Original Article

Impact of laparoscopic experience on virtual robotic simulator dexterity Byung Eun Yoo, Jin Kim, Jae Sung Cho, Jae Won Shin, Dong Won Lee, Jung Myun Kwak, Seon Hahn Kim Division of Colorectal Surgery, Department of Surgery, Korea University College of Medicine, Seoul, Korea Address for Correspondence: Dr. Jin Kim, Division of Colorectal Surgery, Department of Surgery, Korea University College of Medicine, 126-1 Anam-dong, Seongbuk-gu, Seoul 136-705, Korea. E-mail: [email protected]

Abstract BACKGROUND: Different skills are required for robotic surgery and laparoscopic surgery. We hypothesized that the laparoscopic experience would not affect the performance with the da Vinci® system. A virtual robotic simulator was used to estimate the operator’s robotic dexterity. MATERIALS AND METHODS: The performance of 11 surgical fellows with laparoscopic experience and 14 medical students were compared using the dV-trainer®. Each subject completed three virtual endo-wrist modules (“Pick and Place,” “Peg Board,” and “Match Board”). Performance was recorded using a builtin scoring algorithm. RESULTS: In the Peg Board module, the performance of surgical fellows was better in terms of the number of instrument collisions and number of drops (P < 0.05). However, no significant differences were found in the percentage scores of the three endo-wrist modules between the groups. CONCLUSION: Robotic dexterity was not significantly affected by laparoscopic experience in this study. Laparoscopic experience is not an important factor for learning robotic skills. Key words: Da Vinci, dV-trainer, laparoscopic experience, robotic surgery

INTRODUCTION The advent of laparoscopic surgery has led to great advances in the field of general surgery, including shorter hospitalizations, reduced postoperative pain, Access this article online Quick Response Code:

Website: www.journalofmas.com

DOI: 10.4103/0972-9941.147696

68

fewer wound infections, and improved cosmesis. However, laparoscopic techniques also have limitations, including an unstable camera platform, the limited motion of straight laparoscopic instruments, two-dimensional (2D) vision, and poor ergonomics for the surgeon.[1] The da Vinci surgical system (Intuitive Surgical ®, Sunnyvale, CA, USA) was specifically designed to overcome the limitations of current laparoscopic technology.[2] The skills required for robotic surgery are, therefore, different from those required for laparoscopic surgery. The surgeon sits at the console and views a three-dimensional (3D) image of the procedure through two viewing holes, while maneuvering the arms with two foot pedals and two hand controllers. Specifically, the endo-wrist instruments allow maneuvering of the robotic arms in a manner that simulates fine human movements. These characteristics enable robotic surgery to overcome the technical limitations of laparoscopy by restoring vision and manual control of open surgery in a minimally invasive environment. We hypothesized that the laparoscopic experience does not affect robotic dexterity, because the techniques necessary for laparoscopic surgery and robotic surgery are different from each other. A dry lab using the da Vinci surgical system is optimal for comparing robotic dexterity, but this is limited because the expensive robot can only be used for this study, when surgery is not being performed. The dV-trainer (Mimic Technologies®, Seattle, WA, USA) is a compact virtual reality platform that closely reproduces the experience of the da Vinci surgical console. It is the only robotic simulator demonstrated to have face (degree of resemblance with the actual robot), content (usefulness as a training tool as viewed by experts), construct (degree to which the results on the simulator reflect the actual skill of the subject), and concurrent (equivalence between assessment on the simulator and assessment on an actual da Vinci surgical system) validity in multiple studies.[3-12] Virtual reality simulations can be performed at any time, and

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Yoo, et al.: Laparoscopic experience and robotic dexterity

they can provide a real-time, objective assessment of users’ performance. Accordingly, surgical fellows experienced in laparoscopic surgery were compared with medical students using the well-validated dV-trainer.

MATERIALS AND METHODS In February 2011, surgical fellows and medical students were invited to participate in this prospective study. All surgical fellows had >3 years of experience as a surgeon or an assistant in laparoscopic surgery including laparoscopic appendectomy, cholecystectomy, gastrectomy, and colectomy, with no experience with the da Vinci surgical system. All subjects in both groups had not previously used the dV-trainer. After a standardized introduction and 10 min of practice, each subject completed three virtual endo-wrist modules (“Pick and Place,” “Peg Board,” and “Match Board”) in sequence [Figure 1]. Pick and Place consists of placing red, blue, or yellow objects in the corresponding colored boxes. Peg Board consists of grasping rings on a vertical stand with the left hand and then passing these to the right hand before placing them on a peg. Match Board consists of placing nine numbers and letters in specific squares on the board. Performance was recorded using a computerized built-in scoring algorithm created by the manufacturer. The measured variables included the time to complete the exercise (seconds), economy of motion (cm), number of instrument collisions, excessive instrument force (seconds), instruments out of view (cm), master workspace range (cm), and number of drops. A percentage score derived from a proprietary algorithm that combined a selection of these variables was also reported. After completion of all tests, the data were statistically evaluated using IBM SPSS version 20.0 (IBM, Armonk, NY,

USA). Continuous variables are presented as mean, and standard deviation. Direct comparisons of surgical fellows and medical students were performed using an independentsample t-test or the Mann-Whitney U-test depending on the data distribution. Differences of P < 0.05 were considered as statistically significant.

RESULTS Eleven surgical fellows and 14 medical students participated in this study. There was no significant difference between the groups in terms of the sex of the participants (male:female = 10:4 vs. 8:3, P = 1.000), but surgical fellows were significantly older than the students (age: 25.57 ± 2.14 years vs. 35.63 ± 2.25 years, P < 0.001). In the Pick and Place module, none of the variables was significantly different between the groups [Table 1]. Surgical fellows scored significantly a better in the number of instrument collisions (4.11 ± 2.98 vs. 1.18 ± 1.60, P = 0.016), and the number of drops (2.67 ± 1.80 vs. 1.00 ± 1.01, P = 0.028), but the percentage score was not significantly different in the Peg Board module (41.56 ± 16.31 vs. 51.36 ± 18.27, P = 0.239) [Table 2]. No significant differences were found between surgical fellows and medical students in the Match Board module [Table 3]. When the scores for all three modules were tallied, the mean score was 53.21 ± 20.12 for the medical students and 54.61 ± 19.58 for the surgical fellows (P = 0.764).

DISCUSSION The intensive training needed for laparoscopic surgery, and the demand for high technical standards may discourage surgeons, who perform open surgery from performing minimally invasive surgery. However, the advent of robotics has increased the interest in minimally invasive surgery among laparoscopically naïve surgeons. Nevertheless, the Table 1: Pick and place

a

b

c Figure 1: Three virtual endo-wrist modules: (a) Pick and Place, (b) Peg Board, (c) Match Board

Score (%) Time (s) Economy of motion (cm) Instrument collisions (n) Excessive instrument force (s) Out of view (cm) Master workspace range (cm) Drops (n)

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Medical students (n = 14)

Surgical fellows (n = 11)

P

75.71±10.41 104.62±35.46 150.84±32.08

67.55±17.25 128.35±89.71 201.25±134.72

0.337 0.784 0.250

0.43±0.94

1.91±4.01

0.635

0.04±0.13

0.23±0.52

0.357

0 7.56±0.88

0.01±0.03 8.43±1.02

0.259 0.070

0.21±0.58

0.18±0.60

0.734

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Yoo, et al.: Laparoscopic experience and robotic dexterity Table 2: Peg board Medical students (n = 14)

Surgical fellows (n = 11)

P

41.56±16.31 469.06±176.38 616.00±275.05

51.36±18.27 399.53±239.76 590.71±338.09

0.239 0.160 0.518

4.11±2.98

1.18±1.60

0.016

11.06±17.74

11.54±22.10

0.672

0.68±1.71 9.29±1.69

4.02±6.85 10.50±1.95

0.624 0.239

2.67±1.80

1.00±1.01

0.028

Medical students (n = 14)

Surgical fellows (n = 11)

P

42.31±14.19 531.97±166.78 704.45±282.60

43.30±13.34 440.06±82.88 639.76±141.28

0.706 0.193 0.901

8.54±10.46

8.70±12.57

0.754

3.88±5.82

3.24±9.10

0.767

7.15±9.01 10.12±2.19

7.37±9.10 9.85±1.75

0.683 0.598

0.23±44

0.20±0.42

0.862

Score (%) Time (s) Economy of motion (cm) Instrument collisions (n) Excessive instrument force (s) Out of view (cm) Master workspace range (cm) Drops (n)

Table 3: Match board

Score (%) Time (s) Economy of motion (cm) Instrument collisions (n) Excessive instrument force (s) Out of view (cm) Master workspace range (cm) Drops (n)

surgeons may be reluctant to perform robotic surgery, assuming that learning robotic skills will be difficult without laparoscopic experience. In a previous study,[13] that evaluated the impact of laparoscopic experience on performance with the da Vinci surgical system, the authors concluded that the laparoscopic experience was the strongest predictor of performance. They assessed robotic dexterity using three tasks performed with the da Vinci surgical system: Two of the three tasks involved creating a double knot and needle driving. However, these two tasks require an understanding of tying knots, and handling a round needle, skills that may have been lacking among the medical students participating in the previous study. We, therefore, assessed robotic dexterity using three endo-wrist modules of the dV-trainer, as these are not related to surgical skills and knowledge. Construct validity is regarded as one of the most important aspects of simulator evaluation, because it determines whether a device can discriminate between experienced and inexperienced surgeons.[14] Perrenot et al.[10] performed a large study of the validity of the dV-trainer and found that the Pick and Place and Peg Board modules offered good construct validity. The Match Board module was less relevant 70

because of its difficulty. Conversely, the Match Board module has been associated with good construct validity in other studies.[7,9] The current study used these three virtual endowrist modules, as they have been proven useful for comparing robotic skills. Our results indicated that the laparoscopic experience is not strongly correlated with robotic dexterity when using the dV-trainer. The total scores for the three modules were broadly similar. This finding can be explained by difference between laparoscopic and robotic techniques. For example, with the da Vinci surgical system, a hand movement to the right outside the body causes the instrument inside a patient to be moved to the right. By contrast, during laparoscopy, the instrument tip moves in the opposite direction of the surgeon’s hand, and surgeons have to adjust their handeye coordination to translate their hand movements in this “reverse” environment. Moreover, endo-wrist instruments are unique in that they allow seven-degrees of freedom of motion, which replicates the full range of motion of the surgeon’s hand. In addition, our results can also be affected by the fact that learning robotic skills is relatively easy. Hubens et al.[15] compared the efficacy of the da Vinci surgical system using both the 3D and 2D view options with traditional manually assisted laparoscopic techniques for performing standardized exercises. The inexperienced students performed the tasks significantly quicker and with fewer errors, when assisted by the robot in the 3D and 2D view modes compared with traditional laparoscopic surgery. Ahlering et al.[16] reported the initial experience of a surgeon without laparoscopic experience with robot-assisted radical prostatectomy. They concluded that a laparoscopically naïve yet, experienced open surgeon could successfully apply open surgical skills to the minimally invasive environment in 8-12 cases using the da Vinci surgical system. However, laparoscopic experience is clearly beneficial for some aspects of robotic surgery.[17] In particular, laparoscopic experience is useful for access, not only for placement of ports but also for laparoscopically treatable adhesions that prevent the placement of the ports. In addition, when multiquadrant abdominal access is needed, laparoscopic skills can be used to reduce docking time. For example, in rectal cancer surgery, colonic mobilization is laparoscopically performed by some surgeons before bringing the robot to the bedside for rectal dissection.[18] Estimating robotic dexterity using the dV-trainer is a weakness of this study. The dV-trainer is a well-validated

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Yoo, et al.: Laparoscopic experience and robotic dexterity

simulator of the da Vinci system that can discriminate between expert and novice robotic surgeons. However, the instrument cannot simulate the da Vinci system completely, which results in instrument bias. Another possible study limitation is the small number of participants. Surgical fellows outperformed medical students in some variables of the Peg Board module, but the percentage score was not significantly different between the groups. If the number of participants was larger, then the percentage score in the Peg Board module may have been significantly, different between the groups.

CONCLUSION Our study found that scores of three virtual endo-wrist modules were not significantly affected by the operator’s laparoscopic experience. These results greatly suggest that the laparoscopic experience is not an important factor for learning robotic performance, although laparoscopic experience is beneficial for some aspects of robotic surgery so far.

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Cite this article as: Yoo BE, Kim J, Cho JS, Shin JW, Lee DW, Kwak JM, et al. Impact of laparoscopic experience on virtual robotic simulator dexterity. J Min Access Surg 2015;11:68-71. Date of submission: 03/10/2014, Date of acceptance: 09/10/2014 Source of Support: This study was supported by a Korea University Grant (K1132271), Conflict of Interest: None declared.

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Impact of laparoscopic experience on virtual robotic simulator dexterity.

Different skills are required for robotic surgery and laparoscopic surgery. We hypothesized that the laparoscopic experience would not affect the perf...
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