정상 장딴지 신경 반응을 보이는 다발 신경병증 환자에서의 등쪽 장딴지 신경 전도 검사의 임상적 유용성

Abstract

Background: The most distal sensory fibers of the feet are often affected first in polyneuropathy. However, they are not evaluated in routine nerve conduction studies. Thus we evaluated the dorsal sural sensory nerve in patients with sensorimotor polyneuropathy with normal sural response, in order to assess the usefulness in electrodiagnostic practice. Methods: In this study, 53 healthy subjects and 27 patients with clinical evidence of sensorimotor polyneuropathy were included. In all subjects, peripheral motor and sensory nerve studies were performed on the upper and lower limbs including dorsal sural nerve conduction studies. On electrodiagnostic testing, all patients had normal sural responses. Results: The dorsal sural sensory nerve action potentials (SNAPs) mean amplitude was 13.12± 5.68?V, mean latency was 3.12±0.43 msec, and mean sensory conduction velocity (SCV) was 36.50±3.40 m/s in healthy subjects. In 7 of 27 patients, the dorsal sural nerve SNAPs were absent bilaterally, and in 20 patients, the mean dorsal sural nerve distal latency was longer(3.40±0.48 ms, P=0.006), and mean SCV was slower than in healthy subjects(35.08±4 . 5 9 , P=0.043). However, dorsal sural nerve amplitude was not different between the groups (P=0.072). Conclusions: Our findings suggest that dorsal sural nerve conduction studies should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses.