Research Article

Relevance of Non-Anatomic Basic Skills Training in Simulator Based Learning of Laparoscopic Cholecystectomy

Cui Yang1,3*, Peter Zimmermann1, Jens R Helmert2, Juergen Weitz1, Christoph Reissfelder1,3 and Soeren Torge Mees1
1Department of Visceral, University Hospital Dresden, Germany
2Unit of Engineering Psychology and Applied Cognitive Research, Institute of Psychology III, Technische Universität Dresden, Germany
3Surgical Clinic, University of Heidelberg, Germany

*Corresponding author: Cui Yang, Surgical Clinic, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany

Published: 01 Oct, 2018
Cite this article as: Yang C, Zimmermann P, Helmert JR, Weitz J, Reissfelder C, Mees ST. Relevance of Non-Anatomic Basic Skills Training in Simulator Based Learning of Laparoscopic Cholecystectomy. Clin Surg. 2018; 3: 2129.


Background: A variety of training modules exist for Virtual Reality Simulators (VRS); however, their effectiveness needs to be validated before integrating VRS into training curricula. The aim of this study is to evaluate the efficacy of basic skills training within the learning process of a laparoscopic cholecystectomy.
Methods: From February to May 2016, 40 surgical novices were randomized into group A or B. In group A (n=20), participants underwent a proficiency-based, non-anatomic basic skills training using the VRS prior to the tutorial procedural tasks of Laparoscopic Cholecystectomy (LC). Participants in group B (n=20) started with the tutorial procedural tasks of LC directly. Afterwards, participants were required to perform a complete LC on the VRS. Task performance was evaluated by analyzing time and accuracy of the tasks.
Results: Group A was significantly faster extracting the gallbladder (512 seconds ± 154 seconds vs. 671 seconds ± 187 seconds, P<0.05) and had significantly less movements to complete the procedure, either with the left or right hand (right hand: 366 ± 105 vs. 449 ± 125, P<0.05; left hand: 183 ± 59 vs. 238 ± 84, P<0.05) compared to group B. The safety parameters did not differ between both groups.
Conclusion: The data in the current study demonstrate that proficiency-based basic skills training using the virtual reality simulator could improve motor skills but not cognitive ability. Further training components, such as procedure-specific training and stepwise integration in the operating room seem to be necessary for an effective training curriculum of laparoscopic cholecystectomy.


The traditional surgical skills acquisition is based on the mentor-trainee model and takes place mainly in the Operating Room (OR), which is time-consuming and ethically questionable [1,2]. Without previous training, inexperienced residents are susceptible to external disturbances [3] and might endanger patient safety. To improve effectiveness and patient safety, surgical education is partly conducted in skills labs prior to surgical training in the OR, where residents should require novel skills with the help of development and implementation of surgical education curricula including new and innovative training tools [4,5].
Along with the wide acceptance of Minimally Invasive Surgery (MIS) in various surgical disciplines, surgical education in MIS encounters new challenges comparing to open surgery: motor skills acquisition is more difficult due to the impaired depth perception and reduced degrees of freedom for laparoscopic instruments [6]. Cognitive skills as procedure planning and surgical error awareness are especially important, since an immediate intervention in emergency is only possible to a limited extent.
Within the last decade, Virtual Reality Simulators (VRS) have gained increasing attention and have become an important part of laparoscopic surgical training. Its efficacy has been confirmed in multiples studies: VRS training can shorten the length of the learning curve and improve laparoscopic performance in the OR5, [7-9]. Usually, a VRS provides a wide range of training tasks from non-anatomic basic skills training to high fidelity simulation of minimally invasive procedures. An optimal and time-effective training curriculum should contain evidence-based training tasks due to restricted work hours and desired work-life-balance of the modern surgical generation.
The aim of this study was to evaluate the value of non-anatomic, basic skills training on VRS for laparoscopic cholecystectomy representing a typical laparoscopic procedure for junior surgical residents.

Table 1

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Table 1
Proficiency and penalty time of each basic training.

Materials and Methods

Study design and participants
This prospective, randomized study was conducted at the University Hospital Dresden from February to May 2016. The study has been approved by the ethics committee of the University Dresden (EK 416092015).
Participants (n=40) were laparoscopically naive medical students at the University Dresden and showed a special interest in surgery. Written informed consent was obtained from all participants. Prior to commencement of training, participants were required to complete a questionnaire consisting of personal details (gender, age, dominant hand etc.), experience of non-surgical skills (computer games, musical instruments etc.). Previous experience was rated subjectively on a 5-point Likert scale, with 1 indicating no experience and 5 indicating very experienced.
Participants were randomized into group A or B by choosing a sealed envelope. All training and test sessions were supervised by co-author PZ, who offered an introduction to the VRS before the training started. In group A (n=20), participants underwent a proficiency based basic training on the VRS prior to the tutorial procedural tasks of Laparoscopic Cholecystectomy (LC). Participants in group B (n=20) started with the tutorial procedural tasks of LC directly. Finishing the training, the participants of both groups were required to perform a complete LC on the VRS.
Virtual reality simulator lap mentor®
Training and testing were performed on the LapMentor® (Figure 1A, 2nd generation, 3D Systems, Cleveland, OH, USA). For selfauditing, an immediate feedback considering time to completion, accuracy, efficiency and safety is displayed on the screen at the end of each task.
Basic trainings
Participants in group A were required to perform a basic training containing five tasks until they reached defined proficiency levels. These proficiency levels were derived from the performance of a group (n=10) of surgical residents and medical students with laparoscopic experience in a pilot study prior to this study. Detailed proficiency criteria consist of time and safety parameters and are described below (Table 1). The penalty time was added to the actual time. All students were required to perform the tasks for at least three times and reach proficiency in two consecutive attempts. The selected simulated laparoscopic tasks have been previously described and validated [10- 12].
Clipping and grasping: Participants were required to use both hands in a complimentary manner to grasp and clip leaking ducts safely. By grasping a leaking duct on the blue area and retracting it, the red target segment turned to green. Only then, a clip could be applied within the green target segment to stop the leakage. The task must be completed before the water level reached the red line.
Cutting: In this exercise, the use of traction while cutting should be trained. After exposing a safe cutting area by retracting the form, a circular form could be cut and separated safely. Overstretch or cutting into tissue was noted by the computer. The accuracy rate was defined as the number of cutting maneuvers without causing injury divided by the total number of cutting maneuvers in percent.
Electro cautery: To practice safe and accurate use of electro cautery, participants should use both instruments to retract the green highlighted band or the surrounding bands before applying energy. By pressing the right/left foot pedal, energy was applied on the right/ left hook electrode.
Peg transfer: Participants were required to transfer six rubber triangles with two dissectors. After picking up one triangle using the left hand, they need to transfer the triangle to the dissector in right hand and place it on the opposite side of the board. After six triangles were transferred, the process had to be repeated starting with the right hand. If a triangle was dropped inside the field of view, participants could pick it up and continued with the task. Triangles dropped outside the field of view were documented by the computer. Timing started with the appearance of instruments on the screen and ended on correct placement of the last triangle.
Pattern cutting (Training Gauze): The training gauze required participants to cut accurately in the area between the two lines on a square piece of gauze suspended between clips. With a grasper providing traction on the gauze, participants should use a pair of laparoscopic scissors to cut with accuracy respecting the pre-marked line. If needed, instruments might be exchanged at any time during this task.
Tutorial procedural tasks of LC
Participants of both groups were required to complete a stepby- step tutorial of the LC procedure. After going through the tasks, participants should be familiar with critical steps of the procedure: clipping and cutting a retracted gallbladder, clipping and cutting - two hands, dissection - achieving "critical view of safety" and gallbladder separation from the liver bed. Each task was repeated 3 times.
Complete procedure
All participants performed a simulation case of LC with normal anatomy using the VRS. The procedure was repeated three times by each participant. 17 parameters, such as time of completion, safety and economy, were documented by the computer. For the analysis, we chose the six most relevant parameters: Time to extract the gallbladder was recorded from appearance of instruments on the screen until the complete separation of gallbladder from the liver bed. Safe cautery was defined as the time in which cautery was applied more than five mm from the biliary system in percent. Number of non-cauterized bleedings, lost clips, liver perforations as well as serious complications was also documented, whereby serious complications were described to include cutting and/or cautery of unclipped ducts or arteries with any tool or clipping of common bile duct or hepatic artery. Minimum of three mm continuous movement counted as a movement and the total path length was documented in centimeters.
Statistical analysis
Data were analyzed in SPSS version 24 (IBM SPSS Chicago, IL, USA). Wilk-Shapiro-Test (α=0.3) was used to check the distribution. For skewed data, paired data were compared by matched pairs signed ranks test (Wilcoxon-test). Pearson correlation coefficient measures correlations between two variables. A P-value of <0.05 was defined as statistically significant.

Table 2

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Table 2
Participant demographics.

Results and Discussion

Significant differences in the demographic characteristics between the two groups were not detected. In addition, statistically significant differences regarding previous fine motor skills training (computer games, music instruments, etc.) between the two groups did not exist (Table 2).
The complete procedure of LC was repeated three times by each participant and six selected parameters concerning time to completion, safety and economy were used for further analysis (Table 3).
Time parameter: Participants with basic training were significantly faster regarding extraction of the gallbladder (512 seconds ± 154 seconds vs. 671 seconds ± 187 seconds, P<0.05).
Safety parameter: The safety parameters including safe cautery, number of non-cauterized bleedings and number of serious complications did not differ between both groups.
Economy parameter: In group A, significantly less movements were needed to complete the procedure, either with left or right hand (right hand: 366 ± 105 vs. 449 ± 125, P<0.05; left hand: 183 ± 59 vs. 238 ± 84, P<0.05), compared to group B.
We analyzed the correlation between time to extract the gallbladder and all assessed parameters as shown in (Table 3). A longer time to extract the gallbladder was associated with higher percentage of safe cautery and more movements of both hands (P<0.001). Furthermore, the previous fine motor experience was not significantly correlated with any of the test parameters. A correlation between time to extract the gallbladder and number of non-cauterized bleedings or serious complications was not identified.
Training effect
A positive training effect was demonstrated on both groups: the time to extract the gallbladder was significantly shorter in the last attempt of the complete procedure compared to the first attempt (group A: 576 seconds vs. 456 seconds, P<0.001; Group B: 760 seconds vs. 617 seconds; P<0.001).
In this study, we aimed to assess the efficacy of a proficiencybased basic training using the VRS within the training process of a Laparoscopic Cholecystectomy (LC). The present data provide objective evidence that non-anatomic, basic skills training on VRS can improve manual dexterity and physical amplification of movement in performing LC. However, cognitive performance as procedure planning and error awareness was not influenced by the previous non-anatomic, basic skills training.
The most crucial step of a LC is the dissection of the cystic duct and artery to achieve the critical view of safety [13]. To perform the dissection safely and effectively, basic skills such as traction/ counter-traction, safe electro cautery, cutting and cutting need to be acquired. Based on these requirements, five basic training tasks were selected to train participants for safe and economical use of diathermy instruments and positioning of objects with both hands. The requirement that a defined proficiency level had to be reached on two consecutive attempts made it less possible that the participants meet the acquirement accidentally. Proficiency-based training has been demonstrated to have significant benefits in skills outcomes and patient-based outcomes, even though it is time-consuming [14]. In the test session, a standard LC needed to be performed, providing a setting of identical difficulty without bias by anatomical variations or physiological reactions as in real patients.
Participants with non-anatomic basic skills training seemed to be superior in motor performance comparing to participants without, since they were faster and required less movements for the completion of LC. Through repeated training, participants overcame the difficulties with impaired depth perception and reduced degrees of freedom for laparoscopic instruments. With improved hand-eye coordination, they gained better control over their movements. More required movements lead to distress and muscular fatigue in operating rooms, which could be an extra source of errors, especially during major surgeries [3,15]. This is in line with the theory that functional task alignment is of great importance in surgical education [16-18] and generalizable motor skills can be imparted [19]. In contrast, basic skills training did not improve the cognitive performance as error awareness. Since the basic skills training was performed on non-anatomic objects, it is not similar with anatomic structure in the LC. According to cognitive psychology, a positive transfer effect is more likely if the content to be transferred and the context to which it is transferred are similar [20]. For acquisition of cognitive skills, extra procedure-specific training might be necessary. Additionally, non-anatomic, basic skills training could not provide a deep, strategic understanding of the procedure, making it less possible to improve cognitive skills [20,21].
We are living in an era, where the health care system is faced with quality and cost challenges [22]. Surgeons are supposed to perform more surgeries in the same period of time and arrange several things simultaneously. To stay on the tough schedule, attendings might need to take over the surgery if junior residents do not operate fast enough. Through undergoing non-anatomic, basic skills training, junior residents could improve the speed of their surgical performance. Thus, it could increase the possibility for junior surgeons to perform the complete procedure, which could promote their self-awareness. It is known that time pressures and distractions on junior residents hamper their ability to accurately perform critical steps [3,23]. According to our data, basic skills training does not seem to improve safety of patients. However, given the same amount of time, residents undergoing basic training might feel less time pressure if they could perform faster than residents without previous training. Under these circumstances, they might even make less failure.
Today, 15 years after Seymour et al validated the utility of VRS in training operative skills8, the question regarding the use of VR simulator has shifted from “Is it effective?” to “How should a training curriculum using VRS be constructed [24]?” Based on our data, non-anatomic, basic skills training can improve the acquisition of motor skills but not cognitive skills. To fill this gap, further training components are needed. Task specific training [25,26], “web lab” using cadaveric animal organs or even live animals [27-29] and gradual involvement in the operating room [30] have been shown to be effective for junior surgical residents to develop expert technical skills and establish independence over the residency.
In our study population, previous manual experience seems to have a minor influence on learning of LC, which is controversially discussed in the literature [31,32]. Training effects could be demonstrated in our data.

Table 3

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Table 3
Comparison of time, safety and economy parameters for both groups in the complete LC procedure. All values are shown as means.


This study has limitations. The effect of basic skill training was verified with simulated laparoscopic cholecystectomy. Further trials are required to confirm if the results can be transferred into the clinical environment in the OR. The efficacy of our curriculum has been tested in a group of novices and in a single center. Therefore, the results need to be verified testing surgical trainees of different training levels and in additional training centers. Due to logistic reasons, all participants were medical students. However, motivated medical students represent young surgical residents at the beginning of their carrier adequately.


Based on the data in the current study, proficiency-based basic skills training using the virtual reality simulator could improve motor skills but not cognitive ability. Further training components such as procedure-specific training, “web lab” and gradual integration in the operating room might be necessary for an effective training curriculum of laparoscopic cholecystectomy.


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