Comparative diagnostic sensitivity of inching technique with other electrophysiologic tests of mild carpal tunnel syndrome

Abstract EN

Objectives : To study the prevalence of mild carpal tunnel syndrome (CTS).

Also, to study the sensitivity and reliability of the inching technique as well as various electrophysiological tests for the diagnosis of mild CTS in a trial to reach an electrophysiological protocol.

Methods : All patients referred for electrophysiological studies with clinically suspected CTS over five years’ period were included in the study.

If distal median motor latency (DML) was less than 4 ms and orthodromic sensory conduction velocity (OSCV) (14 cm wrist, 8 cm palm) was greater than 45 m / s, the patient was diagnosed as mild CTS underwent the following tests: 1- Inching technique, 3rd digit, 2- Median motor nerve stimulation mid palm, 3- Antidromic sensory latency, 3rd digit, split time, 4- Median / ulnar sensory nerve conduction 4th digit global, 5- Median /ulnar sensory nerve conduction study 4th digit, specific, 6- Median and ulnar nerves stimulation 14 cm proximal (antidromic) and ring finger recording, 7- Median / radial sensory nerve conduction study, 1st digit, 8- Electromyography (EMG) was done for exclusion criteria.

Results : 179 cases were investigated, 43 (24%) were diagnosed as mild CTS.

The sensitivity for tests 1, 2, 3 and 4 were (73.3%), for test 5 (50%) and for tests 6 and 7 (32.3%).

Conclusion : Inching technique, mid palmer stimulation, Median / ulnar global and split time are the most sensitive tests in diagnosing mild CTS.

If conventional tests fail to diagnose CTS we recommended using mid palmer stimulation and modified inching technique, if failed the most affected finger is examined, ring or thumb.