Electromyography-related pain: muscle selection is the key modifiable study characteristic.

INTRODUCTION

The aim of this study was to estimate the effects of patient, provider, and study characteristics on electromyography (EMG)-related pain.

METHODS

Patients undergoing EMG rated their EMG-related pain after each muscle was studied on a 100-point visual analog scale (VAS). Investigators recorded the order in which the muscles were sampled, the total time spent with the needle in each muscle, and whether electrical endplate noise was noted.

RESULTS

A total of 1781 muscles were studied in 304 patients. Eleven muscles were associated with significantly more or less pain than the others. Endplate noise was associated with more pain (5.4 mm, 95% CI 2.8-7.0). There was a small, but significant effect from needling time (0.02 mm, 95% CI 0.00-0.04).

CONCLUSIONS

Among factors that electromyographers can control, muscle selection has the greatest impact on pain. Our data include an extensive list of muscle-specific EMG-related pain scores. Provider and other study characteristics have little or no impact on EMG-related pain.