Neuraxial medication delivery: the development and maturity of a concept for treating chronic pain of spinal origin.

Abstract

A literature review and synthesis were performed. To summarize the history, use, and innovation related to neuraxial drug delivery for the treatment of intractable back pain. The discovery of opioid receptors in the early 1970s provided a rational basis for the delivery of opioid drugs intraspinally. Epidural or intrathecal infusions deliver drugs directly to opioid receptors, limit systemic exposure, and by decreasing the opioid dosage required for pain relief, generally reduce side effects. The benefits of short-term spinal analgesia led to investigation of longer-term continuous subarachnoid opioid infusions for the management of both cancer pain and noncancer pain, such as that of spinal origin. Unique features of this article include an updated pain continuum, updated indications for intrathecal therapy, a detailed comparison of trial techniques, a detailed comparison of the advantages of different types of pumps, a synopsis of troubleshooting for inadequate efficacy, and an updated statement regarding intrathecal pumps and radiologic procedures, including MRI scanning. Some challenges remain. Large-scale well-controlled studies could answer some perplexing questions regarding efficacy in patients with noncancer or neuropathic pain. Patient selection criteria undoubtedly will be refined and validated as more patients are treated. In addition, further investigation of specifically targeted medications or drug combinations for intraspinal use could increase efficacy, reduce side effects, and expand indications. Intraspinal medication delivery has become an effective technique for control of intractable pain in appropriately selected patients seen by spine surgeons.