Spinal Cord Stimulation to Restore Walking in Patients with Spinal Cord Injury
UC San Diego is one of the only medical centers in the country using epidural spinal cord stimulation to reduce lower extremity spasticity and to facilitate walking in individuals with spinal cord injury.
What is spinal cord stimulation?
More commonly used to treat chronic pain in the limbs and trunk, spinal cord stimulation can also help increase control, reduce spasticity, and facilitate walking after a spinal cord injury.
How does it work?
Electrodes are strategically placed into the space outside of the dura (covering of spinal cord). These electrodes are connected to a small pulse generator that is placed under the skin.
The exact site of stimulation is critical for obtaining the desired effects.
Is spinal cord stimulation right for you?
To determine whether you are a candidate for epidural spinal cord stimulation, you will first undergo trial stimulator placement.
A trial stimulator placement involves insertion of an electrode (using a needle and local anesthesia). This simple procedure is done in an outpatient setting. Once the electrode is inserted, you will begin gait training and be given a generator to carry for one week.
If results are positive, our team will proceed with surgical placement of a paddle lead. Paddle leads offer more precise stimulation to targeted nerves and can activate the most ideal parts of the spinal cord. Unlike wire leads, which can move out of place over time, paddle leads are designed for long-term placement.
In the last two decades, scientists have demonstrated the efficacy of spinal cord stimulation as a treatment for chronic pain and motor control.
In 2000, researchers showed that the exact site of stimulation was critical for obtaining the desired effects. They determined that the lumbar enlargement of the spinal cord achieved the best results. This area is typically found at the T11-L1 spinal levels.
Using stimulation levels of 50 Hz-100 Hz and 1 V-10 V, they were able to reduce spasticity in a number of patients. Many of these patients were even able to stop taking their spasticity medications.
Using the same kind of stimulator in the lumbar enlargement but at a different frequency, researchers demonstrated that stimulation could also produce stepping and lower limb extension in complete spinal cord injury patients. This frequency was not enough to restore the ability to walk, as these patients had no voluntary control of their legs prior to the stimulation.
In 2002, researchers applied step-generating frequencies on the impaired motor control of an ASIA-C-wheelchair dependent patient with moderate spasticity.
Prior to stimulation, the patient underwent partial weight-bearing therapy. Stimulation generated immediate improvement in the patient’s gait rhythm, and walking was achieved.
A recent study at the Kentucky Spinal Cord Injury Research Center at the University of Louisville, funded by the Christopher Reeve Foundation, showed impressive results with four paraplegic patients. After receiving spinal cord stimulation, the participants, who had been paralyzed for two years, were able to flex their knees, ankles and toes.
While those results are impressive, such dramatic results are not typically achieved, and expectations should be tempered.
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