Pediatric Movement Disorders - Spasticity

Treatment

There is much research investigating possible repair of damaged cells in the brain or spinal cord; however, there is no effective treatment that reverses the injury. (See the more complete description of treatments.)

Physical therapy is essential in order to stretch the muscles, maintain mobility about joints, and reduce the potential for joint injury and freezing. In a very stiff muscle, serial casting may be used to gradually stretch out the involved muscles. In severe cases, surgical procedures may be needed to cut the muscle or lengthen the tendons.

Medications
Medications to treat spasticity are aimed at reducing symptoms by decreasing the strength of the stretch reflex. Medications to reduce spasticity operate by different mechanisms, some of which involve receptors in the spinal cord, while others involve receptors in the brain. Baclofen is an activator of the inhibitory GABA type B receptors. These receptors are present in the spinal cord and modulate the stretch reflex. Often, doses of oral baclofen as high as 100 mg per day or more are required for optimal effect. Tizanidine (Zanaflex®) operates in the brain on a different receptor, and it is often helpful in spasticity as well. Diazepam (Valium®) and other benzodiazepines are often used; they are more effective at the GABA type A receptors. Some clinicians use dantrolene, which directly weakens the muscles. Since dopa-responsive dystonia (DRD) may produce a syndrome very similar to spastic diplegia, all children with unexplained spasticity should receive a trial of L-dopa therapy.

Chemodenervation
Botulinum toxin is an effective treatment for children with spasticity as it causes a temporary weakening of spastic muscles. It is also possible that the toxin decreases the signals coming from the muscle stretch receptors, thereby directly reducing the signals that result in spasticity. Botulinum toxin is most effective when only a small number of muscles are involved; injections usually need to be repeated every 3 to 6 months. Alternatives to botulinum toxin include injections of phenol or ethanol onto the nerves supplying the muscles. Larger and more powerful muscles are more often the target for these treatments. These treatments are also temporary, and carry a risk for pain in some nerves.

Intrathecal Baclofen
Some children benefit from using an implanted pump to deliver baclofen directly to the space around the spinal cord, called the intrathecal space. This allows a high local concentration of the medication to be achieved, without the same degree of side effects as oral medications. The pump is implanted surgically below the skin in the abdomen and refilled by injecting the medication through a sealed, sterile port. A tube from the pump is inserted into the space surrounding the spinal cord. The baclofen pump may have serious complications, including meningitis and withdrawal reactions. Therefore, it must be used with caution.

Surgery
Dorsal rhizotomy has been used for many years for the treatment of spasticity. Improvements in this surgical technique have led to better results. During this procedure, the sensory nerves from the muscles are cut. It is hoped that this will interrupt the reflex loops that are causing the spasticity. The procedure is not always effective; some disappointing results may be due to surgery on children whose primary problem is more likely to be dystonia. This procedure is not reversible, and, in some cases, may make children worse by loosening muscles to the point where children can no longer stand.

Treatment Summary
Any treatment for spasticity needs to take into account that the spasticity itself is only part of the problem. Because the connection from the brain to the spinal cord is damaged, the muscles are also weak in the sense that the child has reduced voluntary control. In some cases, the spasticity actually improves overall function. For example, a spastic knee that extends involuntarily may allow a child to stand. If medication or surgery is used to reduce the spasticity, the child may no longer be able to stand.