Sympathetic blocks: the evidence.

The sympathetic nervous system has been implicated in numerous pain syndromes ranging from neuropathic pain to vascular pain to visceral pain. In light of this, sympathetic ganglia have been the target of local anesthetic blockade to determine the sympathetic role in the transmission of pain. If analgesia is afforded with local anesthetic blockade, chemical or thermal neurolysis have been utilized to attempt to provide long-term relief. Despite frequent use of minimally invasive sympathetic blocks and neurolysis by pain practitioners, their efficacy for providing analgesia has been sparsely reported in the literature. Many case reports and case series have been published, but few placebo-controlled, blinded studies exist. This manuscript will review the literature on sympathetic blocks and summarize existing studies for each of the sympathetic blocks. The goal is to provide past, current, and future pain physicians with evidence that they can use to provide appropriate care for their patients.