Role of Instruction Method in Novices' Acquisition of Minimally Invasive Surgical Basic Skills

Abstract

Introduction:

We investigated the impact of instruction method on novices' acquisition of minimally invasive surgical (MIS) basic skills.

Materials and Methods:

One hundred five novice medical students underwent text-based (TB), video-based (VB), or faculty-tutored (FT) single-session instruction in three basic MIS skill tasks on a box trainer. Pre- and postsession, participants completed a 12-item, 5-point Likert-type scale (1=Not confident at all, 5=Completely confident) of self-efficacy for performing basic MIS skills and had performances on each task recorded. Four raters evaluated every video performance of one task, a two-handed peg transfer, using a 16-cm visual analog measurement (VAM). Inter-rater reliability was good (intra-class correlation coefficient=0.82). The relationship between instruction method, self-efficacy mean score change, and mean VAM change was examined using ANOVA analysis.

Results:

Eighty-five participants (TB=32, VB=24, FT=29) had valid matched data. Mean scores in self-efficacy and task performance increased from pre- to postsession for every instruction method: (1) Δ self-efficacy=1.04±0.64 (TB), 1.36±0.69 (VB), and 1.41±0.82 (FT); (2) Δ VAM=3.77±2.87 (TB), 3.82±2.35 (VB), and 2.57±2.60 (FT). Analysis of variance revealed no relationship between instruction method and self-efficacy (P=.10) or VAM mean score change (P=.14).

Conclusions:

Self-directed instruction methods (e.g., TB and VB) for novices' acquisition of MIS basic skills offer flexible, learner-centered, and cost-effective alternatives to the more expensive FT method.

Introduction

Teaching basic skills in minimally invasive surgery (MIS) presents a challenge to surgical educators because of its unique technical difficulties. The three-dimensional to two-dimensional depth alteration¹ associated with the use of a fiber optic camera and video monitor to observe the operative field, the fulcrum effect² created by the use of long instruments passing through fixed ports in the abdominal wall, and the altered tactile sensation³ transmitted by the long MIS instruments are unlike any open surgical equivalent. They combine to make the localization of instruments as well as the movement of objects more difficult for individuals new to MIS.

Teaching can also be time intensive for busy surgical educators trying to manage clinical and academic responsibilities. In an era of advanced computer and multimedia technology, developing alternative modes of instruction that would substitute for an experienced teacher is an attractive option. In this manner, learner receptiveness and retention during training sessions could be optimized without overburdening the already time-pressured faculty. Although researchers have looked at the usefulness of various modalities in teaching basic open surgical skills for more than a decade,^4–14 research regarding the effectiveness of different modes of teaching MIS basic skills has only recently been undertaken. Such work has focused on the usefulness of one particular type of teaching modality,^15,16 the comparison of two types of escalating feedback,¹⁷or the evaluation of differing types of trainers.^18–21 For this study, the authors choose to expand on this literature by investigating the relationship between mode of instruction and MIS basic skills acquisition among novice learners.

Materials and Methods

Training overview

From September 2006 to January 2008, 105 third-year medical students rotating on the Obstetrics/Gynecology (OB/GYN) service at the Louisiana State University Health Sciences Center, New Orleans (LSUHSC-NO), underwent instruction in basic skills through the minimally invasive surgical simulation training (MISST) program at the Isidore Cohn, Jr., MD Learning Center as part of a weeklong introductory “boot camp” focusing on cognitive and technical skills related to the OB/GYN rotation. Training consisted of performing three basic tasks on an inanimate box trainer. Learners were systematically assigned on a rotating basis to one of three modes of instruction: text-based (TB) tables, computer-based videos, and individualized faculty-tutored (FT) encounters. Instructional content was standardized throughout all modes. This project was part of a larger Institutional Review Board protocol studying the effectiveness of simulation-based education within the School of Medicine that had been approved at an exempt status prior to initiation of activities.

Training equipment, format, and tasks

Training was conducted using an inanimate pop-up box simulator with attached digital camera (LapTrainer with Simuvision™; Simulab Corporation, Seattle, WA). This digital camera was linked to a laptop computer (Latitude D610; Dell Computer, Round Rock, TX) capable of recording each participant's performance. The box simulator had an opaque membrane in which a right-handed 5-mm trocar (Endopath Tristar Surgical Trocar, 355L; Ethicon Endo-Surgery, Inc., Cincinnati, OH) and a left-handed 10-mm trocar (Endopath Tristar Surgical Trocar, 512S; Ethicon Endo-Surgery, Inc.) with multiseal cap (Endopath, MS512; Ethicon Endo-Surgery, Inc.) were placed on either side of the digital camera at convenient, standardized working angles. Participants used two 5-mm curved dissectors (Endopath, 5DCD; Ethicon Endo-Surgery, Inc.) for conducting all three tasks.

Training was standardized across all three modes of instructions. Participants initially watched two introductory videos providing an overall orientation to the training, use of the computer, and demonstration of the proper method of performing the tasks. After this introduction, participants trained on the tasks in a standardized order and format. For each task, they completed an initial untutored performance that was recorded. They then underwent tutored instruction and practice lasting 20 minutes. Instructional content was standardized and involved explanations of both proper and improper techniques for performing the tasks. These explanations were presented to the learner in one of three modes: (1) TB descriptions in table format, (2) a computer-based interactive digital video disc, or (3) FT instruction. After the practice session, participants took a 1-minute break before completing a final untutored performance of the task that was also recorded.

The tasks involved in the training focused on basic MIS skills emphasizing hand–eye coordination. A description of each task follows in the order in which it was performed during the training:

1. Two-handed peg transfer. This task was one of the original seven (now five) drills of the McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) system that has been validated^22,23 and incorporated into the Fundamentals of Laparoscopic Surgery (FLS) program.²⁴ It consisted of picking up a series of pegs from one side of a pegboard with one hand, transferring them to the other hand, and placing them on the other side of a pegboard. This process was then reversed to complete the drill. The two-handed peg transfer tests gross hand–eye coordination and ambidexterity.

2. One-handed peg transfer. This commercially available task (LapTrainer Skills Set I; Simulab Corporation) involved picking up and transferring two different sets of cylinders (i.e., tall and squat) on a pegboard using alternating hands. The tall cylinders could only be lightly grasped (i.e., no crushing) on their outer surface during transfer. This task tests fine hand–eye coordination and ambidexterity.

3. Key task. This commercially available task (LapTrainer Skills Set I; Simulab Corporation) involved threading a key through a slot in a forward and backward manner grasping only the flat portions of the key on the proximal portion of the slot in the direction of threading. This task tests complex rotational hand–eye coordination, ambidexterity, and supination/pronation manipulation.

Training participants

As stated above, the 105 participants were third-year medical students rotating on the OB/GYN service at LSUHSC-NO. These students participated in a weeklong boot camp in which they were taught both cognitive and technical skills related to the specialty. The MISST session had been incorporated into this curriculum in an effort to introduce the students to basic hand–eye MIS skills. Students were all novices in MIS skills.

Evaluation

The relationship between mode of instruction and MIS skill acquisition was evaluated by comparing both learner self-efficacy and technical performance on a single selected task before and after the training intervention. Participants were given pre- and postsession questionnaires that included items pertaining to learner status, prior operative experience, task degree of difficulty, and number of repetitions performed. These questionnaires also included a 12-item list using a 5-point Likert-type scale (1=Not confident at all to 5=Completely confident) targeting learners' self-efficacy for performing objectives-related, basic MIS skills. Total scale mean scores were calculated for participants' pre- and postsession responses. Mean gain scores were calculated by subtracting the presession score from the postsession score.

Skill performance pre- and postsession was assessed by evaluating the recorded videos of the two-handed peg transfer. This task was selected from the three tasks given its prior extensive use in the literature as part of the MISTELS/FLS curriculum.^16–18 Video recordings of performance were edited to remove any identifying characteristic (i.e., pre- versus postsession performance marker or specific identifier such as tracking number) and were then reviewed and rated using a 16-cm (0 cm=Unacceptable, 16 cm=Ideal), behaviorally anchored visual analog measurement (VAM) evaluating overall performance on the drill. Four raters (three clinical faculty members and one senior resident within the OB/GYN Department) evaluated each video recording. Before evaluating the videos, the raters had received training using the scale by viewing sample examples of performance. An intra-class correlation coefficient (ICC) was computed to check the inter-rater reliability of the VAM. Following rating, videos were matched and mean VAM gain scores calculated by subtracting the presession VAM from the postsession VAM.

SAS 9.1 was used to perform the statistical analysis. The relationship between method of instruction, self-efficacy mean score change, and mean VAM change was examined using analysis of variance (ANOVA).

Results

Twenty of the 105 participants were excluded from analysis due to mismatched identification information or missing data (e.g., no video available), leaving 85 participants (81% of original cohort) for analysis. Of these 85 learners, 32 (38%) received TB instruction, 24 (28%) received video-based (VB) instruction, and 29 (34%) had faculty tutoring. ICC of VAM rating was 0.82, which indicated a good inter-rater reliability. Results of ANOVA revealed no significant relationship between method of instruction, self-efficacy score change, and performance score change. Table 1 summarizes the findings related to learners' self-efficacy and performance changes following instruction via each of the three modes examined (P=.10 and 0.14, respectively).

Table 1.

Effect of Instruction Method on Novice Learners' Acquisition of Basic Minimally Invasive Surgical Skills

	Instruction method ^a
	Text	Video	Faculty
Self-efficacy score change^b	1.04 (0.64)^c	1.36 (0.69)	1.41 (0.81)
Training video score change^d	3.77 (2.87)	3.82 (2.35)	2.57 (2.60)

32 received text instruction, 24 received video instruction, and 29 received faculty instruction.

Instruction methods had no effect on student's self-efficacy score (ANOVA, P=.10).

Mean (standard deviation).

Instruction methods had no effect on student's training video score (ANOVA, P=.14).

ANOVA, analysis of variance.

Table 2 summarizes the mean number of opportunities that participants reported having for performing each task during the 20-minute deliberate practice interval. In general, participants had the most opportunities to practice using the two-handed peg transfer and the least number of opportunities to practice instruction using the key task. The ANOVA revealed that instruction method had no effect on the number of opportunities for practice (P=.06 for two-handed peg transfer and one-handed peg transfer, P=.08 for the key task).

Table 2.

Summary of the Number of Opportunities for Deliberate Practice of Specific Task According to Instruction Method

	Instruction method
	Text	Video	Faculty
Two-handed peg transfer^a	5.34 (3.40)^b	5.49 (3.90)	6.62 (4.72)
One-handed peg transfer^c	4.13 (2.76)	4.65 (3.07)	5.38 (3.44)
Key task^d	3.50 (1.76)	3.09 (2.37)	3.72 (2.78)

Instruction methods had no effect on attempted times of two-handed peg transfer (ANOVA, P=.06).

Mean (standard deviation).

Instruction methods had no effect on attempted times of one-handed peg transfer (ANOVA, P=.06).

Instruction methods had no effect on attempted times of key task (ANOVA, P=.08).

Discussion

The current study is one of the first to look at the relationship between method of instruction and novices' acquisition of basic MIS skills, demonstrating an equivalency between TB, VB, and FT instruction. In doing so, it builds upon the excellent research looking at the impact of method of instruction on aspects of open basic surgical skills acquisition. For example, in one randomized controlled trial, Summers et al.⁵ demonstrated that computer-based training significantly improved medical student performance of open knot tying and suturing skills 1 month after instruction compared with didactic and VB instruction. Interestingly, like our study, they did not find an immediate difference in performance among the three methods of instruction. In contrast, Rogers et al.⁴ found in their randomized study of medical students comparing computer-assisted learning with lecture with feedback that the computer-assisted learning group had lower skill performance scores. In a follow-up study,⁶ they demonstrated that the addition of external feedback to computer-assisted learning improved performance in knot tying. More recently, Nousiainen et al.¹³ have demonstrated equivalency between expert instruction and computer-based instruction for teaching knot tying to medical students, and Jensen et al.¹⁴ have shown that self-directed learning is equivalent to faculty-tutoring in teaching bowel anastomosis to junior residents. Such findings, when taken into consideration with the results from our study, suggest that, although MIS skills present unique psychomotor challenges compared with open surgical skills, both skill sets have a variety of different methods of instruction that may be employed to teach novices.

Because of its technological nature, MIS quickly attracted virtual reality models designed to assist in skills acquisition. Consequently, research has focused more on comparing training models^18–21 or validating trainers²⁵ rather than evaluating teaching techniques. Recent studies, however, have begun to emphasize them. Akle et al.¹⁵ demonstrated the benefit of video instruction in teaching MIS suturing skills in an OB/GYN setting. Schaafsma et al.¹⁶ found a particular benefit of expert feedback for more complex tasks like suturing. Van Sickle et al.¹⁷ investigated the useful of escalating auditory and visual feedback in skills acquisition. Given the 80-hour limit work week of residents, such studies focusing on teaching technique will become increasingly important as efforts are made to maximize learning MIS skills in the shortest time interval possible.

In an era of proficiency-driven curricula for MIS basic skills acquisition,^26,27 this study's finding of equivalency between method of instruction and novice skill acquisition has the important implication of permitting the creation of a learner-centered educational model. In such a model, the learner would be screened to determine his/her preferred learning style (i.e., reading, listening, and watching video) and would then receive specific instruction in that preferred manner. The learner would then proceed with the self-directed proficiency-based curriculum using the resources most suited to his/her learning style. In this manner, the rate of attaining proficiency could potentially be accelerated, providing valuable time for other learning situations. Given that the acquisition of basic MIS skills has been demonstrated to accelerate the acquisition of more complex MIS skills such as suturing,²⁸ the entire MIS skill acquisition process could potentially be shortened by tailoring basic skill acquisition to a learner's learning style.

This study does have several limitations. First, only 85 of the original 105 participants could be included in the final analysis due to problems with matching questionnaires and videos. Nonetheless, the authors believe that the findings are still worthwhile given large remaining number. Second, only one of the three tasks was evaluated for performance. This decision was made because of the two-handed peg transfer's recognized use as part of the FLS and its acceptance as a valid tool for measuring basic MIS skill. Finally, we used a different scale to rate the two-handed peg transfer. Given the fact that FLS is now used to certify surgeons, getting the rating system for any of the drills has become very difficult unless one is a testing center for the FLS. As a result, the authors had to create a new rating system. Given our very good inter-rater reliability, we feel that this tool was acceptable in this study as a performance assessment tool.

In conclusion, method of instruction does not appear to impact MIS skills acquisition in novice learners. As a result, an opportunity exists for developing a learner-centered training system in which the novice in MIS skills has access to instruction via his/her preferred style of learning. Given that such instruction may not require the actual presence of a faculty member, it could be tailored to minimize time lost to acquiring MIS basic skills within the constraints of the 80-hour work week. For example, those learners with TB or VB learning preferences could perform drills at home on the now available portable trainers. Additionally, opportunities for practice and learning could be made available during periods of down time on call nights. In this manner, MIS basic skills training could potentially be accelerated, and more of the limited 80 hours of the resident work week could be devoted to actual learning in the operating room. The authors are currently investigating this possibility.

Footnotes

Acknowledgments

The authors would like to thank all the students at LSUHSC-NO who participated in this project.

Disclosure Statement

No competing financial interests exist.

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