What is an "Intrathecal Baclofen trial?"
In persons with severe spasticity, especially affecting
legs and feet, oral medications sometimes fail to provide much relief.
Sometimes they work OK but only at doses that cause drowsiness or marked
fatigue. A few years ago, researchers discovered that when Baclofen (also
called Lioresal) was injected directly into the spinal fluid of persons with
severe spasticity due to spinal cord disorders, the degree of relaxation of
tone was often much greater than is seen with oral medication. It was also
found that noxious side effects (like drowsiness) were rarely experienced when
the medication was given that way. These researchers further discovered that
giving the medication via an small battery-operated pump under the skin
provided lasting benefit in a way that was convenient, quite safe and effective
for long periods of time. But the medication didn’t work for everyone with
spasticity. To find out if Baclofen delivered by a pump right into the spinal
fluid is going to work in someone, a set of test doses are given by direct
injection into the spinal canal during a ‘spinal tap’. An "intrathecal"
(means ‘in the spinal canal’) Baclofen trial involves coming in as an inpatient
to Northeast Rehab Hospital for anywhere from two to five days. An outline of
the experience you should expect follows:
Arrive early in the morning on a Monday or Tuesday. An
admission history and physical is done by the physician who is going to be
doing the injections. Baseline assessments of function and tone are also done
by physical and occupational therapists. An intravenous line is placed (so
that if you need any medicine to counteract the effect of the Baclofen, it can
be given through the intravenous line);
The first injection is given through a spinal needle
inserted in the lower back just long enough for the injection to take place;
The rest of the day is spent on bedrest (with possible exceptions for
toileting). A physical therapist makes periodic checks of your tone/spasticity
through the day while a nurse keeps tabs on how you’re feeling while monitoring
things like blood pressure, pulse and breathing.
If the first injection did not produce enough decrease in
tone, or if the peak effect didn’t last at least 4 hours, then a second
injection is done. Everything is the same as the injection on DAY ONE except
that the dose of Baclofen is slightly higher. If the first injection worked
well enough to meet the criteria used to tell whether someone is a candidate
for the pump, then there is no second injection. You get discharged on the
morning of DAY TWO. There can be a maximum of three injections into the spinal
canal, each on separate days.
Discharge is generally on the morning following the last
injection. "How do you know if it works? What if it doesn’t work?"
When an injection produces the desired result, there is a dramatic relaxation
of tone and/or decrease in spasms which lasts at least 4 hours and sometimes up
to 12-16 hours. Then it wears off and you go back on oral Lioresal if you were
taking it. When an injection "works", it means that giving Baclofen
continuously through a pump should also work just as well. If you get to the
highest injected dose of Baclofen and there still is not adequate effect, it
means that implantation of the pump would not be expected to provide better
results. If it is obvious to both you and us that there was some important
improvement in function or relief of symptoms, you and your doctors can discuss
the pros and cons of a pump. In general, people failing to meet the criteria
which we use for "adequate effect" will not be candidates for the
"Are there any risks associated with these test injections?"
A spinal tap can result in headache, but this is more
common if large amounts of fluid are drained (not the case here) or during
repeated taps at the same location. There is a very remote possibility of
serious infection (simply because something is passing through the skin into
the spinal canal). If enough Baclofen makes its way to the brain, it can cause
low blood pressure, difficulty breathing and sedation or coma. The small
amounts of medication being used during the test are very unlikely to cause any
problem. If any problem were to occur, it would most likely be in the first
hours after an injection. It would also be most likely to have a gradual
onset. There is an injectable antedote which can help if any problem develops.
That’s why you have an intravenous line. Epileptics have had seizures during
administration of intrathecal Baclofen (on the pump). Again, the low doses
used during the test are unlikely to cause a problem, even in epileptics.
"What should be done before I come into Northeast?"
If you are taking Lioresal (by mouth), it needs to be
stopped 12 hours before the first injection. This may be somewhat unpleasant
in that spasms and tone may increase significantly. There is also a
possibility of hallucinations (seeing things that aren’t there) during a `cold
turkey’ off of Lioresal. If the prospect of stopping Lioresal abruptly is
worrisome to you or your regular physician, you can wait until you’re admitted
to the rehab. The only down side to this is that the first injection will have
to occur on the morning after the day you come in. Please have a WRITTEN LIST
OF ALL MEDICATIONS THAT YOU ARE CURRENTLY TAKING when you come in. This
information may not be readily available in referral information or physician
office notes. Bring comfortable clothing and toys that can be used in bed. TV
at the bedside is available.
"But I have a few more questions."
Remember, while there are many dumb answers, there is no
such thing as a stupid question. If there are questions on your mind, move
them to your lips or jot them down so you don’t forget to ask your physician(s). In general, the more informed you are, the more comfortable you
should be about going through the Baclofen trial.