Abstract Details

Title Factors Influencing the Pain Associated with Needle Electromyography of Individual Muscles

Topic Clinical Neurophysiology

Presentation(s) P02 - (-)

Poster/Presentation
Number 223

Objective

Background BACKGROUND: Sixty seven percent of electromyographers alter more than 10% of their needle examinations because of their perception of patient pain. The choice of which muscles to study, in what order, and for how long may impact the diagnostic utility of the test, so it is important to understand how these factors affect patient pain levels.

Design/Methods DESIGN/METHODS: Patients undergoing routine electromyography rated their pain on a 100 point visual analog scale after each muscle was studied. Investigators recorded the order in which the muscles were sampled, the total time spent with the needle in each muscle, and whether electrical endplate activity was noted. An adjusted linear regression analysis looking at the impact of these factors on patient pain levels was performed.

Results RESULTS: A total of 1781 muscles were studied in 301 patients. Among muscles sampled more than 40 times, the muscles with the highest mean pain scores were abductor pollicis brevis (44, SD 30) and medial gastrocnemius (39, SD 26). The least painful were deltoid (21, SD 22) and gluteus medius (25, SD 21). When endplate noise was seen, the mean pain score was higher by a value of 8 (P<0.001). Compared to the first insertion, the mean pain score with the second and third insertions were higher by values of 5 (p=0.02) and 8 (p=0.0003), respectively. The insertion time did not significantly alter pain scores.

Conclusions CONCLUSIONS: There is a high degree of variation in pain scores among patients who undergo electromyography of the same muscle. The least painful muscles are relatively proximal. Patients experience less pain with the first muscle studied than with subsequent muscles and less pain if the endplate is avoided. The amount of time spent needling is not a significant factor in reported pain.

Authors/Disclosures
Zachary N. London, MD, FAAN (University of Michigan) PRESENTER	Dr. London has nothing to disclose.
Brian Callaghan, MD, MS, FAAN (University of Michigan Health System)	Dr. Callaghan has received personal compensation for serving as an employee of University of Michigan. Dr. Callaghan has received personal compensation for serving as an employee of Ann Arbor Veterans Affairs. Dr. Callaghan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Dynamed. Dr. Callaghan has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for ��ɫ��. Dr. Callaghan has received personal compensation in the range of $50,000-$99,999 for serving as an Expert Witness for Medico-legal work. Dr. Callaghan has received personal compensation in the range of $50,000-$99,999 for serving as an Expert Witness for Vaccine Injury Compensation Program. The institution of Dr. Callaghan has received research support from ��ɫ��. The institution of Dr. Callaghan has received research support from JDRF. The institution of Dr. Callaghan has received research support from NIA. Dr. Callaghan has received personal compensation in the range of $500-$4,999 for serving as a Grant Reviewer with NIH.
	No disclosure on file
Matthew M. Hastings, MD (Specialty Care / Remote Neuromonitoring Physicians Group)	No disclosure on file
Pascal L. Rufi (Sanofi, Research and Development)	Mr. Rufi has nothing to disclose.

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