Complications of sympathetic blocks for extremity pain

Sympathetic blockade is often undertaken to diagnose or treat sympathetically maintained pain in painful extremities. A thorough understanding of the anatomy and physiology of the sympathetic nervous system is essential to understand complications that may arise as a result of sympathetic blocks and to develop strategies to prevent them. Complications of sympathetic blockade vary depending on the sympathetic ganglia blocked, the location, the approach, and the agents used. Complications related to sympathetic blocks can be generally divided into unwanted results related to blockade of sympathetic fibers and untoward events related to injuring other organs as a result of the procedure. This article describes complications that may occur with sympathetic blocks performed for extremity pain and potential strategies to minimize such events.