Carpal Tunnel Syndrome in Patients with Diabetes

The aim of this study was to evaluate the relation of clinical and neurographic data and their possible influence factors on the course of carpal tunnel syndrome (CTS) in patients with diabetes. From a cohort of 230 patients with diabetes, CTS was found in 1/3 of these patients, 52 patients with 82 affected hands were included in our study. Number of examinations varied from 2 to 11 (mean 5) over 1 to 15 years (mean 5,4 years). Outcome variables were: duration of diabetes, type of diabetes, diabetic neuropathy and grade of CTS affection. Measurement were made of sensible and motor nerve conduction velocity of the Nn. medianus, ulnaris, peronaeus, tibialis and suralis. In 51% of the affected hands we found a latent – and in 49% a symptomatic – CTS at study onset. Women were 3-fold more affected than men, 56% of the patients showed diabetic neuropathy. In regard to the neurographic data, in 61% the results decreased, in 22% they increased the course and in 17% the course remained stable. There was a significant difference (p<0.05) between type 1 and type 2 diabetes, i.e., patients with type 1 (+3.09 pts) decreased in our affection scale (0–21) more than type 2 patients (+0.6 pts). Duration of diabetes as covariate showed a significantly better outcome (p=0.003) for patients with a shorter time of affection. A neuropathy had no severe influence on the course of CTS, in only 1/3 of the patients was there a correlation between the course of CTS and the course of neuropathy. 2/3 of 42 latent courses of CTS turned into a symptomatic one, 1/3 remained clinically latent but with decreasing neurographic values. Due to decreased neurographic and/or clinical results, 26 hands had an operation. Most of these patients suffered from type 2 diabetes with a neuropathy. Post-operatively all patients had an increase in the course of CTS, especially patients without neuropathy. Type 2 patients have a better prognosis in the course of CTS than type 1 and patients with a shorter time of diabetes affection had also a better prognosis. The courses of neuropathy and CTS were not parallel, i.e., neuropathy had no direct influence on the course of CTS. All patients who underwent an operation for CTS improved; especially those without neuropathy. Patients should be neurographically and clinically examined regarding a possible entrapment with a focus on the N. medianus. An operation should not always be the first step in the treatment of CTS.