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Intrathecal Baclofen _ITB_ in the management of spasticity of

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					Intrathecal Baclofen (ITB) in the ma nagement of spasticity of cere bra l
origin in childre n

This is an update article written by Michael Vloeberghs, MD, PhD (Senior Lecturer,
Consultant Paediatric Neurosurgeon - University of Nottingham) for the Bobath
Society to be published soon.

The purpose of this article is to describe the use of ITB in cerebral palsy, the
difficulties encountered in the setting up of the service in Nottingham and the results
of ITB (so far). Baclofen is an old drug (developed in the 20’s as anticonvulsant) and
intrathecal drug delivery is also an old technique, which came of age in the late
seventies. Baclofen is a Gamma amino butyric acid (GABA) agonist and enhances the
inhibitory effect of GABA in the spinal cord. At least this is what we are made to
believe. The indications for ITB have broadened over the years. Spinal cord injury is
still the most common and also most successful indication, next comes Multiple
sclerosis, next spasticity of cerebral origin e.g. stroke, head injury et c. From this list
of indications it becomes clear that childhood conditions don’ t really feature.
Conditions as Cerebral Palsy (CP), Dystonia, Paediatric head injury don’t appear in
the list. This exactly the problem I faced in Nottingham. When the first children were
put forward for ITB, the health authorities refused to fund the procedure claiming
that the procedure was experimental, despite the evidence for USA and Europe that
there had been good results in children with CP. I must admit that running through
the “state of the art” medical literature, you find that the data is poorly collected.
Series of patients are rarely homogenous combining all age groups and all
conditions. This is a common problem in medical literature, where evidence is based
on personal experience and anecdote. Unfortunately this doesn’t convince health
authorities. This led to the creation of the Scharr report. The Scharr group reports on
the use and efficiency of medical procedure or drugs and puts guidelines to
purchasers e.g. health authorities, by means of meta-analysis of the literature. As
part of the group advising on CP we came to the following conclusion: within CP
there are two defined groups. One group is the spastic tetraparetics or tetraplegic
children. The other group are the diplegic children e.g. the group where gait
disturbance is the most pressing problem. The conclusion of the meta -analysis is that
ITB has a massive impact on the ease of care and nursing of a severely disabled
spastic tetraplegic or tetraparetic c hild but that the effect in diplegic children e.g.
whether ITB improves gait, is unproven. The Scharr group then issued the following
guidelines:

ITB should be reserved for spastic tetraplegic or tetraparetic children with increasing
nursing demands due to their spasticity. The Ashwort scale needs to be >4

All data should be collected in a clinical outcome study or clinical trial.

Diplegics can be considered for IT B but this must be done within the framework of a
randomized controlled trial.

In Nottingham only children with tetraparesis or tetraplegia are treated. This is a
voluntary choice because of the dire need of these children and the limited funding
available for ITB. This restriction has the bonus that the series is homogenous, age
ranging from 2 years to 16 years and all children present in more or less the same
condition.
The procedure:

ITB implies that the suitability for treatment is tested before a pump is implanted.
The testing in Nottingham is done by
1) An examination under general anaesthetic. During this brief anaesthetic, which
includes paralysis, all joint are examined including the spine. This led to the
observation that the older the CP child is the more contractures are found. This
seems common sense but has major implications for IT B and also the expectations of
the parents. Contractures per se will not be affected by ITB. Mobility will improve
with ITB. Relieving contractures can be done by intensive physio, Botox or
orthopaedic surgery.

2) Under the same general anaesthetic a lumbar catheter is inserted into the
intrathecal space and the child is returned to the ward after recovery.

3) When the child is on the ward and comfortable, a bolus injection of baclofen is
given. Usually 30 to 50 micrograms.

4) The child is then regularly assessed by the parents, the physiotherapist and me.

The peak effect of baclofen is at four hours after injection. The effect then wears off,
to disappear by eight hours after injection. It is important for one of the usual cares
to remain with the child for the entire testing period. This is the only way the effect
of Baclofen can be evaluated. Although a physiotherapist and me review the child,
our opinion is of no importance. It is the carer who decides whether the effect is
beneficial and whether further IT B will be worthwhile. The results of the anaesthetic
test are important at this stage. The carers are made aware of the contractures and
of then fact that baclofen will have little effect on these. This leads to a contract if
and when we all agree on c ontinuing with IT B e.g. pump implant. It is crucial that
carers are aware of the limitations and possibilities of ITB. Parents of a CP child have
often been through so much. Realistic options are discussed and no false hope is
given.

The next stage is pump implant, where, under general anaesthetic a programmable
pump is implanted. This pump delivers Baclofen to the intrathecal space by means of
a catheter in the spine. CP children are often very catabolic and barely have
subcutaneous fat for which reason I choose to implant the pump under the fascia of
the abdominal muscles. A perk of this technique is that the pump, which is quite
sizeable, blends better into the body image. The pump is started at the last stage of
the operation, in theatre and regular refills are scheduled. The interval for refills
varies between 4 weeks to three months depending on the delivered dose and the
concentration of Baclofen.

Overvie w of the activity at Queens Medical Centre, University of Nottingham
since January 1999:

This review is based on the clinical outcome study in which all children treated in
Nottingham are enrolled in order to comply with the Scharr criteria. All children are
have are tetraplegic or tetraparetic with an Ashworth score >4. All children have
increasing care and nursing demands because of their spasticity. Some children have
become so rigid that seating in a regular wheelchair is impossible.
All children are wheelchair bound.

The group consists of 35 patients, 24 Male and 11 Female.
The dose of Intrathecal baclofen varies between 150 to 500 Micrograms / 24 hours.
Cognition is normal, e.g. normally performing children, in mainstream school, in 13
children of the 35.

Age distribution:
1-4: 1
5-8: 8
9-12: 9
13-16: 15
17-20: 2 *

There is no age restriction for implanting a ITB pump. Pump implant is purely
restricted by the physical size of the child and the expertise of the implanting
clinician. There is however a license limitation for the use of Baclofen. Industrial
Baclofen comes with a disclaimer, which states that the effect and the side effects of
Baclofen in children under four is not proven or researched. Permission for the
“under age” implant was obtained through the Committee for Ethics in Clinical
Practice. The committee’s recommendation was that use of ITB in a child under four
years of age is the decision of the clinician bearing in mind the best interest of the
child. Separate consent for ITB, above the informed consent for operation w ith
appropriate time for ref lection must be obtained from the carers.

*Both children had been assessed for IT B before the age of sixteen. One child
incurred an inordinate delay in obtaining funding in the beginning of the Nottingham
program. It would have been unethical, not to say cruel, not to offer implant to this
child/person. This potentially difficult situation led to a change of practice. To avoid
delay in funding of the implant I now only assess children who are referred by a
specialist colleague, where the child meets the Scharr criteria and the health
authority has agreed to fund both the test and the implant. This avoids raising hope
for a swift conclusion in often very desperate parents who need ITB. Fortunately
these delays have become shorter.

Orthopaedic deformity:

This section addresses the contractures, which are of great concern in spastic
children. The effect of Baclofen on deformity is variable and does not follow a
predictable pattern. The next table gives a non-quantified subjective overview of
“Orthopaedic deformity” in the form of severe, moderate and no deformity. More
accurate date are recorded during the anaesthetic test. (e.g. angles of fixed flexion,
presence of lordosis etc).

Pre-op deformity:
Severe: 31
Moderate: 3
None: 1

Post-op deformity:
No deformity: 1*
Unchanged: 4
Improved: 30

*This is the two year old mentioned in the previous section.
The overall observation is that the more severe orthopaedic deformity is seen in the
older the child. Recovery of deformity is only possible in the relatively young child.
Although there is no statistical proof of this, experience and observation leads me to
believe that early ITB treatment, possibly in the under five, before the first growth
spurt should be considered

Bonus effect:

This is a miscellaneous category containing anecdotal observations. The bo nus
effects may seem minor to us but may make great difference to the quality of life
and the ease of care of the child.

-3 children became mobile: After being wheelchair bound, these children had in part
overcome the deformity related to their spasticity and regained enough strength and
coordination to use a frame and one even crutches. Although their gait is far from
normal and not sustainable, it is a major moral boost.

-6 children started to weight bear: Weight bearing in these children had become
impossible because of the contractures and the flexion deformity of hips and knees.
After several months of ITB, their deformity had decreased and muscle tone
improved so much that they were able to support themselves. This is a major help in
transfers especially in the larger adolescent. This also leads to a change in
physiotherapy. Where before the Baclofen infusion, physiotherapy concentrated on
keeping function and range of movement, muscle bulk needs to be generated after
the infusion. The spastic muscle has been in disuse and needs to be rebuilt.

-5 children regained use of their upper limbs: This bonus effect has a huge impact on
quality of life. These children were now able to play, use a computer and execute
simple activities of daily living. Others felt a big improvement in fine motor control
allow ing them to colour between the lines and have legible handw riting.

Other bonus effects are hard to categorize. Impaired bulbar function can improve,
leading to better swallowing, less drooling and better speech. One child reduced a
longstanding squint when on ITB.
There is a legend in the ITB literature that the position of the spinal catheter dictates
where the main effect of Baclofen will be e.g. a high position leads to more effect on
the upper limbs and a low position has more effect on the lower limbs. This is not my
experience; to the point that I believe the catheter position is not important.
Whatever the position, baclofen diffuses through the entire nervous system
accounting for the bulbar effects.

Adverse events:

As with any type of surgery there are adverse events related to the implant. So far
no child has come to serious harm, there has never been a death or an overdose of
Baclofen. The main adverse event remains catheter migration, which despite
adequate method continues to occur.
-5 cases of catheter migration, all catheters were replaced on request from the child
or the parents.
-1 secondary infection in a child where an aggressive strap was used in school,
directly over the pump site. This strap eroded through the skin and caused a
secondary pump infection. The pump was removed and a new system was implanted
on request of the child and the parents.
-1 event of Baclofen side effects e.g. headache and weight loss despite having only a
moderate daily dose (approx 200 micrograms/24h in a ten year old) Decrease of the
dose eliminated the side effects.

Conclusion:

ITB has a definite proven effect on spasticity of cerebral origin. The difficulty lies in
patient selection and the limited funding. At the present we are treating spastic
tetraparetic and tetraplegic children and the main aim is to improve activities of daily
living and nursing care. This relatively homogenous series of children with Ashworth
>4 and spasticity affecting all four limbs, shows more can be accomplished w ith ITB
than initially expected effect. These “bonus effects” are discussed with the carers but
are variable in outcome and unpredictable. This returns us to the issue of contract
where the carers and the clinicians agree on the pit falls and benefits of Baclofen in
the specific child. Measuring outcome of ITB proves to be another difficulty. The
Ashworth scale is a helpful guide before implant but loses its interest once ITB is
started, mainly because the clinician has control of the Ashworth by using the
programming wand of the pump to increase or reduce the daily dose of Baclofen.
Other outcome scales such as WEE-FIM, CHQ and COPM have only limited value. To
the multidisciplinary team in Nottingham the most effective outcome measure is the
satisfaction of the carers and the child. This may lie in very small things and effects
of ITB which to us seem negligible but are seen to be a major improvement by the
carers. Further work is in progress, a randomized controlled trial is in the ma king for
ITB hoping to offer better patient selection and more standardized outcome
measures. ITB now has its place in the treatment of severe spasticity of cerebral
origin in children but is not the answer to the whole. ITB has to be seen as an
adjuvant to Botox, Multilevel surgery and Physiotherapy, a concert of these different
treatment options has to be considered .

				
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posted:9/30/2011
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