Electrophysiological evidence of a relationship between idiopathic carpal and tarsal tunnel syndromes

Electrophysiological findings are reported suggesting a relationship betwee n idiopathic tarsal (TTS) and carpal tunnel syndromes (CTS) to explain that the coexistence of both entrapment syndromes in the same patients is not c oincidental. Sixty-five patients with idiopathic CTS and 15 with idiopathic TITS were selected. None of the patients with CTS reported any symptoms, n or did they have any signs of TTS, and vice versa. Distal sensory conductio n velocity (SCV) of the tibial nerve was reduced in ten of 65 patients with CTS; in five of these ten patients, tibial distal motor latency (DML) was also delayed. Reduced SCV and increased DML were evident in the median nerv e of two patients with TTS. The mean of DML and SCV of the tibial nerve in the CTS group and of the median nerve in the TTS group were significantly r educed with respect to the control group without differences in the conduct ion of the ulnar, deep peroneal and sural nerves. This indicates that there was subclinical involvement of the median and tibial nerves in these patie nts. Besides having a narrow carpal tunnel, patients with CTS presumably al so have a narrow tarsal tunnel and vice versa, and are therefore prone to d evelop both nerve entrapment syndromes. The different incidence of the two syndromes is explained on the basis of anatomical and functional difference s between the two nerves. (C) 1998 Elsevier, Paris.