Electrophysiological evaluation of ulnar nerve in carpal tunnel syndrome / 中华神经科杂志

ABSTRACT

Objective To evaluate the impairment of ulnar nerve and its relationship with sensory symptoms in the ulnar territory in patients with carpal tunnel syndrome (CTS) through electrophysiological approach.Methods We retrospectively reviewed 55 cases with CTS admitted in our hospital from January 2012 to February 2013.Patients with CTS were graded as mild-moderate (35 cases) and severe (20 cases) according to Stevens standard and were divided into symptomatic and non-symptomatic group according to the presence of sensory symptom in little finger region.Twenty healthy volunteers were included as control.Median and ulnar nerves electrophysiological study were performed using the Keypoint.net (Medoc Ltd) electromyogram device.Results Finger 5-wrist sensory conduction velocities (SCVs) of ulnar nerve were reduced ((51.71 ± 2.93) m/s vs (58.62 ± 3.21) m/s,t =8.80,P ＜ 0.01) in CTS group,compared with control group.But the sensory nerve action potential (SNAP) amplitudes had no difference.Pearson correlation analysis showed that finger 5-wrist SCVs and the SNAP amplitudes of ulnar nerve were negatively correlated with the distal motor latency of the median nerve,while positively correlated with the compound muscle action potential amplitudes,finger 1-wrist,finger 3-wrist SCVs and SNAP amplitudes of median nerve,in mild-moderate group,finger 5-wrist SCVs of ulnar nerve were slowed and the SNAP amplitudes were reduced ((51.59 ±2.70) m/s vs (53.72 ±2.58) m/s; (13.51 ± 1.84) μV vs (15.21 ±2.16) μV,t =2.24,2.30,P ＜ 0.05 respectively) in the symptomatic group,compared with the non-symptomatic group.However,in severe group,only 2 cases had sensory symptom in little finger region.Conclusions CTS patients may have impairments due to ulnar nerve entrapments at wrist,which aggravate with disease progression.Sensory symptoms in ulnar territory are more frequent during the mild-moderate stage,and may relate with ulnar nerve involvement.