Higher physical workload risks with NOTES versus laparoscopy: A quantitative ergonomic assessment

Background: Research confirms that surgeons experience physical symptoms due to the unfavorable ergonomics of laparoscopy. The physical effects of performing Natural Orifice Transluminal Endoscopic Surgery (NOTES)-potentially the next evolutionary surgical step-are only now being quantitatively and systematically assessed. This study investigates NOTES- and laparoscopy-related physical workloads through biomechanical analyses. Methods: Fourteen surgeons with varying laparoscopic experience were recruited. Each participant completed ring transfer and triangle transfer tasks using two surgical platforms: laparoscopy and NOTES. Motion capture and electromyography (EMG) systems recorded biomechanical data for quantitative physical workload assessment. The normalized cumulative muscular workload (NCMW) and mean muscular workload (MMW) were obtained from EMG data. Then normalized performance time (NPT) was compared between the two surgical platforms. The overall NCMW was considerably greater when participants performed tasks using the NOTES platform (1315.8 ± 116.9%) compared with traditional laparoscopy (153.9 ± 18.8%). Results: Performing NOTES required eight to nine times higher muscular workload (NCMW: NOTES 1315.8%, laparoscopy 153.9%, p < 0.05) when compared with traditional laparoscopy. This result was shown to be caused by the following: (1) six to eight times longer NPT with NOTES (p < 0.05) and (2) higher average activation levels shown in regard to biceps, extensor digitorum communis, and thenar compartment (p < 0.05), the muscles responsible for specific joint movements to hold and operate the scope. Conclusion: This study demonstrated that performing NOTES is significantly more challenging for surgeons than laparoscopy. The greater amount of muscular exertion required is linked to higher ergonomic risks. Based on the depth and strength of our results, we propose that an alternative NOTES platform be designed, one that overcomes the awkward operational mechanism of the dual-working-channel flexible endoscope.