ABSTRACT
Sympathetic efferent fibers are involved in nociception and transmission of pain impulses. Selective sympathetic blocks of the upper and lower extremities can be performed effectively with low risk of complications. The evidence-base for long-term effects of sympathetic blocks on chronic complex pain conditions is limited: negative studies are often flawed by not selecting patients with proven sympathetically maintained pain, whereas the reported long-term positive outcomes in the hands of experts are considered weak evidence. Specific sympathetic blockade is possible at the cervicothoracic and lumbar areas as well as at the celiac and hypogastric sympathetic plexa. Experienced clinicians continue to carry out these blocks because we have seen otherwise intractable patients in whom repeated sympathetic blocks give significant relief. Sympathetic blocks can only be a part of the management of these complex patients. Some patients who initially had good pain relief with sympathetic blockade gradually, after several years, lost their component of sympathetically maintained pain.
