ABSTRACT
The role of the sympathetic nervous system as a factor in a variety of painful conditions in humans has been a part of conventional medical wisdom for over 100 years. Early interest in the role of the sympathetic nervous system as part of the pain puzzle was limited primarily to its role as an anatomic pathway to carry the pain impulses to the brain in a manner analogous to the somatic nervous system. The unique anatomic nature of the sympathetic nervous system relative to the better anatomically defined somatic nervous system doomed this line of inquiry to raising more questions than were ultimately answered. It took the landmark work of Melzak and Wall and their gate control theory to move the prosaic thinking of the nerve as simply a wire to carry a pain message from a receptor to the brain to allow early pain clinicians such as Alon Winne to more clearly delineate the role of the sympathetic nervous system as a unique contributor to the evolution and continuation of pain in humans. As our specialty began to understand the unique way that the sympathetic nervous system interacted at both the peripheral and spinal cord levels, many of the things we were observing clinically begin to make sense, and for the first time, the specialty could put forth a rational explanation of how interruption of the sympathetic nervous system could provide prolonged pain relief. The advent of computerized tomography and magnetic resonance imaging further advanced our understanding of the structure and functional anatomy sympathetic nervous system in health and disease, enabling refinement of the techniques described below to allow for improved safety and efficacy. This chapter provides the reader with an overview of the current clinical thinking on the uses and abuses of sympathetic neural blockade in the treatment of pain.
