The near-nerve sensory nerve conduction in tarsal tunnel syndrome.

The near-nerve sensory nerve conduction in the medial and lateral plantar nerves was studied in 25 cases of tarsal tunnel syndrome. Sensory nerve conduction was abnormal in 24 cases (96%) The most common abnormalities were slow nerve conduction velocities and dispersion phenomenon (prolonged duration of compound nerve action potentials). These two electrophysiological abnormalities are indicative of a focal segmental demyelination as the primary pathological process in tarsal tunnel syndrome.