Use of botulinum toxin in complex regional pain syndrome in the hand

This is the first report of the use of botulinum toxin injected into the hand to treat complex regional pain syndrome (CRPS). Botulinum toxin has been shown to improve pain in Raynaud's syndrome, carpal tunnel syndrome, and CRPS of the lower limb. Botulinum toxin has also been shown to act on pain neurotransmitters directly. A 40-year-old man was referred to us with bilateral CRPS after falling onto his hands. Fifty units of Botox® were injected into the carpal tunnel and 50 units around the digital neurovascular bundles of the left non-dominant hand. Hand assessments were performed before injection, and weekly for 6 weeks post-injection. The dominant hand acted as a control. A steady improvement of power grip strength in the left hand was shown. Power in his left hand was greater than the right, despite him being right handed. Total active movement did not change significantly. He felt the injection was beneficial. Botulinum toxin may have improved the signs and symptoms of CRPS in the hand due to its combined effect on the vascular and nervous systems. Botulinum toxin may block the self-perpetuation cycle of pain and sympathetic stimulation by blocking neurotransmitters and warrants further studies on CRPS.