1. Supporting Procedural and Perceptual Learning in Laparoscopic
Surgery
1
Lou,Y., 1
Flinn, J. T., 1
Ganapathy, S., 2
Weyhrauch, P., 2
Niehaus, J., 2
Myers. B., 1
Cao, C. G. L.
1
Department of Biomedical, Industrial and Human Factors Engineering, Wright State University
2
Charles River Analytics, Cambridge, MA
Expertise in surgical performance requires mastery of both technical skills such as suturing, and non-
technical skills such as perceptual and procedural knowledge. “Refresher-training” after skill decay due to
nonuse should consider the fact that non-technical skills often decay faster than technical skills. To support
the re-learning of perceptual and procedural knowledge, this study examined the effectiveness of different
design factors for digital training material. The factors considered included modality/fidelity of
representation (illustration/cartoon vs. realistic/video images) and task difficulty (easy, medium, and
difficult). Results suggest that low fidelity images are better for perceptual learning, and are equally
effective as high fidelity images for procedural learning. The level of difficulty of the procedures did not
affect performance in this study of novices, but may be an important factor with more experienced trainees.
Time and error results indicate that refresher training in perceptual and procedural knowledge should begin
with a procedural task to review surgical steps, followed by a perceptual task, to achieve greater efficiency
and effectiveness.
INTRODUCTION
Despite the invention of laparoscopic surgery in the early
1900s, it was not widely used until the 1980s (Spaner, &
Warnock, 1997). Now, almost 98% of cholecystectomies are
laparoscopic (Wayand, 2004). Laparoscopic surgery has
become more common according to the US Food and Drug
Administration (FDA), and more than 2 million Americans
each year experience laparoscopic surgery (Fuller, Scott,
Ashar, & Corrado, 2003). Reductions in post-op pain,
incisions, and chance of hemorrhage are all reasons why
laparoscopic surgery is preferred over other alternatives.
However, laparoscopic surgery skills require additional
training over the skills needed to perform traditional open
surgery. A great deal of past research has focused on the
training of technical skills, such as suturing and knot-tying
(Ritter, & Scott, 2007), resulting in standardized certification
programs such as the Fundamentals of Laparoscopic Surgery
(FLS) curriculum that is endorsed by the American College of
Surgeon (ACS) and the Society of American Gastrointestinal
and Endoscopic Surgeons (SAGES). This paper concerns the
non-technical aspect of surgical training, such as perceptual
and procedural skills, as non-technical skills play an equally
important role in determining surgical skill acquisition and
retention (Yule, Flin, Patterson-Brown, Maran, & Rowley,
2006).
Despite the long training schedules and constant practice,
skill decay is observed after periods of nonuse or non-practice
(Arthur, Bennett, Stanush, & Mcnelly, 1998). According to the
meta-analysis of Arthur et al. (1998), after more than 365 days
of nonuse and non-practice, the average participant was
performing at less than 92% of their performance level before
the non-practice interval. The neuroscience of human memory
indicates that there are three types of abilities (job knowledge,
decision skills, and execution skills) that are located and
controlled in different areas of the brain (Gabrieli, 1998). The
job knowledge category is based on the recall of domain
specific information, such as job-related terms and rules; the
decision category hinges on cognitive processing of the
domain specific information such as trouble-shooting faulty
equipment and decision-making (Allen, Secundo, Salas, &
Morgan, 1983), and the execution category refers to both the
perceptual and motor requirement of a task such as target
acquisition and tracking (Fleishman, & Parker, 1962). A study
by Wisher, Sabol, Ellis, and Ellis (1999) showed that the
patterns of forgetting that occur in decision skills, procedural
and perceptual-motor skills are different. For example, gross
motor skills decayed after approximately 10 months while
cognitive skills such as knowledge of procedures decayed
within approximately 6 months.
In military medicine, loss of specialized skill and
knowledge is a great concern for those military surgeons
returning to general practice after deployment. It takes a huge
amount of time for the personnel in the US military medical
community (as in the civilian community) to learn knowledge
and skills to perform lifesaving tasks. However, it is difficult
for military surgeons to maintain their specialized knowledge
and ability after a period of time performing combat casualty
care in a military deployment cycle (Perez et al., 2013).
The ultimate goal of this research is to develop an
effective refresher training system that is appropriate for
surgeons with varying degrees of skill decay. The purpose of
this study was to determine how well re-learning perceptual
and procedural knowledge in laparoscopic surgery (i.e.,
identifying anatomy and knowing operational sequences) can
be supported by digital material after skill decay. The fidelity
and complexity of the digital re-learning material needed to
support learning/re-learning was examined.
We hypothesized that simulation fidelity would have
differential effects on the learning and retention of perceptual
and procedure knowledge in laparoscopic surgery. That is, (1)
realistic visual representation of the surgical site is more

2. important for learning and remembering perceptual knowledge
than for procedural knowledge and (2) a less realistic-looking
visual representation of the surgical site is sufficient for the
purpose of learning and remembering procedural steps in
surgery.
METHODS
The objective of this study was to evaluate how two
types of skills (perceptual and procedural) were affected by
two types of information presentation (illustration
representation vs. realistic representation), and three levels of
task complexity (easy, medium, and difficult).
Based on a cognitive task analysis with experts, who
were surgeons with over 20 years of experience, a set of tasks
in the laparoscopic cholecystectomy procedure was identified
(Grosdemouge, Weyhrauch, Niehaus, Schwaitzberg, & Cao,
2012). These tasks included perceptual skills and procedural
skills. Perceptual tasks related to identifying anatomy,
identification of points where incision had to be made, and
angle of presentation of the image. Procedural tasks included
identifying steps and sequences in the cholecystectomy
procedure. These tasks were used to design the teaching
material and the refresher material in this experiment.
Participant
Twelve participants (6 male, 6 female) were recruited
from the general public. Participants were novices who had no
previous medical or surgical experience. The average age was
31.5 years.
Apparatus
Teaching material was compiled based on the text Atlas of
Minimally Invasive Surgery (Jones, Maithel, & Schneider,
2006). This material covered the basic anatomy and procedure
for laparoscopic cholecystectomy and was prepared using
Microsoft PowerPoint.
The images, videos, and questions presented during the
experimental task were displayed using a custom-developed
software program, which also recorded participants' responses
automatically. This software, the Mobile Interactive
Storyboard Tool (MIST), was developed in C++ using the
Microsoft XNA framework and Direct X API (application
programming interfaces). The MIST software allowed for the
customizable arrangement of media and interactive elements
required for the experiment.
Task and Procedure
Initially, participants were shown a 10-minute PowerPoint
presentation (teaching material) with a brief introduction of
the relevant anatomy, the surgical steps and instrumentations
used in a cholecystectomy procedure. At the end of the
presentation, they were required to answer three basic
questions based on what they have learned. If any one of the
answers was incorrect, participants had to repeat the learning
process until they had all three correct answers. This ensured
that participants had in fact learned the material presented.
To ensure that all trials are performed based on longer
term memory rather than short-term memory, participants
were asked to work on a Sudoku puzzle for 10 minutes
following the training period. Following this, participants
performed the experimental task (refresher task), which
involved answering a series of questions about anatomy or
steps in a laparoscopic cholecystectomy procedure, depending
on the experimental condition (Table 1). The questions were
presented at various points in the cholecystectomy procedure
by the MIST program.
Participants responded to the questions using the mouse
by clicking on specific areas in the scene, or selecting options
in a multiple choice question. The program indicated whether
they were correct or incorrect after they gave their response. If
incorrect, participants were given a second chance to answer
the question.
In this study, two representations of different fidelity
levels (represented by two different modalities) were used to
present the refresher material: illustrated and realistic. Figure 1
shows the screenshot of the illustrated condition and realistic
condition. Three different levels of task difficulty (easy,
medium and difficult), representing the difficulty of the
surgical case, were used (Figure 2).
Six participants began with the perceptual condition first
and the other 6 participants had the procedural condition first
(randomly assigned). Within each condition, all combinations
of the modalities and difficulty of the surgical case were
presented in a random order. At the end of the experiment,
participants were asked for subjective feedback on their
preference of realism of the surgical scenes, and any
comments on their choices during the experiment.
Table 1 Example Questions in Perceptual and Procedural
Conditions
Perceptual Condition Procedural Condition
Locate the cystic artery by
clicking the correct structure.
What is the next step in the
cholecystectomy procedure?
A. Clip the Cystic Artery
B. Clip the Cystic Duct
C. Divide the Cystic Artery
D. Divide the Cystic Duct
Click on the cystic artery to
indicate where clips should be
placed.
Choose how many clips are needed
on the cystic artery?
A. 1
B. 2
C. 3
D. 4
E. 5
How will the clips be positioned on
the cystic artery?

3. Figure 1. Sample screenshots of the Illustration Representation
(top) and Realistic Representation (bottom) of a surgical step
in Laparoscopic Cholecystectomy.
Figure 2. Sample screenshots of the Easy (top), Medium
(middle), and Difficult (bottom) representations of
Laparoscopic Cholecystectomy measures.
Time to task completion was determined as the response
time for answering the questions in each condition. Time for
playing embedded videos was excluded from this measure.
Error was the total number of incorrect responses for each
trial.
RESULTS
Performance data in the perceptual and procedural
conditions were separately analyzed using repeated

4. measurements 3-way ANOVA with order, fidelity and
difficulty level as factors.
Perceptual Knowledge
Error. Only fidelity (F=5.32, p=0.04) and task difficulty
(F=11.22, p<0.01) showed statistically significant differences
in terms of error in the perceptual condition. Order (F=4.09,
p=0.07) didn’t show a significant difference. For fidelity, there
were significantly more errors when the images were realistic
(mean=5.44, SD=0.57) than when they were illustrations
(mean=3.63, SD=0.57). For task difficulty, a post-hoc Tukey
HSD test showed that only the easy (mean=3.48, SD=2.81)
level can be differentiated from the difficult level (mean=4.54,
SD=2.86). As shown in Figure 3, there was an increase in
error in the case of difficult when compared to easy and
medium. However, no significant difference exists between
easy and medium, and between medium and difficult.
Figure 3. Error rate in the perceptual condition as a function of
difficulty level.
Time. Results indicate that order (F=9.81, p=0.01) and
fidelity (F=8.76, p=0.01) had a significant effect on task
completion time. In terms of order, participants who
completed the perceptual condition first (mean=134.8,
SD=55.8) were much slower than participants who completed
the procedural condition first (mean=90.5, SD=53.8). In term
of fidelity, participants spent longer time on the realistic
pictures (mean=127.9, SD=54.8) than the illustrated pictures
(mean=97.4, SD=55.4), as shown in Figure 4.
0
50
100
150
200
Illustration Realistic
Time(seconds)
Fidelity
Perceptual- Time
Perceptual-Procedural
Procedural-Perceptual
Figure 4. Task completion time for the perceptual condition as
a function of fidelity and order.
Procedural Knowledge
Error. In the error of procedural tasks, no significant
main effect was found.
Time. For the procedural conditions, the interaction
effect between fidelity and difficulty (F=4.44, p=0.03) was
statistically significant. However, a post-hoc Tukey HSD test
showed none of the conditions could be differentiated from
one another in the experiment (Figure 5).
0
50
100
150
Easy Medium Difficult
Time(seconds)
Difficulty
Procedural- Time
Illustration
Realistic
Figure 5. Task completion time in the procedural condition as
a function of difficulty and fidelity level.
DISCUSSION
In the perceptual condition as difficulty level was
increased, the number of errors also increased. This is not very
surprising, as it is more difficult to identify the critical
structures when the surgical field is bloodier and poorly
dissected. Experts also mentioned this during the cognitive
task analysis that knowledge and expertise play a bigger role
in those cases that are complicated. There was no significant
difference in procedural error amongst the difficulty levels in
the procedural condition. This was also expected because
procedural knowledge about a surgical operation should not be

5. affected by the perceptual difficulty of the case. However, in
reality, the complicated cases may very well warrant a
different approach that alters the sequence of surgical steps. In
our study, we had limited our teaching material to a routine
procedure for complete novices, so that variations in surgical
procedure were not a consideration. A refresher training
system may consider including variations in procedure to
accommodate more experienced trainees. In the perceptual
condition, participants who started in the perceptual condition
first spent much longer than participants who performed the
procedural condition first. The reason could be that
participants who follow the order of “procedural-perceptual”
had already performed 6 trials in the procedural condition
before they entered the perceptual condition. They were thus
familiar with the procedure of cholecystectomy, which also
contained knowledge of the anatomy implicitly, if not
explicitly. However, there was no effect of order in the
procedural time. This suggests that training/re-training in
procedural knowledge before perceptual knowledge would be
much more efficient than training/re-training perceptual
knowledge first before procedural knowledge. In fact, it may
not be necessary for the perceptual condition after re-training
in the procedural condition.
When it comes to fidelity of training material,
participants spent a longer time and have more errors in the
realistic conditions compared to the illustrated conditions in
the perceptual condition. There is no doubt that visualization
of anatomical structures is much more discernible in the
illustrated representation. There was no difference between
time or errors of the illustration and realistic conditions in the
procedural condition. A possible explanation is that procedural
condition was asking participants what is the next step. As
long as the participants knew what the next step was, there
was no need for them to spend time on distinguishing those
structures. Whereas in the perceptual condition, they needed to
spend time to identify the structures carefully and click on the
correct location in the picture. Therefore, illustrated
representation of structures should be used in re-training
perceptual knowledge. For re-training procedural knowledge,
realism of the surgical site has no effect on relearning.
CONCLUSION
Based on this initial study, refresher training for
laparoscopic surgery should not decouple perceptual and
procedural skills, especially for less experienced trainees. For
an effective training system, procedural knowledge should be
presented before perceptual knowledge. Also, the use of
illustration vs. realistic image is important as it allows
educators to quickly put together multiple scenarios using
illustration which can also be used effectively for procedural
tasks. This would reduce the time and resources required to
create the training material. Potential future work includes
using larger sample sizes to determine the interaction effects
between the variables of interest; testing the current
experimental design with surgeons who have been deployed
and returned to identify skill decay parameters. We will also
examine performance differences on perceptual and
procedural tasks in an interactive laparoscopic simulator.
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