Study of motor and sensory nerve conduction of wrist palm and palm-finger segments of median nerve and studying their contribution in diagnosis of carpal tunnel syndrome

Abstract

Objectives Our objective is to report a modified and simplified technique of sensory and motor segmental conduction studies to improve diagnostic sensitivity, especially in cases with mild carpal tunnel syndrome (CTS). Patients and methods Patients with suspected CTS referred to our electrophysiology laboratory and a control group were included. The data were collected prospectively. The following measurements made: median sensory conduction velocity wrist digit 1(W-1), median sensory conduction velocity wrist digit 3 (W-3), median wrist palm sensory conduction velocity (W-Ps), distoproximal ratio of velocity (D/P), median distal motor latency wrist (MDML) -APB (Abductor pollicis brevis), and median wrist -palm segment motor conduction velocity (W-Pm). Results The highest sensitivity test for an electrodiagnostic CTS diagnosis was D/P (63.7%), W-Pm (43.1%), W-Ps (39.2%), median distal motor latency (33.3%), median sensory conduction velocity wrist digit 1 (31.4%), and median sensory conduction velocity wrist digit 3 (29.4%), correspondingly. A total of 52 patients were diagnosed as having CTS electrophysiologically after containment of W-Ps, 58 patients were defined as having CTS after containment of W-Pm, and 55 patients were diagnosed as having CTS electrophysiologically after containment of D/P. Of 102 hands with CTS, 70 were defined as an electrophysiologically proven CTS using routine electrophysiologic tests together with D/P, W-Pm, and W-Ps segmental studies, increasing the sensitivity of diagnoses by nearly 55.5%. Conclusion The results of this study suggested that motor or sensory segmental studies have an important inputs in the diagnosis, particularly for mild cases of CTS.