Functional Electrical Stimulation (FES) for Spinal Cord Injury
What is functional electrical stimulation (FES) for spinal cord injury?
Functional electrical stimulation (FES) is a treatment method in which low level electrical impulses are applied to nerves or muscles to improve or restore muscle function in people with spinal cord injuries.
What is the spinal cord and how does it work?
The spinal cord is a bundle of nerve fibers and nerve cells that is enclosed by the spine and extends from the brain to the lower back. The spinal cord and the nerves that branch off from it is a shared, two-way communication highway that links to all of the body’s muscles, joints and organs to the brain. Together, the brain and spinal cord make up the central nervous system, which controls most of the body’s functions.
What happens to the nervous system after a spinal cord injury?
When the spinal cord is injured, the signals from the brain no longer reach their intended destinations. The extent of the loss of muscle and bodily functions depends on where the spinal cord injury occurs and the amount of damage to the nerve cells. Damage can range from significant, long-term paralysis to less severe spinal cord injuries that heal over time. Loss of function occurs below the level of the injury, so the higher the site of the injury along the spinal cord, the greater the possible loss of voluntary control over muscle and bodily functions.
How does functional electrical stimulation (FES) help people with spinal cord injuries?
Functional electrical stimulation (FES) activates muscles in people with spinal cord injuries so they may be able to move and function independently. More specifically, FES uses small electrical impulses to activate specific muscles and nerves. These electrical impulses trigger the desired function, which might be, for example, contracting muscles to move a foot or lift an arm. The electrical impulse can also be used to block signals that send messages about pain and restore or improve some bodily functions such as bowel and bladder control.
What other functions can be restored with the use of functional electrical stimulation (FES)?
Functional electrical stimulation can restore function to your legs, arms, and organs. FES can:
- Restore muscle movement to perform such activities as:
- Move hand to grasp and release objects.
- Hold a fork to eat.
- Hold a pen to write.
- Stand, step and walk short distances.
- Sit upright/improve posture.
- Move from sitting to standing position.
- Regain the sensations of pressure, touch, and temperature.
- Regain bladder and bowel control.
- Restore breathing by stimulating the diaphragm to eliminate the need for a ventilator.
- Treat or prevent pressure sores/ulcers due to sitting by stimulating gluteus muscles.
- Provide male erection and ejaculation.
- Reduces pain by blocking signals that send messages about pain.
Exercising muscle tissue not only gains strength and tone but also results in a number of related general health benefits, such as:
- Decreases the risk of fractures by building muscle mass.
- Increases blood circulation.
- Helps manage weight through the ability to exercise.
- Reduces the risk of cardiovascular disease and diabetes with improvements in general health.
- Regains lost bone mass.
- Reduces muscle spasms and the effects of spasticity.
- Allows unassisted coughing to clear secretions, which reduces the risks of pneumonia and other lung infections and choking hazards.
- Prevents and reverses muscle atrophy (shrinking and weakening of tissue due to lack of use.)
- Improves the quality of life for people with a spinal cord injury.
Who is not a candidate for functional electrical stimulation (FES)?
In general, people who are not candidates for functional electrical stimulation (FES) are those with:
- Other implanted electrical devices.
- History of thrombosis/hemorrhage.
- Severe muscle spasticity/contractures.
- A current pregnancy.
Talk with your doctors and therapists about these conditions, other medical conditions you may have and any other concerns about if FES is right for you.
What are the components of functional electrical stimulation (FES) equipment?
Functional electrical stimulation (FES) equipment comes in all shapes and sizes. The type of equipment depends on the location of the spinal cord injury and the desired function(s) to be regained.
In the simplest terms, most FES devices include an external small electrical box (called the neuromuscular electrical stimulator unit), wires that lead from the box and carry the electrical impulse, and an electrode to which the wires are attached. (Other FES devices use wireless connectors that use radio waves to transmit electrical signals.) The electrodes touch or stimulate the targeted muscles or nerves.
Electrodes can be:
- Attached to the surface of the skin with sticky pads.
- Placed directly under the skin (percutaneous placement) during an office visit.
- Fully embedded deeper into the muscle (implanted) or the area surrounding the targeted nerve during outpatient surgery.
Your doctors, neuromuscular rehabilitation therapist or physical therapist may recommend surface or percutaneous electrodes for short-term treatment while you recover from a spinal cord injury. If your treatment goals involve longer-term improvements in function, your electrodes may be implanted.
Your neuromuscular rehabilitation team will determine which device is the right device to you, which muscles or nerves need to be stimulated, and how (voltage and stimulation pattern) they need to be stimulated.
Risks / Benefits
What are the risks of functional electrical stimulation (FES) for spinal cord injury?
Most of the risks of functional electrical stimulation (FES) pertain to the wires and electrodes that are positioned under the skin or in deep tissue and not FES systems that are external to the body. The risks include:
- Irritation or infection at the site of electrode placement (internal and external systems).
- Scar tissue that forms around the electrode (called encapsulation).
- Broken wires.
- Electrodes that move after placement.
Your neuromuscular rehabilitation therapist or physical therapist will work with you to determine the proper type and placement of electrodes to avoid these complications. Check in regularly with your therapist to reduce your risk. Be sure you know when to contact your doctor if you suspect an issue.
Note: Because of the metal used in FES systems (from the wires and other components), you may not be able to undergo magnetic resonance imaging if you have an FES system that is implanted in your body. MRI is a useful tool in diagnosing future health problems. Discuss this issue with your doctor.
Recovery and Outlook
How long will I have functional electrical stimulation (FES) for my spinal cord injury?
Functional electrical stimulation (FES) for spinal cord injury is an ongoing therapy. Learning to use and control it can take weeks or months. You will work with a physical therapist in a series of sessions to master the technology.
The length of time the therapy lasts varies depending on the person and the spinal cord injury. With practice, you may be able to use FES on your own as you go about your daily life.
What is the prognosis (outlook) for people who have functional electrical stimulation (FES) after a spinal cord injury?
Many people who receive functional electrical stimulation (FES) for spinal cord injury regain or improve function and experience better quality of life. These people may sit up, stand, walk short distances, use their hands again and have some bodily functions restored.
Over time, you may need to follow up with your neuromuscular rehabilitation therapist or physical therapist to adjust the position of the electrodes or the strength of the stimulation. These changes may be needed as your muscles get stronger and your nerves react to the stimulation levels.
When to Call the Doctor
When should I call my doctor?
Contact your physical therapist if you feel pain or skin irritation at the electrode site while receiving FES for spinal cord injury. Your therapist may be able to use a different type of electrode or change the stimulation to solve the problem.
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