Intrathecal Pain Pump

Overview

An intrathecal pain pump is a small, programmable device implanted under the skin, usually in the abdomen, that delivers medication directly into the intrathecal space, the fluid-filled space surrounding the spinal cord. A thin catheter carries the medication from the pump to the spinal fluid, where it acts directly on pain or spasticity pathways. Because the medication bypasses the digestive system and bloodstream, doses given intrathecally can be a small fraction, often around 1/100th to 1/300th, of an equivalent oral dose.

The three medications approved by the FDA for intrathecal use are morphine, ziconotide, and baclofen. Morphine and ziconotide are used for chronic pain, including neuropathic and cancer-related pain, while baclofen is used to treat severe spasticity from conditions such as spinal cord injury, multiple sclerosis, or cerebral palsy. Because delivering the drug this precisely lowers the systemic dose needed, patients can sometimes achieve better symptom control with fewer whole-body side effects than they experienced on oral medication.

When it's recommended

Intrathecal drug delivery is generally considered for chronic pain or spasticity that has not responded adequately to conservative treatment, oral medications, injections, or, for pain, other interventions such as spinal cord stimulation. It is commonly used for failed back surgery syndrome, other forms of persistent post-surgical or mechanical spine pain, cancer-related pain, and spasticity from neurological conditions. It may also be considered when oral opioid doses needed for relief are causing intolerable side effects, since intrathecal dosing can achieve similar or better relief at a much lower systemic exposure.

This therapy is typically reserved for cases where less invasive options have been tried and have not provided lasting relief, and it always follows a trial period to confirm the medication is likely to help before a permanent pump is implanted.

How it works

The system has two main parts: the pump, a round, battery-powered device roughly the size of a hockey puck, and a catheter that runs from the pump under the skin to the intrathecal space, usually placed at a lumbar level. The pump is programmed to release medication on a steady schedule, and some models include a handheld patient-controlled device that allows limited extra doses within safety limits set by the physician.

Before permanent implantation, a trial is performed, either with a temporary catheter or a single intrathecal injection, to confirm the medication provides meaningful relief with tolerable side effects, generally defined as at least 50 percent improvement. If the trial succeeds, the permanent pump and catheter are implanted in a separate, minimally invasive surgery, typically under sedation or general anesthesia, with the pump pocket created under the skin of the abdomen and the catheter tunneled to the spine.

Preparing for the procedure

Before the trial and again before permanent implantation, your team will review your medications, medical history, and imaging, and may ask you to stop blood thinners or certain other medications in advance. You may also complete a psychological evaluation, which is standard before many implanted pain devices, to help ensure realistic expectations and to screen for factors that could affect outcomes. Arrange for a ride home and for help with daily activities for the first several days, since bending, twisting, and heavy lifting are typically restricted after the implant surgery.

Recovery and aftercare

After the trial, you and your care team review how well your pain or spasticity responded and decide together whether to proceed with permanent implantation. After the permanent pump is placed, most patients go home the same day or after a short hospital stay, with initial restrictions on lifting more than about 10 pounds, bending, and twisting while the pocket and catheter site heal over several weeks. You will receive training on the device, including what refill schedule to expect and, if applicable, how to use a patient-controlled dosing device within your prescribed limits.

Ongoing care includes refills at your pain clinic, typically every one to six months depending on the drug and dose, along with periodic reprogramming as your needs change. The pump's battery generally lasts about 4 to 7 years, after which a scheduled outpatient surgery replaces the device; the catheter usually does not need to be replaced at that time unless there is a separate problem with it.

Risks and considerations

Reported complications include infection at the pump pocket or along the catheter, catheter kinking, blockage, or migration, and, less commonly, a mass called a granuloma that can form at the catheter tip and reduce or block drug delivery. Trial-related risks include bleeding, spinal headache, and temporary nerve irritation. Device-related risks include mechanical malfunction and the general risks of any implant, such as the pocket eroding through the skin over time. Medication side effects vary by drug and can include fatigue, constipation, urinary retention, and sexual dysfunction, though many patients tolerate intrathecal dosing better than the equivalent oral dose.

Two situations deserve particular attention. An abrupt interruption in baclofen delivery, from a pump malfunction, empty reservoir, or catheter problem, can cause a withdrawal syndrome with rebound spasticity, itching, fever, confusion, or seizures, and is a medical emergency. An overdose, from a programming error or pump malfunction, can cause confusion, slowed or shallow breathing, and excessive drowsiness, and also requires immediate care.

Contact your care team or seek emergency care right away for fever or drainage at the incision, a severe headache that worsens when upright, new weakness, numbness, or loss of bladder or bowel control, any pump alarm, or symptoms suggesting withdrawal or overdose. These findings should never wait for a scheduled follow-up appointment.