Cold-induced vasospasm after finger replantation; abnormal sensory regeneration and sensitisation of cold nociceptors.

Cold-induced vasospasm which may present clinically as "white fingers", after hand injuries has been reported to be as high as 100% after replanted digital amputations. The exact cause of this is obscure and no specific treatment is available. To try to shed light on the cause of post-traumatic cold-induced vasospasm we evaluated replanted digits in seven patients who had had replantations more than 10 years ago. Our results show that cold-induced vasospasm occurred in six out of seven patients. Cold nociceptors were sensitised in patients who had abnormal two point discrimination, all of whom responded to cooling by vasospasm. One patient with normal circulation did not recover cold nociception during cooling. This indicates that secondary Raynaud's syndrome after injuries to the hand may be related to sensitisation of cold nociceptors. Even simple nerve injuries may lead to secondary Raynaud's syndrome.