Abstract ID: A11
Abstract Title: Perineuromal administration of norepinephrine evokes
Poster Type: Either
ABSTRACT BODY
Introduction: More than fifty percent of amputees report experiencing significant stump or phantom pain. Stump pain is often attributed to the formation of a neuroma at the amputation site. Experimental evidence support a role for catecholamines and -adrenoceptors in the mechanisms of pain associated with neuromas. We investigated if perineuromal administration of physiological doses of norepinephrine (NE) evoked pain and if administration of phentolamine attenuated pain in patients with postamputation stump pain.
Methods: Twenty patients with postamputation stump pain participated in the study. In 15 patients, 0.2 ml of saline and NE at 10-7, 10-6, and 10-5 molar concentrations were administered sequentially in a single blinded fashion in the region of the neuroma. In 12 of these 15 patients, pain evoked by 0.2 ml of 10-5 M NE was examined before and after the injection of 0.2 ml phentolamine 10-4 M. Subjects rated their pain using a computer-based visual analogue scale. The area under the curve was calculated for pain evoked by each injection and the scores were normalized to the first saline injection.
Results: The perineuromal administration of NE had a dose-dependent increase in pain (p = 0.01). In contrast, repeated saline injection did not result in increased evoked pain. Pain ratings from 10-5 M NE after pretreatment with phentolamine were not statistically different (p=0.29).
Discussion: Our data suggest that alpha-adrenoceptor mechanisms contribute to pain associated with neuromas in amputees. Sympathectomy and adrenergic blockade should be explored in controlled clinical trials as therapeutic options in patients with postamputation pain.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A11