Epidural Infusion
The outer layer of the sheath surrounding the spinal cord is called the dura mater. Between this and the surrounding vertebrae is the epidural space, filled with connective tissue, fat and blood vessels, and crossed by the spinal nerve roots. A catheter may be inserted into this space for three to six months, to deliver anesthetics or analgesics. The line carrying the drug may be threaded under the skin to emerge at the front of the patient, a process called tunneling. This is recommended with long term use so as to reduce the chance of any infection at the exit site reaching the epidural space.
Read more about this topic: Interventional Pain Medicine