Pinch force and forearm-muscle load during routine colonoscopy: a pilot study

San Francisco Veterans Affairs Medical Center, San Francisco, California 94121, USA.
Gastrointestinal endoscopy (Impact Factor: 5.37). 02/2009; 69(1):142-6. DOI: 10.1016/j.gie.2008.09.030
Source: PubMed


Overuse injuries of the hand, wrist, forearm, and shoulder are common among endoscopists and may be from repetitive pinching and gripping forces or awkward posturing. In this pilot study, we evaluated distal upper-extremity musculoskeletal load during colonoscopy (1) to confirm the feasibility of performing ergonomic measurements in endoscopists and (2) to identify tasks that may contribute to overuse injuries.
Three experienced gastroenterologists were evaluated during 3 colonoscopies each.
Veterans Affairs Medical Center, San Francisco, California.
Right-thumb pinch force using a thumb-force sensor and bilateral forearm-muscle activity using electromyography.
The mean duration of the 9 colonoscopies was 19.5 minutes. The highest mean (SD) right-thumb peak pinch forces occurred during left (10.4 [4.1] N) and right (10.1 [4.5] N) colon insertion, which exceeded the injury threshold of 10 N. Mean peak forearm-muscle activity was also greatest during left and right colon insertion. Activity of the left abductor pollicis longus, left extensor carpi radialis, and right extensor carpi radialis exceeded the American Conference of Industrial Hygienists (ACGIH) hand activity level (HAL) action limit. The left extensor carpi radialis was at the ACGIH HAL threshold limit.
The small sample size, no force measurement for the left thumb, and all the gastroenterologists were men.
The pinch forces and forearm-muscle loads applied during routine colonoscopy may pose a risk for overuse injuries at the elbow and wrist.

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    • "Reduced sensation in gripping may cause individuals to exert a higher/lower grip force due to a diminished sense of touch or a skinobject micro-slippage sensation Moberg (1962, 1964, 1975), Nowak et al. (2003), Johansson (1996), Johansson and Westling (1984b, 1987, 1991), Westling and Johansson (1984a, b), Lowe and Freivalds (1999), Thonnard et al. (1997, 1999), Hermsdorfer et al. (2004), Nowak and Hermsdorfer (2003) and Nowak et al. (2001) Increased sensation Increased sensation in gripping may cause individuals to exert a higher grip force based on the sensation of a more secure grip Seo et al. (2009), Adams et al. (2007), Asserin et al. (2000), Bobjer et al. (1993), Buchholz et al. (1988), Koudine et al. (2000), Savescu et al. (2008), Sivamani et al. (2003), Enders and Seo (2011) and O'Meara and Smith (2001) Pinch force Controlled pinch force Pinch forces are controlled, maintained and regulated in order to elaborately manipulate objects Freund et al. (2002), Iyengar et al. (2009), Rost et al. (2005), Seo and Armstrong (2008), Smaby et al. (2004) and Towles et al. (2002) High/low pinch force High/low pinch forces may affect the development of hand-related musculoskeletal disorders or injuries Eksioglu et al. (1996), Ellis et al. (2004), Shergill et al. (2009), Sokas et al. (1989) and Keir et al. (1998) Adjusted pinch force Pinch forces may vary when different pinch techniques are applied while conducting pinch-related tasks Smaby et al. (2004), Choi et al. (2010), Ellis et al. (2004) and Lau and Ip (2006) P.K. Ng et al. 198 can also be created. As such, the framework of this study can be proposed as shown in Figure 1. "
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    ABSTRACT: Although studies show that torque and sensation are important factors to consider in grip force, there appears to be few frameworks that focus on their roles in pinch force. This study proposes a framework that potentially explains the roles of torque and sensation in pinch force. A review was done on these factors followed by a literature synthesis which categorised them into sub-factors. The sub-factors were combined to output a framework that explains the mechanisms of their interactions. This framework enriches the knowledge on pinch force levels for reduced injury risks by identifying preliminary factors that may influence pinch force. It can potentially be used to improve the effectiveness of manufacturing tasks. Although further research on it is required, it still provides researchers with more factors to consider for studies on occupational risks and injuries. With this framework, researchers can potentially improve predictions on functional outcomes in precision manufacturing tasks.
    Theoretical Issues in Ergonomics Science 04/2014; 15(2):193-204. DOI:10.1080/1463922x.2012.691185
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