S.P. Schwab1, K. Nair2,4, L. Reyes3, N. Delson4, M. Krinsky1,5, S. Liu1,6 1University Of California – San Diego, School Of Medicine, San Diego, CA, USA 2University Of California – San Diego, Department Of Bioengineering, San Diego, CA, USA 3Massachusetts Institute Of Technology, Department Of Mechanical Engineering, Cambridge, MA, USA 4University Of California – San Diego, Department Of Mechanical And Aerospace Engineering, San Diego, CA, USA 5University Of California – San Diego, Division Of Gastroenterology, San Diego, CA, USA 6University Of California – San Diego, Division Of Colon & Rectal Surgery, San Diego, CA, USA
Introduction:
Physicians who perform colonoscopies experience a high incidence of musculoskeletal pain due to its repetitive and strenuous motion. This causes physical harm and can reduce the career lifespan of the physician. We designed a novel ergonomic grip adaptor that fits over the endoscope. This device is aimed to mitigate muscle fatigue by improving ergonomics during colonoscopy. This study evaluates the efficacy of our device using surface electromyography (sEMG) to measure muscle activity and fatigue during simulated colonoscopy procedures.
Methods:
Participants were affixed with Delsys sEMG electrodes on upper extremity muscles including flexor carpi radialis (FCR), abductor pollicis brevis (APB), flexor digitorum superficialis (FDS), and extensor carpi radialis (ECR). These muscles were chosen to capture the squeezing and torquing motion that occurs during colonoscopy. Baseline maximal voluntary isometric contraction (MVIC) trials were done on wrist flexion, grip strength, thumb abduction, and wrist extension. Participants then performed virtual colonoscopy using the Simbionix Endoscopy Simulator after practicing on the training modules. Participants were randomized to perform either modules #2 and #9 while unassisted or using the novel grip adaptor. The grip adaptor was fitted on the participant's right hand, and continuous sEMG data was collected during colonoscopy. Rest intervals were provided between trials to mitigate cumulative fatigue. After each trial, participants completed a subjective assessment using the NASA Task Load Index (NASA-TLX).
Results:
Root mean square (RMS) and average rectified value (ARV) metrics were significantly lower when using the grip adaptor, confirming reduced muscle effort. Participants reported reduced fatigue on the NASA-TLX (p=0.02), aligning with the sEMG data. The adaptor significantly reduced the percent RMS values in the FCR (p=0.010) and APB (p=0.024) muscles, indicating decreased muscle activation and potential fatigue reduction. Conversely, ECR activity increased as indicated by a downward shift in mean frequency (p=0.044), reflecting a change in the grip dynamic with adaptor use.
Conclusion:
The novel endoscope grip adaptor objectively reduces muscle fatigue in endoscopists by improving the ergonomics of colonoscopy. Our analysis revealed significant reductions in forearm muscle activity without hindering the performance of endoscopists. One explanation for this is the change in workload distribution among forearm muscles as seen by the increased power output in ECR when using the adaptor. This innovative design offers a practical solution for enhancing endoscopist comfort and reducing the risk of long-term musculoskeletal injuries associated with endoscopic procedures.