Ergonomic analysis of muscle activity in the forearm and back muscles during laparoscopic surgery: influence of previous experience and performed task

Assessing posture and fatigue during neonatal positive pressure ventilation

Healthcare professionals (HCPs) are often required to complete their work under suboptimal ergonomic conditions in critical situations, inducing fatigue and musculoskeletal injury risk. These risks may vary depending on equipment and technique choices, which could require differing postures. Neonatal positive pressure ventilation (PPV) is administered to newborns who require resuscitation by holding a face mask over the nose and mouth and forcing air into the lungs with a device, such as a T-piece or a self-inflating bag (SIB). This study assessed if varying PPV device type and mask hold strategies impacted fatigue and musculoskeletal injury risk. Results show that using a SIB caused more frequent forearm extensor muscle fatigue (47.61% of trials) compared to the T-piece (14.29% of trials) and increased shoulder musculoskeletal injury risk (mean shoulder elevation angles: 45.58°(SIB) vs. 27.29°(T-piece)). When these devices are clinically comparable, the T-piece should be implemented for improved ergonomic outcomes.

Development and clinical validation of passive shoulder exoskeleton with novel gravity compensation mechanism for stabilizing arm tremor of surgeons during minimally invasive surgery

Introduction

During tasks like minimally invasive surgery (MIS), various factors can make working environment not be ergonomic, and those situations will accumulate fatigue in the surgeon's muscles which will inevitably lead to poor surgical performance. Therefore, there has been a need for technical solutions to solve this problem and one of the methods is exoskeleton robots.

Methods

We designed a passive shoulder exoskeleton whose workspace could be used for MIS to assist the surgeon's movements and performed computational and clinical validation. First, the joint order of the shoulder exoskeleton, which consists of three degrees of freedom, was configured differently from previous studies so that the singularity can be located outside the workspace. And a novel gravity compensation mechanism was developed to replace the existing one, which could no longer be used due to these changes on order of joints. Afterwards, it was computationally verified using statics and kinematics whether sufficient shoulder muscle assistance could be implemented for the entire developed system. Lastly, we manufactured an apparatus that simulated the surgical environment in which the shoulder exoskeleton robot would actually be used, recruited human participants, and conducted an experiment.

Results

Through computational validation, we can guess that the developed shoulder exoskeleton can provide 18.14% reduction of muscle activation to the wearers in workspace. And the results of clinical experiments with human subjects show that activation of deltoid posterior, medial and anterior decreased with average -8.33%, -14.55%, and -21.0%, respectively during MIS-simulated tasks with developed shoulder exoskeleton than without it. And arm tremor which is equals to movement variability also decreased with average 9.85% by using shoulder exoskeleton and maximum -19.5% in a certain position.

Discussion

These experimental results show that our shoulder exoskeleton and its novel gravity compensation mechanism has enough clinical effectiveness for workers of underhead tasks, especially surgeons who conduct MIS. It reduced deltoid activations of wearers and also stabilized arm tremor which are directly related to performance of fine manipulative task, so that this research implies that shoulder exoskeletons are also need for underhead tasks and our shoulder exoskeleton has possibility to contribute to those utilities.

Ergonomics in Laparoscopic Box Training and Virtual Reality (VR) Simulations: A Systematic Review

Laparoscopic surgery has now become the gold standard in managing most surgical cases. Despite its advantages, working hours and in-theatre training restrictions have prompted trainees to explore alternatives like virtual reality (VR) simulations and box training. Furthermore, given the increased frequency of minimally invasive surgery and the prevalence of musculoskeletal issues among surgeons, there's a growing effort to optimize ergonomics. There is currently a lack of focus on ergonomics in training, prompting our study to inspect VR and box training's ergonomic outcomes and their impact on task performance. This systematic review was conducted at Barts Cancer Institute, Queen Mary University, from January 27, 2024, to April 22, 2024. Multiple databases were searched electronically from January 1980 to March 2024, including only articles that utilized electromyography (EMG) or the NASA Task Load Index (NASA-TLX) to measure ergonomics. Two reviewers independently conducted eligibility assessment, data extraction, and risk of bias evaluation, with discrepancies resolved through consensus discussions. Ultimately, 12 studies were selected. EMG results indicated a higher %MVC (maximum voluntary contraction) in box training in poor ergonomic settings and a negative correlation between skills and muscle activity. Both modalities showed a significant decrease in NASA-TLX scores after training on the simulators and when comparing novice and experienced surgeons. Furthermore, a reduction in physical demand and improved task performance was observed, with significant differences found between experts and novices in a VR appendicectomy scenario. This systematic review reveals reduced muscle activity and physical demand among trained individuals in laparoscopic surgery with both box trainers and VR simulators, emphasizing the importance of addressing ergonomic considerations. To advance our understanding of surgical ergonomics, the standardization of measurement methods and higher-quality evidence, particularly through randomized controlled trials, are recommended.

Using wearable technology for Posture Regulation to Improve Surgical Ergonomics in the paediatric operating room: the UPRISE trial: a pilot study

BACKGROUND

The rising prevalence of work-related musculoskeletal disorders has numerous physical, financial, and mental repercussions for surgeons. This study aims to establish whether the use of a wearable posture device can improve the operating time spent in suboptimal, high-risk postures.

METHODS

Surgeons were recruited in Phase 1 of this prospective randomised study and baseline postural data was obtained. In Phase 2, participants were randomised to receive either a traditional educational workshop or intraoperative vibrations from the device to correct postural lapses. During minor elective day cases, intraoperative postural data was collected and stratified by forward flexion angle, into five risk categories (negligible to very high). Participants' experience with the sensor was also assessed.

RESULTS

A total of 100 surgical procedures (Phase 1: n = 50; Phase 2: n = 50) were performed by eight surgeons of varying seniority. Exposure to the educational intervention increased time spent in suboptimal posture (Phase 1 vs. Phase 2); 47.5% vs. 67.8%, p = 0.05. However, the vibrational intervention significantly reduced this time; 50.0% vs. 20.7%, p = 0.005. Procedure type didn't influence posture although, laparoscopic interventions spent most time in negligible-risk postures; 47.7% vs. 49.3%, compared to open procedures. Surgical consultants spent less time in suboptimal posture compared to fellow/registrars; 30.3% vs. 72.6% (Phase 1) and 33.8% vs. 65.3% (Phase 2).

CONCLUSION

Vibrational intervention from the device significantly decreased the time spent in suboptimal, high-risk postures. As procedure type wasn't correlated with postural changes, surgeon-specific factors in regulating posture are paramount. Finally, surgeon experience was positively correlated with improved surgical ergonomics.

Stress responses in surgical trainees during simulation-based training courses in laparoscopy

BACKGROUND

Simulation-based training courses in laparoscopy have become a fundamental part of surgical training programs. Surgical skills in laparoscopy are challenging to master, and training in these skills induces stress responses in trainees. There is limited data on trainees' stress levels, the stress responses related to training on different laparoscopic simulators, and how previous experiences influence trainees' stress response during a course. This study investigates physiologic, endocrine and self-reported stress responses during simulation-based surgical skills training in a course setting.

METHODS

We conducted a prospective observational study of trainees attending basic laparoscopic skills training courses at a national training centre. During the three-day course, participants trained on different laparoscopic simulators: Two box-trainers (the D-box and P.O.P. trainer) and a virtual reality simulator (LAPMentor™). Participants' stress responses were examined through heart rate variability (HRV), saliva cortisol, and the State Trait Anxiety Inventory-6 (STAI-6). The correlation between previous laparoscopic experiences and stress response measurements was explored.

RESULTS

Twenty-four surgical trainees were included in the study. Compared to resting conditions, stress measures were significantly higher during simulation-training activity (the D-box (SDNN = 58.5 ± 23.4; LF/HF-ratio = 4.58 ± 2.71; STAI-6 = 12.3 ± 3.9, P < 0.05), the P.O.P trainer (SDNN = 55.7 ± 7.4; RMSSD = 32.4 ± 17.1; STAI-6 = 12.1 ± 3.9, P < 0.05), and the LAPMentor™ (SDNN = 59.1 ± 18.5; RMSSD = 34.3 ± 19.7; LF/HF-ratio = 4.71 ± 2.64; STAI-6 = 9.9 ± 3.0, P < 0.05)). A significant difference in endocrine stress response was seen for the simulation-training activity on the D-box (saliva cortisol: 3.48 ± 1.92, P < 0.05), however, no significant differences were observed between the three simulators. A moderate correlation between surgical experience, and physiologic and endocrine stress response was observed (RMSSD: r=-0.31; SDNN: r=-0.42; SD2/SD1 ratio: r = 0.29; Saliva cortisol: r = 0.46; P < 0.05), and a negative moderate correlation to self-reported stress (r=-0.42, P < 0.05).

CONCLUSION

Trainees have a significant higher stress response during simulation-training compared to resting conditions, with no difference in stress response between the simulators. Significantly higher cortisol levels were observed on the D-box, indicating that simulation tasks with time pressure stress participants the most. Trainees with more surgical experience are associated with higher physiologic stress measures, but lower self-reported stress scores, demonstrating that surgical experience influences trainees' stress response during simulation-based skills training courses.

Advances in objective assessment of ergonomics in endoscopic surgery: a review

Background

Minimally invasive surgery, in particular endoscopic surgery, has revolutionized the benefits for patients, but poses greater challenges for surgeons in terms of ergonomics. Integrating ergonomic assessments and interventions into the multi-stage endoscopic procedure contributes to the surgeon's musculoskeletal health and the patient's intraoperative safety and postoperative recovery.

Objective

The purpose of this study was to overview the objective assessment techniques, tools and assessment settings involved in endoscopic procedures over the past decade and to identify the potential factors that induce differences in high workloads in endoscopic procedures and ultimately to design a framework for ergonomic assessment in endoscopic surgery.

Methods

Literature searches were systematically conducted in the OVID, pubmed and web of science database before October 2022, and studies evaluating ergonomics during the process of endoscopic procedures or simulated procedures were both recognized.

Results

Our systematic review of 56 studies underscores ergonomic variations in endoscopic surgery. While endoscopic procedures, predominantly laparoscopy, typically incur less physical load than open surgery, extended surgical durations notably elevate ergonomic risks. Surgeon characteristics, such as experience level and gender, significantly influence these risks, with less experienced and female surgeons facing greater challenges. Key assessment tools employed include electromyography for muscle fatigue and motion analysis for postural evaluation.

Conclusion

This review aims to provide a comprehensive analysis and framework of objective ergonomic assessments in endoscopic surgery, and suggesting avenues for future research and intervention strategies. By improving the ergonomic conditions for surgeons, we can enhance their overall health, mitigate the risk of WMSDs, and ultimately improve patient outcomes.

Ergonomics in the OR: Electromyographic Evaluation of Common Muscle Groups Used During Simulated Flexible Ureteroscopy - a Pilot Study

OBJECTIVE

To assess the effects of different surgeon positions and ureteroscope types on muscle activation as measured by surface electromyography (sEMG) during simulated ureteroscopy in an endourology box-trainer model and kidney phantom.

METHODS

For this exploratory study, sEMG was used to quantify muscle activation of three endourology fellows during various ureteroscopic tasks. Electrodes were placed on the ureteroscope-holding side of the following muscles: thenar, forearm flexor, forearm extensor, biceps, triceps, deltoid, and trapezius. Subjects wore fitted lead aprons in an operating room and used a cystoscopy table with surgical drapes and an endoscopic video tower. Trials were completed with a disposable and reusable ureteroscope, both in the standing and sitting positions. Each subject performed an identical set of tasks in a phantom silicone kidney and ureteroscopy box trainer to recreate the procedural components of basketing, navigating a renal collecting system, and dusting. Raw EMG data for each task was processed and normalized as a percent of each subject's maximum voluntary contraction to allow comparison.

RESULTS

The forearm extensor was the most heavily utilized muscle. The trapezius and deltoid muscles were activated more during sitting whereas the forearm flexors had increased activity during standing. The heavier reusable ureteroscope had increased forearm extensor activation compared to the disposable ureteroscope.

CONCLUSIONS

Preliminary data show measurable differences in muscle activation based on both surgical posture and type of ureteroscope used. This highlights the need for more extensive EMG studies to identify techniques and equipment to optimize ergonomics and potentially minimize injury during flexible ureteroscopy.

The effects of operating height and the passage of time on the end-point performance of fine manipulative tasks that require high accuracy

Sustained shoulder abduction, which results from an inappropriate worktable height or tool shape and long task hours, leads to an accumulation of muscle fatigue and subsequent work-related injuries in workers. It can be alleviated by controlling the table height or ergonomic tool design, but workers who are doing some types of work that require a discomfortable posture, such as minimally invasive surgery, cannot avoid these situations. Loads to the shoulder joint or muscles result in several problems, such as muscle fatigue, deterioration of proprioception or changing movement strategies of the central nervous system, and these are critical to work that requires a high accuracy of the upper extremities. Therefore, in this paper, we designed and conducted an experiment with human participants to discuss how an inappropriate height of the work-table affects the task performance of workers who are performing a fine manipulative task that requires high accuracy of the end point. We developed an apparatus that can control the height and has four touch screens to evaluate the end-point accuracy with two different heights. Eighteen adults (9 women and 9 men) participated in the experiments, and the electromyography of their shoulder muscles, their movement stability, and task performance were measured for the analysis. We found that inappropriate height of a table brings about muscle fatigue, and time elapsed for conducting tasks accelerated the phenomenon. Task performance deteriorated according to increased fatigue, and improved movement stability is not enough to compensate for these situations.

Evaluating the Ergonomics of Surgical Residents During Laparoscopic Simulation: A Novel Computerized Approach

BACKGROUND

Assessment of residents' body positioning during laparoscopy has not been adequately investigated. This study presents a novel computer vision technique to automate ergonomic evaluation and demonstrates this approach through simulated laparoscopy.

METHODS

Surgical residents at a single academic institution were video recorded performing tasks from the Fundamentals of Laparoscopic Surgery (FLS). Ergonomics were assessed by 2 raters using the Rapid Upper Limb Assessment (RULA) tool. Additionally, a novel computer software program was used to measure ergonomics from the video recordings. All participants completed a survey on musculoskeletal complaints, which was graded by severity.

RESULTS

Ten residents participated; all performed FLS in postures that exceeded acceptable ergonomic risks as determined by both the human and computerized RULA scores (P < .001). Lower-level residents scored worse than upper-level residents on the human-graded RULA assessment (P = .04). There was no difference in computer-graded RULA scores by resident level (P = .39) and computer-graded scores did not correlate with human scores (P = .75). Shoulder and wrist position were the greatest contributors to higher computer-graded scores (P < .001). Self-reported musculoskeletal complaints did not differ at resident level (P = .74); however, all residents reported having at least 1 form of musculoskeletal complaint occurring "often."

CONCLUSIONS

Surgery residents demonstrated suboptimal ergonomics while performing simulated laparoscopic tasks. A novel computer program to measure ergonomics did not agree with the scores generated by the human raters, although it concluded that resident ergonomics remain a concern, especially regarding shoulder and wrist positioning.

Effect of structured training in improving the ergonomic stress in laparoscopic surgery among general surgery residents

BACKGROUND

Minimal access surgery has fast become the standard of care for many operative procedures, but is associated with lot of ergonomic stress to the surgeons performing these procedures, which may result in reduction in surgeon's performance and work capacity. In this study, we evaluated the impact of structured training program in improving the ergonomic stress in trainee laparoscopic surgeons.

METHODS

Laparoscopic surgeons were divided in 2 groups: trainee surgeons (ten) and expert surgeons (three). Baseline surface electromyography (sEMG) data were collected from bilateral deltoid, biceps brachii, forearm extensors, and pronator teres during a predefined suturing task on Tuebingen trainer with integrated porcine organs in both the groups. Trainee surgeons underwent 20 h of laparoscopic intra-corporeal suturing training and surface electromyography data were recorded at the end of training again and compared with baseline.

RESULTS

Experts were found to have lower muscle activation (p < 0.05) and muscle work (p < 0.05) and better bimanual dexterity than the trainee surgeons at baseline. After training, the trainee surgeons showed significant improvement (p = 0.01), but still did not reach the values of the expert surgeons (p = 0.01). Right deltoid and pronator teres muscles were found to have maximal activity while performing intra-corporeal suturing.

CONCLUSION

Structured and focused training outside operation theater can significantly reduce unnecessary muscle activation of trainee laparoscopic surgeons and better dexterity leading on to lesser ergonomic stress and thus possibly may reduce the risk of development of future musculo-skeletal disorders.

Comparative Study of the Use of Different Sizes of an Ergonomic Instrument Handle for Laparoscopic Surgery

Previous studies have shown that the handle design of laparoscopic instruments is crucial to surgical performance and surgeon’s ergonomics. In this study, four different sizes of an ergonomic laparoscopic handle design were tested in a blind and randomized fashion with twelve surgeons. They performed three laparoscopic tasks in order to analyze the influence of handle size. Execution time, wrist posture, and finger and palm pressure were evaluated during the performance of each task. The results show a significant reduction in the time required to complete the eye-manual coordination task using the appropriate handle. The incorrectly sized handle resulted in a rise in palm pressure and a reduction in the force exerted by the thumb during the transfer task. In the hand-eye coordination task, the use of the right handle size led to an increase in middle finger pressure. In general, surgeons had an ergonomically adequate wrist flexion in all tasks and an acceptable radio-ulnar deviation during the transfer task using the ergonomic instrument handle. Surgeons found it comfortable the use of the ergonomic handle. Therefore, the use of an appropriately sized instrument handle allows surgeons to improve ergonomics and surgical performance during the laparoscopic practice.

Assessment of Postural Ergonomics and Surgical Performance in Laparoendoscopic Single-Site Surgery Using a Handheld Robotic Device

Purpose. New laparoscopic devices are being continuously developed to overcome some of the technical and ergonomic limitations of laparoendoscopic single-site (LESS) surgery. This study aims to assess the surgeon’s surgical performance and ergonomics during the use of a handheld, robotic-driven, articulating laparoscopic instrument during LESS surgery. Methods. Seven right-handed experienced surgeons took part in this study. A set of basic suturing tasks and digestive and urological procedures in a porcine model were performed. Surgeons used both a conventional laparoscopic needle holder and a robotic device. The learning curve, execution time, and precision using the surgical needle were assessed. The surgeon’s posture was analyzed using a motion tracking system and a data glove. Results. After the training period, execution time on the intracorporeal suturing was significantly shorter using the conventional needle holder. The precision was higher using the conventional instrument in the horizontal plane, but the number of attempts to position the needle was lower using the robotic device (1.625 ± 0.250 vs 1.188 ± 0.375 attempts). The extension of the elbow (134.681 ± 14.35° vs 120.631 ± 13.134°) and the flexion of the shoulder (26.122 ± 7.411° vs 18.475 ± 14.166°) were significantly lower using the robotic instrument. The wrist posture using the robotic device was ergonomically acceptable during both surgical procedures. Conclusions. Results show a positive learning curve in ergonomics and surgical performance using the robotic instrument during LESS surgery. This instrument improves the surgeon’s body posture and the needle positioning errors. The use of the robotic instrument is feasible and safe during LESS partial nephrectomy and sigmoidectomy procedures.

Initial experience using a robotic-driven laparoscopic needle holder with ergonomic handle: assessment of surgeons' task performance and ergonomics

PURPOSE

The objective of this study is to assess the surgeons' performance and ergonomics during the use of a robotic-driven needle holder in laparoscopic suturing tasks.

METHODS

Six right-handed laparoscopic surgeons with different levels of experience took part in this study. Participants performed a set of three different intracorporeal suturing tasks organized in ten trials during a period of five weeks. Surgeons used both conventional (Conv) and robotic (Rob) laparoscopic needle holders. Precision using the surgical needle, quality of the intracorporeal suturing performance, execution time and leakage pressure for the urethrovesical anastomosis, as well as the ergonomics of the surgeon's hand posture, were analyzed during the first, fifth and last trials.

RESULTS

No statistically significant differences in precision and quality of suturing performance were obtained between both groups of instruments. Surgeons required more time using the robotic instrument than using the conventional needle holder to perform the urethrovesical anastomosis, but execution time was significantly reduced after training ([Formula: see text] 0.05). There were no differences in leakage pressure for the anastomoses carried out by both instruments. After training, novice surgeons significantly improved the ergonomics of the wrist ([Formula: see text] 0.05) and index finger (Conv: 36.381[Formula: see text], Rob: 30.389[Formula: see text]; p = 0.024) when using the robotic instrument compared to the conventional needle holder.

CONCLUSIONS

Results have shown that, although both instruments offer similar technical performance, the robotic-driven instrument results in better ergonomics for the surgeon's hand posture compared to the use of a conventional laparoscopic needle holder in intracorporeal suturing.

Muscular workload of veterinary students during simulated open and laparoscopic surgery: A pilot study

OBJECTIVE

To compare upper extremity muscle activity and workload between simulated open surgery, multiple port laparoscopic surgery (MLS), and single incision laparoscopic surgery (SLS) techniques in veterinary students.

STUDY DESIGN

Pilot study.

POPULATION

Veterinary students (n = 10) from years 1 to 4.

METHODS

Bipolar skin surface electrodes were fixed bilaterally to the forearm flexor, forearm extensor, biceps brachii, triceps brachii, and upper trapezius muscles. Electromyography data were recorded during one repetition of 2 simulated surgical exercises via open surgery, MLS, and SLS. Participants completed a validated workload survey after each simulated surgical technique. Muscle activity and perceived workload were compared between surgical techniques with 1-way ANOVAs and Fisher's LSD post hoc tests.

RESULTS

Muscle activity during peg transfer was higher with MLS and SLS compared to simulated open surgery in the right and left forearm extensors (both P < .0001), right (P < .0001) and left biceps (P = .0005), right triceps (P = .0004), and right upper trapezius muscles (P = .0211). Similar results were found for the right and left forearm extensors (both P < .0001), right (P = .0381) and left (P = .0147) forearm flexors, right biceps (P < .0001), and right triceps (P = .0004) during a simulated suture task. Participants found laparoscopic techniques more mentally demanding, physically demanding, complex, and stressful compared to a simulated open surgical technique.

CONCLUSION

In veterinary students, average muscle activity and perceived workload were highest using MLS and SLS compared to an open surgical technique when performing simulated surgical exercises in a laparoscopic box trainer.

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

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.

Objective analysis of surgeons' ergonomy during laparoendoscopic single-site surgery through the use of surface electromyography and a motion capture data glove

BACKGROUND

Adding to the ergonomic inconveniences already presented by traditional laparoscopy (LAP), laparoendoscopic single-site (LESS) surgery has been found to entail other more specific problems, including greater reduction in movement freedom, in-line vision with loss of triangulation, and greater proximity of instruments. The objective of this study was to evaluate surgeons' ergonomy during LESS surgery, through the study of muscular activity, wrist angle, and hand movements, and compare it with conventional laparoscopy.

METHODS

The study group was composed by 14 experienced laparoscopic surgeons, all right-handed. Each one performed dissection tasks on a physical simulator through LAP and LESS approaches. For LAP, straight laparoscopic scissors and dissector were used, whilst for LESS articulating tip scissors and dissector were chosen. During both tasks, muscular activity of biceps brachii, triceps brachii, forearm flexors and extensors, and trapezius muscles was registered through surface electromyography. Simultaneously right-hand movements and wrist angles were obtained through a motion capture data glove (CyberGlove(®)), which allowed for the use of a modified RULA test applied to the recorded angles with subsequent establishment of risk levels for the wrist joint.

RESULTS

Muscular activity for trapezius (LAP 6.94 ± 4.12 vs. LESS 11.32 ± 4.68; p ≤ 0.05) and forearm extensor muscles (LAP 9.2 ± 2.45 vs. LESS 37.07 ≤ 16.05; p ≤ 0.001) was significantly lower in conventional laparoscopy compared with LESS approach. No statistical significance was obtained between the different sensors, except in 3 of the 11 analyzed CyberGlove(®) sensors. The modified RULA test showed a score of 3 for laparoscopy (unacceptable), whereas for LESS a score of 2 was obtained (acceptable), with statistically significant differences between them (p ≤ 0.05).

CONCLUSIONS

The LESS approach entails greater level of muscular activity in the trapezius and forearm extensor muscles, but we have found evidences of a better wrist position during LESS compared with traditional laparoscopy.