Distribution of paresthesias in Carpal Tunnel Syndrome reflects the degree of nerve damage at wrist

Objective To verify whether the distribution of paresthesias in patients with Carpal Tunnel Syndrome (CTS) is related to the degree of the neurophysiological involvement. Methods We performed a cross-sectional study and retrospectively evaluated 163 patients who referred to our electromyography lab and to which a clinical and electrophysiological diagnosis of CTS was made. We divided the patients into two groups: (1) patients complaining of paresthesias at the hand as a whole and (2) patients with paresthesias in the territory of the median nerve. We referred to the distribution of paresthesias at the hand as GLOVE and to the distribution in the territory of the median nerve as MEDIAN. We compared the neurophysiological impairment in GLOVE and MEDIAN distributions. Moreover, we performed multiple regression analysis to evaluate which clinical–neurophysiological variables determined GLOVE and MEDIAN distribution. Results In our sample, 70.4% of patients had GLOVE distribution and 29.6% of patients MEDIAN distribution. The risk of presenting MEDIAN distribution increases about twice (OR=2.07; 95% IC: 1.51–2.83) for each unitary increment of neurophysiological class. Conclusions The distribution of paresthesias reflects the degree of nerve damage at wrist; patients suffering of SEV/EXT CTS present MEDIAN distribution. Significance Our data have important clinical implications because they strongly suggest that we have to consider the possibility of a severe neurophysiological involvement of the median nerve at wrist in patients complaining of MEDIAN distribution