Copyright © 2008 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Vernon T. Tolo, MD*,
Children's Hospital Los Angeles, Los Angeles, California
Posted January 2008
This prospective study provides Level-I evidence that Botox
(botulinum toxin A) injections into the adductor longus and medial hamstrings
of young children with spastic cerebral palsy, used in combination with
part-time use of a hip abduction orthosis, is not effective in
preventing hip subluxation in this patient population. This study is reflective
of a very welcome change in orthopaedic clinical research, with an increasing
number of prospective clinical research studies being reported.
Botox intramuscular injections have been widely used in
children with spastic cerebral palsy for well over a decade to temporarily
decrease spasticity. It is anticipated that this decrease in spasticity of
overactive muscles will allow for potential improvement in function, in part by
allowing these and other less spastic muscles to be used more efficiently. The
most common lower extremity muscles into which Botox is injected are the hip
adductors, the medial and/or lateral hamstrings, and the gastrocnemius-soleus. The
Botox injection usually will have a pharmacological effect on the treated
muscle for anywhere from three to six months, so injections are commonly
repeated every four to six months if the initial injection has been useful and
if spasticity has returned to its pre-injection baseline level.
Most parents will want to try any effective nonoperative
treatment that may prevent the need for surgery in their child with spastic
cerebral palsy. But treatment with Botox can be expensive. In terms of cost in United
States dollars in California, the cost to the institution for the Botox
injections in the dosage used in this study each six months is approximately
$1000 and the charge to the patient is about $2500. What the cost is in
Australia, where this study was carried out, was not noted. In addition, the
cost of the hip abduction orthosis is substantial. With the data from this
study, it would seem inappropriate to offer parents this combined treatment of periodic Botox injections and
part-time abduction bracing just to avoid or delay surgical treatment.
The children in this study only wore the hip abduction
orthosis during the day for an average of just under six hours, with parents
reporting the total amount of time that the child wore the brace. It is
important to remember, however, that parental reports may contain
overestimations of the actual time of brace wear, as parents want to be thought
of as participating fully in the care of their child. The hip abduction
orthosis only abducted the hips 15° to 30°, possibly because it is difficult to
abduct the hips widely if the child is in a wheelchair during the day. The
question arises whether use of a hip abduction orthosis at nighttime in wider abduction
would have provided more of a treatment effect than the small nonsignificant
difference that was seen with the approach reported here. I have often prescribed
the use of a hip abduction orthosis at nighttime to maintain symmetrical wide
hip abduction, even though the use of a medication such as diazepam may be
needed to somewhat reduce muscle tone and allow sleep.
It should be emphasized that Botox is used to minimize
dynamic contractures due to spasticity and is not usually used to improve
actual contractures of the muscle-tendon unit. In the clinical trial reported
here, the Botox was used to decrease the spasticity of the hip adductors and
medial hamstring muscles, but, in combination with the hip abduction brace, was
also being used to prevent further fixed contractures of the hip. In 2004, Kay
and associates1 in Los Angeles reported on the results of a
randomized controlled study of treatment for equinus contracture in children
with spastic cerebral palsy with use of either stretching casts alone or Botox
injection followed by stretching casts. While the results were equally good for
both groups at three months after treatment completion, at the time of the one-year
follow-up, the children treated with Botox and casts had a higher rate of
recurrence of equinus contracture than did those treated with stretching casts
alone, leading these authors to recommend avoiding the use of Botox in
conjunction with stretching casts for equinus contractures in these children. Now,
in the prospective study by Kerr Graham et al., Botox has once again been found
to be ineffective as a clinical treatment.
It is important that this study was published in JBJS, as the majority of studies
involving orthopaedic treatment for spastic cerebral palsy are published in
journals that are not usually seen by most orthopaedists. Since dislocation of
the hip can occur with the hypotonic and dystonic forms of cerebral palsy as
well as with the spastic type, it is not too surprising that the temporary
reduction of the spasticity of muscles around the hip, as achieved in this
study, did not significantly modify the natural course of hip displacement that
was seen in the children with more involved disease. The fact that Botox and
daytime bracing did not delay early hip subluxation in these children with
spastic cerebral palsy suggests the need to consider early soft-tissue or
tendon-lengthening surgery around the hip to prevent progressive hip
subluxation and dislocation. Given the results of this study, it would appear
that clinical recommendations should be limited to careful, periodic clinical
examination and radiographic follow-up of the hips, with surgical treatment
instituted early once progressive hip subluxation is identified. With
preservation of symmetrical abduction of the hips, a more normal hip
development can result, potentially decreasing the need for more extensive
femoral and pelvic osteotomies at an older age. Preventing hip dislocation and
pelvic obliquity should continue to be a goal of orthopaedic management in these
young patients, many of whom are either limited walkers or nonwalkers. This
report has clearly outlined one means of treatment that no longer should be
recommended for the purpose of delaying or avoiding surgery for the treatment
of early hip displacement in children with spastic cerebral palsy.
*The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.
References
1. Kay RM, Rethlefsen SA, Fern-Buneo A, Wren TA, Skaggs DL. Botulinum toxin as an adjunct to serial casting treatment in children with cerebral palsy. J Bone Joint Surg Am. 2004;86:2377-84.
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