BACKGROUND: Carpal tunnel syndrome (CTS) is diagnosed mainly according to clinical symptoms, physical sign and neurodiagnostic laboratory examination. The therapeutic effect of conservative management and surgical operation in treating CTS need to be further observed and evaluated. OBJECTIVE: To analyze the clinical characteristics, neurophysiological grade and outcome in patients with CTS.DESIGN: Retrospective case-analysis.SETTING: Department of Neurology, First Affiliated Hospital, Medical College, Xian Jiaotong University. PARTICIPANTS: Totally 161 patients with suspected CTS from National Neuroscience Institute of Singapore referred to the Neurodiagnostic Laboratory for the confirmatory testing between January and September 2002. The involved patients, 137 male and 24 female, were aged 21-85 years. METHODS:①The condition of diabetes mellitus complicated by abnormal thyroid function was observed.②The effect on predominant hand, and paraesthesia were observed.③Neuroelectrophysiological studies were performed and the results were graded into mild, moderate and severe CTS according to the American Association of Electrodiagnostic Medicine (AAEM) criteria.④Conservative management and surgical intervention were followed up 3 months later, and symptoms and physical sign basically disappeared, and function was basically recovered, which indicated that disease condition improved.MAIN OUTCOME MEASURES:①Condition of CTS complicated by metabolic disease;②Effects on predominant hand and paraesthesia;③Electrophysiological grading; ④Prognosis.RESULTS: Totally 161 patients participated in the final analysis.①Condition of CTS complicated by metabolic disease: Among 161 patients, 17.4% (28/161) were documented to have diabetes mellitus and 7(4.3%) had hypothyroidism.②Effects on predominant hand and paraesthesia: Dominant hand involvement was present in 134 patients (83.2%) and more than 75% had onset of symptoms in the dominant hand. Sensory symptoms like numbness and paresthesias were the predominant symptoms, accounting for 89.1% (134/161), this discomfort was felt in all 5 digits of the hand in 47.6%, and lateral three and half digits in 21.4%. The noctural symptoms were present in 30.4% (49/161) patients.③Electrophysiological typing: The most frequent abnormality was that of the prolonged mid-palm median and ulnar latency difference in 146(54.7%) hands; 103(38.6%) hands had prolonged median motor distal latency. Absent response from thenar muscle was present in 35 (13.1%) hands. Nerve conduction study showed bilateral CTS in 105 (65.2%) patients and unilateral CTS in 56 (34.8%) patients. Sixteen patients with bilateral CTS had symptoms in one hand only. Overall, 36.8% had mild, 49.2 % had moderate and 13.9 % had severe CTS, with median duration of symptoms of 6, 9 and 14 months, respectively.④Delay in diagnosis: 37(22.9%) patients delayed in diagnosis from 1-4 months, 16(43.2%) were misdiagnosed as cervical spondylosis; 6(16.2%) were ignored due to their condition by busy work; 15(40.5%) were unware of their symptoms.⑤Prognosis: Follow up data was available for only 72.7% (117/161) patients. Conservative management was conducted in 73.5% (86/117). Clinical symptoms were resolved or improved in 65.1% (56/86) patients with 17 mild CTS, 29 moderate CTS, and 10 severe CTS. 26.5% (31/117) patients underwent surgery for CTS release, and clinical symptoms were improved in 12(38.7%) with moderate CTS and 2 (6.5%) with severe CTS at 3 months of follow up.CONCLUSION:①Sensory symptoms in CTS are more in severe and common in dominant hand.②Conservative management showed resolution or improvement for mild and moderate CTS. Surgical intervention shows either resolution or improvement in clinical symptoms in moderate CTS.③The common reasons for delay in diagnosis were due to misdiagnosis as cervical spondylosis and lack of awareness of the condition.④Assessment on severity of CTS by electrophysiological grade is of important significance for determining therapeutic mean.