Carpal tunnel syndrome and ulnar neuropathy at the wrist: comorbid disease or not?

The aim of this study was to elucidate the possible association between carpal tunnel syndrome (CTS) and ulnar neuropathy at the wrist because of the contradictory results of previous studies. Thus, a retrospective case-control study was arranged with an electromyographic database including patients between 2003 and 2009. Patients were selected according to initial diagnosis and the examiner's criteria, and data were plotted by computer. One thousand nine hundred twenty-four patients were evaluated for CTS and 1,024 patients for diabetic CTS or diabetic polyneuropathy. CTS and ulnar neuropathy co-occurrence and CTS alone at the wrist was found in 54/404, 19/50, 20/27 patients, respectively. Logistic regression analysis revealed that having CTS was associated with a doubled risk of ulnar neuropathy at the wrist in both idiopathic CTS and diabetic CTS groups but not in diabetic polyneuropathy. Being male and of advanced age were other risk factors for ulnar neuropathy at the wrist. Correlation analysis (age and sex were controlled) revealed decreased but significant correlations between median and ulnar sensory amplitudes in CTS cases in all groups.