This method of treating pain uses a pump that is minuscule in order to deliver medication to the spinal cord directly. The pump is placed surgically under the skin in the abdomen. Pain medication is then delivered through a small catheter placing the medication around the spinal cord. This can be much more effective than oral medications since there is no need to for the medication to travel through your system before reaching your spinal cord. Smaller doses are able to be used for pain control as well which can aid in the reduction of side effects.
Intrathecal Drug Delivery Joseph Smith, PhD