Secondary Condition: Spasticity
by J. Glen House, MD
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.
