Spasticity is a motor disorder, manifested in increasing muscle tone (tension) and involving overactive muscle contractions. It occurs due to damage in areas of the central nervous system responsible for tone. It can be described as hyperactivity of reflexes that normally protect against the sudden stretching of a muscle. This condition can interfere with mobility and performance of day to day activities. Over time, spasticity may lead to contractures, which involve loss of range of joint motion.
Disorders that may cause spasticity include stroke, head injury, brain injury, spinal cord injury, multiple sclerosis, cerebral palsy, brain or spinal cord tumors, and other disorders of the central nervous system. The treatment of spacticity includes physical, pharmacological and surgical procedures, but each has its drawbacks in addition to many benefits. Physical therapy on its own is often not enough in severe cases, and drug treatment can cause significant sleepiness and other side effects. Treatment with injections of phenol or alcohol is often irreversible and can cause severe sensory disorders, and surgical treatment can sometimes cause uncontrolled and irreversible paralysis. Against this background, the treatment by injection of botulinum toxin has been the subject of much interest in the last decade, and in recent years, the toxin has become one of the most important methods to treat spasticity.
Botulinum toxin type A (Botox) is a neurotoxin produced by the bacterium Clostridium botulinum, first reported by Dr J. Kerner (1786-1862). The effects of botulinum toxin have been known since the early 1900s, but the toxin was used medically for the first time by Dr Alan B. Scott on a monkey in 1973 and than was used to treat strabismus. Recently it was approved for treatment of dystonia, spasticity and other neurological conditions.
How does botulinum toxin work?
Botox therapy is used to treat patients with spasticity that restricts function or causes pain. Botox is a nerve impulse ''blocker.'' It attaches to motor nerve endings in the synapses (where nerve meets muscle) and prevents the release of the chemical transmitter acetylcholine, which carries the ''message'' from the brain that tells a muscle to contract. If the message is blocked, the muscle doesn't spasm, and hence Botox causes partial paralysis, that can last a number of months. However, nerve endings usually grow new connections to muscles that have not yet been exposed to Botox so treatment may have to be repeated as often as every three months.
In our clinic, small amounts of Botox are injected into several locations along the muscle group as determined by the EMG test. This helps maximize the benefits of the medicine and to reduce the amount of Botox injected. The maximum dose of Botox is less than 500 units per visit. Botox is given by injection directly into the affected muscles.
Botox usually takes full effect within two to four weeks after injection. Patients should resume physical activity slowly and carefully after Botox injection. The most common side effects of Botox are generally light, local and transient, depending on the location of injection. Reactions include effects similar to a light flu, discoloration, redness, pain, or discomfort at the injection site.
There are now two commercial vaccines of botulinum toxin manufactured by companies in Israel - Botox and Dysport. They are used in many medical sectors, including ophthalmology, neurology, gastroenterology, urology, and cosmetics. Starting in September 2002, the Ministry of Health approved botulinum toxin for treatment of spasticity in an upper limb after stroke. In treating spasticity, botulinum toxin is used in situations where physical rehabilitation or systemic medication have elicited no response, when there is a high likelihood od developing stiffness (contracture) and also when pain develops and there is evident disability in day to day functioning.
Contraindications to botulinum toxin treatment include: muscle and nerve diseases, having permanent joint stiffness, known sensitivity to botulinum toxin, or being pregnant.
Injection of botulinum toxin in our department is performed in the Institute for Electrophysiological Diagnosis (EMG). The botulinum toxin is injected by a rehabilitation specialist who is specialized in performing this technique accurately and directing the toxin to the spastic muscle through a special electrode needle, at points where the electrode shows a tracing typical for spasticity by involuntary outbursts. This technique allows administration of the minimum possible dose of toxin required for maximum effect, thus reducing the chance of side effects and early formation of antibodies and sensitivity. A reduction in spasticity following the injection begins within a few days, reaches a peak after two weeks and lasts about 4 months on average.
In the last 5 years, 56 stroke victims were treated in our clinic by injection of botulinum toxin, most of whom were suffering from upper limb spasticity. Follow up of treatment results was performed using video and quantification of function before and after injection. The results showed a significant decrease in the level of disability in all areas already in the first month after injection, with maximum improvement after a month and a subsequent gradual withdrawal, but with a clear functional gain even at the end of the 4th month post injection.
Treatment by injection of botulinum toxin to reduce spasticity is effective, simple and safe. It improves the degree of independence and quality of life of stroke victims with severe spasticity. EMG supervision is important to get the most from the treatment using the minimum possible dose of the medicine, and the prevention of unresponsiveness to repeated injections. The still high cost of the treatment prevents its more widespread use and it is our hope that treatment with botulinum toxin injections will be added to the health basket as soon as possible, also for other indications.