Aetiology of the so-called 'idiopathic' carpal tunnel syndrome

A large number of factors have been linked factually and statistically with the ætiology of so-called idiopathic CTS. Unfortunately a large number of studies have concentrated on only one or two of these factors in an attempt to show a causal relationship between the work-place and CTS and have totally ignored the multi-factorial ætiology. Anatomic factors such as canal stenosis and intrusion of muscle bellies into the canal significantly alter the pressure within the carpal canal. The condition is significantly more common in females over the age of 40, especially in white races. This has been linked with a hormonal changes associated with the menopause, œstrogen replacement therapy and the taking of oral contraceptives. Obesity is a significant risk factor as are the use of alcohol and tobacco. Vibration, repetitive actions with the hands and forceful gripping have also been termed risk factors but there is no evidence that these mechanical factors cause CTS, only that they exacerbate the symptoms. Just because these activities provoke the symptoms of CTS, it does not mean that they have caused the CTS. The confusion arises in the terminology and the use of the term risk factors. Anything that causes the patient to become aware of the symptoms of CTS has been termed a 'risk factor'. A less confusing terminology would be divided into two: ætioloical risk factors for CTS and risk factors for provocation of the symptoms of CTS.