Early Evaluation Of Electrical Diagnostics Of Motor Nerve Damage In Carpal Tunnel Syndrome

Objective:To early evaluate the function status of motor nerve in patients with carpal tunnel sydrome (CTS) by single-fiber conduction studies and motor unit number estimation, assess the function status of motor nerve in patients with CTS, at the same time, assess the function status of ulnar nerve in patients with CTS by nerve conduction studies, and analysis the relationship between the function status of ulnar nerve with extra-median spread of symptoms.Methods:60cases of CTS patients according to the AANEM diagnostic criteria30healthy people as controls, the motor unit number of abductor pollicis brevis (APB) museles were counted by Keypointfour electromyographic evoked potential machine, we also access the latency from the wrist to the APB to stimulating with the saddle Shaped stimulating electrodes and to record with the single fiber EMG electrode. According to Stevens, patients were divided into three groups of mild, moderate and severe and according to the existence of the syndromes in the fifth finger, the mild and moderate patients would be divided into two groups, the severe patients would be divided into two groups.Results:1. SF-CS parameters and motor units in CTS patients and control subjects. In CTS patients and the control subjects, median nerve SFAP latency are4.54±0.92ms vs3.44±0.24ms.the motor units of the abductor pollicis brevis are132.24±43.24vs180.29±19.56. Compared with the controls, median nerve SFAP latency prolonged and the motor unit number are less in CTS patients,(P＜0.001respectively).2. SF-CS parameters in the four groups. The latency of single-fiber conduction of median nerve in mild、 moderate and severe group and control group were3.86±0.35ms、4.55±0.69ms±5.75±0.55ms、3.44±0.24ms; The latency of nerve conduction studies of median nerve were3.42±0.29ms、4.10±0.46ms、4.55±0.42ms、3.29±0.30ms.3. The motor units in the four groups. The motor units of the abductor pollicis brevis musele in mild、 moderate and severe group and control group were171.78± 20.85、111.67±24.34、85.77±21.91、180.29±19.56, the CMAP amplitude of median nerve were9.35±1.09mV、9.10±1.08mV、6.10±0.95mV、9.75±1.29mV.4. Nerve conduction studies parameters in CTS patients and control subjects. Ulnar nerve wrist-fifth digit SCVs were slower and SNAP amplitudes were lower in CTS patients(P＜0.001). SCVs and SNAP amplitude of the DUC branch were similar in both CTS patients and controls. Also, there was no statistically significant difference between CTS subjects and controls with regard to ulnar nerve motor conduction parameters(P>0.05).5. Nerve conduction studies parameters in the four groups. Compared with the control group, ulnar nerve wrist-fifth digit SCVs were slower(P<0.05) and SNAP amplitudes were similar(p＜0.05) in the mild group, and ulnar nerve wrist-fifth digit SCVs were slower and SNAP amplitudes were lower(p＜0.05respectively) in the moderate and severe group. Compared with the mild group, ulnar nerve wrist-fifth digit SCVs were slower and SNAP amplitudes were lower(P<0.05respectively) in the moderate and severe group. Compared with the moderate group, ulnar nerve wrist-fifth digit SCVs were slower and SNAP amplitudes were lower(P<0.05respectively) in the severe group. There was no statistically significant difference with regard to ulnar nerve motor conduction and the DUC branch sensory conduction parameters(P>0.05) in the four groups.6. When mide and moderate CTS patients were existence of the syndromes in the fifth finger, we found that, in cases with symptoms in the fifth finger in addition to symptoms in the median nerve innervation area, ulnar nerve wrist-fifth digit SCVs were slower and SNAP amplitudes were lower (P<0.05respectively), there was no statistically significant difference with regard to ulnar nerve motor conduction parameters.7. In cases of the severe group with symptoms in the fifth finger in addition to symptoms in the median nerve innervation area, there was no statistically significant difference with regard to ulnar nerve conduction parameters.Conclusion:SF-CS and MUNE can be used to assess the functional status of the motor nerve in CTS patients,and may become an effective means of detection for early evaluation of motor nerve function state. There is clinical motor nerve damage in patients with CTS sensory neuropathy. There is ulnar nerve conduction abnormalities in CTS patients, the degree of ulnar nerve damage is related with the severity of CTS. The extra-median spread of sensory symptoms in CTS patients may offen be occurred in the mide and moderate CTS patients and may be related with the damage of ulnar nerve, but in the severe group there was no significant correlation.