[Are conduction studies in the median nerve obligatory for the diagnosis of the carpal tunnel syndrome: a review]

Abstract

Most the of doctors, including surgeons, who deal with diagnosing and treatment of carpal tunnel syndrome believe that median nerve conduction studies are obligatory for accurate diagnosis of the syndrome, providing various arguments to support this opinion. Based on available, current literature, a critical analysis of such an attitude was conducted. There is no definitive scientific evidence supporting a greater diagnostic importance of abnormal conduction in median nerve, than classical symptoms and signs of carpal tunnel syndrome. There is no enough evidence that electrophysiological studies are necessary for differential diagnosis, because clinical features of other pathologies are sufficiently different from classical carpal tunnel syndrome to avoid a false diagnosis. Relief of the symptoms and signs, but not normalisation of the conduction in median nerve is enough substantial as an evidence of effective therapy. The available evidence suggests the need of treatment of patients with typical symptoms of carpal tunnel syndrome associated with normal conduction studies, and non-treatment of those, with abnormal conduction but asymptomatic. Electrophysiological studies are thus not really a gold standard for carpal tunnel diagnosis and doing them in all patients presenting with typical history is not justified. Presence of classical features is enough convincing to make a diagnosis and qualify to the treatment. Nerve conduction studies may be helpful in cases with atypical history, when more than one site of compression is suspected, in failures and complications of surgery. The presented approach is associated with undoubted advantages of reducing time from referral to operation, costs and workload of neurophysiologists. There is no account for fear that meeting these rules may deteriorate results of the treatment of carpal tunnel syndrome.