification, and recertification of airline and military pilots for more than 50 years. It is probable that in the near future, board certification and recertification will no longer be confined to cognitive knowledge. As further validation studies are conducted and benchmarks established, surgeons will be required to demonstrate technical skills competency via surgical simulation.4,16 But as promising as VRS appears, it will never replace a well-designed surgical curriculum or experienced educators. However, it can serve a vital purpose in such a curriculum by training surgeons without increasing the risk to patients.12

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Gregory J. Raff, MD, is assistant clinical professor and director of minimally invasive surgery, Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis.

Disclosure
Dr Raff reports that he is a consultant to Ethicon Women’s Health and Urology, and Ethicon Endosurgery.

References

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