neuromodulation used as a treatment for chronic pain. It is used to deliver medications
directly to the spinal cord. When all other therapies fail, then intrathecal infusion
therapies are considered.
SPECIAL NOTE REGARDING CANCER PAIN
In the treatment of cancer pain, intrathecal pump therapy is sometimes the only possible
way to provide pain relief without making the patient so looped on narcotics that they are
a vegetable. Intrathecal therapies permit cancer patients to be more lucid and spend
more quality time with their family at the end of life, and have been demonstrated to
prolong life by up to several months. Also medication costs for intrathecal pumps are
covered by Medicare and other insurance and are only a small fraction of the cost of oral
narcotic costs. At the end of life, the cost of oral narcotic medications may exceed
$3,000 per month and may not be covered by insurance.
The implanted system consists of a refillable pump and a catheter leading to the spine,
all implanted under the skin. Usually refills are performed in the office by placing a
needle through the skin directly into the port of the pump approximately every 2-6
months depending on which pump is used, the dosage of medicine required, and the
available concentrations of the drug.
How It Works: Intrathecal infusion pumps are implanted delivery devices which deliver
one of several drugs to the spine. There are several pain control receptors on the spinal
cord and these medications work directly on these receptors to block pain. Because one
drug tends to work on only one type of receptor, multiple drugs may be used in the pump
when necessary to act on more than one receptor simultaneously. The most commonly
used drugs are morphine and hydromorphone which act on the narcotic receptors in the
spine to block pain. Other drugs used are local anesthetics which attaches to a different
receptor, Baclofen which attaches to another, and clonidine which attaches to yet
another receptor. Most of these drugs have a much higher concentration in the spine
than in the brain leading to less side effects compared with oral or transdermal drugs.
Candidates for intrathecal infusion pumps require all the following to be true:
1. Chronic intractable pain which has failed conservative therapies
2. A failed trial of high dose oral narcotics which resulted in severe side effects or ineffective pain relief
3. Stable psychological profile as determined by psychometric testing with a psychologist (except cancer
patients)
4. Physical therapy assessment which demonstrates no further improvement will occur without better pain
control
5. An intrathecal functional trial with a 3-7 day period of continuous infusion of medications into the spine. The
pain relief from this trial should be better than 60% and the functional improvement should be marked. Also
there should be no significant side effects
6. Insurance approval. Primary Medicaid will not pay for intrathecal infusion pumps.
INTRATHECAL TRIAL:
A small catheter is placed into the spinal fluid by inserting the catheter through a needle placed
into the skin. The needle is removed once the catheter tip placement is confirmed to be in the
proper location. A continuous infusion of medication is delivered at home (most patients) or in
the hospital (Medicare) for several days and the patient is encouraged to walk and engage in
most normal activities to assess the degree of relief produced by the intrathecal drugs. During
the trial, the external pump device attached may be adjusted upwards or downwards by the
doctors or nurses at Advanced Pain Management. If there are no significant side effects and pain
relief is sufficient, the trial catheter is pulled out in the office (takes about 2 seconds) and the
patient is scheduled for an implantation of a programmable or non-programmable permanent
pump and catheter under the skin (see below description).
Depending on the insurance, the trial used may be inpatient or outpatient. The implant of
the actual pump system is always an outpatient basis unless there are severe medical
problems.
Types of Pumps:
Programmable: More expensive, used for patients where frequent dosage adjustments
are anticipated (eg. cancer pain) or in those who have much higher dose requirements
during a specific period of time during 24 hours (eg. significantly more pain during the
day when up and moving) These pumps contain a computer chip and batteries. They
are programmed using an external hand held physician operated programmer. Refills are
at up to 6 month intervals.
Nonprogrammable: Less expensive, have no batteries, last forever. Refills are usually
every 3 months. The medication dosage is changed only during refills.
The Implant Procedure: Under general anesthesia, an incision is made over the spinal
insertion site and the anterior abdomen. The spinal incision is carried down to the
spinal ligaments and a needle is inserted into the spinal fluid. A catheter (one or two
piece) is inserted into the intrathecal space containing spinal fluid. Under the abdominal
incision, a pocket is created to hold the pump and the catheter from the spinal incision is
"tunneled" under the skin to the abdominal incision. The pump is inserted into the
abdominal incision and is connected to the spinal catheter which was anchored to the
spinous ligaments. Both incisions are closed with subcutaneous suture followed by skin
closure with either nylon suture or with skin staples. Usually these sutures or staples
are removed within 10 days.
Risks/Benefits Risks are failure to relieve pain, complications such as bleeding,
infection, nerve or spinal cord injury, need for further surgery including spine surgery if
granuloma on the cord forms (rare) and anesthetic risks. The benefits are a vast
reduction of oral medications, side effects, and avoiding feeling loopy or sedated due to
the cerebral spread of these potent medications.
Alternatives: Do nothing, medications, other interventtional pain procedures,
chiropractice, PT, medication management
After the Implant: Home same day, no lifting, no twisting until staples or skin stitches are
taken out. No immersion bathing (shower or in bathtub) until the stitches are removed
(which will occur in 7-10 days), Pump will have medicine infusing, but the patient will
require continued short acting narcotic pain medications during the healing period from
the pump implant (approximately 3-5 days). There should be no long acting oral or
transdermal medications taken after the pump implant.
Antibiotics may be given for approximately 1 week.
For bleeding, if soaking through bandages, page your physician who performed the
implant or designated substitute. For severe nausea, vomiting, diarrhea, severe low
back pain, fever or chills, loss of bowel or bladder control, or new onset lower extremity
weakness or numbness, call your physician immediately.
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