In rare cases, pain can’t be controlled by the medications already described or their side effects are too severe. In these cases, an implanted catheter can deliver the medications using a small, computerized pump to the space directly outside the spinal cord (epidural pump) or to the fluid around the spinal cord itself (intrathecal pump). The pump is carried in a backpack or “fanny pack” (for epidural pumps) or implanted under the skin (for intrathecal pumps). The pumps allow both continuous medication and patient-controlled extra doses for pain flares. The pumps are programed to prevent an overdose.
Source: Susan G. Komen 2019