• View in gallery
    Figure 1—

    Photographs of the experimental setup used to evaluate muscle activity and hand motion in 12 veterinarians performing a standard set of laparoscopic training tasks with a box trainer.

  • View in gallery
    Figure 2—

    Photographs of the laparoscopic instruments used during the study illustrated in Figure 1. Instruments consisted of ring-handled Kelly-Maryland laparoscopic dissectors (5 mm × 36 cm long; a), ring-handled laparoscopic scissors (5 mm × 35 cm long; b), and an axial-handled laparoscopic needle holder (5 mm × 33 cm long; c).

  • View in gallery
    Figure 3—

    Photographs of the laparoscopic training tasks performed during the study illustrated in Figure 1. A—Coordination plate used during peg transfer and coordination tasks. B—Foam latex template with straight and curved patterns used during the precision cutting task. C—Inorganic intestinal tissue used during the suturing task.

  • View in gallery
    Figure 4—

    Photograph of electrode placement sites for surface electromyography of muscle activity during the study illustrated in Figure 1.

  • View in gallery
    Figure 5—

    Photograph of the motion-capture data glove used to monitor hand position during the study illustrated in Figure 1. Numbers represent sensor position.

  • View in gallery
    Figure 6—

    Box-and-whisker plots of wrist joint angles (lower values represent wrist joint flexion, and higher values represent wrist joint extension) for 12 veterinarians performing 4 standard laparoscopic training tasks in a box trainer. For each plot, the box represents the interquartile (25th to 75th percentiles) range, the horizontal line within each box represents the median, and the whiskers represent the range. Horizontal dotted lines represent limits of wrist joint angles corresponding with neutral (RULA score, 1), acceptable (RULA score, 2), and unacceptable (RULA score, 3) wrist joint angles.

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Muscle activity and hand motion in veterinarians performing laparoscopic training tasks with a box trainer

Angelo E. Tapia-ArayaLaparoscopy Unit, Jesús Usón Minimally Invasive Surgery Centre (JUMISC), Carretera N-521, Km. 41,8. Postcode 10071, Cáceres, Spain.

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Jesús Usón-GargalloLaparoscopy Unit, Jesús Usón Minimally Invasive Surgery Centre (JUMISC), Carretera N-521, Km. 41,8. Postcode 10071, Cáceres, Spain.

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Juan A. Sánchez-MargalloLaparoscopy Unit, Jesús Usón Minimally Invasive Surgery Centre (JUMISC), Carretera N-521, Km. 41,8. Postcode 10071, Cáceres, Spain.

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Francisco J. Pérez-DuarteLaparoscopy Unit, Jesús Usón Minimally Invasive Surgery Centre (JUMISC), Carretera N-521, Km. 41,8. Postcode 10071, Cáceres, Spain.

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Idoia Díaz-Güemes Martin-PortuguésLaparoscopy Unit, Jesús Usón Minimally Invasive Surgery Centre (JUMISC), Carretera N-521, Km. 41,8. Postcode 10071, Cáceres, Spain.

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Abstract

OBJECTIVE To evaluate muscle activity and hand motion in veterinarians performing a standard set of laparoscopic training tasks.

SAMPLE 12 veterinarians with experience performing laparoscopic procedures.

PROCEDURES Participants were asked to perform peg transfer, coordination, precision cutting, and suturing tasks in a laparoscopic box trainer. Activity of the right biceps brachii, triceps brachii, forearm flexor, forearm extensor, and trapezius muscles was analyzed by means of surface electromyography. Right hand movements and wrist angle data were registered through the use of a data glove, and risk levels for the wrist joint were determined by use of a modified rapid upper limb assessment (RULA) method. One-way repeated-measures ANOVA with a Bonferroni post hoc test was performed to compare values between tasks.

RESULTS Activity in the biceps muscle did not differ significantly among the 4 tasks. Activity in the triceps, forearm flexor, and forearm extensor muscles was significantly higher during precision cutting than during the coordination task. Activity in the trapezius muscle was highest during the suturing task and did not differ significantly among the other 3 tasks. The RULA score was unacceptable (score, 3) for the coordination, peg transfer, and precision cutting tasks but was acceptable (score, 2) for the suturing task.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the ergonomics of laparoscopic training depended on the tasks performed and the design of the instruments used. Precision cutting and suturing tasks were associated with the highest muscle activity. Acceptable wrist position, as determined with the RULA method, was found with the suturing task, which was performed with an axial-handled instrument. (Am J Vet Res 2016;77:186–193)

Abstract

OBJECTIVE To evaluate muscle activity and hand motion in veterinarians performing a standard set of laparoscopic training tasks.

SAMPLE 12 veterinarians with experience performing laparoscopic procedures.

PROCEDURES Participants were asked to perform peg transfer, coordination, precision cutting, and suturing tasks in a laparoscopic box trainer. Activity of the right biceps brachii, triceps brachii, forearm flexor, forearm extensor, and trapezius muscles was analyzed by means of surface electromyography. Right hand movements and wrist angle data were registered through the use of a data glove, and risk levels for the wrist joint were determined by use of a modified rapid upper limb assessment (RULA) method. One-way repeated-measures ANOVA with a Bonferroni post hoc test was performed to compare values between tasks.

RESULTS Activity in the biceps muscle did not differ significantly among the 4 tasks. Activity in the triceps, forearm flexor, and forearm extensor muscles was significantly higher during precision cutting than during the coordination task. Activity in the trapezius muscle was highest during the suturing task and did not differ significantly among the other 3 tasks. The RULA score was unacceptable (score, 3) for the coordination, peg transfer, and precision cutting tasks but was acceptable (score, 2) for the suturing task.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the ergonomics of laparoscopic training depended on the tasks performed and the design of the instruments used. Precision cutting and suturing tasks were associated with the highest muscle activity. Acceptable wrist position, as determined with the RULA method, was found with the suturing task, which was performed with an axial-handled instrument. (Am J Vet Res 2016;77:186–193)

Ergonomics, the science of adapting work environments to workers,1 is a multidisciplinary field that studies people's characteristics, needs, abilities, and skills and focuses on those aspects that affect product design or work processes. Ergonomics attempts to adapt products, tasks, tools, spaces, and the overall environment to the ability and needs of people, improving the efficiency, safety, and welfare of consumers, users, or workers. The ergonomic approach consists of designing products and tasks so that they are adapted to people and not vice versa.2,3

In surgery, ergonomics aims to optimize equipment to reduce muscle fatigue and associated disorders in surgeons.4 Previous studies5–7 performed to gain a better understanding of the ergonomics of minimally invasive surgery include the use of video analysis to describe variations in the relative orientation of the surgeon's body and the range of joint movements, electromyography with surface electrodes to determine muscle activity and identify local muscle fatigue, and epidemiological surveys to obtain information about the conditions and habits of surgeons in their working environment. The knowledge acquired from these studies has been used to define body postures and muscle tension associated with the risk of developing work-associated injuries.

Laparoscopic training and laparoscopic surgery may lead to high levels of musculoskeletal stress as a result of reduced freedom of movement and forced postures, and laparoscopy has been associated with greater muscle fatigue than observed during conventional surgery, which may, in turn, increase the risk of injuries.8,9 A basic ergonomic problem associated with laparoscopy is the surgeon's nonneutral posture during laparoscopic procedures.10 As physical fatigue and musculoskeletal pain increase, surgeon performance and precision decrease.5 The 5 issues in laparoscopic surgery having the greatest influence on surgeon posture consist of (handheld) instrument design, position of the monitor, use of foot pedals to control diathermy, height of the operating table, and static body posture.11 For correct body posture during laparoscopic surgery, no body segment should be in a forced posture, the screen should be facing the surgeon and at eye level or slightly lower, excessive bending or twisting of the cervical vertebrae should be avoided, the elbow's flexion-extension angle should be between 90° and 120°, and hyperflexion of the wrist should be avoided.1,7,12

The use of simulators for teaching and training in laparoscopy has increased in both human and veterinary medicine.13,14 Along with the various technical limitations associated with laparoscopic box trainers, there are a number of disadvantages for surgeons, including magnified monocular vision, loss of tactile sensation, tremor amplification, fixed access ports, fulcrum effect, and reduction in the degrees of freedom, resulting in poor ergonomic postures usually maintained for relatively long periods of time.15

Some studies16,17 have found that veterinarians have significantly greater problems with musculoskeletal pain than dentists and nurses, who have already been identified as having a higher risk of musculoskeletal pain than the general population. Understanding the causes of musculoskeletal pain, especially work-related causes, remains critical to prevention.18,19

To our knowledge, only a few studies on the application of ergonomics in laparoscopic training programs have been published.20 There is no clear consensus about the best methods for laparoscopic skills assessment or certification in veterinary medicine, and there are no published studies on body posture or muscle activity in veterinary surgeons during laparoscopy. Therefore, further ergonomic studies of laparoscopic training and tools are needed. The purpose of the study reported here was to evaluate muscle activity and hand motion in veterinarians performing a standard set of laparoscopic training tasks with a box trainer.

Materials and Methods

Subjects

All study trials were performed in the experimental surgery theaters at the Jesús Usón Minimally Invasive Surgery Centre, Cáceres, Spain. Twelve veterinarians (6 men and 6 women; mean ± SD age, 33 ± 5.1 years) who had at least 3 years' experience performing laparoscopic surgery, had performed at least 30 laparoscopic procedures involving intracorporeal suturing, and had experience with laparoscopic simulation training were included in the study.

Eleven of the participants were right-handed, and 1 was left-handed. Six had previously earned a doctoral degree in minimally invasive surgery; the remaining 6 were predoctoral students in laparoscopic surgery at our institution. All participants signed a consent form.

Instruments

Laparoscopic training tasks were performed in a box trainera developed at our institution.21 Access ports were arranged in a triangular configuration with the optic system focused on the work area and 2 instrument trocars positioned at approximately 45° with respect to the optic system (Figure 1). During the peg transfer and coordination tasks, all subjects used ring-handled Kelly-Maryland laparoscopic dissectorsb (5 mm × 36 cm long) in each hand. For the precision cutting task, subjects used ring-handled laparoscopic scissorsc (5 mm × 35 cm long) in the dominant hand and a laparoscopic dissector in the nondominant hand. Finally, for the suturing task, subjects used an axial-handled laparoscopic needle holderd (5 mm × 33 cm long) in the dominant hand and a laparoscopic dissector in the nondominant hand (Figure 2). The box trainer was placed on a training carte equipped with a monitor. The height of the platform for the box trainer was adjusted according to the height of the subject, and the monitor was placed on an adjustable stand so that it could be positioned at eye level, in accordance with current recommendations.1

Figure 1—
Figure 1—

Photographs of the experimental setup used to evaluate muscle activity and hand motion in 12 veterinarians performing a standard set of laparoscopic training tasks with a box trainer.

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

Figure 2—
Figure 2—

Photographs of the laparoscopic instruments used during the study illustrated in Figure 1. Instruments consisted of ring-handled Kelly-Maryland laparoscopic dissectors (5 mm × 36 cm long; a), ring-handled laparoscopic scissors (5 mm × 35 cm long; b), and an axial-handled laparoscopic needle holder (5 mm × 33 cm long; c).

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

Skills assessment protocol

Prior to study trials, all participants read written instructions describing the tasks to be performed and watched a video demonstrating the tasks. Subsequently, they completed 4 laparoscopic training tasks on the box trainer in the following order: peg transfer, eye-hand and hand-hand coordination, precision cutting, and suturing21 (Figure 3). All tasks were performed by the conventional laparoscopic approach, and a time limit of 10 minutes was established for each task. The exercises were modified and adapted from those used in laparoscopic training in human medicine.22

Figure 3—
Figure 3—

Photographs of the laparoscopic training tasks performed during the study illustrated in Figure 1. A—Coordination plate used during peg transfer and coordination tasks. B—Foam latex template with straight and curved patterns used during the precision cutting task. C—Inorganic intestinal tissue used during the suturing task.

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

Peg transfer—Subjects were instructed, while holding dissectors in both hands, to pick up smooth and rough objects and place them on a coordination plate. There were 6 objects located at the top of the coordination plate. The subjects picked up the first object with the dominant hand, picked up the second object with the nondominant hand, and picked up successive objects with alternating hands. The objects were to be placed in the indicated wells.

Coordination—Subjects were instructed, while holding dissectors in both hands, to touch specific wells at the same time on the coordination plate.f Subjects were then required to lift an object from the top of the coordination plate with the instrument held in the dominant hand, transfer it to the instrument in the nondominant hand in midair, and place it in the center well of the coordination plate. The entire exercise was then repeated in reverse order.

Precision cutting—Subjects were instructed, while holding scissors in the dominant hand and a dissector in the nondominant hand, to cut 2 foam latex templates along patterns that progressively increased in difficulty; straight, curved, and sigmoid cutting paths were executed with both hands.

Suturing—Subjects were instructed, while holding a needle holder in the dominant hand and a dissector in the nondominant hand, to create vertical and horizontal intracorporeal sutures through 2 marks.g

Muscle activity

To measure muscle activity, surface electromyography, performed according to a previously validated protocol, was used.23,24 Data were recorded with a data acquisition and analysis systemh connected to a laptop computeri equipped with acquisition software,j allowing for simultaneous data acquisition from up to 16 analog and digital channels, with a maximum sampling speed of 400 KHz. Electromyography signals were obtained from the right biceps brachii, right triceps brachii, right forearm flexor, right forearm extensor, and right trapezius muscles (Figure 4). All data were acquired through triple-surface electrodes placed on the medial area of each muscle group. Once electrodes were adequately positioned, a maximal voluntary contraction test was performed to allow subsequent normalization of electromyography data. The electromyography signals were acquired at an acquisition frequency of 1,000 Hz during performance of laparoscopic tasks. Before processing, the acquired data were visually inspected for detection of any artifacts that could interfere with the analysis. Signals were then full-wave rectified, and low-pass and smoothing filters were applied. Mean amplitude of the electromyography data was calculated for each muscle, and final results were expressed as a percentage of the maximal voluntary contraction.

Figure 4—
Figure 4—

Photograph of electrode placement sites for surface electromyography of muscle activity during the study illustrated in Figure 1.

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

Hand motion

To record hand and wrist positions, a motion-capture data glovek was used (Figure 5). This device consisted of 16 conductive sensors with resistance flows sensitive to variations in flexion. The sensors registered the metacarpophalangeal and interphalangeal deviation of each finger as well as each finger's extension and flexion, torsion of the thumb and fifth digit in relation to the palm, flexion and extension of the wrist joint, and mediolateral deviation of the normal wrist joint. Before data acquisition, a calibration process was performed to record the morphological features of each subject's hand. For the present study, we considered the thumb, index finger, and middle finger as the most relevant fingers for holding laparoscopic instruments. Therefore, the angle between the thumb and index finger (sensor 0), the angle between the index and middle fingers (sensor 8), and the flexion-extension of these 3 fingers (thumb, sensors 1 to 3; index finger, sensors 4 and 5; middle finger, sensors 7 and 11) were analyzed.

Figure 5—
Figure 5—

Photograph of the motion-capture data glove used to monitor hand position during the study illustrated in Figure 1. Numbers represent sensor position.

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

The data glove recorded angles ranging from 0° of wrist flexion to 120° of wrist extension (sensor 16), although these limits varied slightly from one subject to another depending on biometric characteristics. Risk analysis of wrist joint posture was performed according to a modified version of the RULA method25–27 that focused exclusively on flexion and extension angles of the wrist. Potential scores ranged from 1 to 3, where a score of 1 indicated a neutral position (ie, wrist joint angle ranging from 57° to 63° during the time the task was performed), a score of 2 indicated an acceptable position (ie, wrist joint angle ≥ 45° but < 57° or > 63° but ≤ 75° during the time the task was performed), and a score of 3 indicated excessive flexion or extension of the wrist joint (ie, wrist joint angle < 45° or > 75° during the time the task was performed) that was considered unacceptable or hazardous.27

During the performance of each task, signals from the data glove's sensors were registered by the use of specific softwarel at a frequency of 100 samples/s. Then, all data were analyzed with specialized softwarem developed at our institution.27 This software converted sample data into angle values, facilitating interpretation.

Statistical analysis

All statistical analyses were performed with standard software.n Descriptive statistics (mean, SD, and range) were calculated for each variable. The Shapiro-Wilk test was used to determine whether data were normally distributed. One-way repeated-measures ANOVA with the Bonferroni post hoc test was performed to compare values between tasks. Values of P < 0.05 were considered significant.

Results

Muscle activity

Muscle activity recorded during peg transfer was not significantly different from muscle activity recorded during the other 3 tasks, except that activity in the trapezius muscle was significantly lower during peg transfer than during suturing (Table 1). Activity in the triceps, forearm flexor, and forearm extensor muscles was significantly higher during precision cutting than during the coordination task. Activity in the biceps muscle did not differ significantly among the 4 tasks. Activity in the trapezius muscle was highest during the suturing task and did not differ significantly among the other 3 tasks.

Table 1—

Mean ± SD muscle activity in the right biceps brachii, right triceps brachii, right forearm flexor, right forearm extensor, and right trapezius muscles of 12 veterinarians performing 4 standard laparoscopic training tasks in a box trainer.

 Laparoscopic training task
MuscleCoordinationPeg transferPrecision cuttingSuturing
Biceps8.4 ± 4.98.1 ± 5.17.4 ± 3.78.8 ± 4.5
Triceps4.0 ± 2.5a5.4 ± 2.2a,b7.9 ± 3.6b8.9 ± 4.1b
Flexors11.4 ± 10.5a17.4 ± 6.7a,b25.7 ± 14.2b19.0 ± 13.2a,b
Extensors16.7 ± 13.8a20.1 ± 15.9a,b36.6 ± 21.4b27.2 ± 19.1a,b
Trapezius16.4 ± 8.5a15.0 ± 7.5a19.4 ± 13.9a39.5 ± 18.9b

Muscle activity was recorded by means of surface electromyography; values are expressed as a percentage of the maximal voluntary contraction for each muscle in each subject.

In each row, values with different superscript letters were significantly (P < 0.05) different.

Hand motion

For 3 of the 10 data glove sensors (sensors 0, 1, and 8), significant differences in hand position were not found among the 4 laparoscopic tasks (Table 2). For the remaining 7 sensors, no significant differences between the coordination and peg transfer tasks were detected. Significant differences were found for 2 sensors (sensors 4 and 7) between the precision cutting and coordination tasks. Significant differences were found for 5 sensors (sensors 2, 3, 5, 11, and 16) between the suturing task and the other 3 tasks.

Table 2—

Mean ± SD angles of various segments of the right hands of 12 veterinarians performing 4 standard laparoscopic training tasks in a box trainer.

 Laparoscopic training task
Sensor numberCoordinationPeg transferPrecision cuttingSuturing
044.4 ± 30.731.5 ± 30.542.5 ± 31.451.6 ± 22.7
I54.4 ± 31.553.7 ± 39.159.1 ± 37.562.2 ± 25.2
267.2 ± 32.6a67.6 ± 29.9a72.3 ± 30.3a41.2 ± 29.9b
376.9 ± 23.0a78.0 ± 15.5a71.7 ± 20.4a50.5 ± 22.5b
467.9 ± 15.4a71.0 ± 16.1a91.5 ± 12.0b66.7 ± 10.0a
578.7 ± 13.2a79.2 ± 10.8a78.0 ± 11.9a68.8 ± 11.9b
733.1 ± 11.2a29.4 ± 9.8a,b21.1 ± 15.7b27.9 ± 7.2a,b
827.1 ± 25.843.8 ± 28.540.1 ± 24.328.6 ± 17.4
II36.9 ± 115.7a38.1 ± 15.4a44.1 ± 16.3a76.9 ± 25.2b
1622.8 ± 10.3a21.7 ± 10.2a23.6 ± 15.0a45.4 ± 4.9b

Positions of the various segments were measured with a motion-capture data glove; sensor numbers correspond to positions shown in Figure 5.

See Table 1 for remainder of key.

The RULA score was considered unacceptable (score, 3) during the coordination, peg transfer, and precision cutting tasks (Figure 6). The RULA score during the suturing task (score, 2) was considered acceptable.

Figure 6—
Figure 6—

Box-and-whisker plots of wrist joint angles (lower values represent wrist joint flexion, and higher values represent wrist joint extension) for 12 veterinarians performing 4 standard laparoscopic training tasks in a box trainer. For each plot, the box represents the interquartile (25th to 75th percentiles) range, the horizontal line within each box represents the median, and the whiskers represent the range. Horizontal dotted lines represent limits of wrist joint angles corresponding with neutral (RULA score, 1), acceptable (RULA score, 2), and unacceptable (RULA score, 3) wrist joint angles.

Citation: American Journal of Veterinary Research 77, 2; 10.2460/ajvr.77.2.186

Discussion

Results of the present study suggested that the ergonomics of laparoscopic training exercises depended on the tasks performed and the design of the instruments used. Specifically, although activity in the biceps muscle did not differ significantly among the 4 tasks evaluated in the present study, activity in the triceps, forearm flexor, and forearm extensor muscles was significantly higher during precision cutting than during the coordination task, and activity in the trapezius muscle was highest during the suturing task. In addition, wrist position, as assessed with a modified RULA method, was considered unacceptable during the coordination, peg transfer, and precision cutting tasks, which were all performed with ring-handled instruments, and was considered acceptable only during the suturing task, which was performed with an axial-handled instrument.

One of the most important ergonomic problems in laparoscopic surgery is the cramped position that surgeons sometimes have to adopt during these procedures.28 The design of instruments and equipment used in laparoscopic surgery is often not compatible with current ergonomic criteria, and laparoscopic surgeons can suffer repetitive strain injuries.29 We believe that physical and mental fatigue in surgeons can be reduced by redesigning operating rooms and equipment.30 For example, in 1 study,31 the optimal table height for laparoscopic surgery was determined to be 64 to 77 cm, depending on the surgeon's physical characteristics, which is lower than the limit of most surgical tables currently used in clinical operating rooms.

In the present study, we used surface electromyography and a motion-capture data glove for ergonomic assessment of veterinarians performing 4 standard laparoscopic training tasks in a box trainer. Surface electromyography is a widely used tool in ergonomic studies, allowing for the analysis of muscle activity during surgery.32,33 We chose to use surface electrodes because they are noninvasive and more reliable than depth electrodes.34 Amplitude of the electromyographic signal is the most frequently analyzed variable in similar studies,6,35 which is why we elected to use it in the present study. To allow comparison of results among individuals, the electromyographic signals were normalized on the basis of maximal voluntary contraction of each muscle in each participant. The 5 muscles analyzed in the present study were chosen because we believe they are the most relevant during laparoscopic surgery. For the forearm flexor and extensor muscles, we could not analyze each muscle individually because of the difficulty in detecting a single muscle signal without interference from adjacent muscles.36 During the precision cutting task in the present study, muscle activity (as a percentage of maximal voluntary contraction) was particularly high in the forearm flexor and extensor muscles, presumably as a result of the constant opening and closing movements of the scissors while cutting on the specific templates. It should be noted that the laparoscopic scissors used during these tasks were equipped with ring handles. Muscle activity in the trapezius muscle was significantly higher during the suturing task than during any of the other 3 tasks. Suturing was performed with an axial-handled needle holder, which could explain the increased trapezius muscle activity. We have observed that the height of the table can influence activity of the trapezius muscle because differences in table height change the angle of the elbow, particularly when using axial-handled instruments, with greater table height resulting in greater trapezius muscle activity. In the present study, the height of the training cart was adjusted once, according to surgeon's height, and remained the same for all 4 tasks.

To record hand and wrist positions in the present study, we used a motion-capture data glove. Motion-capture data gloves have been used in a variety of studies, including ergonomic analyses of tools and studies of hand precision and coordination while gripping objects.37,38 In addition, several studies39–41 have used the RULA method for analyzing ergonomic conditions in various environments (eg, offices and factories). To our knowledge, this is the first time that a motion-capture data glove has been used in conjunction with the RULA method for ergonomic assessment during laparoscopic training by veterinarians.

In analyzing data from the motion-capture data glove in the present study, we did not identify significant differences between the coordination and peg transfer tasks and found differences for only 2 sensors between the precision cutting and coordination tasks. All 3 of these tasks were performed with ring-handled instruments. In contrast, significant differences were found for 5 sensors between the suturing task, which was performed with an axial-handled instrument, and the other 3 tasks. Thus, the motion-capture data glove was also able to differentiate between tasks performed with different types of instruments and, in agreement with results of previous studies, our results suggested that the ergonomics of laparoscopic surgery depend both on the task performed and the instrument design.

Data generated by the motion-capture data glove allowed us to establish postural risks for the wrist joint through use of a modified version of the RULA method. The conventional RULA method evaluates the arm, forearm, and wrist joint, but in the present study, we focused exclusively on flexion-extension of the wrist joint. While performing laparoscopic training tasks, flexion-extension of the wrist joint can be greatly affected as a result of movement restrictions imposed by the surgical ports, the types of laparoscopic instrument used, and the tasks performed. We found that wrist joint position was unacceptable during 3 of the laparoscopic training tasks (coordination, peg transfer, and cutting tasks), which may correspond to less comfortable postures. In contrast, wrist joint position during the suturing task was considered acceptable.

The present study was largely exploratory in nature. Limitations of the study included the low number of subjects evaluated, the fact that all subjects were associated with the same institution, and the fact that each subject was evaluated during only a single training session. We believe that additional studies are warranted with subjects from multiple institutions and with subjects who have various levels of experience in laparoscopy to obtain more representative data about how instrument design and tasks could affect laparoscopic skills performance. Because subjects were evaluated during a single training session in the present study, more in-depth studies should be performed to detect ergonomic problems during longer training programs and to analyze how ergonomics may affect the learning curve. Also, we focused on the subjects' upper limbs in the present study, and it would be interesting to include lower limb muscles in future studies to further assess ideal hand and surgeon positions.

A final limitation of the present study was that a restricted set of laparoscopic instruments was used for the 4 tasks. Subjects could potentially have developed familiarity with the laparoscopic instruments, which may have biased our results. To extend the scope of this study, additional studies comparing tasks performed with different types of instruments are needed. Care should be exercised before concluding that our results can be applied to the clinical setting, especially considering that only specific models of a dissector, scissors, and needle holder were used. Therefore, these results should not be generalized to other instruments produced by the same or different manufacturers.

We believe it is imperative to perform studies that objectively evaluate the ergonomics of laparoscopic training for veterinarians. Studies are needed to obtain more information about the ergonomics of the various laparoscopic instruments that are used, and performance on a box trainer should be compared with performance on other types of training simulators. Also, once the ergonomics of laparoscopic training has been assessed, the next step should be to perform an ergonomic study in a clinical scenario to assess the effects of various surgical procedures. Ultimately, results of these types of studies could be used to elaborate a series of ergonomics guidelines for laparoscopic training programs for veterinarians to prevent ergonomic problems during laparoscopy.

Acknowledgments

This manuscript represents a portion of a dissertation submitted by Dr. Tapia-Araya to the veterinary school of the Autonomous University of Barcelona, Barcelona, Spain, as partial fulfillment of the requirements for a Doctor of Philosophy degree.

No third-party funding or support was received in connection with this study or the writing or publication of the manuscript. The authors declare that there were no financial or personal conflicts of interest.

Presented as an abstract at the 47th European Veterinary Conference, Voorjaarsdagen, Amsterdam, April 2014.

The authors thank Dr. Laura Fresno Bermejo for technical assistance.

ABBREVIATIONS

RULA

Rapid upper limb assessment

Footnotes

a.

SIMULVET, JUMISC, Cáceres, Spain.

b.

Click Line, No. 33310 MC, Karl Storz, Tuttlingen, Germany.

c.

Click Line, No. 34310 MC, Karl Storz, Tuttlingen, Germany.

d.

Macro Needle Holder, No. 26173 KAT, Karl Storz, Tuttlingen, Germany.

e.

CARROLAP, JUMISC, Cáceres, Spain.

f.

LAP-PLATE, JUMISC, Cáceres, Spain.

g.

Inorganic Intestine Tissue, JUMISC, Cáceres, Spain.

h.

MP 150 System, Biopac Systems Inc, Goleta, Calif.

i.

Sony VAIO, Sony Europe Ltd, Weybridge, Surrey, England.

j.

AcqKnowledge, version 3.7, Biopac Systems Inc, Calif.

k.

CyberGlove, CiberGlove Systems LLC, San Jóse, Calif.

l.

ErgoRec, JUMISC, Cáceres, Spain.

m.

ErgoStatistics, JUMISC, Cáceres, Spain.

n.

SPSS, version 15.0 for Windows, SPSS Inc, Chicago, Ill.

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Contributor Notes

Address correspondence to Dr. Tapia-Araya (angelo.tapia@gmail.com).