Spinal Drug Pump (Intrathecal Drug Pump)

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A spinal drug pump may help provide chronic pain patients round-the-clock pain relief.  Intrathecal drug pump and infusion pump are other names for these devices.  Spinal pumps are implanted inside the body. These programmable devices deliver measured and safe drug doses of pain medicine.

Unlike oral pain medication, an intrathecal drug pump bypasses the gastrointestinal system and delivers medication directly into the cerebrospinal fluid (CSF). The brain and spinal cord float in CSF.  

Potential advantages:
 

• Less pain medication is needed
• More sustainable pain relief, better control
• Side effects reduced (e.g., constipation, nausea)
• May increase quality of life

Successful use of an intrathecal drug pump depends on (1) careful patient selection and (2) a successful trial.  Not all pain patients are candidates for this therapy.  Careful patient selection may include a psychological evaluation.  Physicians consider the following:
 

• Non-operative treatments do not relieve pain
• Surgery is not an option
• Surgery is not expected to reduce pain
• Spine surgery has failed (failed back syndrome)
• Patient does not have substance abuse issues

About Intrathecal Pumps

The intrathecal pump is a system consisting of an implantable pump unit and one or more catheters. The pump is about the size of a deck of cards and contains a reservoir to hold medication. The pump is implanted beneath the skin usually in the abdomen. The catheter(s) are implanted beneath the skin and implanted in the intrathecal space of the spine at one end and plugged into the pump unit at the other. The pump delivers small amounts of medication through the catheter into the intrathecal space.

Trial Period

During the trial period, the patient's response to therapy is carefully evaluated. 
 

• Intraspinal morphine injection evaluates the patient's response
• Epidural injection
• Continuous drug infusion via a catheter system

Pain reduction in response to spinal drug therapy varies among patients, even patient who have the same diagnosis

Most physicians consider a trial successful if it can reduce pain by 50% or more.  Furthermore, the trial evaluates possible side effects.  If the trial is successful, the physician discusses permanent surgical implantation of the pump system.

Possible Risks and Complications

Implantation of a spinal pump, like other surgical and medical procedures, has risks.  Potential complications include infection, bleeding, headache, allergic reaction, spinal fluid leakage, paralysis, and device malfunction. The physician discusses the risks and benefits with the individual patient before the trial.

Intrathecal Pump Implantation

General anesthesia is used during surgical implantation of the pump and catheters. Surgery is guided by fluoroscopy. The pump is implanted within the abdomen on the right or left side, depending on the patient’s anatomy, preferences, and the implanting physician’s discretion. The catheter is plugged into the pump at one end and then fixated in the intrathecal space.

The pump's reservior is filled with medication and tested during surgery to test proper function.

Procedure Aftercare

Surgical implantation of the pump system may require a short hospital stay. At discharge, written instructions regarding home care are provided. Patients are encouraged to walk and gradually resume everyday activities. Restrictions include lifting, twisting, bending, and stretching. The physician provides more specific aftercare advice.

The physician follow ups with the patient 24- to 48-hours after the surgery. The patient may be asked to maintain a pain diary to record symptoms and activities. Such records helps the physician refine therapy to provide optimal pain relief.

Refills

The reservoir in the pump contains a limited amount of medication. At scheduled appointment times, often once per month, the patient returns to their doctor to have the medication reservior refilled. The pump's reservior has a self-sealing membrane that faces toward the skin. The physician or nurse injects medication through the membrane to refill the pump.

The refill procedure also allows the physician and his or her staff to:
 

• Check the patient’s condition
• Adjust the dose of medication, as needed
• Determine if other pain management strategies are required
• Discuss and re-evaluate therapeutic goals

Conclusion

The intrathecal drug pump benefits many pain patients. It is permanently implanted in the body and delivers small amounts of pain medications directly into the cerebrospinal fluid.  This therapy helps patients to reduce side effects associated with certain types of oral medication.