J Korean Neurol Assoc.  1996 Dec;14(4):959-964.

Tarsal Tunnel Syndrome: Electrophysiological Study Using Interdigital Nerve Condition Test

• Kim OK
• Heo K
• Cho HK

Abstract

BACKGROUND AND OBJECTIVES: Tarsal tunnel syndrome is a rare compressive neuropathy. Reported cases of the tarsal tunnel syndrome in Korea were diagnosed by conventional nerve conduction and EMG studies, so their sensitivity was low and the differentiation from similar disorder such as lumbosacral radiculopathy was difficult. We report the usefulness of the interdigital nerve conduction study by using needle recording electrodes in the tarsal tunnel syndrome.
METHODS
Sensory compound nerve action potentials were recorded orthodromically using the near-nerve needle and signal averaging techniques. Active and reference recording electrodes were inserted behind the medial malleolus above the flexor retinaculum. When the great toe was contracting minimally with less than 3mA for a stimulus of 0.05ms duration, the needle was considered to be adequately positioned. The first and fifth digital nerves were stimulated with ring electrodes and various interdigital nerves with interdigital stimulating surface electrodes which were specially designed. Averaged sensory action potential were recorded 3 times and superimposed after 64 stimuli per each time of recording. Amplitude of sensory nerve action potential, sensory nerve conduction velocity, and the presence of the temporal dispersion were checked. The results were as follow, 1. The causes of the 775 were trauma in 3 cases, sprain in 2 cases, unknown in 5 cases. 2. Associated disease were radiculopathy in 6 cases, rheumatoid arthritis In 1 case, carpal tunnel syndrome In 1 case. 3. Clinical findings included pain on the in 5 cases, tingling sensation in 4 cases, hyperesthesia in 4 cases, numbness in 2 cases and Tinnel's sign in 2 4. Five cases showed absent potential, 5 cases low amplitude, 4 cases dispersion, 2 cases slow nerve conduction velocity and 2 cases low amplitude and slow nerve conduction velocity by Interdigital nerve condution study. 5. Five lumbosacral radiculopathy without tarsal tunnel syndrome showed normal results in interdigital nerve conduction test. We concluded that interdigital nerve conduction test using needle recording electrode is useful methods of diagnosing tarsal tunnel syndrome as well as differentiating to other disorders having similar symptoms.

MeSH Terms

Action Potentials
Arthritis, Rheumatoid
Carpal Tunnel Syndrome
Electrodes
Hyperesthesia
Hypesthesia
Korea
Needles
Neural Conduction
Radiculopathy
Sensation
Sprains and Strains
Tarsal Tunnel Syndrome*
Toes