Intrathecal Space and Drug Pumps

Also known as the subarachnoid space, the intrathecal space is the fluid-filled area located between the innermost layer of covering (the pia mater) of the spinal cord and the middle layer of covering (the arachnoid mater).

The intrathecal space may serve as a route of administration for drugs used in implantable pain management treatments. For example, implanted drug pumps, also known as pain pumps or morphine pump, use this route.

Distributing pain medication into the intrathecal space instead of taking a pill bypasses the need for the body to digest and absorb the medication. This usually translates into better pain control with smaller doses. For this reason, an injection of pain medication into the intrathecal space may provide significantly more pain relief compared to other therapies to people with severe, relentless pain. It's also a non-permanent solution to challenging chronic back pain. In other words, if you try it and don't like it, or if you decide on a different treatment approach, you don't have to continue — the pump can easily be surgically removed.

Implanted intrathecal drug-delivery systems may be suggested to you by your pain physician if you have long-term, severe pain and you've tried many types of conservative (i.e., non-invasive or non-surgical) treatments with little to no improvement in your symptoms.

According to Ghafoor, Epshteyn, Carlson, Terhaar, Charry, and Phelps in their article, "Intrathecal drug for long-term pain management," which was published in the December 2007 issue of the American Journal of Health System Pharmacy, there is a lack of evidence to support the use of intrathecal drug delivery based on randomized, controlled clinical trials. (Randomized controlled clinical trials are a high-quality type of medical research study that compares one treatment with either another treatment, no treatment or a sham treatment.)

Ghafoor, et. al also say that because most of the medication types used in intrathecal drug pumps are not available on the market, they have to be compounded by pharmacists. Such medication types include opioids, local anesthetics, clonidine, baclofen, and ziconotide, they say. 

The researchers add that pharmacists are key in the quality assurance aspect of intrathecal drug use because they are involved in so much of the process — from concentration and dosing to avoid complications in vulnerable patients, to documentation, monitoring and ordering, and compounding the drugs.

Although a pump that delivers medication into the intrathecal space helps many people reduce their pain and resume their lives, this procedure does come with a few risks. Medtronic, a manufacturer of drug pumps list infection, spinal fluid leaks, and headaches as the top three. Device malfunction is another potential risk, they say.