intrathecal pump

Overview

A “pain pump” is a method of giving medication directly to your spinal cord. The system uses a small pump that is surgically placed under the skin of your abdomen. The pump delivers medication through a catheter to the area around your spinal cord. Because the drug is delivered directly to the pain area, your symptoms can be controlled with a much smaller dose than is needed with oral medication. Thus reducing the side effects of medication.

What is an intrathecal drug pump?

The fluid filled space around your spinal cord is called the subarachnoid or intrathecal space. Cerebrospinal fluid (CSF) flows through this area, bathing and protecting your brain and spinal cord. An intrathecal drug pump works more efficiently than oral medication because it delivers medicine directly into the CSF, bypassing the path that oral medication takes through your body. In fact, you generally need about 1/300 the amount of medication (morphine or baclofen) with a pump than when taken orally.

The pump is a round metal device about the size of a hockey puck that is surgically implanted beneath the skin of your abdomen. A small plastic tube, called a catheter, is surgically placed in the intrathecal space of the spine and is connected to the pump (Fig. 1). A space inside the pump called the reservoir holds the medication.

Figure 1. The intrathecal pump system consists of a pump/reservoir implanted between the muscle and skin of your abdomen and a catheter that carries pain medication (blue area) from the pump to the spinal cord and nerves.

The pump is programmed to slowly release medication over a period of time. It can also be programmed to release different amounts of medication at different times of the day, depending on your changing needs. The pump stores the information about your prescription in its memory, and your doctor can easily review this information with the programmer. When the reservoir is empty, the doctor or nurse refills the pump by inserting a needle through your skin and into the fill port on top of the reservoir.

This therapy is completely reversible if you should ever decide to have the pump removed.

Who is a candidate?

You may be a candidate for intrathecal drug delivery if you meet the following criteria:

• Conservative therapies have failed
• You would not benefit from additional surgery
• You are dependent on pain medication
• You do not have psychological problems
• You have no medical conditions that would keep you from undergoing implantation
• You are not allergic to any of the drugs used in the pump
• You have had positive response with a trial dose of medication

A pump can help lessen chronic pain caused by:

• Failed back surgery syndrome: failure of one or more surgeries to control persistent leg pain (sciatica), but not technical failure of the original procedure.
• Cancer pain: constant pain caused by tumors compressing the spinal nerves, or scarring from previous radiation therapy.
• Reflex sympathetic dystrophy: a progressive disease of the nervous system in which patients feel constant chronic burning pain.
• Causalgia: a burning pain caused by peripheral nerve injury.
• Arachnoiditis: painful inflammation and scarring of the meninges (protective layers) of the spinal nerves.
• Chronic pancreatitis: chronic abdominal pain caused by inflammation or blockage of the pancreatic duct.

A pump can help lessen spasticity (muscle rigidity and spasms that make movement of the arms and legs difficult) caused by:

• Cerebral palsy: a nervous disorder that impairs control of body movement.
• Multiple sclerosis: a disorder of the brain and spinal cord caused by damage to the outer layer (myelin) of nerve cells.
• Stroke: damage to the brain from lack of oxygen; due to an interruption of the blood supply.
• Brain injury
• Spinal cord injury

Who performs the procedure?

Neurosurgeons who specialize in pain management and spine disorders implant drug pumps.

The surgical decision

Determining whether an implantable drug pump will be a good pain management option for you is a complex process. Before a permanent pump can be implanted, you must undergo a trial to see if the device decreases your level of pain or spasticity. Depending on your particular condition, one of the following screening tests will be necessary:

1. Single injection: you will receive one injection of intrathecal medicine (morphine or baclofen) through a lumbar puncture.
2. Multiple injections: you are given multiple injections over a series of days by either a lumbar puncture or catheter.
3. Continuous trial: a catheter is placed in the correct area of your spine and connected to an external pump. The dose is increased every 2 hours until you notice pain relief.

During the trial, the doctor gathers information about the best location for the catheter and the type and amount of drug that works best for you. If the trial is successful, you will be scheduled for surgery.

What happens before surgery?

You may be scheduled for presurgical tests (e.g., blood test, electrocardiogram, chest X-ray) several days before surgery. In the doctors office you will fill out paperwork and sign consent forms. Patients are admitted to the hospital the morning of the procedure. No food or drink is permitted past midnight the night before surgery. An intravenous (IV) line is started in your arm. An anesthesiologist will explain the effects of anesthesia and its risks.

What happens during surgery?

There are two parts to the procedure: 1) placement of the catheter in the intrathecal space surrounding the spinal cord, and 2) placement of the pump/reservoir in the abdomen. There are five main steps of the procedure. The operation generally takes 3 to 4 hours.

Step 1: prepare the patient
You are placed on the operative table and given anesthesia. Once asleep, your body is rolled onto its side. Next, the areas of your back and stomach are shaved and prepped where the catheter and the pump are to be placed.

Step 2: placement of the catheter
A small skin incision is made in the middle of your back. The bony arch (lamina) of the vertebra is exposed. The catheter is placed in the subarachnoid, or intrathecal space, above the spinal cord and secured in place with sutures (Fig. 2).

Figure 2. The catheter is inserted into the intrathecal (subarachnoid) space in the low back area. The catheter is then positioned in the best location to bathe the spinal cord with medication (blue) and block the transmission of pain signals to the brain.

Step 3: tunneling of the extension
Once the catheter is in place, an extension catheter is passed under the skin from the spine, around your torso to the abdomen where the pump will be implanted.

Step 4: placement of the pump
A 4-6 inch skin incision is made in the side of your abdomen below the waistline. The surgeon creates a pocket for the pump between the skin and muscle layers. The extension catheter is attached to the pump. Next, the pump is correctly positioned under the skin and sutured to the thick fascia layer overlying the stomach muscles.

Step 5: close the incisions
The incision in your back and abdomen are closed with sutures or staples and a dressing is applied.

What happens after surgery?

You will wake up in the postoperative recovery area, called the PACU. Your blood pressure, heart rate, and respiration will be monitored, and your pain will be addressed. Most patients are discharged home the same day. You will be given written instructions to follow when you go home.

Discharge instructions

Discomfort

• • Take pain medication as directed by your surgeon. Narcotics can be addictive and are used for a limited period of time.
  • Narcotics can also cause constipation. Drink lots of water and eat high-fiber foods. Laxatives and stool softeners such as Dulcolax, Senokot, Colace, and Milk of Magnesia are available without a prescription.
  • Ice your incision 3-4 times per day for 15-20 minutes to reduce pain and swelling. 
  • Spinal headaches may be caused by leakage of cerebrospinal fluid around the catheter site. The leak often heals on it’s own. Lie flat and drink plenty of caffeinated non-carbonated fluids (tea, coffee).

    Restrictions

  • Do not bend, lift, twist your back or reach overhead for the next 6 weeks. This is to prevent the catheter from moving out of place until it heals.
  • Do not lift anything heavier than 5 pounds for 2 weeks after surgery.
  • No strenuous activity for the next 2 weeks including yard work, housework and sex.
  • Avoid straining when having a bowel movement.
  • Do not drive until your follow-up appointment. You may ride in a car for short distances of 45 minutes or less if necessary.
  • Do not drink alcohol for 2 weeks after surgery or while you are taking narcotic medication.

    Activity

  • Avoid sitting for long periods of time.
  • Get up and walk 5-10 minutes every 3-4 hours. Gradually increase your walking time, as you are able.

    Bathing/Incision Care

  • Wash your hands thoroughly before and after cleaning your incision to prevent infection.
  • You may shower the day after surgery.
  • Gently wash the incision covered in Dermabond (skin glue) with soap and water. Pat dry. Inspect and wash the incision daily.
  • Do not submerge or soak the incision in water (bath, pool or tub).
  • Do not apply any lotions or ointments over the incision.
  • Some drainage from the incision is normal. A large amount of drainage, foul smelling drainage, or drainage that is yellow or green should be reported to your surgeon’s office immediately.
  • Fluid may accumulate under the skin around the leads or the device, creating a visible swelling (seroma). Call the doctor if this occurs.

Brace

• You may have been given an elastic abdominal binder to support the pump while the incision heals. Wear it at all times except when bathing.

When to Call Your Doctor

• Fever over 101.5° F (unrelieved by Tylenol)
• Unrelieved nausea or pain
• Incision complications
• Sudden severe back pain, sudden onset of leg weakness and spasm, loss of bladder and/or bowel function – this is an emergency – go to a hospital and call your surgeon.
• If your headache persists after 48 hours.

What are the results?

Results will vary depending on the underlying condition being treated and its severity. Chronic pain patients may experience a reduction in pain, as well as overall improvement in activities of daily living [1]. Spasticity patients may experience a reduction in rigidity and muscle spasms [2]. Oral medications are reduced because the medicine is delivered directly to the spinal cord and much smaller dosages are needed.

What are the risks?

Side effects for intrathecal drug pumps are minimal, although they do exist. As with all surgeries, complications may include infection and bleeding. The catheter could move or become blocked, or the pump could stop working (rare). Accumulation of fluid (cerebrospinal fluid leak) can occur around the pump causing a clear watery discharge from your incisions or a headache. These usually disappear on their own, but may require a drain. Reasons for removal of the device include infection, failure to relieve pain, and patient misuse.

Side effects from the drugs (over- or underdose) may include respiratory depression, twitching, muscle spasm, urinary retention, constipation, nausea, vomiting, dizziness, anxiety, depression, and edema.

Depending on how much medication the pump delivers, the battery will eventually need to be replaced every 5 to 7 years.

Living with an intrathecal pump

You must schedule medication refills on a regular basis with the surgeon or a pain management specialist. At your refill appointment, the effectiveness of your treatment will be assessed and your pump will be adjusted accordingly. The goal is to find the optimal amount of pain or spasticity control while having minimal side effects. You should tell your doctor if you experience unusual symptoms, drug overdose, or feel that your dosage is ineffective. You may need to take supplemental oral medicine if you have periods of stronger pain.

Just like a cardiac pacemaker, other devices such as cellular phones, pagers, microwaves, security doors, and anti theft sensors will not affect your pump. Be sure to carry your Implanted Device Identification card when flying, since the device is detected at airport security gates.

If you hear the pump making beeping sounds, call the doctor’s office immediately. This may indicate that the pump needs refilled, battery needs replaced, or other maintenance.

Withdrawal symptoms from the medication you are receiving may cause you some discomfort or in extreme cases may require emergency treatment. Inform family members and friends about what to do in an emergency; always carry your Emergency Information and Procedure cards with you at all times.

Sources & links

If you have more questions, please contact Bay State Pain Associates at (508)4362555 

Sources

1. Winkelmuller M, Winkelmuller W. Long-term effects of continuous intrathecal opioid treatment in chronic pain of nonmalignant etiology. J Neurosurg 85:458-467, 1996.
2. Coffey RJ, Cahill D, Steers W. Intrathecal baclofen for intractable spasticity of spinal origin: results of a long-term multicenter study. J Neurosurg 78:226-232, 1993.

Links

Spine-health.com
theacpa.org

Glossary

baclofen: a muscle relaxing drug used to treat spasticity; Lioresal.

intrathecal space: the space surrounding the spinal cord through which cerebral spinal fluid (CSF) flows; also called the subarachnoid space.

morphine: a potent drug used to treat severe and persistent pain.

seroma: a mass formed by the collection of tissue fluids following a wound or surgery.

spasticity: severe muscle rigidity and spasms caused by damage to motor pathways; makes movement of the arms and legs difficult.

spinal hygroma: an accumulation of cerebrospinal fluid under the skin, which produces a visible swelling, caused by leakage around a catheter, drain, or shunt.