Clinical Significance of Paresthesia Distribution in Carpal Tunnel Syndrome

ABSTRACT

BACKGROUND: Carpal tunnel syndrome (CTS) is defined by symptoms associated with damage to the median nerve within the carpal tunnel. Abnormal sensation in the median nerve territory is one of the primary clinical diagnostic criteria for CTS. However, extramedian sensory abnormalities in CTS are common. The purpose of this study was to identify the clinical significance of the paresthesia distribution in CTS. METHODS: This was a cross-sectional retrospective study involving patients with CTS diagnosed based on the American Academy of Neurology criteria between January 2009 and January 2011. In total, 109 hands of 57 enrolled patients were analyzed. The participants were divided into two groups according to the distribution of sensory abnormalities (1) sensory symptoms confined to the median nerve distribution (median group), and (2) sensory symptoms distributed diffusely over the entire hand (glove group). Clinical features and electrophysiological findings were investigated by thorough chart reviews. RESULTS: Forty-seven (43.1%) hands belonged to the glove group. The frequency of sensory abnormalities and motor weakness was higher in the median group (38.7 vs 9.7%) than in the glove group (12.8% vs. 0.0%) on neurological examination. The conduction velocities of sensory nerves of the wrist and finger were significantly slower in the median group than in the glove group. CONCLUSIONS: Evaluation of the sensory symptom distribution in CTS may predict the degree of nerve damage, with sensory abnormality restricted to the median nerve distribution reflecting more severe nerve damage in CTS.