Radial Extracorporeal Shock Wave Therapy in the Treatment of Carpal Tunnel Syndrome

Overview

Carpal tunnel syndrome (CTS) is the most common of all entrapment syndromes with a prevalence of 1-5%. Electrodiagnostic testing is used to make a definite diagnosis. The mainstay of the pathophysiology of CTS includes mechanical damage to the median nerve due to build up of pressure in the carpal tunnel and nerve ischaemia. Physical therapy (PT) in particular is the conventional non-surgical treatment of choice in the management of mild to moderate CTS, resulting in pain reduction and improved function. Extracorporeal shock wave therapy (ESWT) is a non invasive treatment method in which high frequency sound waves are applied to the body. The mechanism of action of ESWT in the treatment of CTS remains largely unknown. Eventhough there are many therapeutic options in the treatment of mild to moderate CTS, there is no consensus on the most effective treatment (4). ESWT has become a desirable treatment option in recent years. However, due to small patients numbers in trials to date and a lack of placebo controlled studies, the efficacy of this treatment option is still under debate. This study aims to compare the efficacy of RESWT to the recommended conventional PT modalities, including therapeutic US, in the treatment of CTS with regards to nociceptive and neuropathic pain, functionality and nerve conduction study outcomes.

Carpal tunnel syndrome (CTS) is the most common of all entrapment syndromes with a prevalence of 1-5%. CTS describes the compression of the median nerve as it travels through the carpal tunnel of the wrist, largely resulting in sensory symptoms of paraesthesia and pain in the areas of the hand innervated by the nerve. CTS can also lead to muscle atrophy, loss of motor function and disability of the hand. Electrodiagnostic testing is used to make a definite diagnosis. The mainstay of the pathophysiology of CTS includes mechanical damage to the median nerve due to build up of pressure in the carpal tunnel and nerve ischaemia. Chronic compression of the median nerve also results in neuronal depolarisation and the release of neuropeptides such as substance P and calcitonin-gene-related peptide. These neuropeptides stimulate the release of endothelial nitric oxide thus triggering vasodilatation and neurogenic inflammation . Management of CTS depends on disease severity. Physical therapy (PT) in particular is the conventional non-surgical treatment of choice in the management of mild to moderate CTS, resulting in pain reduction and improved function. Recommended PT modalities include laser, ultrasound and liquid paraffin therapy. US therapy in particular has given satisfactory results in the treatment of mild to moderate CTS. The biophysical effects of US have been shown to trigger nerve regeneration and healing. Extracorporeal shock wave therapy (ESWT) is a non invasive treatment method in which high frequency sound waves are applied to the body . ESWT can be divided into radial (RESWT) and focused (FESWT) based on the design of the reflector and resultant pressure and energy applied. Animal studies have shown that ESWT, and especially RESWT can be successfully used in the treatment of peripheral nerve lesions, improving nerve regeneration and functional activity . Human studies on its uses in the treatment of peripheral neuropathies such as interdigital neuroma, distally symmetric polyneuropathy and CTS have also given promising results . The mechanism of action of ESWT in the treatment of CTS remains largely unknown. However, it is believed that the antiinflammatory, angio- and neuro-genic, effects of ESWT encourages tissue regeneration in CTS thus reducing the patient's symptoms and promoting an improvement in function. Moreover, RESWT rather than FESWT maybe the better therapeutic option in CTS as it can be applied to a wider area, incorporating both the median nerve and surrounding tissues. Eventhough there are many therapeutic options in the treatment of mild to moderate CTS, there is no consensus on the most effective treatment. ESWT has become a desirable treatment option in recent years. However, due to small patients numbers in trials to date and a lack of placebo controlled studies, the efficacy of this treatment option is still under debate. This study aims to compare the efficacy of RESWT to the recommended conventional PT modalities, including therapeutic US, in the treatment of CTS with regards to nociceptive and neuropathic pain, functionality and nerve conduction study outcomes.