Introduction
As for any hand tool, the weight of the endoscope influences user comfort and the risk of developing musculoskeletal injuries, frequently occurring among gastrointestinal endoscopists [1; 2]. As a result, the endoscope weight reduction has been recommended to optimize the ergonomics of the endoscopes [3]. Because of the constituent material, single-use endoscopes are lighter than reusable ones, with a possible reduction of the muscle activation needed to hold and operate the endoscope.
Aims & Methods
The aim of the study was to compare the muscle activation while holding and operating two different gastroscopes with different weights. The activation of the forearm muscles using a single-use and a reusable gastroscope was measured using wearable superficial electromyogram (sEMG) sensors while holding the endoscopes and performing a set of standardized manoeuvres. 14 subjects (six females; median age 34 years; range 25-65 years) participated. The gastroscopes were a single-use (aScope Gastro, Ambu A/S, Denmark; weight: 0.6 kg) and a reusable gastroscope (GIF-1TH190, Olympus, Japan; 1.4 kg). The set of exercises included an initial 30-second rest position holding the endoscope statically; followed by two left-hand wheel rotations reaching a 90° tip up and down bend, respectively, and maintaining these positions for 10 seconds. Finally, the valves were pressed for 10 seconds each. The exercises were repeated three times with a 30-second rest position in between. The two gastroscopes were used in randomized order. A sleeve with embedded sEMG electrodes (ErgoSleeve, Myontec Ltd., Finland) was worn by the participants on the left arm to detect activation of the wrist flexor and extensor muscles. Before starting, the maximal voluntary contraction (MVC) was measured. sEMG data were processed using the connected software (Ergolink, Myontec Ltd., Finland), reported as muscle load (%MVC) i.e., the percentage of sEMG data normalized to MVC and displayed as average and standard deviation of the muscle load. Data were compared with paired t-test with statistical significance set at p<0.05 and calculated using Excel (Microsoft Corporation, USA).
Results
The muscle load was higher with the reusable gastroscope in the rest positions and during all manoeuvres (flexors [%MVC]: 6±2 vs. 5±2; extensors [%MVC]: 7±3 vs. 6±3; all p<0.001). We deduced that the gastroscopes’ weight difference played a major role. In fact, also during the rest position during which no manipulation of wheels or valves was required, the muscle load was higher when the reusable gastroscope was used (flexors [%MVC]: 4±2 vs. 3±2; extensors [%MVC]: 3±1 vs. 2±1; all p<0.001). In a previous study regarding hand tool weight and its relationship with the development of postural tremor [4], the authors demonstrated that the heavier the tool, the shorter the time before detecting postural tremor (as example, 9 minutes for tools weighing 0.8 kg, 12 min for 0.4 kg). Considering that the majority of diagnostic gastroscopies last a minimum of 10 min [1], tremor is assumed to be inevitable when using reusable endoscopes. In fact, despite the weight is partially distributed on the insertion tube and the connection cord, the total weight of reusable gastroscopes is higher than 1.2 kg, while the one of single-use gastroscopes less than 0.6 kg.
Conclusion
Holding and operating a single-use gastroscope reduces the load on the left wrist muscles compared to a heavier reusable gastroscope. This benefits the user ergonomics, and may prevent or delay the development of tremor, fatigue, and musculoskeletal injuries.
References
- Bessone V, Adamsen S. Gastrointestinal endoscopy and work-related injuries: an international survey. Endosc Int Open 2022; 10(5): E562-E569
- El Bacha H, Mariam K, Nadia B, Errabih I. Prevalence of musculoskeletal disorders among digestive endoscopy physicians. Endoscopy 2023; 55(S2): S85
- Khanicheh A, Shergill AK. Endoscope design for the future. Tech Gastrointest Endosc 2019; 21(3): 167-173
- Kim JY, Song HY, Yun MH, Yun MW. Effect of tool weight and hand posture on the postural tremor of the upper extremity. J Erg Society of Korea 1996; 15(2): 177-184
Disclosure
At the time of abstract submission, Dr. Veronica Bessone declares to be employed by Ambu Innovation GmbH, while Dr. Sven Adamsen to be medical advisor for Ambu A/S.
