The fluid-filled space around your spinal cord is called the subarachnoid or intrathecal space. Cerebrospinal fluid (CSF) flows through this area, bathing and protecting your brain and spinal cord. An intrathecal drug pump works more efficiently than oral medication because it delivers medicine directly into the CSF, bypassing the path that oral medication takes through your body. In fact, you generally need about 1/300 the amount of medication (morphine or baclofen) with a pump than when taken orally.
The pump is a round metal device about the size of a hockey puck that is surgically implanted beneath the skin of your abdomen. A small plastic tube, called a catheter, is surgically placed in the intrathecal space of the spine and is connected to the pump. A space inside the pump called the reservoir holds the medication. The pump is programmed to slowly release medication over a period of time. It can also be programmed to release different amounts of medication at different times of the day, depending on your changing needs. The pump stores the information about your prescription in its memory, and your doctor can easily review this information with the programmer. When the reservoir is empty, the doctor or nurse refills the pump by inserting a needle through your skin and into the fill port on top of the reservoir.
This therapy is completely reversible if you should ever decide to have the pump removed.