As a clinical neurophysiologist, I deal daily with referrals to investigate carpal tunnel syndrome (CTS). Bongers et al's study of CTS in general practice1 concerned me on a number of points.
Firstly, in 70% of patients, the clinical diagnosis of CTS was not confirmed by investigation. In our experience in Cardiff, both GPs and hand surgeons only get the diagnosis of median nerve entrapment and resulting CTS correct two-thirds of the time. As a result, we regularly see those who have undergone bilateral carpal tunnel decompression, but are still symptomatic, as their symptoms originate from undiagnosed cervical radiculopathies.
I am also concerned that the basis on which the diagnosis has been made is unstable. A meta-analysis by D'Arcy and McGee2 demonstrated that the following were of little or no value in diagnosing CTS: age, bilateral or nocturnal symptoms thenar atrophy, sensory abnormalities, Tinel sign, Phalen sign, pressure provocation test, and the tourniquet test.
Finally the assertion that there is no gold standard investigation for CTS is incorrect. Although not perfect, nerve conduction studies have been shown to have a specificity of 99% and a sensitivity of 89% in diagnosing CTS.3
I would also like to suggest that a possible reason for women being affected by CTS more than men is that common causes include endocrinological and rheumatological disease, both of which are more common in women. There is also a distribution of fat in the arms which is also sex specific.
- © British Journal of General Practice, 2007.