Training of basic laparoscopic skills in surgical education

1 Clinic of Gastroenterology, Nephrourology and Surgery, Center of Abdominal Surgery, Faculty of Medicine, Vilnius University, Santariškių Str. 2, LT-08661 Vilnius, Lithuania 2 Clinic of Gastroenterology, Nephrourology and Surgery, Center of General Surgery, Faculty of Medicine, Vilnius University, Šiltnamių Str. 29, LT-04130 Vilnius, Lithuania 3 Department of Physiology, Biochemistry and Laboratory Medicine, Center of Laboratory Medicine, Faculty of Medicine, Vilnius University, Santariškių Str. 2, LT-08661 Vilnius, Lithuania El. paštas: Gintaras.Simutis@santa.lt


Background / objective
The study was carried out to evaluate the potential use of laparoscopic simulators to enhance basic laparoscopic skills until proficiency is reached.

Materials and methods
The study participants were divided into two groups according to their experience in laparoscopic procedures: no prior experience (group A; n = 16) and laparoscope navigation experience (group B; n = 16).All the participants performed nine attempts of three basic laparoscopic skill tasks ("Instrument navigation", "Cutting", "Clip applying") on the LapSim® simulator during three sessions within one month.The distribution of practice sessions was standardized by performing three attempts for each task per session and no more than one session per week.The assessment of laparoscopic skills was based on the cumulative score for each task measured by the computer system.

Results
Trainees in the group A were younger (22.2 ± 1.3 vs. 26.1 ± 1.3 years, P < 0.001).There were statistically significant differences in cumulative scores for all three tasks after the first five attempts between the two groups (P < 0.001).Comparison of the cumulative scores for the task "Instrument navigation" after the sixth attempt (P = 0.073), for the task "Clip applying" after the

Introduction
Laparoscopic surgery has become a new standard in many operations and positively affects patient outcomes, but has also introduced new skill sets that need to be mastered.In contrast to open surgery, laparoscopic surgery allows the handling of organs only with instruments managed through small holes in the abdominal wall; this reduces motion freedom, the tip of the instrument is moved in the direction opposite to the surgeon's hand, and the loss of depth perception due to the twodimensional imaging makes laparoscopic techniques difcult to acquire and necessitate dedicated training [1][2].
The absence of appropriate training can compromise patient safety, which has been evident from the early experience with laparoscopic cholecystectomy [3].However, although the need for additional training exists, the operating room may be a less than ideal learning environment due to time and fiscal limitations and in addition to ethical and medico-legal concerns of learning new skills on actual patients.Teaching and evaluation of technical skills outside the operating room has become very important in modern surgical education.Laparoscopic simulators currently can be used for initial training in simulated setting and without any risk to patients.
There are a few kinds of laparoscopic simulators, a high-fidelity virtual reality (VR) simulator and lowfidelity physical models.Simulation using physical objects usually involves models of plastic, rubber and latex, which are used to render different organs and pathologies, allowing a trainee to perform specific tasks and procedures.Several VR simulators (MIST-VR [Minimally Invasive Surgery Trainer-Virtual Reality], LapSim®, SimSurgery®, Lap-Mentor®) currently are available for surgical simulation.VR simulators are designed to measure instrument handling and effectiveness, the time to complete tasks, errors and the use of electrocautery.Basic and procedural tasks can be simulated in a high-fidelity virtual environment that is closely similar to the operative field.First studies using VR simulators have shown that practice on a simulator leads to an improved performance of similar tasks in the operating room [4,5].Moreover, it is at least as effective as video training in supplementing standard laparoscopic training [5].Additionally, VR simulators may be useful in the objective assessment of competence, progression, and maintenance of technical skills using detailed parameters.It has been shown that performance of various tasks on a laparoscopic surgical simulator corresponds to the respective level of laparoscopic surgery experience [6].
However, there is still a big question of how in the future to select candidates for laparoscopic training and which characteristics predict good surgical performance.
Studies attempting to answer this question gave mixed results.Preliminary data suggest that age, gender, hand dominance, video and computer game experience, visual spatial perception, psychomotor aptitude, as well as academic achievements may contribute to the acquisition of laparoscopic technical skills [7,8].
The purpose of the present study was to evaluate the application of a VR laparoscopic simulator to enhance the basic laparoscopic skills until proficiency was reached.

Materials and methods
The study was carried out at the Centre of Abdominal Surgery of the Vilnius University Hospital Santariskiu Clinics from November 2012 up to December 2012.Sixteen students (13 male, 3 female) with no prior experience in laparoscopic surgery were involved from the Faculty of Medicine of Vilnius University, and sixteen surgical residents (14 male, 2 female) from Vilnius University hospitals with laparoscope navigation experience participated in this study.
The study participants were divided into two groups according to their experience with laparoscopic procedures: no prior experience (group A; medical students; n = 16) and laparoscope navigation experience (group B; surgical residents; n = 16).None of the participants had any previous experience with the VR simulator.The nature of the study was explained to all subjects prior to enrolment.Questionnaires on the demographic, computer and video game experience variables had been completed before training.
The VR simulator used in this study was the LapSim® (Surgical Science, Gothenburg, Sweden) which consists of a computer-based platform and virtual laparoscopic interface (Fig. 1).The virtual laparoscopic interface contains two laparoscopic instruments and a diathermy pedal.All participants' movements are translated into a real-time Fig. 1.The LapSim® virtual reality training system graphic display.All subjects were given a brief introduction to the system, including task design and avoidance of errors, and were familiarized with the tasks of the LapSim® using the 15-minute introductory video material.
All the participants performed nine attempts of three basic laparoscopic skill tasks ("Instrument navigation" [IN], "Cutting" [C], "Clip applying" [CA]) on the LapSim® simulator during three sessions within one month.The distribution of practice sessions was standardized by performing three attempts for each task per session and no more than one session per week.The tasks were of constant difculty.A description of each of the three LapSim® tasks is presented in Table 1.Assessment of skills was based on time, path length, angular path, and other parameters also are measured depending on the nature of each task.The total score represents a cumulative score of time and the economy of movements.All data were automatically measured and recorded by the simulator.The final data were based on the weighted score of displayed parameter score results.
All statistical analyses were performed using the SPSS software (version 20.0).Normally distributed continuous data are given as a mean ± standard deviation and non-normally distributed data as a median.The Mann-Whitney U test was used to evaluate continuous data differences in task performance between the two groups.
Categorical data were analyzed using Fisher's exact test.The P value at the level of <0.05 was considered statistically significant.

Task name
Task description Displayed parameter

I. Instrument navigation
The task requires a participant to to touch the colored laparoscopic instrument tip to the gallstone Left and right instrument time (s), misses (%), path length (m), angular path (degrees), tissue damage (#), and maximum damage (mm)

II. Cutting
The task requires a participant to grasp the vessel with the right instrument and apply thermocautery with the left instrument.A diathermy foot pedal is attached to the system and is pressed down to simulate the burning of the tissue Total time (s), rip failure (%), drop failure (%), timeout failure (%), cutter path length (m) and angular path (degrees), grasper path length (m) and angular path (degrees), maximum stretch damage (%), tissue damage (#), and maximum damage (mm) III.Clip applying The task requires a participant to grasp the vessel with one instrument while applying clips to a predetermined marked area on the vessel.This manoeuvre is repeated at the other end of the vessel, with instruments reversed.When the clips are properly placed, the vessel is transected using scissors Total time (s), incomplete target areas (#), badly placed clips (#), dropped clips (#), left and right instrument path length (m), angular path (degrees), maximum stretch damage (%) and blood loss (litre) Trainees achieved similar cumulative scores for "Instrument navigation", "Cutting" and "Clip applying" on 6, 8 and 7 repetition, respectively, but group A outperformed group B during their first 5 repetitions (Fig. 2; Fig. 3; Fig. 4).There were no significant differences in the "Instrument navigation" task performance scores after the sixth attempt (100% vs. 100%, respec-    tively, P = 0.073), in the "Cutting" task performance scores after the eight attempt (100% vs. 99%, respectively, P = 0.080), and in the "Clip applying" task performance scores after the seventh attempt (100% vs. 100%, respectively, P = 0.287) between medical students and surgical residents.After the three-week session, medical students were not superior to surgical length of training, usually after the residency, without an objective evaluation of the acquired skills.However, the variability in individual learning rates is not taken into account.Therefore, the majority of training in abdominal surgery still occurs on real patients during operations with a direct supervision of experienced surgeons.Assessment of acquired laparoscopic skills has become increasingly important because of the widespread use of laparoscopic surgery.Moreover, reports of serious complications have emphasized the importance of a strict training and evaluation on surgical skills before practicing of real patients in the operating room.According to Rosser, a procedure-based technical skills training must begin by teaching the basic psychomotor skills, such as hand-eye coordination, the fulcrum effect and depth perception necessary for laparoscopic surgery [9].
One of the fortes of our study is that none of the participants had been previously exposed to virtual reality in laparoscopy.The results showed that younger medical students acquired laparoscopic technical skills significantly faster that surgical residents.The effect of age on acquiring laparoscopic skills has been shown in several recent studies [10][11][12].Salkini et al. data have shown that younger individuals may be able to acquire laparoscopic skills faster and with more efciency than older students and residents [11].Moreover, Van Hove et al. in a series of studies of laparoscopic skills acquisition among 35 first-year surgical residents suggest that older residents beginning their surgical careers may be slower in developing technical skills required for laparoscopic surgery [12].The authors found a negative  residents in any of the three basic laparoscopic tasks (P > 0.05).

Discussion
Traditionally, it is supposed that a surgical resident becomes a proficient surgeon after performing a procedure or operation a certain number of times or after a certain correlation between trainee age and both the degree of improvement during training and the final scores.This raises the question whether the innate abilities may predict an excellent acquisition of laparoscopic technical skills.Recently, many authors have reported the benefit of video, computer and television (TV) game use in training laparoscopic skills using a surgical simulator [12,13].According to Rosser et al., video game skills and the past video game experience are significant predictors of laparoscopic skills [14].A study by Van Hove et al. indicates that a history of video game use correlates with significantly higher initial scores and a better retention of laparoscopic skills [12].Other authors have recently concluded that medical students and experienced laparoscopic surgeons with an ongoing video game experience have superior laparoscopic skills for simulated tasks in terms of time to completion, improved efciency and fewer errors as compared with non-gaming colleagues [15].Moreover, a study from Japan by Nomura et al. reported that medical students who had an interest in TV games completed the task on a simulator in less time and had a shorter left instrument path length [16].Another study has reported that spatial skills are essential for VR laparoscopic task performance, thus the use of computer games may contribute to the improvement of skills relevant for sufcient performance in VR laparoscopic tasks [17].In contrast to the previous study, Kennedy et al. found that students who played video games for at least 7 hours per week demonstrated significantly better psychomotor skills than students who did not play video games regularly; however, the authors did not find any significant differences in data on visual and spatial perceptual abilities [18].However, Adams et al. have shown that residents who engage in video games have a better visual, spatial and motor coordination [13].Interestingly, most residents that participated in this study stated that playing video games helped to reduce stress; also, a cooperative play stimulated better relationships among colleagues.
Hand dominance was reported to influence skill acquisition during the basic laparoscopic skills training [8,19].Grantcharov et al. in their study showed that trainees with right hand dominance performed fewer unnecessary movements [8].Moreover, the authors observed a trend towards better results in terms of time and errors among residents with right hand dominance than among those with left hand dominance.However, Powers et al. showed no difference in laparoscopic skills acquisition between right-handed and left-handed surgeons, although surgeons with left hand dominance demonstrated a better initial performance [19].In our study, we did not evaluate the relation of hand dominance to overall performance scores of exercises due to the highly different percentages of right-and lefthanded participants among both medical students and surgical residents.
Sleep deprivation and fatigue have been reported to influence the acquisition of laparoscopic skills [20,21].Call-associated sleep deprivation and fatigue are associated with increased technical errors in the performance of simulated laparoscopic technical skills [20].According to Kahol et al., fatigue and sleep deprivation cause a significant deterioration in the surgical residents' cognitive skills [22].As a result, psychomotor skills, which are essential for good performance, are negatively impacted during tasks that require a combination of psychomotor and cognitive skills.Similarly, negative effects on dexterity, error rate, mental workload and cognitive function have also been described [22,23].However, a number of studies focusing on motor skills did not show a significant negative effect of fatigue on task performance or skills acquisition [21,24].A recent study by Tomasko et al. showed that sleep-deprived subjects were able to complete the tasks despite an increased workload and were able to learn a new task proficiently despite an increased sleepiness [24].
At least one research showed that in motor skills acquisition of a basic task, the component of declarative learning, which appears to be influenced by the circadian rhythm, was influenced by the time of the day with better results in the morning, whereas the kinematic component of motor skills acquisition was independent of the time of the day [25].However, a recent study by Bonrath et al., which was aimed to examine the difference in training effectiveness depending on the time of the day, using a VR simulator, showed that all participants significantly improved their technical skills throughout the training irrespective of the time of the day the training had been conducted [26].Moreover, no differences were observed between the groups as regards the post-training skill levels.In our study, we did not evaluate individual attentiveness nor did we account for daily activities and work shifts.Consequently, we cannot exclude the possibility that participants in either group may have been more tired than others.
The other factors that may contribute to the development of skills which could be relevant for the performance of laparoscopic surgery are gender, choice of subspeciality, and even confidence in car driving [8,12,16,27].Gratcharov et al. found that men completed the tasks in less time than women, but there was no statistically significant difference between the genders in the number of errors and unnecessary movements [8].However, a recent study from Canada, performed by Kolozsvari et al., showed that gender did not affect the learning curve for a fundamental laparoscopic task [27].Van Hove et al. reported that medical interns designated for the general surgery training program had significantly higher final scores than those entering other fields [12].Similarly, the previously mentioned study by Kolozsvari et al. reported that interest in surgery, as well as perceptual abilities influence the early performance of the basic laparoscopic skills [27].According to Nomura, both students who were confident about driving and who thought themselves manually dexterous completed the task on laparoscopic simulator in less time [16].
Interestingly, recently Kuzbari et al. have reported that laparoscopic performance may be related to measures of the frontal lobe function [28].This raises the larger question of how we may need to select future candidates for surgical training based, in part, on innate abilities, psychomotor information and skills acquisition.

Conclusions
The results of our study demonstrate that a group of trainees with no prior laparoscopic experience acquired basic laparoscopic skills significantly faster.Proficiency in the laparoscopic basic tasks was achieved within 6-8 repetitions in both groups.These findings suggest that practical skills training using laparoscopic simulators should be integrated into medical education much earlier.

Fig. 2 .
Fig. 2. Box plots of cumulative score for the "Instrument navigation" task showing the difference between groups A (medical students) and B (surgical residents) with an example of the graphical representation of the basic laparoscopic task "Instrument navigation" from the virtual reality simulator LapSim®

Fig. 3 .
Fig. 3. Box plots of cumulative score for the "Cutting" task showing the difference between groups A (medical students) and B (surgical residents) with an example of the graphical representation of the basic laparoscopic task "Cutting" from the virtual reality simulator LapSim®

Fig. 4 .
Fig. 4. Box plots of cumulative score for the "Clip applying" task showing the difference between groups A (medical students) and B (surgical residents) with an example of the graphical representation of the basic laparoscopic task "Clip applying" from the virtual reality simulator LapSim®.

Table 2 .
Comparison of participants' characteristics

Table 3 .
Comparison of cumulative scores for all three basic laparoscopic tasks in two study groups