Spasticity and Its Treatment in
Children with Cerebral Palsy

Steven Bachrach, M.D., Medical Director
HMS School for Children with Cerebral Palsy

What is spasticity?

Spasticity is the involuntary, persistent contraction of muscles that cannot be voluntarily stopped, resulting in high muscle tone (hypertonicity). While some spasticity can help a child with CP, it is often a problem that causes discomfort and interferes with the attainment of
motor skills. Increased muscle tone or spasticity may cause difficulty with positioning, problems with proper hygiene, or sometimes pain. Spasticity can vary throughout the day, related to the child’s activity, mood and the time of day. The Ashworth scale has been used to quantify the amount of spasticity present in a child.

Spasticity is the most common motor disorder in cerebral palsy, and is seen in approximately two thirds of those with CP. Spasticity is rarely present early in life, even in an infant with cerebral palsy. Therefore, an infant may be very floppy for the first year of life, with spasticity developing with maturity, often
between six months and 24 months of age. Over long periods of time, spasticity can and often does cause dislocated hips, scoliosis and/or foot deformities.

How is spasticity treated?

Treatment of spasticity involves many different options, including physical and occupational therapy, braces, inhibitive casting, medications given orally (by mouth) or intrathecally (into the spinal fluid), Botox injections and orthopedic or neurosurgical operations. Some of these treatments are used to decrease high muscle tone (such as Botox or the baclofen pump), while others treat the secondary effects, such as PT to stretch out the muscles or orthopedic surgery to correct deformities

How does therapy help?

Proper positioning and postural control can decrease spasticity to some extent. Physical and occupational therapists will use therapy to stretch tight muscles, and doing so in a warm pool of water (aquatherapy) will help achieve even better results. There are a variety of special kinds of therapy that may help reduce tone, such as hippatherapy (horseback riding) and massage, but they all have
the same goal of relaxing the muscles and allowing them to be stretched. But in all these situations, the stretched muscles quickly return to their previous "tightness" because the underlying spasticity remains.

Therapy can also be combined with various braces (known as orthoses) to help stretch tight muscles and to properly position an extremity, such as the foot.

What is inhibitive casting?

Sometimes, physical therapy is combined with casts to achieve longer lasting results. Inhibitive casts are usually applied to the legs and sometimes to the arms to inhibit a specific movement. Initially the cast may be used to stretch out a contracture, such as a tight Achilles tendon. By keeping the ankle from flexing, other movements are improved, and the elbows flex better, fingers move more easily and spasticity decreases in the hips or knees. The inhibitive ankle-foot orthosis (AFO) is useful in stabilizing the ankle for standing. In general, the use of inhibitive casts for children with cerebral palsy is decreasing, though they are used by some after botulinum toxin injection.

Which medications are used for spasticity?

Oral medications that are used include valium and drugs in the same "family" (such as diazepam, lorazepam and clonazepam), as well as other unrelated drugs, such as baclofen, tizanidine and dantrium. The side effects of these medications, especially drowsiness, often make them unsuitable for long-term use, and they often lose their effectiveness after a few weeks to months, requiring increasing doses to achieve the same relaxation. An exception is the use of baclofen given directly into the spinal canal by a small pump surgically implanted under the skin (called intrathecal baclofen or ITB). This method allows the baclofen to be given in much smaller doses than the oral medication because it is acting directly on the nerves in the spinal cord to control the high muscle tone. While baclofen given by mouth causes severe drowsiness, when it is given continuously via a pump, this side effect can often be avoided.

What is the baclofen pump?

This is a device that is programmed to deliver a small but continuous amount of baclofen into the spinal fluid surrounding the spinal column and nerves. The pump itself is implanted in the abdomen under general anesthesia, and a small plastic catheter is tunneled under the skin, around to the back and into the spinal canal. You typically can see and feel the pump under the skin. It is about the size and shape of a hockey puck. The pump is best placed and managed at a medical center that is set up to do a preoperative assessment and trial to test the effects of the medication in the child before the pump is actually surgically implanted.

The parents must be willing to bring the child to the physician who is managing the pump every two to four months to refill the medication inside the pump. This is done with a small needle stick through the skin into a port on the pump. Dosage adjustments are made via an external computer/programmer and transmitted to the pump by a hand-held computer. Doses can be programmed to deliver the baclofen continuously, with the same dose all day long, or with occasional extra medication given when spasticity is highest.

The patient must be big enough and have enough room in his abdomen to accommodate the pump. When a patient is felt to be a potential candidate for ITB therapy, a screening trial is scheduled. This involves a lumbar puncture and injection of an ITB test dose. Spasticity scores are recorded before and after the injection, for up to six to eight hours. If the trial dose is felt to have benefited the child, and if the parents agree, then placement of the pump is the next step. Patients who have had a spinal fusion cannot undergo a trial, but they can have the pump implanted. A history of seizures or the presence of a VP shunt are not contraindications to ITB therapy.

What is botulinum toxin and when is it used for spasticity?

Botulinum toxin is a drug that may be injected directly into a muscle in order to temporarily weaken or partially paralyze very spastic muscles. There are two commercially available types: Botox® (botulinum toxin A) and Myobloc® (botulinum toxin B). The drug is injected through a very small needle and causes little pain. It acts locally within the muscle injected to block the release of some of the nerve signals to the muscle. The effect of the botulinum toxin injection lasts four to six months, and can be given multiple times. Botulinum toxin is best used when there are specific muscles (six or less) that are spastic. It is a relatively safe drug without known systemic effects if it is not injected into the bloodstream. It does not seem to prevent, but may delay the development of contractures. There are very few side effects, which may include some temporary soreness within the muscle injected.

Spasticity in the child with cerebral palsy does not change significantly, and it is almost certain that six months after the injection the spasticity will return to the same degree as before. In these children, injections are used primarily to delay surgery, or to help make therapy more effective. After botulinum toxin injections, normal activity may be immediately resumed.

What are the risks of using botulinum toxin?

The risks of botulinum toxin injections are very few. The most frequent is temporary muscle weakness for up to 24-48 hours. Acetaminophen (Tylenol) can be given to relieve any discomfort. Rarely, excessive localized or generalized weakness have been reported, which is temporary. Allergic reaction is extremely uncommon. It is common for patients to eventually develop a tolerance to botulinum toxin, meaning the drug becomes ineffective, or that it will take an increase in dosage to achieve the same effect. This is occasionally due to true antibody formation against the drug. When this happens, the other form of the medication can be substituted (toxin A instead of B).

What orthopedic procedures are used to treat spasticity?

Another option is orthopedic surgery, where specific muscles whose spasticity is causing problems may be lengthened, released, or occasionally transferred. Spasticity prevents muscles from growing normally. As children grow, their spastic muscles become shortened, resulting in a joint that cannot move normally. Lengthening or releasing tight muscles allows normal movement and frees up the joint, though the underlying spasticity is still present, and the muscles will retighten as the child grows. Usually the first such operation is performed before the child starts first grade. Often, a second such procedure is performed during adolescence. Care must be taken so that lengthening one muscle does not create an imbalance, creating a situation where the antagonistic muscles, which may also be spastic, cause the opposite deformity to develop.

What neurosurgical procedure is used to treat spasticity?

A dorsal rhizotomy is a neurosurgical treatment in which the nerves as they exit from the spinal cord are identified and the ones found to be most involved with the spasticity are cut. The result is a great decrease in spasticity, at least for a short period of time. There is still a great deal of controversy within the medical community as to how much benefit this operation gives to the child with spasticity over time, which child is a candidate for this surgery, and whether the risks outweigh the benefits.

Most physicians would agree that dorsal rhizotomies are most effective when done in children between three and seven years of age who are able to walk, but are significantly limited in their walking by spasticity. The relative merits of undergoing rhizotomy surgery versus orthopedic surgery need to be considered, but in these children, it is generally recommended that if the rhizotomy is done, orthopedic surgery should follow in one year to fine-tune the problems that the rhizotomy did not address.

The child with severe involvement who is having difficulty sitting in a wheelchair because of spasticity or posturing is also a candidate for rhizotomy surgery. If the child is under 10 years of age, the surgery does provide a significant decrease in the spasticity. However, if the child’s posturing is due to pain from a dislocated hip or severe scoliosis, the rhizotomy is absolutely not indicated, because it will in no way diminish the discomfort. Those areas of pain and discomfort should be treated directly by addressing the painful hip or the scoliosis. Children with athetosis should not have a rhizotomy, because almost always, the athetosis will become significantly worse after the rhizotomy has been done.

What are the risks associated with the rhizotomy procedure?

The short-term complications can include infection, and the incision can be quite difficult to close because of the cerebrospinal fluid that continues to leak from the spine. Infections can be treated with repeated closures and antibiotics. Loss of bladder and bowel function can occur if too many nerves are cut. Severe deformities of the spine can develop a number of years after rhizotomy.

Severe weakness, which is difficult to define in children with CP, is always seen after rhizotomy surgery, but is due in part to the fact that the muscles are no longer spastic and their underlying weakness is brought out. For a while, the child may be floppy throughout his whole body and may have difficulty sitting up, looking rather like a limp rag doll.

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This article presents abbreviated excerpts from the forthcoming book titled Cerebral Palsy: A Complete Guide for Caregiving, to be published in Spring 2006, reprinted with permission of The Johns Hopkins University Press.

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