Accuracy of electromyography needle placement in cadavers: non-guided vs. ultrasound guided.

Introduction: Accuracy of needle electromyography is typically ensured by use of anatomical landmarks and auditory feedback related to voluntary activation of the targeted muscle; however, in certain clinical situations, landmarks may not be palpable, auditory feedback may be limited or not present, and targeting a specific muscle may be more critical. In such settings, image guidance might significantly enhance accuracy.

Methods: Two electromyographers with different levels of experience examined 14 muscles in each of 4 fresh-frozen cadaver lower limbs. Each muscle was tested a total of eight times; four fine wires were inserted without ultrasound (US) guidance and four were inserted under US guidance. Overall accuracy as well as accuracy rates for the individual electromyographers were calculated.

Results: Non-guided needle placement was significantly less accurate than US-guided needle placement, particularly in the hands of less experienced electromyographers, supporting the use of real-time US guidance in certain challenging situations in the electromyography laboratory.