Health

Spasticity is a condition that commonly occurs after a spinal cord injury that occurs at T12 and above. It is associated with an upper motor neuron injury and can occur in individuals with a complete or an incomplete spinal cord injury. Spasticity is best described by an increase in muscle tone (difficulty moving an arm or leg through its range of motion), increase in reflexes (when a physician taps on a tendon), involuntary movements and the presence of clonus (i.e., foot placed on the ground continues to beat up and down).

After a spinal cord injury, spasticity does not occur during the period of spinal shock. As the person emerges from spinal shock, spasticity and an increase in muscle tone usually occur. This can worsen over the next several weeks to months but usually reaches a fairly consistent degree of spasticity.

Spasticity can vary throughout the day and can be affected by other stimulus. For example, individuals who push a wheelchair often notice that their spasticity is decreased with a greater amount of activity. Medical issues can also lead to an increase in spasticity, commonly occurring when individuals develop a urinary tract infection. Any irritating stimulus below the level of lesion can lead to an increase in spasticity.

Why does spasticity occur after a spinal cord injury?
The normally functioning brain and spinal cord have nervous tissue and nerve tracts that are inhibitory (decreases tone and spasticity) and excitatory (increases tone and spasticity). Before a spinal cord injury, the two systems which maintain a condition of normal tone are well-balanced.

After a spinal cord injury this ideal balance is disrupted and an increase in tone and spasticity occurs. For example, there are nerve tracts that travel down the spinal cord that function to inhibit or dampen the reflexes and tone in the muscles. If these are damaged the balance is tilted toward being more spastic. After a spinal cord injury there is also a condition that likely occurs called “denervation hypersensitivity.” This means that after a spinal cord injury there is an abnormal increase in receptors that are involved in the balance of tone and spasticity. This is likely an explanation of why spasticity gradually increases during the first several months after a spinal cord injury.

What can be done about spasticity?
First, it’s important to mention that not all spasticity requires treatment. Spasticity can be beneficial because it can maintain muscle bulk and circulation by causing muscle contractions that return blood flow to the heart. Spasticity should be treated if it is interfering with function.  For example, if the spasticity is interfering with transfers, keeping you up at night, painful or continuous and annoying, it probably should be treated.

What is the treatment for spasticity?
The first approach to treatment does not involve medications. Some individuals can control their spasticity simply by stretching several times throughout the day. Stretching does decrease the spasticity, but the beneficial results are usually temporary.

For individuals who use a wheelchair, correct positioning of the patient is important in managing spasticity. Spasticity is usually increased when the hip angle is increased as when one goes from the sitting position to the lying position. This positional change of the hip can also occur when an individual in a reclining wheelchair changes from the sitting position to the reclined position. Therefore many individuals use a tilt-in-space seating system instead of a reclining back. A tilt-in-space wheelchair keeps the angle between the legs and torso in the same position but tilts the user backwards to change the area of pressure. In addition, the position of the foot on the footplate can have an effect on spasticity. If the ball of the foot is the only part of the foot that is touching the footplate, spasticity will likely be increased and clonus will occur.

Splints can also be made to help inhibit spasticity in the upper and lower extremities. Some individuals use cryotherapy (cold), which involves the placement of ice bags (some use a bag of frozen peas) over the muscle groups that suffered the most problematic spasticity. A cool or cold object should not be kept in the same location for more than 20 minutes. Applying cold can often decrease the spasticity for up to several hours, but is a temporary method of relief. Finally, some individuals use a home neuromuscular electrical stimulation device to contract the muscle and decrease the spasticity, but these results are also temporary.

What medications are used to treat spasticity?
Oral medications are often used to treat spasticity in spinal cord injury. When medications are used it is recommended to start at a low dose and slowly and gradually  test dosage increases under the care of a physician. Some medications also require monitoring of liver function.

Baclofen is frequently used and is often considered the first drug of choice in spinal cord injury. Baclofen is usually started at 5 mg three times a day and gradually increased as needed. The Physician’s Desk Reference (PDR) states that the total amount of Baclofen to be used in a 24-hour period is 80 mg. In practice, physicians who treat individuals with Baclofen often use up to 120 mg per day or more. Baclofen also has a short duration of action which is referred to as the half-life. The half-life is a measure of when half of the medication is out of the body; Baclofen’s half-life is 3 1/2 hours. Therefore this medication is given three to four times per day. If discontinued, Baclofen must be slowly titrated down in dosage because it can cause hallucinations, delusions and seizures if stopped abruptly.

Zanaflex (generic: tizanidine) is one of the newest medications used in the treatment of spasticity. This medication is often used alone but can be combined with other medications such as Baclofen. Zanaflex has been shown to be beneficial in patients with spinal cord injury. This medication has a relatively short half-life and is usually given three to four times per day. Drowsiness is a common side effect; it is recommended to start giving this medication at night only for several days. Often Zanaflex is started at 2 mg at night and gradually increased every two to four days by 2 mg. The maximum dosage of this medication in a 24-hour period is 36 mg per day , given in divided dosages. The manufacturer recommends that a blood test that looks at the function of the liver be monitored after starting this medication. It is been shown that 5% of patients put on this medication were found to have an increase in their liver enzymes, which usually return to normal after stopping this medication.

Dantrium (generic: dantrolene) is the only medication used for the treatment of spasticity that has a direct effect on the muscle instead of the nervous system. This medication affects both normal muscle and spastic muscle and is thought by some to result in muscle weakness. Dantrium is started at 25 mg per day and titrated up to a total of 400 mg per day in divided doses. This is another medication that has a potential serious side effect of elevated liver enzymes or liver failure. Therefore, a blood test that monitors liver enzymes should be followed after starting this medication.

Benzodiazepines are a class of medications used widely throughout the medical field for various reasons, including the treatment of spasticity in patients with a spinal cord injury. This medication has limited use because of the side effects, which include significant drowsiness and decrease in cognitive function. This medication is better at controlling the painful and jerking spasms rather than the constant increased tone. Examples of these medications include Valium (diazepam), Klonopin (clonazepam), and Ativan (lorazepam). Valium is the most commonly used benzodiazepine in spinal cord injury. This medication is usually started at 2 mg twice a day and gradually increased to 15 mg three to four times per day or more as directed by a physician. Unlike the above medications this one has a relatively long half-life of 30 to 60 hours. Because of this, this medication may be used once a day;  it is often given at night to control annoying nighttime spasms.

Clonidine is similar to Zanaflex (tizanidine), although it is felt to have increased side effects of low blood pressure and sedation. Therefore, most individuals will prefer to use Zanaflex instead of clonidine. An exception to that preference is when oral medications cannot be used, because clonidine is available in a transdermal (skin) patch.

Neurontin (gabapentin) falls in the class of anti-seizure medications but has been found to decrease spasticity in individuals with spinal cord injury. This medication is usually not a first-line drug of choice in spinal cord injury, but should be considered in individuals who cannot tolerate other medications. Neurontin is also commonly used to treat neuropathic pain that occurs after spinal cord injury. Therefore, it can be a beneficial medication that treats two problems at the same time — pain and spasticity.

What if medications do not adequately control spasticity?
Some patients cannot tolerate the side effects of the oral medications. Drowsiness and cognitive difficulties are common side effects that prevent some patients from using oral medications. In addition, some individuals are on maximum doses of multiple anti-spasticity medications with inadequate reduction in spasticity.

Some of these individuals are appropriate candidates for intrathecal baclofen. Baclofen can be administered via an intrathecal route to the nervous system. There is a space within the spinal cord referred to as the “thecal space.”

A small catheter can be inserted into this intrathecal space and anchored to the surrounding spinal column. A small tube is routed under the skin to the front lower part of the abdomen and connected to a battery-powered pump. This pump has a reservoir where the baclofen is stored. This stored baclofen is then slowly transported to the thecal catheter which then delivers a predetermined dose of the drug into this intrathecal space. The intrathecal space is an ideal location for the delivery of baclofen, because spasticity begins in the nervous system. In contrast, when pills are taken by mouth they have to be digested, enter the bloodstream and then cross into the fluid surrounding the brain and spinal cord (cerebral spinal fluid or CSF). . Since the baclofen is delivered directly into the CSF, it requires 1/100th the oral dose, resulting in significantly decreased cognitive side effects.

There is approximately ¼ the concentration of baclofen in the cervical CSF as compared to the lumbar CSF where the medication is delivered. The decrease in spasticity is much more effective on the lower extremities as compared to the upper extremities because of the placement of the end of the catheter.

The baclofen pump reservoir is available in a 20 mL and a 40 mL volume. The 20 mL volume baclofen pump external case is smaller than the 40 mL baclofen pump. The reservoir requires a refill every one to three months depending on the specific settings of the rate of infusion. These refills are done by a physician or nurse placing a needle through the skin and into the reservoir of the pump using a sterile technique.

The life of the pump is directly related to the battery life, which is dependent on the rate of medication infusion. It is estimated that a battery will last three to six years before replacement is required. Replacement is performed by a surgeon who removes the pump and replaces it with a new pump. The catheter that is tunneled under the skin and anchored to the spinal column is not removed. The new battery is then hooked up to the previous tubing.

Before patients have a baclofen pump surgically placed, they undergo an evaluation by a physician. If the patient cannot tolerate oral medication or is inadequately treated with maximum doses of medication, they are considered for a trial. A trial consists of a single intrathecal injection of baclofen followed by an examination to assess a decrease in spasticity or tone. If there is a decrease in spasticity, they are usually referred to a surgeon who places the baclofen pump. Once the pump has been placed, the dosage is increased or decreased by a physician or nurse via a programming machine through the skin.

Can injections help with the treatment of spasticity?
Botulism toxin (Botox or Myobloc) is often used in the treatment of isolated areas of spasticity in spinal cord injury. This medication can show positive results within three days of injection and peak results in 14 days. The resulting muscle weakness can last between three and six months. Another option is to inject phenol, a type of alcohol, onto the nerve which causes nerve damage. This damaged nerve can grow back and repair itself within months to years. Phenol's effect of causing a decrease in spasticity lasts much longer than Botox but can have an increased chance of an unpleasant sensation in the distribution of the nerve.

Is there a role for surgery in the treatment of spasticity?
In the past surgeons have attempted to cut the spinal cord to decrease spasticity with limited success. More recently, a very selective surgery has been performed that cuts the fibers that carry sensation back to the spinal cord. This surgery is called a selective dorsal rhizotomy; it is not used very often today in the treatment of spasticity in spinal cord injury.