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Simulation and Minimally Invasive Colorectal Surgery
Simulation and Minimally Invasive Colorectal Surgery Sandra de Montbrun, MD, FRCSC,* and Helen MacRae, MD, FRCSC† Simulation marks a new era for surgical education. No longer are technical skills solely learned in the OR through a traditional apprenticeship model of training. Instead, the acquisition of new skills and development of basic surgical proficiency are moving to a simulated environment in the surgical skills laboratory. Basic surgical tasks and some advanced surgical techniques can be replicated in the skills laboratory, allowing both trainees and practicing surgeons to gain proficiency in these skills. In addition to being a valuable component of surgical training, simulation provides a venue for the development of colorectal surgical innovation and the advancement of surgical technology. This article will review the use of simulation in minimally invasive colorectal surgery, including laparoscopy, single-incision laparoscopic surgery, robotic surgery, transanal endoscopic surgery, and finally, natural orifice transluminal endoscopy surgery. The role of simulation in surgical board certification and maintenance of certification will also be discussed. Semin Colon Rectal Surg 24:53-60 Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved.
O
ver the past few decades, the pedagogical approach to the teaching and learning of surgical skills has changed significantly. No longer is it acceptable for trainees to acquire surgical skills through the traditional apprenticeship model of “see one, do one, teach one.” Rather, with the use of simulation and the widespread introduction of surgical skills centers, the acquisition of many technical skills is moving from the operating room to the surgical skills laboratory.1 There have been several driving forces that have encouraged this change. First, with an ever-decreasing resident workweek limiting clinical exposure, the skills laboratory has the ability to provide a means to develop skills that may no longer be easily acquired in the clinical setting. Second, the ethical concern of practicing and learning surgical techniques on real patients is avoided by acquiring a basic level of proficiency in the laboratory before patient contact.2 Finally, simulation allows for the advancement of new surgical techniques and development of surgical innovation.2 This article will provide an overview of the simulation technologies that are currently available for minimally inva-
*Division of General Surgery, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada. †Division of General Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada. Address reprint requests to: Sandra de Montbrun, MD, FRCSC, St. Michael’s Hospital, 30 Bond Street, Cardinal Carter Wing, Room 16-064, Toronto, Ontario, Canada M5B 1W8. E-mail: [email protected]
sive colorectal surgery, including simulation for laparoscopic surgery, single-incision laparoscopic surgery (SILS), robotic surgery, transanal endoscopic surgery, and finally, natural orifice transluminal endoscopy surgery (NOTES). Simulation for surgical board certification and maintenance of certification will also be discussed.
Simulation for Laparoscopic Surgery One of the major driving factors that brought to light the importance of simulation for the adoption of new surgical technologies was the significant increase in bile duct injuries after the mass introduction and uptake of laparoscopic cholecystectomies by surgeons in the late 1980s. Many took on this new approach without adequate experience or training, resulting in an increase in bile duct injuries.3 Several technical challenges are encountered with laparoscopic surgery, including a 2-dimensional view, a decrease in ergonomics and dexterity, a magnified tremor, a loss of tactile feedback, and a fulcrum effect.4 Fortunately, simulation has provided a platform to overcome many of these challenges, and there is now significant literature pointing to the benefit of simulation training in laparoscopic surgery. The currently available laparoscopic trainers have the ability to train basic surgical skills common to all laparoscopic procedures (knot tying, clipping, suturing, transferring ob-
1043-1489/13/$-see front matter Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1053/j.scrs.2012.10.013
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S. de Montbrun and H. MacRae
54 jects) as well as some full laparoscopic procedures (laparoscopic cholecystectomy, appendectomy, sigmoidectomy). The platforms currently available vary significantly in their level of fidelity, from box trainers to technologically advanced virtual reality (VR) platforms. The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) is a well-validated low-fidelity platform that uses laparoscopic instruments in a simple box trainer to simulate basic laparoscopic skills.5 Tasks include pattern cutting, laparoscopic suturing, peg transfer, and placement of an endoloop. Despite its technical simplicity, the MISTELS system has been well validated, and has become the basis of the technical skills component of the Fundamentals of Laparoscopic Surgery program (FLS). A randomized controlled trial investigating the transferability of skills acquired using the FLS curriculum found that training to proficiency, using the FLS system, resulted in improved OR performance compared with an untrained group during the dissection of the gallbladder off the liver bed during an elective laparoscopic cholecystectomy.6 Basic laparoscopic skills training can also take place on higher-fidelity VR trainers, such as the Minimally Invasive Surgical Trainer—Virtual Reality, and has also been shown in randomized controlled trials to improve performance in the operating room.7,8 The benefits of the MISTELS system over the more technologically advanced Minimally Invasive Surgical Trainer—Virtual Reality are its simplicity and affordability. Furthermore, a recent Cochrane review found that VR training was at least as effective as box training in supplementing standard laparoscopic training.9 Although basic skills are necessary for laparoscopic sur-
gery, they are not adequate in performing advanced laparoscopic colorectal procedures. Being able to perform an entire surgical procedure requires the ability to perform procedurespecific skills and major/key steps of an entire operation. For the most part, simulation training for laparoscopic surgery has focused mostly on training basic laparoscopic skills, and there are only limited data evaluating the benefit of laparoscopic procedural training. Although some of the available VR platforms have the ability to simulate full surgical procedures, limited data exist on the impact of procedural training on OR performance. One randomized controlled trial that has established the effectiveness of VR procedural training was in gynecology residents, demonstrating that training for a salpingectomy using a VR platform resulted in improved operative performance compared with an untrained group.10 Part of the limitation in using box trainers and VR platforms for training more advanced technical skills, such as full surgical procedures, is the lack of available models. The only VR full procedural module available for advanced laparoscopic colorectal surgery training is a laparoscopic sigmoidectomy model available by Simbionix (Cleveland, OH) (Fig. 1). No trial has looked specifically at the benefit of VR procedural sigmoidectomy training on skill acquisition or OR performance. Another simulation platform that has been developed to train advanced laparoscopic left hemicolectomy is the hybrid ProMIS trainer (CAE Healthcare Inc., Sarasota, FL).11 This platform uses a computerized interface with a synthetic disposable anatomy tray of a simulated colon, liver, spleen, ureter, and blood vessels in a box trainer (Fig. 2).12 A camera
Figure 1 A screenshot of the laparoscopic sigmoidectomy module on the LAP Mentor virtual reality platform. Creating the circular stapled anastomosis. Image reproduced with permission from Simbionix, Inc. (Cleveland, OH). (Color version of figure is available online.)
Simulation and minimally invasive colorectal surgery
55 right hemicolectomy and demonstrated that the curricular trained group performed significantly better than the conventionally trained group. Although this work is promising, the next challenge will be successfully incorporating these types of curricula into surgical training programs. The importance of a comprehensive curricular approach using simulation to train is highlighted by the results of a recent survey of colorectal graduates, which identified many feeling only “somewhat” or “not” comfortable with performing advanced laparoscopic right and left hemicolectomies.16
Simulation for SILS
Figure 2 Image of abdominal tray of the ProMIS laparoscopic left colectomy model. Photo courtesy of CAE Healthcare ©2012 CAE Healthcare. (Color version of figure is available online.)
tracking system converts instrument movement into performance metrics such as time, path length, and smoothness of movement. Performance parameters of the ProMIS VR simulator have demonstrated evidence of construct validity with the ability to distinguish between the performances of novice and expert laparoscopic surgeons.13 Advantages of this hybrid platform include the ability to use real laparoscopic instrumentation and its affordability (ProMIS platform costs $25,000, a single use disposable tray costs $200).14 There has been a growing body of work demonstrating the effectiveness of simulators in teaching technical skills; however, incorporating simulation training into surgical curricula remains a significant challenge. Simulation platforms alone are necessary but not sufficient for a successful training program. Recently, a comprehensive laparoscopic colorectal curriculum was developed and validated by Palter and Grantcharov.15 This randomized controlled trial allocated general surgery residents to either conventional training or to their comprehensive training curriculum for laparoscopic colorectal surgery. The comprehensive curriculum included 3 components: simulation training on a VR platform, cognitive training, and a cadaveric simulation of a laparoscopic colectomy. Surgical performance was then measured in the operating room during the performance of a laparoscopic
SILS has been gaining momentum in colorectal surgery. A recent meta-analysis by Zhou et al found that SILS was a safe and feasible alternative to conventional laparoscopic surgery for colorectal disease and produced a similar oncological specimen.17 Despite the lack of long-term randomized controlled data on recurrence and survival, SILS continues to be incorporated into the field of colorectal surgery. SILS is a technically challenging procedure in which many of the underlying principles of laparoscopic surgery are violated. Difficulties include the lack of triangulation, problems with exposure and retraction, instrument conflict, and an altered field of view.18 Despite simulation being an ideal way for surgeons to develop these challenging skills, there have been limited published data on the use of simulation for SILS. To examine the effect of simulation training on the acquisition of SILS skills, Santos et al randomized medical students to laparoscopic-specific training or to SILS-specific training using an FLS and modified FLS box trainer.19 Baseline testing and posttesting using the peg transfer and pattern cutting task of the FLS program were completed using both a laparoscopic and SILS approach. They found that although SILS performance improved in both groups, the SILS-specific trained group performed significantly better. The authors suggested simulation training as a way to gain proficiency in basic SILS techniques. This same group has demonstrated evidence of construct validity in using the FLS box trainer for SILS training, with SILS-experienced individuals performing better than inexperienced individuals. They also demonstrated that although laparoscopic experience was helpful in performing SILS tasks, it was not as good as SILS experience.20 To safely incorporate SILS into their surgical unit, Kandelwal et al used simulation to train surgeons in SILS techniques before introducing this new technology to the clinical setting.21 Simulation training took place in the dry laboratory using the FLS training system for the acquisition of basic SILS techniques, as well as in the the wet laboratory using a porcine model for simulating an appendectomy and cholecystectomy. Their approach can serve as an example of how simulation can be used to successfully and safely incorporate SILS into surgical practice.
Simulation for Robotic Surgery Robotic surgery is continuing to emerge as a minimally invasive technology in colorectal surgery. A recent systematic
56 review by Kanji et al found that robotic-assisted colorectal surgery was safe and feasible for both benign and malignant colorectal disease.22 However, robotic surgery does require experience and expertise, and as its use becomes more prevalent in colorectal surgery, issues of training and credentialing will need to be addressed. Best practice guidelines for robotic surgery training and credentialing have been published by the American Urological Association,23 which can help to guide the implementation of robotic curricula and training programs across multiple surgical disciplines, including colorectal surgery. The guidelines suggest a training paradigm in which proficiency in many robotic surgical skills is reached outside the OR. Simulation platforms allow the opportunity to develop proficiency in many robotic technical skills in a low-stress lowstakes environment. Robotic simulation can allow trainees to become familiar with robot docking, instrument insertion and exchange, sitting at the surgeon’s console, and manipulating the robotic interface. Unfortunately, unlike laparoscopic skills training, which can take place with basic equipment such as a box trainer, camera, and basic laparoscopic instrumentation, robotic skills training requires either the use of a robotic VR training platform or a fully functional surgical robot. Currently there are 4 commercially available robotic VR simulators on the market. These platforms allow users or trainees to learn basic surgical skills that are common across surgical specialties, including object transferring, camera control, knot tying, vessel clipping, needle handling, and tissue manipulation/dissection.24,25 The VR platforms vary in their user interface: some use the actual surgical console of the da Vinci robot,24 whereas others use a close mock-up or no surgeon console (Fig. 3).25,26 The various VR platforms range in price from $45,000 to $125,000 in addition to an annual maintenance plan.27 Because robotic VR simulation is a newer technology than laparoscopic VR simulation, there remains a relative paucity of literature on the validity of these tools. However, of the published literature that has come out in the past few years, the various VR robotic platforms have demonstrated initial evidence of content and construct validity.27 Lerner et al compared training on a VR robotic simulator with training on the da Vinci surgical system. They found that training on the VR simulator resulted in the same improvement in performance as training on the da Vinci System.28 In a recent randomized trial, Korets et al compared training on either the da Vinci Surgical System or a VR robotic system with no training. They found that training on both the da Vinci Surgical System and the VR robotic platform resulted in a significant improvement in performance. Furthermore, for the most part, there was no difference in performance between the 2 trained groups, providing evidence to support the use of VR robotic training.29 Another recent randomized controlled trial by Hung et al compared the performance of trainees who were randomized to either VR robotic simulator training or no simulator training.30 They found that the simulator training significantly improved robotic performance for individuals with low baseline robotic skills.
S. de Montbrun and H. MacRae
Figure 3 Image of the RoSS robotic simulation platform (Simulated Surgical Systems, Williamsville, NY). Image reproduced with permission from Simulated Surgical Systems, LLC. (Color version of figure is available online.)
One of the main disadvantages of VR robotic simulation is the focus on basic technical skills rather than full surgical procedures. Immense time and costs limit the development of full procedural VR modules. A few procedural simulation models have been described for colorectal robotic simulation training using a fully functioning da Vinci robot. Marecik et al have created a novel model to teach robotic rectal dissection.31 They developed a synthetic human pelvis using platinum silicone putty to create a replica of the anatomic pelvic floor, sidewalls, and anterior pelvic organs. Mesorectal excision was simulated using a kitchen sponge, with the interface between the scouring surface (pelvic sidewall) and the absorptive surface (mesorectum) of the sponge acting as the “holy plane.” After trainees practice setting up the da Vinci surgical system, they can then perform all the key steps of a proper mesorectal dissection. Marecik et al have also described using porcine intestine to simulate a robotic intestinal anastomosis using the da Vinci platform.32 They found that robotic naive general and colorectal surgery residents demonstrated an improvement in the
Simulation and minimally invasive colorectal surgery quality of suturing (as measured by leak pressure) over 3 consecutive exercises. As robotic surgery gains wider acceptance and adoption in the surgical community, validated curriculum will be essential for training both residents and practicing surgeons. Dulan et al have developed and implemented a proficiencybased robotic training program for fundamental robotic technical skills such as transferring, suturing, and pattern cutting.33 The curriculum is generic, allowing it to be applied across multiple surgical specialties (urology, gynecology, general surgery) and also across various training levels (residents, fellows, staff). The curriculum has established initial evidence of validity,33,34 reliability, and feasibility.35 Unlike laparoscopic surgery, which has a well-developed and validated tool for assessing competency in basic laparoscopic skills (FLS), a validated tool for the purposes of assessing competence in robotic technical skills has not yet been developed. Thus, robotic privileging is currently institution dependent.27
Simulation for Transanal Endoscopic Surgery Transanal endoscopic microsurgery (TEM) has become an established tool in the local excision of rectal tumors and a part of the colorectal surgeon’s armamentarium. However, since its introduction in the early 1980s, colorectal surgeons have been slow to universally adopt this technique. As of 2004, there were 45 TEM systems in use in the United States.36 Some of the reasons for a lag in uptake include the challenges in training and its associated steep learning curve, as well as the cost of the unit.37 Before initiating a TEM program, it is essential for the surgeon to gain hands-on experience with both the equipment and the technique. In 1988, shortly after the introduction of TEM, Kipfmuller et al developed a training system for TEM using simulation.38 Interestingly, at this time, simulation was still a relatively novel training concept in the field of general surgery. Their training course involved several steps. After becoming familiar with and learning how to set up the TEM equipment, participants would (1) excise and close a piece of cloth in a training box, (2) perform a mucosectomy on opened bovine bowel, and (3) excise a lesion and close the defect on closed insufflated bovine bowel. Currently, TEM skills can be acquired through training courses, which are offered several times a year at national society meetings or through surgical mentorship. Furthermore, commercially available TEM trainers can be used with both synthetic material and animal tissue for deliberate practice and development of proficiency. These methods of training, although intuitive, have not been formally validated. As technologies for minimally invasive surgery continue to rapidly evolve, techniques for transanal excision continue to be developed. In 2009, transanal minimally invasive surgery (TAMIS), which is a hybrid between TEM and single-port laparoscopy, was pioneered as a novel technique in transanal resection. This same group has continued to advance inno-
57 vation in transanal surgery and has done so using simulation. They have demonstrated the feasibility of robotic TAMIS in the laboratory setting using a cadaveric model.39 Training in these various transanal techniques can be challenging. Currently, various hands-on simulation courses are available, providing a venue for surgeons at all stages in their careers to become familiar with these surgical platforms.
Simulation for NOTES The interest in NOTES has been growing over the past several years. The first reported use of NOTES was by Kalloo et al, who described a peroral transgastric approach to access the peritoneal cavity with liver biopsy in a porcine model.40 One of the criticisms for NOTES is the need to breach an otherwise intact organ to gain access to the peritoneal cavity. For transanal/transrectal excisions, this problem is avoided, making NOTES for colorectal resections more appealing. Furthermore, TEM provides an ideal NOTES platform.41 Since the initial introduction of NOTES, much of the research and advancement of this technology within colorectal surgery has benefited from the use of simulation.42 Simulation for NOTES has 2 main roles. First, simulation using animal and cadaveric models has allowed for the evaluation of the feasibility of colorectal NOTES procedures.43 Second, newly developed ex vivo synthetic models have been developed for training. Whiteford et al used a fresh frozen cadaveric model to demonstrate the feasibility of a NOTES sigmoid resection. Using TEM instrumentation in a simulated setting, they demonstrated the ability to mobilize the sigmoid colon with an en bloc lymphadenectomy, performing a primary stapled endto-end anastomosis.44 Preclinical investigations have also been carried out with animal models. Several authors have used porcine models to demonstrate the feasibility of NOTES sigmoidectomy using a transanal (with or without a combined transgastric) approach.45-47 An ex vivo bovine model has also been used to investigate the development of new, long, steerable instruments for NOTES rectosigmoid resection.48 These longer instruments were designed to overcome the limited access to mid and upper abdominal structures with the traditional shorter instrumentation. Testing of these instruments in this ex vivo simulation model demonstrated the ability to ligate the inferior mesenteric pedicle at its root, and the ability to mobilize the descending colon up to the splenic flexure. All these studies demonstrate the utility of simulation in the advancement and innovation of colorectal NOTES procedures. Simulators have been developed for the training of either laparoscopic or endoscopic skills; however, NOTES requires proficiency in both laparoscopy and flexible endoscopy. Recently, a novel training system for combined endoscopic– laparoscopic procedures has been developed (the endoscopic–laparoscopic interdisciplinary training entity [ELITE]).49 This ex vivo model uses a life-sized replica of a human female torso with synthetic intra-abdominal organs (liver, gall bladder, spleen, gastrointestinal tract with mesentery and omentum). The esophagus, stomach, and rectum provide translu-
S. de Montbrun and H. MacRae
58 minal access to the peritoneal cavity. This model has been used for NOTES cholecystectomy and NOTES appendectomy.49,50 Initial evidence of construct validity of the ELITE trainer has been demonstrated, showing that individuals with expert endoscopic skills outperformed novices (measured as time to completion) on a simulated ELITE procedure.51 Construct validity has also been demonstrated for the ELITE appendectomy model, demonstrating that participants with endoscopic or laparoscopic experience were significantly faster than inexperienced individuals in performing a NOTES appendectomy.50 Furthermore, endoscopic experience was found to have the strongest influence on total time to completion of the task. Currently, no advanced colorectal models are available for the ELITE trainer. Until this becomes a reality, animal and cadaveric models will remain as the only currently available research and training modality for advanced colorectal NOTES procedures. Whether specific NOTES training will become a common part of surgical training remains to be determined.52 However, because the principles of NOTES are based on laparoscopic and flexible endoscopic skills, the acquisition of both of these skills will continue to be an important component of surgical training.
The Use of Simulation for Certification and Maintenance of Certification The discussion thus far had focused on the use of simulation as a platform to develop and advance new surgical technology as well as a platform to learn technical skills. However, using simulation as a method to assess technical skills in a formal structured setting for certification is on the horizon for surgical specialties and on the agenda for many surgical societies. High-stakes assessments, such as certification, require that the assessment tool be reliable to draw valid inferences about the competence of test takers.53 Simulation has been incorporated into high-stakes examinations in anesthesia and internal medicine.54,55 Within the domain of surgery, the only validated and implemented simulation platform that is currently in widespread use to assess competency is the FLS program for basic laparoscopic skills.56 Fundamentals of laparoscopic surgery is now a requirement for the American Board of Surgery.56 A significant gap in assessment remains at the more advanced level of training, where competence in an entire domain of surgical practice is not directly assessed at the time of certification. With the major goal of certification being to ensure that a candidate is competent in all facets that are required of the profession, surgical bodies are realizing the necessity to formally and directly assess technical skills at the time of surgical certification. Recognizing this gap in assessment at the time of certification, the American Society of Colon and Rectal Surgeons in conjunction with the American Board of Colon and Rectal Surgery has developed the Colorectal Objective Structured Assessment of Technical Skill (COSATS) with the intent of incorporating this assessment
into the board certification process.57 Preliminary data on the COSATS have demonstrated that a performance-based colorectal technical skills examination using simulation could be developed that has the ability to differentiate between different levels of training (providing evidence of construct validity) with good reliability. Additional work is being carried out to further establish evidence of reliability and validity of the COSATS as well as initiatives to set competency standards. Simulation has not been introduced into the realm of Maintenance of Certification (MOC). Currently, the American Board of Surgery MOC program relies on the use of databases to track patient outcomes to ensure adequate surgical performance.58 The role of simulation in the setting of MOC remains to be determined. However, as already discussed, simulation provides a useful platform for practicing surgeons to develop new technical skills to incorporate into their surgical armamentarium.
Conclusion The face of surgical education has changed dramatically over the past decade with the introduction and advancement of simulation platforms. As simulation models continue to be developed and refined, they will play an increasingly important role in the acquisition of colorectal surgical skills and the advancement of colorectal surgical technology. One of the challenges in the use of simulation for training is the successful incorporation of these methods into a validated surgical curriculum. A new frontier lies ahead, as simulation is being introduced into the assessment of advanced surgical competence at the time of surgical board certification.
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59 34. Dulan G, Rege RV, Hogg DC, et al: Content and face validity of a comprehensive robotic skills training program for general surgery, urology, and gynecology. Am J Surg 203:535-539, 2012 35. Arain NA, Dulan G, Hogg DC, et al: Comprehensive proficiency-based inanimate training for robotic surgery: Reliability, feasibility, and educational benefit. Surg Endosc 26:2740-2745, 2012 36. Saclarides TJ: Transanal endoscopic microsurgery. Semin Laparosc Surg 11:45-51, 2004 37. Cataldo PA, Buess G (eds): Transanal Endoscopic Microsurgery. New York: Springer Science, 2009 38. Kipfmüller K, Buess G, Naruhn M, et al: Training program for transanal endoscopic microsurgery. Surg Endosc 2:24-27, 1988 39. Atallah SB, Albert MR, deBeche-Adams TH, et al: Robotic transanal minimally invasive surgery in a cadaveric model. Tech Coloproctol 15:461-464, 2011 40. Kalloo AN, Singh VK, Jagannath SB, et al: Flexible transgastric peritoneoscopy: A novel approach to diagnostic and therapeutic interventions in the peritoneal cavity. Gastrointest Endosc 60:114-117, 2004 41. Rieder E, Whiteford MH: Transrectal natural orifice translumenal endoscopic surgery (NOTES) for colorectal resection. Colorectal Dis 13(suppl 7):51-54, 2011 42. Tomikawa M, Xu H, Hashizume M: Current status and prerequisites for natural orifice translumenal endoscopic surgery (NOTES). Surg Today 40:909-916, 2010 43. Denk PM, Swanström LL, Whiteford MH: Transanal endoscopic microsurgical platform for natural orifice surgery. Gastrointest Endosc 68:954-959, 2008 44. Whiteford MH, Denk PM, Swanström LL: Feasibility of radical sigmoid colectomy performed as natural orifice translumenal endoscopic surgery (NOTES) using transanal endoscopic microsurgery. Surg Endosc 21:1870-1874, 2007 45. Leroy J, Cahill RA, Perretta S, et al: Natural orifice translumenal endoscopic surgery (NOTES) applied totally to sigmoidectomy: An original technique with survival in a porcine model. Surg Endosc 23:24-30, 2009 46. Sylla P, Sohn DK, Cizginer S, et al: Survival study of natural orifice translumenal endoscopic surgery for rectosigmoid resection using transanal endoscopic microsurgery with or without transgastric endoscopic assistance in a swine model. Surg Endosc 24:2022-2030, 2010 47. Sylla P, Willingham FF, Sohn DK, et al: NOTES rectosigmoid resection using transanal endoscopic microsurgery (TEM) with transgastric endoscopic assistance: A pilot study in swine. J Gastrointest Surg 12: 1717-1723, 2008 48. Bhattacharjee HK, Buess GF, Becerra Garcia FC, et al: A novel singleport technique for transanal rectosigmoid resection and colorectal anastomosis on an ex vivo experimental model. Surg Endosc 25:18441857, 2011 49. Fiolka A, Gillen S, Meining A, et al: ELITE—The ex vivo training unit for NOTES: Development and validation. Minim Invasive Ther Allied Technol 19:281-286, 2010 50. Gillen S, Grone J, Knodgen F, et al: Educational and training aspects of new surgical techniques: Experience with the endoscopic-laparoscopic interdisciplinary training entity (ELITE) model in training for a natural orifice translumenal endoscopic surgery (NOTES) approach to appendectomy. Surg Endosc 26:2376-2382, 2012 51. Gillen S, Wilhelm D, Meining A, et al: The “ELITE” model: Construct validation of a new training system for natural orifice transluminal endoscopic surgery (NOTES). Endoscopy 41:395-399, 2009 52. Rieder E, Swanstrom LL: Advances in cancer surgery: Natural orifice surgery (NOTES) for oncological diseases. Surg Oncol 20:211-218, 2011 53. McGaghie WC, Issenberg SB, Petrusa ER, et al: A critical review of simulation-based medical education research: 2003-2009. Med Educ 44:50-63, 2010 54. Berkenstadt H, Ziv A, Gafni N, et al: Incorporating simulation-based objective structured clinical examination into the Israeli National
60 Board Examination in Anesthesiology. Anesth Analg 102:853-858, 2006 55. Hatala R, Kassen BO, Nishikawa J, et al: Incorporating simulation technology in a Canadian internal medicine specialty examination: A descriptive report. Acad Med 80:554-556, 2005 56. Vassiliou MC, Dunkin BJ, Marks JM, et al: FLS and FES: Comprehensive models of training and assessment. Surg Clin North Am 90:535-558, 2010
S. de Montbrun and H. MacRae 57. de Montbrun S, Roberts PL, Lowry AC, et al: A novel approach to assessing technical competence of colorectal surgery residents: The development and evaluation of the colorectal objective structured assessment of technical skill (COSATS). Ann Surg (in press) 58. American Board of Surgery. Maintenance of certification (MOC)— Overview, 2011. Available at: http://www.absurgery.org/default.jsp? exam-moc. Accessed June 15, 2012
O
ver the past few decades, the pedagogical approach to the teaching and learning of surgical skills has changed significantly. No longer is it acceptable for trainees to acquire surgical skills through the traditional apprenticeship model of “see one, do one, teach one.” Rather, with the use of simulation and the widespread introduction of surgical skills centers, the acquisition of many technical skills is moving from the operating room to the surgical skills laboratory.1 There have been several driving forces that have encouraged this change. First, with an ever-decreasing resident workweek limiting clinical exposure, the skills laboratory has the ability to provide a means to develop skills that may no longer be easily acquired in the clinical setting. Second, the ethical concern of practicing and learning surgical techniques on real patients is avoided by acquiring a basic level of proficiency in the laboratory before patient contact.2 Finally, simulation allows for the advancement of new surgical techniques and development of surgical innovation.2 This article will provide an overview of the simulation technologies that are currently available for minimally inva-
*Division of General Surgery, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada. †Division of General Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada. Address reprint requests to: Sandra de Montbrun, MD, FRCSC, St. Michael’s Hospital, 30 Bond Street, Cardinal Carter Wing, Room 16-064, Toronto, Ontario, Canada M5B 1W8. E-mail: [email protected]
sive colorectal surgery, including simulation for laparoscopic surgery, single-incision laparoscopic surgery (SILS), robotic surgery, transanal endoscopic surgery, and finally, natural orifice transluminal endoscopy surgery (NOTES). Simulation for surgical board certification and maintenance of certification will also be discussed.
Simulation for Laparoscopic Surgery One of the major driving factors that brought to light the importance of simulation for the adoption of new surgical technologies was the significant increase in bile duct injuries after the mass introduction and uptake of laparoscopic cholecystectomies by surgeons in the late 1980s. Many took on this new approach without adequate experience or training, resulting in an increase in bile duct injuries.3 Several technical challenges are encountered with laparoscopic surgery, including a 2-dimensional view, a decrease in ergonomics and dexterity, a magnified tremor, a loss of tactile feedback, and a fulcrum effect.4 Fortunately, simulation has provided a platform to overcome many of these challenges, and there is now significant literature pointing to the benefit of simulation training in laparoscopic surgery. The currently available laparoscopic trainers have the ability to train basic surgical skills common to all laparoscopic procedures (knot tying, clipping, suturing, transferring ob-
1043-1489/13/$-see front matter Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1053/j.scrs.2012.10.013
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54 jects) as well as some full laparoscopic procedures (laparoscopic cholecystectomy, appendectomy, sigmoidectomy). The platforms currently available vary significantly in their level of fidelity, from box trainers to technologically advanced virtual reality (VR) platforms. The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) is a well-validated low-fidelity platform that uses laparoscopic instruments in a simple box trainer to simulate basic laparoscopic skills.5 Tasks include pattern cutting, laparoscopic suturing, peg transfer, and placement of an endoloop. Despite its technical simplicity, the MISTELS system has been well validated, and has become the basis of the technical skills component of the Fundamentals of Laparoscopic Surgery program (FLS). A randomized controlled trial investigating the transferability of skills acquired using the FLS curriculum found that training to proficiency, using the FLS system, resulted in improved OR performance compared with an untrained group during the dissection of the gallbladder off the liver bed during an elective laparoscopic cholecystectomy.6 Basic laparoscopic skills training can also take place on higher-fidelity VR trainers, such as the Minimally Invasive Surgical Trainer—Virtual Reality, and has also been shown in randomized controlled trials to improve performance in the operating room.7,8 The benefits of the MISTELS system over the more technologically advanced Minimally Invasive Surgical Trainer—Virtual Reality are its simplicity and affordability. Furthermore, a recent Cochrane review found that VR training was at least as effective as box training in supplementing standard laparoscopic training.9 Although basic skills are necessary for laparoscopic sur-
gery, they are not adequate in performing advanced laparoscopic colorectal procedures. Being able to perform an entire surgical procedure requires the ability to perform procedurespecific skills and major/key steps of an entire operation. For the most part, simulation training for laparoscopic surgery has focused mostly on training basic laparoscopic skills, and there are only limited data evaluating the benefit of laparoscopic procedural training. Although some of the available VR platforms have the ability to simulate full surgical procedures, limited data exist on the impact of procedural training on OR performance. One randomized controlled trial that has established the effectiveness of VR procedural training was in gynecology residents, demonstrating that training for a salpingectomy using a VR platform resulted in improved operative performance compared with an untrained group.10 Part of the limitation in using box trainers and VR platforms for training more advanced technical skills, such as full surgical procedures, is the lack of available models. The only VR full procedural module available for advanced laparoscopic colorectal surgery training is a laparoscopic sigmoidectomy model available by Simbionix (Cleveland, OH) (Fig. 1). No trial has looked specifically at the benefit of VR procedural sigmoidectomy training on skill acquisition or OR performance. Another simulation platform that has been developed to train advanced laparoscopic left hemicolectomy is the hybrid ProMIS trainer (CAE Healthcare Inc., Sarasota, FL).11 This platform uses a computerized interface with a synthetic disposable anatomy tray of a simulated colon, liver, spleen, ureter, and blood vessels in a box trainer (Fig. 2).12 A camera
Figure 1 A screenshot of the laparoscopic sigmoidectomy module on the LAP Mentor virtual reality platform. Creating the circular stapled anastomosis. Image reproduced with permission from Simbionix, Inc. (Cleveland, OH). (Color version of figure is available online.)
Simulation and minimally invasive colorectal surgery
55 right hemicolectomy and demonstrated that the curricular trained group performed significantly better than the conventionally trained group. Although this work is promising, the next challenge will be successfully incorporating these types of curricula into surgical training programs. The importance of a comprehensive curricular approach using simulation to train is highlighted by the results of a recent survey of colorectal graduates, which identified many feeling only “somewhat” or “not” comfortable with performing advanced laparoscopic right and left hemicolectomies.16
Simulation for SILS
Figure 2 Image of abdominal tray of the ProMIS laparoscopic left colectomy model. Photo courtesy of CAE Healthcare ©2012 CAE Healthcare. (Color version of figure is available online.)
tracking system converts instrument movement into performance metrics such as time, path length, and smoothness of movement. Performance parameters of the ProMIS VR simulator have demonstrated evidence of construct validity with the ability to distinguish between the performances of novice and expert laparoscopic surgeons.13 Advantages of this hybrid platform include the ability to use real laparoscopic instrumentation and its affordability (ProMIS platform costs $25,000, a single use disposable tray costs $200).14 There has been a growing body of work demonstrating the effectiveness of simulators in teaching technical skills; however, incorporating simulation training into surgical curricula remains a significant challenge. Simulation platforms alone are necessary but not sufficient for a successful training program. Recently, a comprehensive laparoscopic colorectal curriculum was developed and validated by Palter and Grantcharov.15 This randomized controlled trial allocated general surgery residents to either conventional training or to their comprehensive training curriculum for laparoscopic colorectal surgery. The comprehensive curriculum included 3 components: simulation training on a VR platform, cognitive training, and a cadaveric simulation of a laparoscopic colectomy. Surgical performance was then measured in the operating room during the performance of a laparoscopic
SILS has been gaining momentum in colorectal surgery. A recent meta-analysis by Zhou et al found that SILS was a safe and feasible alternative to conventional laparoscopic surgery for colorectal disease and produced a similar oncological specimen.17 Despite the lack of long-term randomized controlled data on recurrence and survival, SILS continues to be incorporated into the field of colorectal surgery. SILS is a technically challenging procedure in which many of the underlying principles of laparoscopic surgery are violated. Difficulties include the lack of triangulation, problems with exposure and retraction, instrument conflict, and an altered field of view.18 Despite simulation being an ideal way for surgeons to develop these challenging skills, there have been limited published data on the use of simulation for SILS. To examine the effect of simulation training on the acquisition of SILS skills, Santos et al randomized medical students to laparoscopic-specific training or to SILS-specific training using an FLS and modified FLS box trainer.19 Baseline testing and posttesting using the peg transfer and pattern cutting task of the FLS program were completed using both a laparoscopic and SILS approach. They found that although SILS performance improved in both groups, the SILS-specific trained group performed significantly better. The authors suggested simulation training as a way to gain proficiency in basic SILS techniques. This same group has demonstrated evidence of construct validity in using the FLS box trainer for SILS training, with SILS-experienced individuals performing better than inexperienced individuals. They also demonstrated that although laparoscopic experience was helpful in performing SILS tasks, it was not as good as SILS experience.20 To safely incorporate SILS into their surgical unit, Kandelwal et al used simulation to train surgeons in SILS techniques before introducing this new technology to the clinical setting.21 Simulation training took place in the dry laboratory using the FLS training system for the acquisition of basic SILS techniques, as well as in the the wet laboratory using a porcine model for simulating an appendectomy and cholecystectomy. Their approach can serve as an example of how simulation can be used to successfully and safely incorporate SILS into surgical practice.
Simulation for Robotic Surgery Robotic surgery is continuing to emerge as a minimally invasive technology in colorectal surgery. A recent systematic
56 review by Kanji et al found that robotic-assisted colorectal surgery was safe and feasible for both benign and malignant colorectal disease.22 However, robotic surgery does require experience and expertise, and as its use becomes more prevalent in colorectal surgery, issues of training and credentialing will need to be addressed. Best practice guidelines for robotic surgery training and credentialing have been published by the American Urological Association,23 which can help to guide the implementation of robotic curricula and training programs across multiple surgical disciplines, including colorectal surgery. The guidelines suggest a training paradigm in which proficiency in many robotic surgical skills is reached outside the OR. Simulation platforms allow the opportunity to develop proficiency in many robotic technical skills in a low-stress lowstakes environment. Robotic simulation can allow trainees to become familiar with robot docking, instrument insertion and exchange, sitting at the surgeon’s console, and manipulating the robotic interface. Unfortunately, unlike laparoscopic skills training, which can take place with basic equipment such as a box trainer, camera, and basic laparoscopic instrumentation, robotic skills training requires either the use of a robotic VR training platform or a fully functional surgical robot. Currently there are 4 commercially available robotic VR simulators on the market. These platforms allow users or trainees to learn basic surgical skills that are common across surgical specialties, including object transferring, camera control, knot tying, vessel clipping, needle handling, and tissue manipulation/dissection.24,25 The VR platforms vary in their user interface: some use the actual surgical console of the da Vinci robot,24 whereas others use a close mock-up or no surgeon console (Fig. 3).25,26 The various VR platforms range in price from $45,000 to $125,000 in addition to an annual maintenance plan.27 Because robotic VR simulation is a newer technology than laparoscopic VR simulation, there remains a relative paucity of literature on the validity of these tools. However, of the published literature that has come out in the past few years, the various VR robotic platforms have demonstrated initial evidence of content and construct validity.27 Lerner et al compared training on a VR robotic simulator with training on the da Vinci surgical system. They found that training on the VR simulator resulted in the same improvement in performance as training on the da Vinci System.28 In a recent randomized trial, Korets et al compared training on either the da Vinci Surgical System or a VR robotic system with no training. They found that training on both the da Vinci Surgical System and the VR robotic platform resulted in a significant improvement in performance. Furthermore, for the most part, there was no difference in performance between the 2 trained groups, providing evidence to support the use of VR robotic training.29 Another recent randomized controlled trial by Hung et al compared the performance of trainees who were randomized to either VR robotic simulator training or no simulator training.30 They found that the simulator training significantly improved robotic performance for individuals with low baseline robotic skills.
S. de Montbrun and H. MacRae
Figure 3 Image of the RoSS robotic simulation platform (Simulated Surgical Systems, Williamsville, NY). Image reproduced with permission from Simulated Surgical Systems, LLC. (Color version of figure is available online.)
One of the main disadvantages of VR robotic simulation is the focus on basic technical skills rather than full surgical procedures. Immense time and costs limit the development of full procedural VR modules. A few procedural simulation models have been described for colorectal robotic simulation training using a fully functioning da Vinci robot. Marecik et al have created a novel model to teach robotic rectal dissection.31 They developed a synthetic human pelvis using platinum silicone putty to create a replica of the anatomic pelvic floor, sidewalls, and anterior pelvic organs. Mesorectal excision was simulated using a kitchen sponge, with the interface between the scouring surface (pelvic sidewall) and the absorptive surface (mesorectum) of the sponge acting as the “holy plane.” After trainees practice setting up the da Vinci surgical system, they can then perform all the key steps of a proper mesorectal dissection. Marecik et al have also described using porcine intestine to simulate a robotic intestinal anastomosis using the da Vinci platform.32 They found that robotic naive general and colorectal surgery residents demonstrated an improvement in the
Simulation and minimally invasive colorectal surgery quality of suturing (as measured by leak pressure) over 3 consecutive exercises. As robotic surgery gains wider acceptance and adoption in the surgical community, validated curriculum will be essential for training both residents and practicing surgeons. Dulan et al have developed and implemented a proficiencybased robotic training program for fundamental robotic technical skills such as transferring, suturing, and pattern cutting.33 The curriculum is generic, allowing it to be applied across multiple surgical specialties (urology, gynecology, general surgery) and also across various training levels (residents, fellows, staff). The curriculum has established initial evidence of validity,33,34 reliability, and feasibility.35 Unlike laparoscopic surgery, which has a well-developed and validated tool for assessing competency in basic laparoscopic skills (FLS), a validated tool for the purposes of assessing competence in robotic technical skills has not yet been developed. Thus, robotic privileging is currently institution dependent.27
Simulation for Transanal Endoscopic Surgery Transanal endoscopic microsurgery (TEM) has become an established tool in the local excision of rectal tumors and a part of the colorectal surgeon’s armamentarium. However, since its introduction in the early 1980s, colorectal surgeons have been slow to universally adopt this technique. As of 2004, there were 45 TEM systems in use in the United States.36 Some of the reasons for a lag in uptake include the challenges in training and its associated steep learning curve, as well as the cost of the unit.37 Before initiating a TEM program, it is essential for the surgeon to gain hands-on experience with both the equipment and the technique. In 1988, shortly after the introduction of TEM, Kipfmuller et al developed a training system for TEM using simulation.38 Interestingly, at this time, simulation was still a relatively novel training concept in the field of general surgery. Their training course involved several steps. After becoming familiar with and learning how to set up the TEM equipment, participants would (1) excise and close a piece of cloth in a training box, (2) perform a mucosectomy on opened bovine bowel, and (3) excise a lesion and close the defect on closed insufflated bovine bowel. Currently, TEM skills can be acquired through training courses, which are offered several times a year at national society meetings or through surgical mentorship. Furthermore, commercially available TEM trainers can be used with both synthetic material and animal tissue for deliberate practice and development of proficiency. These methods of training, although intuitive, have not been formally validated. As technologies for minimally invasive surgery continue to rapidly evolve, techniques for transanal excision continue to be developed. In 2009, transanal minimally invasive surgery (TAMIS), which is a hybrid between TEM and single-port laparoscopy, was pioneered as a novel technique in transanal resection. This same group has continued to advance inno-
57 vation in transanal surgery and has done so using simulation. They have demonstrated the feasibility of robotic TAMIS in the laboratory setting using a cadaveric model.39 Training in these various transanal techniques can be challenging. Currently, various hands-on simulation courses are available, providing a venue for surgeons at all stages in their careers to become familiar with these surgical platforms.
Simulation for NOTES The interest in NOTES has been growing over the past several years. The first reported use of NOTES was by Kalloo et al, who described a peroral transgastric approach to access the peritoneal cavity with liver biopsy in a porcine model.40 One of the criticisms for NOTES is the need to breach an otherwise intact organ to gain access to the peritoneal cavity. For transanal/transrectal excisions, this problem is avoided, making NOTES for colorectal resections more appealing. Furthermore, TEM provides an ideal NOTES platform.41 Since the initial introduction of NOTES, much of the research and advancement of this technology within colorectal surgery has benefited from the use of simulation.42 Simulation for NOTES has 2 main roles. First, simulation using animal and cadaveric models has allowed for the evaluation of the feasibility of colorectal NOTES procedures.43 Second, newly developed ex vivo synthetic models have been developed for training. Whiteford et al used a fresh frozen cadaveric model to demonstrate the feasibility of a NOTES sigmoid resection. Using TEM instrumentation in a simulated setting, they demonstrated the ability to mobilize the sigmoid colon with an en bloc lymphadenectomy, performing a primary stapled endto-end anastomosis.44 Preclinical investigations have also been carried out with animal models. Several authors have used porcine models to demonstrate the feasibility of NOTES sigmoidectomy using a transanal (with or without a combined transgastric) approach.45-47 An ex vivo bovine model has also been used to investigate the development of new, long, steerable instruments for NOTES rectosigmoid resection.48 These longer instruments were designed to overcome the limited access to mid and upper abdominal structures with the traditional shorter instrumentation. Testing of these instruments in this ex vivo simulation model demonstrated the ability to ligate the inferior mesenteric pedicle at its root, and the ability to mobilize the descending colon up to the splenic flexure. All these studies demonstrate the utility of simulation in the advancement and innovation of colorectal NOTES procedures. Simulators have been developed for the training of either laparoscopic or endoscopic skills; however, NOTES requires proficiency in both laparoscopy and flexible endoscopy. Recently, a novel training system for combined endoscopic– laparoscopic procedures has been developed (the endoscopic–laparoscopic interdisciplinary training entity [ELITE]).49 This ex vivo model uses a life-sized replica of a human female torso with synthetic intra-abdominal organs (liver, gall bladder, spleen, gastrointestinal tract with mesentery and omentum). The esophagus, stomach, and rectum provide translu-
S. de Montbrun and H. MacRae
58 minal access to the peritoneal cavity. This model has been used for NOTES cholecystectomy and NOTES appendectomy.49,50 Initial evidence of construct validity of the ELITE trainer has been demonstrated, showing that individuals with expert endoscopic skills outperformed novices (measured as time to completion) on a simulated ELITE procedure.51 Construct validity has also been demonstrated for the ELITE appendectomy model, demonstrating that participants with endoscopic or laparoscopic experience were significantly faster than inexperienced individuals in performing a NOTES appendectomy.50 Furthermore, endoscopic experience was found to have the strongest influence on total time to completion of the task. Currently, no advanced colorectal models are available for the ELITE trainer. Until this becomes a reality, animal and cadaveric models will remain as the only currently available research and training modality for advanced colorectal NOTES procedures. Whether specific NOTES training will become a common part of surgical training remains to be determined.52 However, because the principles of NOTES are based on laparoscopic and flexible endoscopic skills, the acquisition of both of these skills will continue to be an important component of surgical training.
The Use of Simulation for Certification and Maintenance of Certification The discussion thus far had focused on the use of simulation as a platform to develop and advance new surgical technology as well as a platform to learn technical skills. However, using simulation as a method to assess technical skills in a formal structured setting for certification is on the horizon for surgical specialties and on the agenda for many surgical societies. High-stakes assessments, such as certification, require that the assessment tool be reliable to draw valid inferences about the competence of test takers.53 Simulation has been incorporated into high-stakes examinations in anesthesia and internal medicine.54,55 Within the domain of surgery, the only validated and implemented simulation platform that is currently in widespread use to assess competency is the FLS program for basic laparoscopic skills.56 Fundamentals of laparoscopic surgery is now a requirement for the American Board of Surgery.56 A significant gap in assessment remains at the more advanced level of training, where competence in an entire domain of surgical practice is not directly assessed at the time of certification. With the major goal of certification being to ensure that a candidate is competent in all facets that are required of the profession, surgical bodies are realizing the necessity to formally and directly assess technical skills at the time of surgical certification. Recognizing this gap in assessment at the time of certification, the American Society of Colon and Rectal Surgeons in conjunction with the American Board of Colon and Rectal Surgery has developed the Colorectal Objective Structured Assessment of Technical Skill (COSATS) with the intent of incorporating this assessment
into the board certification process.57 Preliminary data on the COSATS have demonstrated that a performance-based colorectal technical skills examination using simulation could be developed that has the ability to differentiate between different levels of training (providing evidence of construct validity) with good reliability. Additional work is being carried out to further establish evidence of reliability and validity of the COSATS as well as initiatives to set competency standards. Simulation has not been introduced into the realm of Maintenance of Certification (MOC). Currently, the American Board of Surgery MOC program relies on the use of databases to track patient outcomes to ensure adequate surgical performance.58 The role of simulation in the setting of MOC remains to be determined. However, as already discussed, simulation provides a useful platform for practicing surgeons to develop new technical skills to incorporate into their surgical armamentarium.
Conclusion The face of surgical education has changed dramatically over the past decade with the introduction and advancement of simulation platforms. As simulation models continue to be developed and refined, they will play an increasingly important role in the acquisition of colorectal surgical skills and the advancement of colorectal surgical technology. One of the challenges in the use of simulation for training is the successful incorporation of these methods into a validated surgical curriculum. A new frontier lies ahead, as simulation is being introduced into the assessment of advanced surgical competence at the time of surgical board certification.
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