Percutaneous neuraxial implantation devices for management of chronic intractable pain.

The clinical management of painful conditions has seen great changes and improvements over the past two decades brought about, in a large part, by re-evaluating the basic theories on which we base our clinical practice. At the beginning of this century, we still believed in the model of pain transmission first expressed by Descartes, over 300 years ago. In the mid-1960s, a re-examination of transmission of pain was first promulgated and popularized. The Gate Control Theory of Melzak and Wall revolutionized the way we think about pain, and consequentially, the way we have come to treat it.