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.
Abstract
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.
Introduction
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
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
Results and Discussion
Demographics
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).
Performance
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
Table 3
Comparison of time, safety and economy parameters for both groups in
the complete LC procedure. All values are shown as means.
Limitations
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.
Conclusion
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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