Electrophysiological findings in entrapment of the median nerve at wrist and elbow

Abstract

SYNOPSISIn 117 consecutive patients with carpal tunnel syndrome and 11 patients with a compression syndrome of the median nerve at elbow, motor and sensory conduction along the median and ulnar nerves and quantitative electromyography were compared with findings in 190 normal controls of the same age. In 25% of patients with carpal tunnel syndrome in whom motor conduction and EMG were normal, the lesion was located from abnormalities in sensory conduction. The fact that conduction along the same fibres was moderately slowed from digit to palm, severely slowed across the flexor retinaculum, and normal from wrist to elbow indicates that slowing was due to demyelination at the site of compression. Fifteen per cent of the patients with carpal tunnel syndrome had clinical and electrophysiological signs of ulnar involvement. In the other patients conduction along the ulnar nerve was as in 100 normal controls. Compression at the elbow was located by electromyographical findings rather than by abnormalities in conduction.

Carpal tunnel syndrome in paraplegic patients

“…It was therefore, thought that in accordance to the above studies, paraplegic patients who must rely on increased hand activities, including transfer and wheel-chair propulsion, their median nerves may be subject to increased pressure so that the CTS incidence may be higher than that of the 'normal' population. Different conditions have been well studied (Halter, 1981;McGrath, 1979;Buchtal, 1974;Hauns, 1981). However, no study has been done up to this writing on CTS in paraplegic patients.…”

Anterior Interosseous Nerve Lesions

“…In other lesions of the proximal median nerve (Buchthal et al 1974;Craft et al 1977;Maeda et al 1977;Seror 1986a), depending on the site and the pathophysiology of the lesion, electrodiagnosis has shown abnormal findings on needle examination in the abductor pollicis brevis and the 'medial forearm muscles' with abnormal sensory action potentials and abnormal motor and/or sensory conduction velocities.…”

“…The presence of any additional sensory complaints suggests the possibility of pronator teres or supracondylar process syndromes (Buchthal, Rosenfalck and Trojaborg 1974;Wertsch and Melvin 1982;Seror 1986b), a lateral cord brachial plexus lesion, median neuritis or a carpal tunnel syndrome in association with the AIN lesion. Expert electrodiagnosis is then essential to differentiate and assess the site of the lesion.…”

“…It is also useful to confirm normal median nerve function in the forearm and the wrist and to exclude polyneuropathy (Buchthal et al 1974;Seror 1986a).…”

El examen de seis músculos individuales: ¿puede representar un enfoque diagnóstico de trastornos neuropáticos de los miembros superiores?

“…Más importante aún, la electrofisiología es tema de interpretación y por razones técnicas y otras, no puede servir como estimación válida para la neuropatía focal 19 . Por ejemplo, la compresión del nervio mediano a nivel del codo (síndrome del pronador) rara vez se detecta midiendo la velocidad de la conducción sensorial y motriz 20,21 .…”