Neurophysiological advances in carpal tunnel syndrome: process of central sensitisation or local neuropathy

Carpal tunnel syndrome (CTS) is considered a simple entrapment of the median nerve at the carpal tunnel. In the last years, several studies have demonstrated the presence of peripheral and central sensitization mechanisms. To review the basis neurophysiology of peripheral and central sensitization by applying them to CTS and to determine their clinical repercussions. Several studies have revealed that patients with CTS exhibit somato-sensory changes in areas innervated by the median nerve and also in areas non-related with the median nerve. Individuals with CTS exhibited widespread mechanical and thermal pain hyperalgesia, although they suffered from unilateral symptoms. Further, patients also showed wide-spread impairments in vibration conduction, deficits in fine motor control and changes in the somato-sensory cortex. These evidences support the presence of a complex process of peripheral and central sensitization in patients with CTS which may constitute a negative prognosis factor for the management of these patients. The advances in neurosciences in the last years support the presence of peripheral and central sensitization mechanisms in CTS. These mechanisms justify the necessity of conceptual changes and in the management, both conservative and surgical, of this syndrome. Additionally, central sensitization can also play a relevant role in the prognosis of CTS since it can constitute a negative prognosis factor for its treatment.