An implantable infusion system may be indicated for patients who have tolerated an intrathecal trial and whose life expectancy and analgesic needs are greater than 3 months.
Medtronic's intrathecal drug delivery systems are composed of two implantable components: an infusion pump and an intraspinal catheter. The pump is placed abdominally in a subcutaneous pocket, while the catheter is inserted into the intrathecal space of the spine, tunneled under the skin and connected to the pump. Medication can be delivered at constant or variable flow rates. The pumps weigh approximatley 4 ounces and are approximately 3 inches in diameter and one inch thick. The primary differences between the pump models are the size of the reservoir and the presence of a side catheter access port. The most commonly implanted pump model holds a maximum of 18ml of medication. To avoid the need for frequent pump refills the medicine is concentrated so that the required amount of medication can be delivered in:
Common Concentrations for Implanted Drug Delievery Systems (IDDS)
- Local Anesthetics bupivacaine 3% (30mg/ml) or 2% (20mg/ml)
- Fentanyl 1000mcg/ml
- Morphine (available in solution up to 50mg/ml)
- Hydromorphone (available in solution up to 10mg/ml, powder can be diluted up to 60mg/ml)
- Clonidine varies (available in solution to 500mcg/ml)
Preparation of concentrated solutions for internally implanted pumps requires a minimum of 24 hours notice. Please contact Dave Wegner RPh, (608) 265-0327, as soon as possible (preferrably a week in advance) to assure necessary powders are in stock. Concentrated solution need to compounded by UWHC Pharmacy or Chartwell from powder increasing risk for infection. Patients should be consented [consent form to be developed] about the risk of infection when administered compounded medications via the neuraxial route.
CADD-Solis Pocket Guide