- Email: [email protected]
Simulated surgery: the virtual reality of surgical training
SURGERY JOURNAL PRIZE-WINNING ESSAY
Simulated surgery: the virtual reality of surgical training
The Surgery Journal Prize is a national essay competition run by Surgery and aimed at UK medical undergraduates. For 2010, essays were invited on the topic of Simulation in Surgery and we received a good response. All submitted essays were judged by three assessors chosen from the Editorial Board of Surgery who, after careful deliberation, selected one overall winning entry and two runners-up. Lydia Hanna, a final-year medical student at St George’s University, London was awarded first prize - £500 worth of books and journal subscriptions from www.ElsevierHealth.com and attended the Surgery Journal’s Editorial Board dinner to receive her prize. We are delighted to publish the winning essay below.
Lydia Hanna
Introduction
Two other prizes of £250 worth of books and journal subscriptions were awarded to runners up Shaun Shi Yan Tan, a fourth-year medical student at University of Glasgow and Shehab Jabir, a finalyear medical student, also at St George’s University, London.
Surgical training has traditionally been one of apprenticeship where the surgical trainee learns to perform surgical procedures under the supervision of a trained surgeon. Through repeated exposure to countless procedures over many years, a wide range of operative skills are acquired and perfected with surgical maturity gained through the ability to cope with the unexpected. Professor Lord Ara Darzi proposed that ‘the golden age of surgery is waning. The Industrial Age is being replaced by the Information Age, and conventional surgery is being replaced by a host of minimally invasive therapies and non-invasive procedures’. Such technological advancements, though pioneering in the field of surgery and advantageous to our patients, have led to the traditional surgical training paradigm to be questioned. Growing ethical and economic opinions such as patients being ‘practised’ on and the decreasing length of surgical training due to the European Working Time Directive (EWTD) and the Modernizing Medical Careers (MMC) initiative has also necessitated a transformation of the training programme.1,2 The word ‘simulate’ is defined as the imitation of some real thing or process. Simulation is said to facilitate learning through immersion, reflection, feedback, and practice without the potential risk encountered in comparable real-life experiences. Simulation techniques are used as training tools in a variety of disciplines including aviation, space aeronautics, and the military and have now infiltrated the surgical world. The development of virtual reality surgical simulators (VRS) encompasses the idea of real people using simulated equipment in a simulated world to learn surgical procedural skills that can be transferred to the operating room.3 This article explores the use of VRS as a training tool for the future surgeon.
attainment of proficiency within surgical discipline is known to be one of the lengthiest within medicine. For those who are dedicated, the gruelling years are a time of excitement and thrill in the acquisition of knowledge and skill from admired mentors, and simply a means to an end in achieving an ambition. The unique nature of skills birthed by the introduction and continual evolution of minimally invasive surgery (MIS), and the implementation of the EWTD and MMC threaten to shake the traditional foundations of surgical training. The reduction in working hours has resulted in less surgical exposure and in the face of new technological surgical techniques that undoubtedly require time to master, together with the increasing awareness that it is ethically wrong for novices to ‘practise’ on patients, the appropriateness of the apprenticeship model of training is being questioned.1,2 How then should future surgical training proceed? Laparoscopic training techniques, the most basic form of MIS, include training on human cadavers and live animals, both of which have their drawbacks. The use of human cadavers allows anatomical
This progression of surgical training The apprenticeship nature of surgical training dates back as far as the 16th century with aspiring trainee surgeons observing, assisting and hanging on the every whim of their senior in the hope of one day graduating to independence where they could command their own operating room (Figure 1). To this day, very little has changed in this traditional paradigm, and the
Figure 1 Painting by Rembrandt van Rijn depicting a surgeon dissecting the forearm while trainees observed (http://www.imageofsurgery.com/ Surgery_history_art.htm).
Lydia Hanna is a Final-Year Medical Student at St George’s University of London, UK.
SURGERY 28:9
463
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 4 Coordination.
feedback of one’s performance. While yet to be universally accepted, the evolution of sophisticated VRS heralds the real possibility of future surgical training becoming simulated.
Figure 2 Representation of the components of a virtual reality surgical simulator.
Discussion
knowledge to be gained at the expense of physiological knowledge, while the use of live animals provides physiological knowledge but the anatomical knowledge is inaccurate.3 The box (video) trainer provides another means for learning laparoscopic surgical skill. Comprising a portable rectangular box and surgical accessories, trainee surgeons are able to practise techniques such as transference, precision cutting and suturing while being assessed by a senior surgeon. There are undoubtedly problems with this method of training, namely subjective assessment. In addition, an indication of level of skill attained is not provided neither is progress of training or an evaluation of one’s performance in relation to peers.4,5 In an age hailed as the ‘Information Age’ where MIS surgery has evolved to the invention of robotic surgeons, surgical training techniques have also become influenced by modern technology. VRS encompass computer-generated systems that use ‘realistic graphical renderings and advanced control algorithms to model anatomy and physiology’3 and can provide realistic representations of many operative environments. In addition, systems are able to record, measure and provide
Introducing the simulators The technical and mechanical skills required for laparoscopic surgery have immensely contributed to the surgeon’s armamentarium. However, they differ greatly from those necessitated by traditional open surgery. The former in particular requires ambidexterity, psychomotor and perceptual abilities due to dependence on two-dimensional images, minimal tactile feedback and tooletissue interactions at a distance.1 VRS are now being recognized as an important tool in the acquisition of these skills. VRS consist of a PC connected to a jig that encloses two laparoscopic instruments held in a pivoted support that allows rotation. The PC graphically displays the surgical task and the laparoscopic instruments allow the surgical environment to be manipulated to complete the task (Figures 2e9).6,7 VRS provide a novel method of training through initial learning, repeated practice and refinement of surgical skills. These range from basic component skill such as lifting and grasping, clipping, diathermy and suturing and more recently, to
Figure 3 Camera navigation.
Figure 5 Instrument navigation.
SURGERY 28:9
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Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 6 Grasping.
the training of entire procedures such as laparoscopic cholecystectomy, oophorectomy and Nissen fundoplication1,7 without compromizing patient safety. VRS record all movements made by the instruments, detailing the task attempted, precision during the task, any errors made and by which hand, and the time to completion. These data are then analysed and provide the user with an indication of their overall and individual task performance.1,6 A trainee’s performance can therefore be logged and monitored over successive sessions and comparisons can be made between trainees.4,6 The realism In order for VRS to allow the necessary psychomotor and additional surgical skills to be acquired, it is evident that they need to be realistic of the surgical environment both visually and tactilely. Virtual views do indeed provide an impressive visual component (Figures 10e13) and are consistent with intra-operative views, with virtual soft tissues displaying the texture and consistency of live tissue. The incorporation of tracking and haptic feedback devices has further catapulted VRS into the realistic realm, providing high-fidelity systems. The tracking device is able to detect collisions between virtual tissue and the laparoscopic instruments allowing virtual soft
tissues to respond to interactive manipulation. This includes deformation with contact pressure and the ability to be stretched or cut, thereby displaying physical properties of live tissue.6,8 The surgeon’s actions at the laparoscopic devices are then
Figure 7 Lifting and grasping.
Figure 9 Fine dissection.
SURGERY 28:9
a Cutting b Applying clips. Figure 8
465
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 10 Handling loops. Figure 12 Cholecystectomy.
replicated as a real-time graphical display. The haptic system provides resistance to further advancement when a ‘dangerous’ plane is approached which is transmitted through the instruments, providing force feedback.3,8,9
laparoscopists (score of 33 on objective structured assessment of laparoscopic salpingectomy) whereas non-VRS-trained registrars performed to the level of novices (score of 23). In addition, VRS-trained registrars performed laparoscopic salpingectomy in half the time (12 minutes) it took non-VRStrained registrars.14 Grantcharov et al also demonstrated that VRS-trained surgical trainees exhibited greater improvement in time, error and economy of movement scores during laparoscopic cholecystectomy in the operating room than their controls.15 These studies and a growing body of research in this area conclude that VRS have both face and construct validity.10e12 For our clinical practice, such data reflect that skills acquired from training on VRS are transferable to the operating room and can shorten the learning curve of many procedures.13,14,16,17 VRS may also be used to monitor a trainee’s progress with the scope for early intervention when performance is suboptimal, and as a means of selecting candidates, assessing skill and as a certification tool, without compromising patient safety.6 The prospect of incorporating these ‘virtual tutors’ into the surgical training programme therefore becomes conceivable.
Validated potential Evidence that VRS provide unbiased and reliable assessments of skills for laparoscopic surgery is fast gaining momentum. Firstly, the scoring systems have been found to be both sensitive and specific for quantifying the skills for laparoscopic surgery,10 with test parameters that are surgically relevant.4 Scoring systems are also able to distinguish between experienced surgeons and novices.4,10 Secondly, significant correlations between laparoscopic performance in both animal models and the operating room (through a well-validated rating scale) and VRS performance scores have been described.11,12 Furthermore, in their randomized control trial carried on 16 surgical residents, Seymour et al found that VRS-trained residents performed laparoscopic cholecystectomy 29% faster to non-VRStrained residents and made six times fewer operative errors. NonVRS-trained residents were also five times more likely to injure the gallbladder and five times more likely to burn non-target tissue.13 In a similar endeavour, Larsen et al found that VRS-trained registrars performed to the level of intermediate level
Figure 11 Suturing of bowel.
SURGERY 28:9
Figure 13 Cholecystectomy.
466
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Oversimplification of a complex reality? While it would appear that the implementation of VRS to the surgical training programme has great promise, the question then arises as to why it is to this day not part of the curriculum. Reasons lie in the limitations and many unanswered questions about simulated surgical training. Firstly, training through simulation, while originally envisaged to meet ethical and economic changes in surgical practice, has the potential to compromise patient care through lack of exposure to live tissue and it being used as the means of reduced time to competence. Indeed, no matter how realistic the graphics may be, there is clearly no substitute for the interaction with live tissue, the essence of the art of surgery. Furthermore, certain skills require the wisdom of time and experience for one to reach a proficient and safe level. Following on from this, technical skill is but one of the myriad of skills required of a surgeon for safe practice. Patient communication, teamwork, decision-making and judgement, dealing with the unexpected and the possibility of converting to open surgery are all in their own right of equal importance.14,18 Training on VRS takes place outside the clinical setting, isolating the trainee from human interaction and the pressures of the operating room, without which many of these skills are prohibited from developing. Thirdly, while the results of studies are certainly convincing, they need to be interpreted with caution. Training on VRS in studies so far has not been tested as part of a surgical training programme. It is well known that any skill deteriorates over time unless repeatedly practised, thus the results cannot be wholly relied upon.1 Furthermore, the results discussed are for specific procedures, preventing the generalization of conclusions to other surgical procedures and specialities. There are also no standard predefined ‘benchmark’ criteria to evaluate the use of simulators, with a lack of similarity between the evaluation tasks of different studies. Of note, these tasks are not reflective of perhaps the most important criterion to proficiency, patientorientated outcome and it is questionable as to whether the duration of time to complete a task is reflective of competence and patient safety. Other practicalities of implementing VRS in training, for example, length of a training session, frequency of training, should VRS replace or supplement current surgical training methods, what score constitutes proficiency and does the type of VR model affect skill acquisition, have as of yet not been fully elucidated. Aggarwal et al19 have attempted to devise a curriculum, but conclude that in order for their results to be applicable to the clinical setting an international multicentre randomized controlled trial is required. Finally, VRS carry a costly price tag and with all the uncertainty that surrounds simulated surgery, it is clear that many institutions will be unwilling to make such an investment.
imported into virtual reality software that has the ability to reconstruct a three-dimensional image,1,20,21 affording the surgeon the technical experience of a patient-specific procedure before the patient is ‘practised’ on clinically. This software may also allow a library of graphical patient data to be built up for use as images for the simulators, providing greater realism for trainees. Training through these images rather than computer-generated images will also accelerate learning as anatomic variation and true pathology is factored into the images. The diversity of pathology will also facilitate cognitive and procedure specific learning, and improve decision-making skills. Hybrid simulation may also prove to be essential for future training. This involves the use of standardized ‘patients’ (played by actors) within the simulation environment to allow the development of non-technical skills in addition to the technical skills, such as communication, decision-making and clinical judgements.14,22
Conclusion Advances in MIS, together with ethical and economic opinions in the surgical world have led to the recognition that the traditional surgical training paradigm needs to be revised for the future surgeon. Virtual reality surgical simulators have the potential to address many of these issues by providing the future surgeon with a ‘virtual tutor’ that enables the learning and refinement of technical surgical skills necessitated by MIS, as well as provide objective, reliable and unbiased assessment of skill. The demonstration of face and construct validity, and the transferability of skills acquired from VRS to the operating room further support its implementation as a future surgical training tool. However, there are many unanswered questions that need further research and validation in order to incorporate VRS into surgical training programmes. Given the complexity of skill required to be a competent and safe surgeon, simulated training should perhaps serve as an adjunct to existing traditional methods affording the trainee surgeon an armamentarium of training tools to acquire surgical proficiency. A
REFERENCES 1 Gurusamy KS, Aggarwal R, Palanivelu L, Davidson BR. Virtual reality training for surgical trainees in laparoscopic surgery. Cochrane Database of Systematic Reviews; 2009. 2 Grantcharov TP, Reznick RK. Teaching procedural skills. BMJ 2008; 336: 1129e31. 3 Simulated surgery feels more like the OR. Also available at: http:// medicaldesign.com/engineering-prototyping/simulated_surgery_feels/. 4 Chaudhry A, Sutton C, Wood J, Stone R, McCloy R. Learning rate for laparoscopic surgical skills on MIST VR, a virtual reality simulator: quality of humanecomputer interface. Ann R Coll Surg Engl 1999; 81: 281e6. 5 Botden SM, Jakimowicz JJ. What is going on in augmented reality simulation in laparoscopic surgery? Surg Endosc 2009; 23: 1693e700. 6 Wilson MS, Middlebrook A, Sutton C, Stone R, McCloy RF. MIST VR: a virtual reality trainer for laparoscopic surgery assesses performance. Ann R Coll Surg Engl 1997; 79: 403e4. 7 LapSim e the surgical skills trainer. Also available at: http://www. surgical-science.com or [email protected].
Future advancements Despite the unknown, there are also many exciting developments taking place that will undoubtedly propel the potential of simulation-based surgery. Recent advances in technology have made it possible to train on three-dimensional reconstructions of patient-specific data. Two-dimensional images of the patient are
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Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
¨nroth H. The transfer of basic 17 Hyltander A, Liljegren E, Rhodin PH, Lo skills learned in a laparoscopic simulator to the operating room. Surg Endosc 2002; 16: 1324e8. 18 Kneebone RL, Nestel D, Chrzanowska J, Barnet AE, Darzi A. Innovative training for new surgical rolesdthe place of evaluation. Med Educ 2006; 40: 987e94. 19 Aggarwal R, Grantcharov TP, Eriksen JR, et al. An evidence-based virtual reality training program for novice laparoscopic surgeons. Ann Surg 2006; 244: 310e4. 20 Marescaux J, Cle´ment JM, Tassetti V, et al. Virtual reality applied to hepatic surgery simulation: the next revolution. Ann Surg 1998; 228: 627e34. 21 Lamade´ W, Glombitza G, Fischer L, et al. The impact of 3-dimensional reconstructions on operation planning in liver surgery. Arch Surg 2000; 135: 1256e61. 22 Kneebone R, Nestel D, Wetzel C, et al. The human face of simulation: patient-focused simulation training. Acad Med 2006; 81: 919e24.
8 Liu A, Tendick F, Cleary K, Kaufmann C. A survey of surgical simulation: applications, technology, and education. Presence 2003; 12: 599e614. 9 Delft University of Technology. New training method helps surgeons evaluate their own minimally invasive surgery. 2009, January 12. 10 Grantcharov TP, Bardram L, Funch-Jensen P, Rosenberg J. Learning curves and impact of previous operative experience on performance on a virtual reality simulator to test laparoscopic surgical skills. Am J Surg 2003; 185: 146e9. 11 Grantcharov TP, Rosenberg J, Pahle E, Fench-Jenson P. Virtual reality computer simulation: an objective method for the evaluation of laparoscopic surgical skills. Surg Endosc 2001; 15: 242e4. 12 Kundhal PS, Grantcharov TP. Psychomotor performance measured in a virtual environment correlates with technical skills in the operating room. Surg Endosc 2009; 23: 645e9. 13 Seymour NE, Gallagher AG, Roman SA, et al. Virtual reality training improves operating room performance: results of a randomized, double-blinded study. Ann Surg 2002; 236: 458e63. 14 Larsen CR, Soerensen JL, Grantcharov TP, et al. Effect of virtual reality training on laparoscopic surgery: randomised controlled trial. BMJ 2009; 338: b1802. 15 Grantcharov TP, Kristiansen VB, Bendix J, Bardram L, Rosenberg J, Funch-Jensen P. Randomized clinical trial of virtual reality simulation for laparoscopic skills training. Br J Surg 2004; 91: 146e50. 16 Munz Y, Kumar BD, Moorthy K, Bann S, Darzi A. Laparoscopic virtual reality and box trainers: is one superior to the other? Surg Endosc 2004; 18: 485e94.
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Acknowledgement Figures 2e13 are reproduced by kind permission of Surgical Science a company dedicated to the development of high-quality tools for the assessment, training and certification of medical professionals (www.surgical-science.com).
468
Ó 2010 Elsevier Ltd. All rights reserved.
Simulated surgery: the virtual reality of surgical training
The Surgery Journal Prize is a national essay competition run by Surgery and aimed at UK medical undergraduates. For 2010, essays were invited on the topic of Simulation in Surgery and we received a good response. All submitted essays were judged by three assessors chosen from the Editorial Board of Surgery who, after careful deliberation, selected one overall winning entry and two runners-up. Lydia Hanna, a final-year medical student at St George’s University, London was awarded first prize - £500 worth of books and journal subscriptions from www.ElsevierHealth.com and attended the Surgery Journal’s Editorial Board dinner to receive her prize. We are delighted to publish the winning essay below.
Lydia Hanna
Introduction
Two other prizes of £250 worth of books and journal subscriptions were awarded to runners up Shaun Shi Yan Tan, a fourth-year medical student at University of Glasgow and Shehab Jabir, a finalyear medical student, also at St George’s University, London.
Surgical training has traditionally been one of apprenticeship where the surgical trainee learns to perform surgical procedures under the supervision of a trained surgeon. Through repeated exposure to countless procedures over many years, a wide range of operative skills are acquired and perfected with surgical maturity gained through the ability to cope with the unexpected. Professor Lord Ara Darzi proposed that ‘the golden age of surgery is waning. The Industrial Age is being replaced by the Information Age, and conventional surgery is being replaced by a host of minimally invasive therapies and non-invasive procedures’. Such technological advancements, though pioneering in the field of surgery and advantageous to our patients, have led to the traditional surgical training paradigm to be questioned. Growing ethical and economic opinions such as patients being ‘practised’ on and the decreasing length of surgical training due to the European Working Time Directive (EWTD) and the Modernizing Medical Careers (MMC) initiative has also necessitated a transformation of the training programme.1,2 The word ‘simulate’ is defined as the imitation of some real thing or process. Simulation is said to facilitate learning through immersion, reflection, feedback, and practice without the potential risk encountered in comparable real-life experiences. Simulation techniques are used as training tools in a variety of disciplines including aviation, space aeronautics, and the military and have now infiltrated the surgical world. The development of virtual reality surgical simulators (VRS) encompasses the idea of real people using simulated equipment in a simulated world to learn surgical procedural skills that can be transferred to the operating room.3 This article explores the use of VRS as a training tool for the future surgeon.
attainment of proficiency within surgical discipline is known to be one of the lengthiest within medicine. For those who are dedicated, the gruelling years are a time of excitement and thrill in the acquisition of knowledge and skill from admired mentors, and simply a means to an end in achieving an ambition. The unique nature of skills birthed by the introduction and continual evolution of minimally invasive surgery (MIS), and the implementation of the EWTD and MMC threaten to shake the traditional foundations of surgical training. The reduction in working hours has resulted in less surgical exposure and in the face of new technological surgical techniques that undoubtedly require time to master, together with the increasing awareness that it is ethically wrong for novices to ‘practise’ on patients, the appropriateness of the apprenticeship model of training is being questioned.1,2 How then should future surgical training proceed? Laparoscopic training techniques, the most basic form of MIS, include training on human cadavers and live animals, both of which have their drawbacks. The use of human cadavers allows anatomical
This progression of surgical training The apprenticeship nature of surgical training dates back as far as the 16th century with aspiring trainee surgeons observing, assisting and hanging on the every whim of their senior in the hope of one day graduating to independence where they could command their own operating room (Figure 1). To this day, very little has changed in this traditional paradigm, and the
Figure 1 Painting by Rembrandt van Rijn depicting a surgeon dissecting the forearm while trainees observed (http://www.imageofsurgery.com/ Surgery_history_art.htm).
Lydia Hanna is a Final-Year Medical Student at St George’s University of London, UK.
SURGERY 28:9
463
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 4 Coordination.
feedback of one’s performance. While yet to be universally accepted, the evolution of sophisticated VRS heralds the real possibility of future surgical training becoming simulated.
Figure 2 Representation of the components of a virtual reality surgical simulator.
Discussion
knowledge to be gained at the expense of physiological knowledge, while the use of live animals provides physiological knowledge but the anatomical knowledge is inaccurate.3 The box (video) trainer provides another means for learning laparoscopic surgical skill. Comprising a portable rectangular box and surgical accessories, trainee surgeons are able to practise techniques such as transference, precision cutting and suturing while being assessed by a senior surgeon. There are undoubtedly problems with this method of training, namely subjective assessment. In addition, an indication of level of skill attained is not provided neither is progress of training or an evaluation of one’s performance in relation to peers.4,5 In an age hailed as the ‘Information Age’ where MIS surgery has evolved to the invention of robotic surgeons, surgical training techniques have also become influenced by modern technology. VRS encompass computer-generated systems that use ‘realistic graphical renderings and advanced control algorithms to model anatomy and physiology’3 and can provide realistic representations of many operative environments. In addition, systems are able to record, measure and provide
Introducing the simulators The technical and mechanical skills required for laparoscopic surgery have immensely contributed to the surgeon’s armamentarium. However, they differ greatly from those necessitated by traditional open surgery. The former in particular requires ambidexterity, psychomotor and perceptual abilities due to dependence on two-dimensional images, minimal tactile feedback and tooletissue interactions at a distance.1 VRS are now being recognized as an important tool in the acquisition of these skills. VRS consist of a PC connected to a jig that encloses two laparoscopic instruments held in a pivoted support that allows rotation. The PC graphically displays the surgical task and the laparoscopic instruments allow the surgical environment to be manipulated to complete the task (Figures 2e9).6,7 VRS provide a novel method of training through initial learning, repeated practice and refinement of surgical skills. These range from basic component skill such as lifting and grasping, clipping, diathermy and suturing and more recently, to
Figure 3 Camera navigation.
Figure 5 Instrument navigation.
SURGERY 28:9
464
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 6 Grasping.
the training of entire procedures such as laparoscopic cholecystectomy, oophorectomy and Nissen fundoplication1,7 without compromizing patient safety. VRS record all movements made by the instruments, detailing the task attempted, precision during the task, any errors made and by which hand, and the time to completion. These data are then analysed and provide the user with an indication of their overall and individual task performance.1,6 A trainee’s performance can therefore be logged and monitored over successive sessions and comparisons can be made between trainees.4,6 The realism In order for VRS to allow the necessary psychomotor and additional surgical skills to be acquired, it is evident that they need to be realistic of the surgical environment both visually and tactilely. Virtual views do indeed provide an impressive visual component (Figures 10e13) and are consistent with intra-operative views, with virtual soft tissues displaying the texture and consistency of live tissue. The incorporation of tracking and haptic feedback devices has further catapulted VRS into the realistic realm, providing high-fidelity systems. The tracking device is able to detect collisions between virtual tissue and the laparoscopic instruments allowing virtual soft
tissues to respond to interactive manipulation. This includes deformation with contact pressure and the ability to be stretched or cut, thereby displaying physical properties of live tissue.6,8 The surgeon’s actions at the laparoscopic devices are then
Figure 7 Lifting and grasping.
Figure 9 Fine dissection.
SURGERY 28:9
a Cutting b Applying clips. Figure 8
465
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Figure 10 Handling loops. Figure 12 Cholecystectomy.
replicated as a real-time graphical display. The haptic system provides resistance to further advancement when a ‘dangerous’ plane is approached which is transmitted through the instruments, providing force feedback.3,8,9
laparoscopists (score of 33 on objective structured assessment of laparoscopic salpingectomy) whereas non-VRS-trained registrars performed to the level of novices (score of 23). In addition, VRS-trained registrars performed laparoscopic salpingectomy in half the time (12 minutes) it took non-VRStrained registrars.14 Grantcharov et al also demonstrated that VRS-trained surgical trainees exhibited greater improvement in time, error and economy of movement scores during laparoscopic cholecystectomy in the operating room than their controls.15 These studies and a growing body of research in this area conclude that VRS have both face and construct validity.10e12 For our clinical practice, such data reflect that skills acquired from training on VRS are transferable to the operating room and can shorten the learning curve of many procedures.13,14,16,17 VRS may also be used to monitor a trainee’s progress with the scope for early intervention when performance is suboptimal, and as a means of selecting candidates, assessing skill and as a certification tool, without compromising patient safety.6 The prospect of incorporating these ‘virtual tutors’ into the surgical training programme therefore becomes conceivable.
Validated potential Evidence that VRS provide unbiased and reliable assessments of skills for laparoscopic surgery is fast gaining momentum. Firstly, the scoring systems have been found to be both sensitive and specific for quantifying the skills for laparoscopic surgery,10 with test parameters that are surgically relevant.4 Scoring systems are also able to distinguish between experienced surgeons and novices.4,10 Secondly, significant correlations between laparoscopic performance in both animal models and the operating room (through a well-validated rating scale) and VRS performance scores have been described.11,12 Furthermore, in their randomized control trial carried on 16 surgical residents, Seymour et al found that VRS-trained residents performed laparoscopic cholecystectomy 29% faster to non-VRStrained residents and made six times fewer operative errors. NonVRS-trained residents were also five times more likely to injure the gallbladder and five times more likely to burn non-target tissue.13 In a similar endeavour, Larsen et al found that VRS-trained registrars performed to the level of intermediate level
Figure 11 Suturing of bowel.
SURGERY 28:9
Figure 13 Cholecystectomy.
466
Ó 2010 Elsevier Ltd. All rights reserved.
SURGERY JOURNAL PRIZE-WINNING ESSAY
Oversimplification of a complex reality? While it would appear that the implementation of VRS to the surgical training programme has great promise, the question then arises as to why it is to this day not part of the curriculum. Reasons lie in the limitations and many unanswered questions about simulated surgical training. Firstly, training through simulation, while originally envisaged to meet ethical and economic changes in surgical practice, has the potential to compromise patient care through lack of exposure to live tissue and it being used as the means of reduced time to competence. Indeed, no matter how realistic the graphics may be, there is clearly no substitute for the interaction with live tissue, the essence of the art of surgery. Furthermore, certain skills require the wisdom of time and experience for one to reach a proficient and safe level. Following on from this, technical skill is but one of the myriad of skills required of a surgeon for safe practice. Patient communication, teamwork, decision-making and judgement, dealing with the unexpected and the possibility of converting to open surgery are all in their own right of equal importance.14,18 Training on VRS takes place outside the clinical setting, isolating the trainee from human interaction and the pressures of the operating room, without which many of these skills are prohibited from developing. Thirdly, while the results of studies are certainly convincing, they need to be interpreted with caution. Training on VRS in studies so far has not been tested as part of a surgical training programme. It is well known that any skill deteriorates over time unless repeatedly practised, thus the results cannot be wholly relied upon.1 Furthermore, the results discussed are for specific procedures, preventing the generalization of conclusions to other surgical procedures and specialities. There are also no standard predefined ‘benchmark’ criteria to evaluate the use of simulators, with a lack of similarity between the evaluation tasks of different studies. Of note, these tasks are not reflective of perhaps the most important criterion to proficiency, patientorientated outcome and it is questionable as to whether the duration of time to complete a task is reflective of competence and patient safety. Other practicalities of implementing VRS in training, for example, length of a training session, frequency of training, should VRS replace or supplement current surgical training methods, what score constitutes proficiency and does the type of VR model affect skill acquisition, have as of yet not been fully elucidated. Aggarwal et al19 have attempted to devise a curriculum, but conclude that in order for their results to be applicable to the clinical setting an international multicentre randomized controlled trial is required. Finally, VRS carry a costly price tag and with all the uncertainty that surrounds simulated surgery, it is clear that many institutions will be unwilling to make such an investment.
imported into virtual reality software that has the ability to reconstruct a three-dimensional image,1,20,21 affording the surgeon the technical experience of a patient-specific procedure before the patient is ‘practised’ on clinically. This software may also allow a library of graphical patient data to be built up for use as images for the simulators, providing greater realism for trainees. Training through these images rather than computer-generated images will also accelerate learning as anatomic variation and true pathology is factored into the images. The diversity of pathology will also facilitate cognitive and procedure specific learning, and improve decision-making skills. Hybrid simulation may also prove to be essential for future training. This involves the use of standardized ‘patients’ (played by actors) within the simulation environment to allow the development of non-technical skills in addition to the technical skills, such as communication, decision-making and clinical judgements.14,22
Conclusion Advances in MIS, together with ethical and economic opinions in the surgical world have led to the recognition that the traditional surgical training paradigm needs to be revised for the future surgeon. Virtual reality surgical simulators have the potential to address many of these issues by providing the future surgeon with a ‘virtual tutor’ that enables the learning and refinement of technical surgical skills necessitated by MIS, as well as provide objective, reliable and unbiased assessment of skill. The demonstration of face and construct validity, and the transferability of skills acquired from VRS to the operating room further support its implementation as a future surgical training tool. However, there are many unanswered questions that need further research and validation in order to incorporate VRS into surgical training programmes. Given the complexity of skill required to be a competent and safe surgeon, simulated training should perhaps serve as an adjunct to existing traditional methods affording the trainee surgeon an armamentarium of training tools to acquire surgical proficiency. A
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Future advancements Despite the unknown, there are also many exciting developments taking place that will undoubtedly propel the potential of simulation-based surgery. Recent advances in technology have made it possible to train on three-dimensional reconstructions of patient-specific data. Two-dimensional images of the patient are
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Acknowledgement Figures 2e13 are reproduced by kind permission of Surgical Science a company dedicated to the development of high-quality tools for the assessment, training and certification of medical professionals (www.surgical-science.com).
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