- Email: [email protected]
Construct and face validity of a virtual reality–based camera navigation curriculum
j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
Available online at www.sciencedirect.com
journal homepage: www.JournalofSurgicalResearch.com
Association for Academic Surgery
Construct and face validity of a virtual realityebased camera navigation curriculum Shohan Shetty, MD,a,* Lucian Panait, MD,b Jacob Baranoski, BSc,b Stanley J. Dudrick, MD, FACS,a,b Robert L. Bell, MD, FACS,b Kurt E. Roberts, MD,b and Andrew J. Duffy, MD, FACSb a b
Stanley J. Dudrick Department of Surgery, Saint Mary’s Hospital, Waterbury, Connecticut Yale University School of Medicine, New Haven, Connecticut
article info
abstract
Article history:
Introduction: Camera handling and navigation are essential skills in laparoscopic surgery.
Received 5 January 2012
Surgeons rely on camera operators, usually the least experienced members of the team, for
Received in revised form
visualization of the operative field. Essential skills for camera operators include main-
9 May 2012
taining orientation, an effective horizon, appropriate zoom control, and a clean lens.
Accepted 31 May 2012
Virtual reality (VR) simulation may be a useful adjunct to developing camera skills in
Available online 17 June 2012
a novice population. No standardized VR-based camera navigation curriculum is currently available. We developed and implemented a novel curriculum on the LapSim VR simulator
Keywords:
platform for our residents and students. We hypothesize that our curriculum will
Surgical education
demonstrate construct and face validity in our trainee population, distinguishing levels of
Virtual reality
laparoscopic experience as part of a realistic training curriculum.
Resident training
Methods: Overall, 41 participants with various levels of laparoscopic training completed the
Medical student training
curriculum. Participants included medical students, surgical residents (Postgraduate Years
Proficiency-based training
1e5), fellows, and attendings. We stratified subjects into three groups (novice, interme-
Construct validity
diate, and advanced) based on previous laparoscopic experience. We assessed face validity with a questionnaire. The proficiency-based curriculum consists of three modules: camera navigation, coordination, and target visualization using 0 and 30 laparoscopes. Metrics include time, target misses, drift, path length, and tissue contact. We analyzed data using analysis of variance and Student’s t-test. Results: We noted significant differences in repetitions required to complete the curriculum: 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group (P < 0.05). In the individual modules, coordination required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for the advanced group (P < 0.05). Target visualization required 19.3 attempts for novices, 13.2 for intermediates, and 8.2 for the advanced group (P < 0.05). Participants believe that training improves camera handling skills (95%), is relevant to surgery (95%), and is a valid training tool (93%). Graphics (98%) and realism (93%) were highly regarded. Conclusions: The VR-based camera navigation curriculum demonstrates construct and face validity for our training population. Camera navigation simulation may be a valuable tool
* Corresponding author. Stanley J. Dudrick Department of Surgery, Saint Mary’s Hospital, 56 Franklin Street, Waterbury, CT 06410, USA. Tel.: þ1 203 727 0676; fax: þ1 203 709 6089. E-mail address: [email protected] (S. Shetty). 0022-4804/$ e see front matter ª 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2012.05.086
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j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
that can be integrated into training protocols for residents and medical students during their surgery rotations. ª 2012 Elsevier Inc. All rights reserved.
1.
Introduction
Challenges to visualization of the operative field in laparoscopy include loss of depth perception (two-dimensional monitors), fixed access points, and the fulcrum effect [1e3]. Visualization in laparoscopic surgery relies on the navigation skills of the camera operator, usually the least experienced member of the team. Moreover, the camera operator must maintain steadiness and orientation (especially in angled scopes), an effective horizon, appropriate zoom control, and a clean lens. Developing camera navigation skills before entering the operating room may enable the operation to flow smoothly and, more importantly, improve patient safety. Developing skills essential for laparoscopic surgery is now possible, and even required, outside the operating room. Simulation training protocols for medical students and residents before entering the operating room can shorten learning curves, improve technical skills, and expedite competency [4,5]. While various simulation tools are available, the virtual reality (VR) simulator facilitates a standardized, individualized, goal-directed, and proficiency-based training experience for the trainee. Few studies have focused on camera navigation simulation training [6e8], and no validated VR simulator curriculum for medical students and residents is currently available. A novel camera navigation curriculum was designed at Yale University using the LapSim VR simulator platform (Surgical Science, Go¨teborg, Sweden) for our residents and students. A curriculum consisting of three modulesdcamera navigation, coordination, and target visualization using 0 and 30 laparoscopesdwas developed. The hypothesis of the study is that the customized Yale camera navigation curriculum can differentiate skill levels among years of operator experience, as part of a realistic curriculum, establishing construct and face validity.
2.
Methods
2.1.
Equipment
The LapSim (Fig. 1A) is a personal computerebased VR simulator with interchangeable laparoscopic instrument handles, which contain sensors for each instrument (Fig. 1B). The software consists of a generic platform containing preinstalled laparoscopic tasks with realistic graphics. Each module can be customized over a wide range of protocols based on individual training requirements. Performance results are stored in a database and can be retrieved or exported as required by the administrator.
2.2.
Curriculum
The Yale University laparoscopic camera navigation curriculum is a proficiency-based program consisting of three modules that assess camera navigation, coordination, and target visualization skills. The camera navigation module involves the task of locating an object, followed by centering and sizing the object (Fig. 2). The coordination module involves locating an object with the camera in the left hand, followed by touching the object with a grasper in the right hand (Fig. 3). The target visualization module involves identifying an abdominal organ in an anatomical location based on the visual cues provided, using the 0 and 30 laparoscopes (Fig. 4). These exercise modules must be completed in a time-efficient manner, avoiding tissue contact and excessive instrument motion. We assessed performance with customized metrics that included time taken to complete the task, number of targets missed, drift (measure of the angle from the horizontal axis), total path length (measure of excess instrument motion), and the number of times the camera was in contact with tissue. Exceeding the preset parameter for each metric is programmed to result in failure to complete the task. The user is thus required to repeat the task as many times as necessary until the established standard
Fig. 1 e (A) LapSim VR simulator platform. (B) Simulator camera handle. (Color version of figure is available online.)
j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
193
Fig. 2 e Camera navigation module. (Color version of figure is available online.)
Fig. 4 e Target visualization module. (Color version of figure is available online.)
has been met. We carefully set the parameters for the metrics, difficulty level, and the pass-fail settings so that they were sufficiently difficult that novices could not demonstrate competency before training; yet all subjects could successfully complete the module with a reasonable amount of practice. The simulator recorded the number of repetitions required to pass each module and the number required to complete the curriculum.
procedures. We assessed face validity with a questionnaire that all of the participants answered upon completing the curriculum. Participants evaluated the curriculum on eight points: realism (graphics and overall), relevance to surgery, validity as a testing and training tool, feedback accuracy, whether the curriculum should be required as part of surgical training, and whether the curriculum improved perceived laparoscopic camera navigation skills.
2.3.
Participants
We assigned subjects to the curriculum after initial familiarization with the simulator and the camera modules. Overall, 41 participants with various levels of laparoscopic training completed the curriculum. Participants included medical students, surgical residents (Postgraduate Years 1e5), fellows, and attendings. None of the participants were involved in designing the curriculum. We stratified participants into three groups (novice, intermediate, and advanced) based on previous laparoscopic experience. The novice group (29 participants) consisted of individuals who had performed or assisted in <10 laparoscopic surgeries. The intermediate group (six participants) consisted of individuals who had performed or assisted in at least 10 but <100 laparoscopic cases. The advanced group (six participants) was composed of individuals who had performed at least 100 laparoscopic cases. We used a questionnaire to assess participant demographic information and level of experience with laparoscopic
Fig. 3 e Coordination module. (Color version of figure is available online.)
2.4.
Data analysis
We downloaded and analyzed all data recorded by the simulator using analysis of variance and Student’s t-tests. The institutional review board approved the protocols and methods of the study.
3.
Results
In all, 41 participants (29 novices, six intermediates, and six advanced) completed the Yale University camera navigation curriculum. We noted significant differences in repetitions required to complete the curriculum among the three groups. The average number of repetitions to complete the curriculum was 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group. The difference between the groups reached statistical significance (P < 0.05) (Fig. 5). In addition, we saw a significant difference among all three groups in two of the three modules. The coordination module demonstrated significant differences in repetitions required for each group. The coordination module required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for advanced participants. The difference between the groups reached statistical significance (P < 0.05) (Fig. 6). The target visualization module required 19.3 repetitions for novices, 13.2 for intermediates, and 8.2 for the advanced group. The difference between the groups reached statistical significance (P < 0.05) (Fig. 7). To complete the camera navigation module, novices required significantly more repetitions (9.2) than both the intermediate (3.8) and the advanced (1.8) group. Statistical significance was achieved between the novice and intermediate groups (P < 0.05), as well as between the novice and the advanced group (P < 0.05) to complete the module. However,
194
j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
Fig. 5 e Number of attempts required to complete the curriculum. We observed a significant difference among the novice, intermediate, and advanced groups. Data are means ± standard error. *P < 0.05.
Fig. 7 e Number of attempts required to complete the target visualization module. We saw a significant difference among the novice, intermediate and advanced groups. Data are means ± standard error. *P < 0.05.
we observed no statistical significance between the number of repetitions for the intermediate and the advanced groups to complete the camera navigation module (Fig. 8). Table 1 lists responses to the face validity questionnaire.
Various strategies for laparoscopic simulation training have been employed, including video box trainers, VR simulators, use of inanimate models, explanted tissue models, and live animal (porcine) laboratories [13]. Benefits and limitations exist for each of these training strategies; however, current work-hour limits, increased patient volume, and evolving requirements for objective proficiency mandate efficient and effective training protocols for subsequent performance. Virtual reality surgical simulation may be a useful tool to meet these ends, but it requires thoughtful implementation. The benefits of VR simulation for the trainee include easy accessibility, opportunity for independent practice, and instant feedback on performance. From the surgical educator’s perspective, VR simulation affords minimal supervision during training, versatile customized curricula, and an objective means for tracking trainee performance [14]. Although there is a high initial startup cost in acquiring the VR simulator, over a 5-y period, VR training may be more cost-effective than conventional laparoscopic training in programs with more than 10 residents [15]. Various
4.
Discussion
Camera navigation is an essential skill in laparoscopic surgery; yet, we found that most medical students have not operated the camera before entering the operating room. The learning curve for camera navigation, especially the use of the angled laparoscope in complex laparoscopic surgery, is steep [9e11]. Fitts and Posner’s [12] theory on motor skill acquisition involves cognition (understanding the task), integration (comprehending the task), and automation (performing the task efficiently with precision). The implications of this theory have a definite bearing on surgical training overall, and laparoscopy in particular. The earlier stages of learning motor skills can take place outside the operating room in a simulation laboratory.
Fig. 6 e Number of attempts required to complete the coordination module. We noted a significant difference among the novice, intermediate and advanced groups. Data are means ± standard error. *P < 0.05.
Fig. 8 e Number of attempts required to complete the camera navigation module. We observed a significant difference between the novice and intermediate groups as well as the novice and the advanced groups. Data are means ± standard error. *P < 0.05.
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Table 1 e Face validity Likert item response frequencies. Question
No. (%) of participants responding Strongly agree
The curriculum improved my camera handling skills The curriculum should be required for novices before assisting in the operating room The feedback from the program is accurate The curriculum is relevant to surgery The curriculum is a valid training tool The curriculum is a valid testing tool
Agree
Neutral
Disagree
Strongly disagree
20 (50%) 24 (60%)
18 (45%) 11 (27.5%)
2 (5%) 5 (12.5%)
0 0
0 0
8 (20%) 16 (40%) 19 (47.5%) 12 (30%)
24 (60%) 22 (55%) 18 (45%) 16 (40%)
0 0 0 0
0 0 0 0
customized curricula have been developed at several institutions for specific tasks [16,17], as well as for global laparoscopic skill acquisition [18,19]. Few VR simulator studies have focused on camera navigation skills, and currently no standardized VRbased camera navigation curriculum is available. Analyses of our results revealed that the camera navigation module was the simplest in the curriculum, as represented by the number of repetitions to complete the task. This was the first module in the curriculum, and the task was deliberately kept simpler than the other two modules to enable users to familiarize themselves with the simulator, metrics, and program requirements. This module did not show statistical significance in differentiating skill levels among the intermediate and advanced groups. We found that as the task became simpler, the performance curves plateaued quickly, resulting in minimal skill improvement for the users once proficiency had been achieved. The factory settings for the individual tasks tended to fall into this category, which thus required customizing the modules in the curriculum. The coordination module was more complex, requiring ambidextrous coordination, efficiency of movement, depth perception, and camera steadiness. The complex target visualization module required the user to learn to use the 30 laparoscope optimally, to have depth perception, to maintain the horizontal axis, and to have a smooth transition from one target to the next in an efficient manner. The complex modules revealed statistical significance in differentiating among the different levels of training. Hyltander et al [7] demonstrated that basic laparoscopic skills obtained with the LapSim VR trainer transferred to the operating room. An obvious future progression of this study will be to assess whether camera navigation skills practiced in this curriculum improve trainee performance in the operating room (predictive validity). The VR-based Yale University camera navigation curriculum demonstrates construct and face validity for our training population. Successful completion of this curriculum may lead to improved technical performance in the operating room. By implementing the curriculum into overall surgical training protocols, we anticipate a benefit in the surgical training of medical students and residents and performance improvement in the operating room.
references
[1] Jones DB, Brewer JD, Soper NJ. The influence of threedimensional video systems on laparoscopic task performance. Surg Laparosc Endosc 1996;6:191.
8 (20%) 2 (5%) 3 (7.5%) 12 (30%)
[2] Jordan JA, Gallagher AG, McGuigan J, et al. Virtual reality training leads to faster adaptation to the novel psychomotor restrictions encountered by laparoscopic surgeons. Surg Endosc 2001;15:1080. [3] Gallagher AG, McClure N, McGuigan J, et al. An ergonomic analysis of the fulcrum effect in the acquisition of endoscopic skills. Endoscopy 1998;30:617. [4] Seymour NE, Gallagher AG, Roman SA, et al. Virtual reality training improves operating room performance: Results of a randomized, double-blinded study. Annal Surg 2002;236: 458. discussion 63. [5] Grantcharov TP, Kristiansen VB, Bendix J, et al. Randomized clinical trial of virtual reality simulation for laparoscopic skills training. Br J Surg 2004;91:146. [6] Haluck RS, Webster RW, Snyder AJ, et al. A virtual reality surgical trainer for navigation in laparoscopic surgery. Stud Health Technol Inform 2001;81:171. [7] Hyltander A, Liljegren E, Rhodin PH, et al. The transfer of basic skills learned in a laparoscopic simulator to the operating room. Surg Endosc 2002;16:1324. [8] Korndorffer JR Jr, Hayes DJ, Dunne JB, et al. Development and transferability of a cost-effective laparoscopic camera navigation simulator. Surg Endosc 2005;19:161. [9] Cuschieri A. Laparoscopic gastric resection. Surg Clin North Am 2000;80:1269. viii. [10] Katkhouda N, Mavor E. Laparoscopic splenectomy. Surg Clin North Am 2000;80:1285. [11] Smith CD, Weber CJ, Amerson JR. Laparoscopic adrenalectomy: New gold standard. World J Surg 1999; 23:389. [12] Fitts PM, Posner MI. Human performance. Belmont, CA: Brooks/Cole; 1967. [13] Reznick RK, MacRae H. Teaching surgical skillsdchanges in the wind. N Engl J Med 2006;355:2664. [14] Aggarwal R, Moorthy K, Darzi A. Laparoscopic skills training and assessment. Br J Surg 2004;91:1549. [15] Orzech N, Palter VN, Reznick RK, et al. A comparison of 2 ex vivo training curricula for advanced laparoscopic skills: A randomized controlled trial. Annal Surg 2012; 255:833. [16] Munz Y, Almoudaris AM, Moorthy K, et al. Curriculum-based solo virtual reality training for laparoscopic intracorporeal knot tying: Objective assessment of the transfer of skill from virtual reality to reality. Am J Surg 2007;193:774. [17] Van Sickle KR, Baghai M, Huang IP, et al. Construct validity of an objective assessment method for laparoscopic intracorporeal suturing and knot tying. Am J Surg 2008; 196:74. [18] Panait L, Bell RL, Roberts KE, et al. Designing and validating a customized virtual reality-based laparoscopic skills curriculum. J Surg Educ 2008;65:413. [19] Panait L, Hogle NJ, Fowler DL, et al. Completion of a novel, virtual-reality-based, advanced laparoscopic curriculum improves advanced laparoscopic skills in senior residents. J Surg Educ 2011;68:121.
Available online at www.sciencedirect.com
journal homepage: www.JournalofSurgicalResearch.com
Association for Academic Surgery
Construct and face validity of a virtual realityebased camera navigation curriculum Shohan Shetty, MD,a,* Lucian Panait, MD,b Jacob Baranoski, BSc,b Stanley J. Dudrick, MD, FACS,a,b Robert L. Bell, MD, FACS,b Kurt E. Roberts, MD,b and Andrew J. Duffy, MD, FACSb a b
Stanley J. Dudrick Department of Surgery, Saint Mary’s Hospital, Waterbury, Connecticut Yale University School of Medicine, New Haven, Connecticut
article info
abstract
Article history:
Introduction: Camera handling and navigation are essential skills in laparoscopic surgery.
Received 5 January 2012
Surgeons rely on camera operators, usually the least experienced members of the team, for
Received in revised form
visualization of the operative field. Essential skills for camera operators include main-
9 May 2012
taining orientation, an effective horizon, appropriate zoom control, and a clean lens.
Accepted 31 May 2012
Virtual reality (VR) simulation may be a useful adjunct to developing camera skills in
Available online 17 June 2012
a novice population. No standardized VR-based camera navigation curriculum is currently available. We developed and implemented a novel curriculum on the LapSim VR simulator
Keywords:
platform for our residents and students. We hypothesize that our curriculum will
Surgical education
demonstrate construct and face validity in our trainee population, distinguishing levels of
Virtual reality
laparoscopic experience as part of a realistic training curriculum.
Resident training
Methods: Overall, 41 participants with various levels of laparoscopic training completed the
Medical student training
curriculum. Participants included medical students, surgical residents (Postgraduate Years
Proficiency-based training
1e5), fellows, and attendings. We stratified subjects into three groups (novice, interme-
Construct validity
diate, and advanced) based on previous laparoscopic experience. We assessed face validity with a questionnaire. The proficiency-based curriculum consists of three modules: camera navigation, coordination, and target visualization using 0 and 30 laparoscopes. Metrics include time, target misses, drift, path length, and tissue contact. We analyzed data using analysis of variance and Student’s t-test. Results: We noted significant differences in repetitions required to complete the curriculum: 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group (P < 0.05). In the individual modules, coordination required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for the advanced group (P < 0.05). Target visualization required 19.3 attempts for novices, 13.2 for intermediates, and 8.2 for the advanced group (P < 0.05). Participants believe that training improves camera handling skills (95%), is relevant to surgery (95%), and is a valid training tool (93%). Graphics (98%) and realism (93%) were highly regarded. Conclusions: The VR-based camera navigation curriculum demonstrates construct and face validity for our training population. Camera navigation simulation may be a valuable tool
* Corresponding author. Stanley J. Dudrick Department of Surgery, Saint Mary’s Hospital, 56 Franklin Street, Waterbury, CT 06410, USA. Tel.: þ1 203 727 0676; fax: þ1 203 709 6089. E-mail address: [email protected] (S. Shetty). 0022-4804/$ e see front matter ª 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2012.05.086
192
j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
that can be integrated into training protocols for residents and medical students during their surgery rotations. ª 2012 Elsevier Inc. All rights reserved.
1.
Introduction
Challenges to visualization of the operative field in laparoscopy include loss of depth perception (two-dimensional monitors), fixed access points, and the fulcrum effect [1e3]. Visualization in laparoscopic surgery relies on the navigation skills of the camera operator, usually the least experienced member of the team. Moreover, the camera operator must maintain steadiness and orientation (especially in angled scopes), an effective horizon, appropriate zoom control, and a clean lens. Developing camera navigation skills before entering the operating room may enable the operation to flow smoothly and, more importantly, improve patient safety. Developing skills essential for laparoscopic surgery is now possible, and even required, outside the operating room. Simulation training protocols for medical students and residents before entering the operating room can shorten learning curves, improve technical skills, and expedite competency [4,5]. While various simulation tools are available, the virtual reality (VR) simulator facilitates a standardized, individualized, goal-directed, and proficiency-based training experience for the trainee. Few studies have focused on camera navigation simulation training [6e8], and no validated VR simulator curriculum for medical students and residents is currently available. A novel camera navigation curriculum was designed at Yale University using the LapSim VR simulator platform (Surgical Science, Go¨teborg, Sweden) for our residents and students. A curriculum consisting of three modulesdcamera navigation, coordination, and target visualization using 0 and 30 laparoscopesdwas developed. The hypothesis of the study is that the customized Yale camera navigation curriculum can differentiate skill levels among years of operator experience, as part of a realistic curriculum, establishing construct and face validity.
2.
Methods
2.1.
Equipment
The LapSim (Fig. 1A) is a personal computerebased VR simulator with interchangeable laparoscopic instrument handles, which contain sensors for each instrument (Fig. 1B). The software consists of a generic platform containing preinstalled laparoscopic tasks with realistic graphics. Each module can be customized over a wide range of protocols based on individual training requirements. Performance results are stored in a database and can be retrieved or exported as required by the administrator.
2.2.
Curriculum
The Yale University laparoscopic camera navigation curriculum is a proficiency-based program consisting of three modules that assess camera navigation, coordination, and target visualization skills. The camera navigation module involves the task of locating an object, followed by centering and sizing the object (Fig. 2). The coordination module involves locating an object with the camera in the left hand, followed by touching the object with a grasper in the right hand (Fig. 3). The target visualization module involves identifying an abdominal organ in an anatomical location based on the visual cues provided, using the 0 and 30 laparoscopes (Fig. 4). These exercise modules must be completed in a time-efficient manner, avoiding tissue contact and excessive instrument motion. We assessed performance with customized metrics that included time taken to complete the task, number of targets missed, drift (measure of the angle from the horizontal axis), total path length (measure of excess instrument motion), and the number of times the camera was in contact with tissue. Exceeding the preset parameter for each metric is programmed to result in failure to complete the task. The user is thus required to repeat the task as many times as necessary until the established standard
Fig. 1 e (A) LapSim VR simulator platform. (B) Simulator camera handle. (Color version of figure is available online.)
j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
193
Fig. 2 e Camera navigation module. (Color version of figure is available online.)
Fig. 4 e Target visualization module. (Color version of figure is available online.)
has been met. We carefully set the parameters for the metrics, difficulty level, and the pass-fail settings so that they were sufficiently difficult that novices could not demonstrate competency before training; yet all subjects could successfully complete the module with a reasonable amount of practice. The simulator recorded the number of repetitions required to pass each module and the number required to complete the curriculum.
procedures. We assessed face validity with a questionnaire that all of the participants answered upon completing the curriculum. Participants evaluated the curriculum on eight points: realism (graphics and overall), relevance to surgery, validity as a testing and training tool, feedback accuracy, whether the curriculum should be required as part of surgical training, and whether the curriculum improved perceived laparoscopic camera navigation skills.
2.3.
Participants
We assigned subjects to the curriculum after initial familiarization with the simulator and the camera modules. Overall, 41 participants with various levels of laparoscopic training completed the curriculum. Participants included medical students, surgical residents (Postgraduate Years 1e5), fellows, and attendings. None of the participants were involved in designing the curriculum. We stratified participants into three groups (novice, intermediate, and advanced) based on previous laparoscopic experience. The novice group (29 participants) consisted of individuals who had performed or assisted in <10 laparoscopic surgeries. The intermediate group (six participants) consisted of individuals who had performed or assisted in at least 10 but <100 laparoscopic cases. The advanced group (six participants) was composed of individuals who had performed at least 100 laparoscopic cases. We used a questionnaire to assess participant demographic information and level of experience with laparoscopic
Fig. 3 e Coordination module. (Color version of figure is available online.)
2.4.
Data analysis
We downloaded and analyzed all data recorded by the simulator using analysis of variance and Student’s t-tests. The institutional review board approved the protocols and methods of the study.
3.
Results
In all, 41 participants (29 novices, six intermediates, and six advanced) completed the Yale University camera navigation curriculum. We noted significant differences in repetitions required to complete the curriculum among the three groups. The average number of repetitions to complete the curriculum was 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group. The difference between the groups reached statistical significance (P < 0.05) (Fig. 5). In addition, we saw a significant difference among all three groups in two of the three modules. The coordination module demonstrated significant differences in repetitions required for each group. The coordination module required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for advanced participants. The difference between the groups reached statistical significance (P < 0.05) (Fig. 6). The target visualization module required 19.3 repetitions for novices, 13.2 for intermediates, and 8.2 for the advanced group. The difference between the groups reached statistical significance (P < 0.05) (Fig. 7). To complete the camera navigation module, novices required significantly more repetitions (9.2) than both the intermediate (3.8) and the advanced (1.8) group. Statistical significance was achieved between the novice and intermediate groups (P < 0.05), as well as between the novice and the advanced group (P < 0.05) to complete the module. However,
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j o u r n a l o f s u r g i c a l r e s e a r c h 1 7 7 ( 2 0 1 2 ) 1 9 1 e1 9 5
Fig. 5 e Number of attempts required to complete the curriculum. We observed a significant difference among the novice, intermediate, and advanced groups. Data are means ± standard error. *P < 0.05.
Fig. 7 e Number of attempts required to complete the target visualization module. We saw a significant difference among the novice, intermediate and advanced groups. Data are means ± standard error. *P < 0.05.
we observed no statistical significance between the number of repetitions for the intermediate and the advanced groups to complete the camera navigation module (Fig. 8). Table 1 lists responses to the face validity questionnaire.
Various strategies for laparoscopic simulation training have been employed, including video box trainers, VR simulators, use of inanimate models, explanted tissue models, and live animal (porcine) laboratories [13]. Benefits and limitations exist for each of these training strategies; however, current work-hour limits, increased patient volume, and evolving requirements for objective proficiency mandate efficient and effective training protocols for subsequent performance. Virtual reality surgical simulation may be a useful tool to meet these ends, but it requires thoughtful implementation. The benefits of VR simulation for the trainee include easy accessibility, opportunity for independent practice, and instant feedback on performance. From the surgical educator’s perspective, VR simulation affords minimal supervision during training, versatile customized curricula, and an objective means for tracking trainee performance [14]. Although there is a high initial startup cost in acquiring the VR simulator, over a 5-y period, VR training may be more cost-effective than conventional laparoscopic training in programs with more than 10 residents [15]. Various
4.
Discussion
Camera navigation is an essential skill in laparoscopic surgery; yet, we found that most medical students have not operated the camera before entering the operating room. The learning curve for camera navigation, especially the use of the angled laparoscope in complex laparoscopic surgery, is steep [9e11]. Fitts and Posner’s [12] theory on motor skill acquisition involves cognition (understanding the task), integration (comprehending the task), and automation (performing the task efficiently with precision). The implications of this theory have a definite bearing on surgical training overall, and laparoscopy in particular. The earlier stages of learning motor skills can take place outside the operating room in a simulation laboratory.
Fig. 6 e Number of attempts required to complete the coordination module. We noted a significant difference among the novice, intermediate and advanced groups. Data are means ± standard error. *P < 0.05.
Fig. 8 e Number of attempts required to complete the camera navigation module. We observed a significant difference between the novice and intermediate groups as well as the novice and the advanced groups. Data are means ± standard error. *P < 0.05.
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Table 1 e Face validity Likert item response frequencies. Question
No. (%) of participants responding Strongly agree
The curriculum improved my camera handling skills The curriculum should be required for novices before assisting in the operating room The feedback from the program is accurate The curriculum is relevant to surgery The curriculum is a valid training tool The curriculum is a valid testing tool
Agree
Neutral
Disagree
Strongly disagree
20 (50%) 24 (60%)
18 (45%) 11 (27.5%)
2 (5%) 5 (12.5%)
0 0
0 0
8 (20%) 16 (40%) 19 (47.5%) 12 (30%)
24 (60%) 22 (55%) 18 (45%) 16 (40%)
0 0 0 0
0 0 0 0
customized curricula have been developed at several institutions for specific tasks [16,17], as well as for global laparoscopic skill acquisition [18,19]. Few VR simulator studies have focused on camera navigation skills, and currently no standardized VRbased camera navigation curriculum is available. Analyses of our results revealed that the camera navigation module was the simplest in the curriculum, as represented by the number of repetitions to complete the task. This was the first module in the curriculum, and the task was deliberately kept simpler than the other two modules to enable users to familiarize themselves with the simulator, metrics, and program requirements. This module did not show statistical significance in differentiating skill levels among the intermediate and advanced groups. We found that as the task became simpler, the performance curves plateaued quickly, resulting in minimal skill improvement for the users once proficiency had been achieved. The factory settings for the individual tasks tended to fall into this category, which thus required customizing the modules in the curriculum. The coordination module was more complex, requiring ambidextrous coordination, efficiency of movement, depth perception, and camera steadiness. The complex target visualization module required the user to learn to use the 30 laparoscope optimally, to have depth perception, to maintain the horizontal axis, and to have a smooth transition from one target to the next in an efficient manner. The complex modules revealed statistical significance in differentiating among the different levels of training. Hyltander et al [7] demonstrated that basic laparoscopic skills obtained with the LapSim VR trainer transferred to the operating room. An obvious future progression of this study will be to assess whether camera navigation skills practiced in this curriculum improve trainee performance in the operating room (predictive validity). The VR-based Yale University camera navigation curriculum demonstrates construct and face validity for our training population. Successful completion of this curriculum may lead to improved technical performance in the operating room. By implementing the curriculum into overall surgical training protocols, we anticipate a benefit in the surgical training of medical students and residents and performance improvement in the operating room.
references
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8 (20%) 2 (5%) 3 (7.5%) 12 (30%)
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