(Download a 16-page guide to the causes of and treatments for spasticity.)
Spasticity is a side effect of paralysis that varies from mild muscle stiffness to severe, uncontrollable leg movements. Generally, doctors now call conditions of extreme muscle tension spastic hypertonia (SH). It may occur in association with spinal cord injury, multiple sclerosis, cerebral palsy, or brain trauma. Symptoms may include increased muscle tone, rapid muscle contractions, exaggerated deep tendon reflexes, muscle spasms, scissoring (involuntary crossing of the legs) and fixed joints.
When an individual is first injured, muscles are weak and flexible because of what's called spinal shock: The body's reflexes are absent below the level of injury; this condition usually lasts for a few weeks or several months. Once the spinal shock is over, reflex activity returns.
Spasticity is usually caused by damage to the portion of the brain or spinal cord that controls voluntary movement. Since the normal flow of nerve messages to below the level of injury is interrupted, those messages may not reach the reflex control center of the brain. The spinal cord then attempts to moderate the body's response. Because the spinal cord is not as efficient as the brain, the signals that are sent back to the site of the sensation are often over-exaggerated in an overactive muscle response or spastic hypertonia: an uncontrollable "jerking" movement, stiffening or straightening of muscles, shock-like contractions of a muscle or group of muscles, and abnormal tone in the muscles.
Most individuals with SCI have some spasms. Persons with cervical injuries and those with incomplete injuries are more likely than those with paraplegia and/or complete injuries to experience SH. The most common muscles that spasm are those that bend the elbow (flexor) or extend the leg (extensor). These reflexes usually occur as a result of an automatic response to painful sensations.
While spasticity can interfere with rehabilitation or daily living activities, it is not always a bad thing. Some people use their spasms for function, to empty their bladders, to transfer or to dress. Others use SH to keep their muscles toned and improve circulation. It may also help maintain bone strength. In a large Swedish study of people with SCI, 68 percent had spasticity but less than half of those said that their spasticity was a significant problem that reduced activities of daily living or caused pain.
Changing spasticity: A change in a person's spasticity is something to pay attention to. For example, increased tone could be the result of a cyst or cavity forming in the spinal cord (post-traumatic syringomyelia). Untreated, cysts can lead to further loss of function. Problems outside your nervous system, such as bladder infections or skin sores, can increase spasticity.
Treatment for spasticity usually includes medications such as baclofen, diazepam or zanaflex. Some people with severe spasms utilize refillable baclofen pumps, which are small, surgically implanted reservoirs that apply the drug directly to the area of spinal cord dysfunction. This allows for a higher concentration of drug without the usual mind-dulling side effects of a high oral dosage.
Physical therapy, including muscle stretching, range of motion exercises, and other physical therapy regimens, can help prevent joint contractures (shrinkage or shortening of a muscle) and reduce the severity of symptoms. Proper posture and positioning are important for people in wheelchairs and those at bed rest to reduce spasms. Orthotics, such as ankle-foot braces, are sometimes used to limit spasticity. Application of cold (cryotherapy) to an affected area can also calm muscle activity.
For many years doctors have used phenol nerve blocks to deaden nerves that cause spasticity. Lately, a better but more expensive nerve block, botulinum toxin (Botox), has become a popular treatment for spasms. An application of Botox lasts about three to six months; the body builds antibodies to the drug, reducing its effectiveness over time.
Sometimes, surgery is recommended for tendon release or to sever the nerve-muscle pathway in children with cerebral palsy. Selective dorsalrhizotomy may be considered if spasms interfere with sitting, bathing or general caretaking.
Spasticity comes with the territory for many people who are paralyzed. Treatment strategy should be based on one's function: Is the spasticity keeping you from certain activities? Are there safety risks, such as losing control while driving your power chair or car? Are spasticity drugs worse than the symptoms, affecting concentration or energy? Check with your physician to discuss your options.
Sources:The National Institute of Neurological Disorders and Stroke, National Multiple Sclerosis Society, United Cerebral Palsy Association, The National Spinal Cord Injury Statistical Center, Craig Hospital