Ultrasound guidance may have advantages over landmark‐based guidance for some nerve conduction studies

• Published in: Muscle & nerve Vol. 63; no. 4; pp. 472 - 476
• Main Authors: Wei, Kuo‐Chang, Chiu, Yi‐Hsiang, Wu, Chueh‐Hung, Liang, Huey‐Wen, Wang, Tyng‐Guey
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2021; Wiley Subscription Services, Inc
• Subjects: Action Potentials - physiology; Adult; Amplitudes; Carpal Tunnel Syndrome - diagnostic imaging; Elbow; Electrodes; electrodiagnosis; Electrodiagnosis - methods; Female; Grooves; Guidelines as Topic; Humans; landmark‐guided; Latency; Localization; Male; Nerve conduction; Neural Conduction - physiology; Neurologic Examination - methods; Neurologic Examination - standards; radial nerve; Sensory neurons; Stimulation; Stimulators; ulnar nerve; Ulnar Nerve - diagnostic imaging; Ultrasonic imaging; Ultrasonography - methods; Ultrasonography - standards; ultrasonography‐guided; Ultrasound; United States > US; ulnar nerve; landmark-guided; radial nerve; electrodiagnosis; ultrasonography-guided
• ISSN: 0148-639X; 1097-4598; 1097-4598
• DOI: 10.1002/mus.27165

Background Precise placement of stimulating and recording electrodes is vital when performing nerve conduction studies (NCSs). In this study, we aimed to determine whether ultrasonography (US) was more precise in localizing the superficial radial nerve (SRN), dorsal ulnar cutaneous nerve (DUCN), ulnar nerve (UN) crossing the cubital tunnel, and radial nerve (RN) crossing the spiral groove (SG) compared to conventional techniques. Methods Thirty healthy young subjects (15 male) were recruited. Each subject underwent both landmark‐based and US‐guided NCS. Onset latencies and amplitudes of compound motor action potentials (CMAPs) and sensory nerve action potentials (SNAPs), and stimulation levels (ie, intensity × duration) required to obtain maximal CMAP amplitudes were compared between the two techniques. Results The mean CMAP amplitudes of the UN above the cubital tunnel (9.55 ± 1.96 vs 8.96 ± 1.94 mV, P = .030), UN below the cubital tunnel (10.11 ± 2.07 vs 9.37 ± 1.95 mV, P < .001), and RN below the SG (5.21 ± 1.56 vs 4.34 ± 1.03 mV, P < .001) were significantly greater using US‐guided NCSs compared to landmark‐based NCSs. The mean onset latency of the DUCN was significantly shorter using US‐guided NCSs (1.49 ± 0.15 vs 1.57 ± 0.14 ms, P = .020). The required stimulation level in the UN and RN was significantly lower using US‐guided NCSs. Conclusions When performing NCSs, US guidance provides a more precise localization of the stimulator and electrodes for the DUCN, UN, and RN, while providing comparable localization for the SRN, compared to landmark‐based techniques.