Nerve Transfer Surgery

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Author: Kelsey Zhao | Reviewer: Michael Berger, Christopher Doherty | Published: 23 January 2024 | Updated: ~

Key Points

  • Nerve transfer surgeries in SCI aim to restore some movement to the arm or hand by connecting a healthy nerve to the nerve of a paralyzed muscle.
  • This surgery is most commonly used to improve finger and thumb movement for people with cervical SCIs.
  • Depending on the type of injury, some nerve transfers are time-sensitive and must be done within 6 months, while others can be done years after the injury.
  • Experts recommend at least two years of physical and occupational therapy after a nerve transfer to rehabilitate the muscles.
  • Although the current evidence is limited, nerve transfers are a promising treatment for improving an individual’s independence and quality of life.

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Spinal cord injury (SCI) disrupts the nerve pathways that send signals between the brain and muscles. This disruption can lead to loss of muscle strength and movement.

Nerve transfer surgery aims to restore some movement to a paralyzed muscle by connecting a nearby functional nerve from above the SCI to the non-functional nerve of the paralyzed muscle. The paralyzed muscle and its non-functional nerve are called the recipient. The functional nerve transferred to the recipient is called the donor. The donor nerve used is expendable (i.e. removing the nerve does not cause any significant loss of movement) or taken from an area where there is more than one muscle that performs the same movement. Over time and with rehabilitation, the healthy cells of the functional nerve will use the non-functional nerve as a scaffold to grow towards the paralyzed muscle. This creates a new pathway for signals to travel between the brain and the muscle.

simple diagram showing how the donor nerve is attached to the recipient nerve to re-innervate a paralyzed muscle in nerve transfer surgery

Nerve transfers involve the transfer of a functional donor nerve to a non-functional recipient nerve to create a new signal pathway to a paralyzed muscle.1

Since the success of nerve transfer techniques were demonstrated in other nerve injuries, like brachial plexus injury, they are now being applied to SCI. Nerve transfers are usually done after a cervical SCI to regain movement in the upper limbs. Some functions commonly targeted in nerve transfers include elbow extension, wrist extension, finger extension, finger flexion, and finger extension.

Table 1: Common nerve transfer surgeries and the donor/recipient nerves that can be used to restore each muscle function.2-5

Function
Donor
Recipient
 

Teres minor nerve Triceps nerve
Teres minor and motor portion of posterior division of axillary nerve Triceps nerve
Motor portion of posterior division of axillary nerve Triceps nerve
Fascicle of anterior division of axillary nerve Triceps nerve
 

Supinator nerve ECRB (Extensor carpi radialis brevis) nerve
 

Supinator nerve PIN (Posterior interosseous nerve)
 

Brachialis nerve AIN (Anterior interosseous nerve)
ECRB nerve AIN
Supinator nerve AIN
Fascicle to pronator teres nerve FDS (Flexor digitorum superficialis) nerve

Although wrist extension (bend wrist up) and wrist flexion (bend wrist down) can be targeted with nerve transfer, wrist movement is often reconstructed with tendon transfers instead. Learn more about tendon transfers in the How do nerve transfers compare to tendon transfers? section below.

Improved movement in the arms and hands can increase an individual’s independence and confidence in many areas of life, including daily activities, mobility, and socializing.

This YouTube video explains the basics of nerve transfer and tendon transfer surgeries, and the differences between the two. This video was created by Neramy Ganesan, a graduate of the University of Toronto MSc Biomedical Communications Program, with the help of content expert Dr. Jana Dengler at Sunnybrook Health Sciences Centre. Please see the end credits in the video for more details.6

Level of injury

Silhouette of a human bust overlayed with the spine and brachial plexus nerves. Spinal levels C2-C7 are labelled to show which spinal cord injury levels are potentially eligible for nerve transfer surgery.

Nerve transfers are usually done on cervical spinal cord injuries levels C5-C7.7

Nerve transfers are typically used to improve arm and hand function for people with higher level spinal cord injuries between C5 and C7. Keep in mind that since nerve transfers are a surgical treatment targeting movement, suitability is based on the level of muscle function. For example, someone with an incomplete SCI whose overall level of injury is C3, but C5 for muscle function, is more likely to be eligible for nerve transfer than someone whose level of injury is C3 for both sensory and muscle function.

Recent studies have shown some success with nerve transfers in injury levels up to C2, but more recovery of movement is associated with lower levels of cervical injury. Consideration for nerve transfer surgery in levels above C5 is made on a case-by-case basis, depending on what donor nerves are available.

Refer to our articles on Spinal Cord Anatomy and Spinal Cord Injury Basics for more information!

Nerve function and time since injury

Two types of neurons make up the nerve pathways that send movement signals to and from the brain and the muscles.

The ideal timing for how long after SCI a nerve transfer can be performed depends on whether the upper or the lower motor neurons in the nerve pathway of the paralyzed muscle are damaged. Which motor neurons are damaged is different for nerve pathways that exit the spinal cord (out to the muscle) at the level of injury and nerve pathways that exit below the level of injury.

Motor neurons at the level of injury

Often, both lower and upper motor neurons are damaged at and around the level of injury. The loss of a functional nerve in the muscle causes it to degenerate and atrophy (waste away). The muscle atrophy becomes irreversible 12-18 months after the injury, at which point a nerve transfer would be unable to restore any movement to the muscle. In this case, a nerve transfer should be done around 6 months after SCI, so that the donor nerve cells can reach the paralyzed muscle before the degeneration becomes irreversible.

Motor neurons below the level of injury

Below the SCI, often the upper motor neuron is damaged but the lower motor neuron that connects the muscle to the spinal cord is still intact. The nerve in the muscle is still functional, but you cannot control it because the connection to the brain is disrupted. The muscle is maintained by the activity of the functional nerve’s connection to the spinal cord so degeneration occurs more slowly. In this case, a nerve transfer may be possible for years after the injury, but patient selection is more specific and surgery outcomes are less predictable.

Diagram showing how a nerve transfer surgery can be time sensitive or not depending on whether there is an upper motor neuron injury or lower motor neuron injury.

The timing of nerve transfer after spinal cord injury depends on whether the nerve that connects to the muscle is damaged. If it is, the muscle will degenerate more quickly, and nerve transfer should be considered earlier.8

Other considerations

Some other factors to consider when deciding whether to do a nerve transfer surgery include:

  • Caregiver availability for the period after surgery when you will need extra support with daily activities.
  • Emotional/psychological supports.
  • Personal goals for function or recovery. Speak to your health care provider to determine whether a nerve transfer is suitable for your goals.
  • Transportation to the clinic or hospital for diagnostic testing, the surgery, and rehabilitation.
  • Other injuries in the arms, hands, or wrists or other neurological conditions that could increase the risk of complications in surgery and/or rehabilitation.
  • General considerations for surgery (e.g., open wounds, infection, high blood pressure, diabetes, heart and lung problems, extreme obesity, mental health).
  • SCI considerations for surgery (e.g., pressure sores, joint stiffness, spasticity, autonomic dysreflexia).
Illustration of the timeline for a time-sensitive nerve transfer after cervical spinal cord injury.

A timeline of the process for time-sensitive nerve transfer for a cervical spinal cord injury where the lower motor neuron of the recipient muscle is injured.9

Before surgery

The irreversible degeneration of muscle needs to be balanced with giving the nerves time to heal from the SCI. However, after 6 months, the probability of nerves recovering on their own becomes much less likely. The timing and type of nerve transfer ultimately depend on the nature of the SCI and what nerves are affected by the injury.

Suitability for nerve transfer is determined through physical examinations of muscle function and electrodiagnostic testing. Physical examination looks at the stability, strength and range of motion (how far you can move a limb in different directions) of the muscles and joints.

Electrodiagnostic tests may include the following:

Electromyography (EMG)

Electromyography measures the activity of nerves in a muscle by inserting a small needle electrode (similar to acupuncture) into the muscle tissue.

Nerve Conduction Studies

Nerve conduction studies measure the strength and speed of the signals travelling through a nerve by sending electrical pulses from a device and measuring with electrodes.

The combination of results from electrodiagnostic tests and physical exams is used to identify nerves and muscles that are functional /non-functional and figure out which muscles and nerves should be used in the nerve transfer. The tests could also determine if there is a possibility that the muscles will recover on their own and not require surgery. The results can also help to estimate what your timeline for surgery might look like.

During surgery

General anesthesia is given before the surgery. Electrical stimulation can be used to make sure the right nerves are being cut. Once the identities of the nerves are confirmed, the healthy nerve is cut and stitched to the cut end of the damaged nerve.

After surgery

In the 1-2 weeks following surgery, activity will be restricted to allow your skin and nerves to heal. After the period of rest, you can return to regular activity and begin intensive physical/occupational therapy. Even though the nerve transfer reconnects the pathway from the paralyzed muscle to the brain/spinal cord, it is not like plugging two extension cords together and having the current run through instantly. Attaching the two nerves allows the recipient nerve to act as a scaffold for the cells of the donor nerve to grow through, towards the muscle. This process can take months or years depending on the distance to the muscle because nerve cells grow at approximately 1mm per day.

Rehabilitation

After healing, you undergo intense physical therapy and occupational therapy to recover and maintain the muscle’s range of motion and strength, and to relearn how to move the muscle with the new nerve pathway. This rehabilitation process will teach you how to use the muscle properly and strengthen the muscles with a variety of exercises. Experts recommend that consistent therapy be continued for a minimum of 2 years.

Research on nerve transfers has found that people can continue to experience improvements in function as far as 4 years after the surgery with physical and occupational therapy.

Some activities to rehabilitate muscle function after nerve transfers include:

Early stage (no movement in the muscle yet)
    • Education: Understanding which muscles and nerves are involved in the nerve transfer and how the surgery has changed the way they work.
    • Range of motion: Exercises to maintain how far the muscle can move in different directions. Splints may be used to manage range of motion and spasticity.
    • Donor activation: Physically moving the donor muscle to activate the donor nerve.
    • Visualization: Moving the donor muscle and visualizing moving the recipient muscle. This is an important exercise in early rehabilitation.
    • Donor co-contraction: Moving the donor muscle and having someone else move the recipient muscle at the same time to strengthen the connection between the nerve and the new movement.
After first sign of muscle movement
    • Donor co-contraction: Moving the donor muscle and recipient muscle at the same time to strengthen the nerve connection.
    • Moving only the recipient muscle.
    • Exercises based on real life activities.
    • Doing exercises in water or with assistive devices like slings and prostheses can make movements easier by reducing the effect of gravity.
    • Biofeedback or neuromuscular electrical stimulation (NMES) may be used to promote movement.
Strength and endurance
    • Gradually increased resistance of exercises (adding weights).
    • Gradually increased repetitions of exercises.
    • Incorporating function of muscle into everyday life.

Visualization for muscle rehabilitation

Visualization (also known as mental practice, mental imagery, and motor imagery) is a technique where you consciously and repeatedly imagine performing a movement without actually moving your body. One theory for why this technique works is that visualizing a movement activates areas of the brain that overlap significantly with the areas that activate when physically doing the movement.

Studies of people without SCI and athletes who use visualization when learning new skills have shown that physical movement performance improves. In rehabilitation for neurological disorders, including SCI, evidence from high-quality studies has shown that visualization used in combination with physical therapy has positive effects on muscle movement.

Tendons are rope-like bands that connect your muscles to your bones. In a tendon transfer, the tendon of a healthy muscle with functional nerves is cut and attached to the tendon of a paralyzed muscle. This transfer allows the working muscle to take over the movement of the paralyzed muscle. This is another way that movement can be restored in the arm or hand for someone with tetraplegia.

simple diagram of tendon transfer surgery

Tendon transfers involve using a working muscle to power a paralyzed muscle movement by transferring the tendon of the working muscle to the paralyzed muscle.10

Nerve transfers and tendon transfers can also be used in combination to restore movement. Patients in one study who underwent both nerve transfer and tendon transfer reported no preference because each was beneficial in a different way. Hands with nerve transfers resulted in more natural and dexterous movement, and hands with tendon transfers felt stronger. Each has characteristics that make the procedure more or less suitable for an individual depending on their injury, timing, and recovery goals.

Table 2: Comparison of nerve transfers and tendon transfers

Nerve Transfer
Tendon Transfer
What kind of movement is improved?
More precise, controlled movements that do not require as much strength. Stronger movements that do not require as much precise coordination.
What kind of activities could this surgery help with?
• Using devices like a phone, keyboard, mouse, or touchscreen.
• Social interactions like a handshake or hug
• Eating and drinking independently
• Holding light objects
• Pressure relief movements
• Some self-catheterization steps
• Lifting and holding heavy objects
• Wheelchair pushing and maneuvering
• Eating and drinking independently
• Dressing
• Improved transfers
• Personal hygiene
• Writing
When can I get this surgery?
Depending on your injury, this surgery is usually done around 6 months after SCI, or could be done years later in some cases. Any time after SCI.
How long does healing take?
You can do light activities immediately after surgery while your skin heals.
You can return to normal activities after 2-4 weeks.
Avoid weight-bearing, repetitive, or straining activities for 1 month.
A splint and cast will be used to immobilize your arm for 1-2 months while the tendon heals.
Avoid weight-bearing activities and sports for 2-3 months.
Some centres may start physical/occupational therapy exercises days after surgery, during the immobilization period.
How long will rehabilitation take?
Daily exercises at home and physical/occupational therapy at least once per month for 2 years. Approximately 3 months
Physical/occupational therapy helps you to learn the new movement and makes sure the tendons heal properly.
How long will it take to see movement?
First improvements in movement usually happen between 3 to 12 months, depending on the type of nerve transfer. There are accounts of initial movement recovery as late as 2.5 years after surgery.
Research shows that movement may continue to improve for years after surgery.
Improvements in movement usually occur between 1-3 months after surgery.
Research shows that movement may continue to improve for up to 12 months after surgery.

Like with any other surgery, there is a risk of bleeding, infection, and other complications in the healing process. Some people who get a nerve transfer experience temporary weakness in the wrist after surgery that usually returns to normal strength during recovery. Similarly, there may be areas of numbness that develop that often go away over time. So far, the evidence shows that nerve transfer surgeries are safe, and people rarely experience permanent losses in movement or sensation because of the surgery.

Having to rely on others to carry out normal daily activities for a period after surgery can be challenging. A strong social support system and mental health supports can be helpful for recovery.

Some people feel disappointment and frustration with the slow pace at which improvements are made after a nerve transfer. It is important to set realistic expectations going into a nerve transfer. That said, even small improvements in function can have significant impacts on independence and confidence.

As with any surgery, there is a possibility that the nerve transfer surgery does not work. If a nerve transfer fails to restore any function to a paralyzed muscle after physical and occupational therapy, it may be possible to do a tendon transfer to try and regain that movement.

The reasons why a nerve transfer succeeds or fails are still an ongoing area of research. Expert opinion suggests that timing (i.e. when in the recovery process the surgery takes place), and the frequency and intensity of physical and occupational therapy influence how successful a nerve transfer is.

Future research directions for nerve transfer surgery

Although nerve transfers are available to people with SCI as a treatment option, it is still a relatively new area of ongoing research.

Some of the research underway in the realm of nerve transfer surgery include:

  • Exploring the possible application of nerve transfer techniques on diaphragm paralysis to reduce ventilator dependence.
  • The use of electrical stimulation in combination with nerve transfer to strengthen the nerve connections.
  • Research to better understand what factors may influence the success of a nerve transfer.
  • A multi-centre Canadian study is currently looking at the effect of nerve transfers on functional results like the ability to pick up an object, eat independently, self-catheterize etc.

There is some evidence that a successful nerve transfer surgery in combination with consistent physical/occupational therapy can lead to increases in the movement, control, and strength of a paralyzed muscle. In recent studies, the nerve transfer surgeries performed were 87.5 – 92% successful at recovering some strength. Better outcomes were seen in people with lower levels of cervical SCI, a greater range of motion and strength in the donor muscle, and more activity in the recipient muscle. More research evidence is needed, but experts are hopeful that nerve transfers can improve the ability to do daily activities such as inserting catheters, relieving pressure, holding and releasing items, and eating. That said, there is some limited evidence that reports people who undergo nerve transfers can experience increases in overall independence and quality of life. It is possible to see improvements for many years after the surgery with continued physical/occupational therapy.

Caleb: Nerve Transfer Trifecta

Age: 35
Level of Injury: C5 ASIA A
Fun fact: Caleb enjoys scuba diving, whitewater kayaking and sitskiing!

Caleb had three nerve transfers on each arm for finger extension, finger flexion, and elbow extension 5 months after SCI. It has been 1 year and 3 months since his surgery.

Three months after the surgery, Caleb started to see flickers of movement. There was some loss in strength after the surgery, but at the time he was still weak from the accident that caused his SCI. Caleb can now grip a 5lb kettle bell, while his triceps is still at a flicker but continues to recover. Caleb plans to continue building his finger extension and grip strength to improve his chair skills and everyday living activities. He is hoping that with time, his triceps will have the strength to help with transfers. Overall, Caleb says, “I am very impressed with the whole team and happy with the results!”.

Ainsley: Nerve and Tendon Transfers

Age: 17
Level Of Injury: C5-C6 complete
Fun fact: Ainsley plans on doing a Bachelor of Arts at the University of British Columbia after graduating high school this year!

Ainsley had three nerve transfers on each arm for hand opening, hand closing, and elbow extension 6 months after SCI. She is now at 2 years post nerve transfer. Ainsley has also had a tendon transfer on the right side.

After the surgery, Ainsley could move around right away but had to be careful and was on strong pain medications because of the many incisions. Scar management was important to heal the incisions with minimal scarring and avoid complications. After 2-3 months of visualization exercises, Ainsley noticed the first flickers of movement. By 5-6 months she was using her left hand for tasks. Unfortunately, her right hand didn’t progress beyond a flicker, so Ainsley and her team decided to do a tendon transfer for that side. Ainsley found that the recovery for tendon transfer was more difficult because she was in a cast for 1.5 months and not allowed to move. Today, Ainsley can open both hands, pick things up with her left hand, and extend both arms against gravity. She continues to improve every day but recalls that even before the surgery, “I definitely knew that I had to put in the work to make it stronger.”

Dan: Nerve Transfer with a Chronic Injury

Age: 37
Level of Injury: C5-C6 ASIA B
Fun fact: Dan is a full-time student at Douglas College in Recreation Therapy! He enjoys cooking and has a dog.

Dan had nerve transfers on both arms for finger flexion and extension 5 years after his SCI. He’s coming up on 3 years post nerve transfer.

Recalling some of the effects right after the surgery, Dan described numbness, loss of strength, and two weeks of pain when raising his arm that “felt like I hit my funny bone but times 100”. Dan’s recovery from nerve transfer was tough and didn’t line up with the picture the surgeons and doctors painted. Because nerve transfers are done more on acute SCIs than chronic SCIs, he suspects the doctors were not aware of how much the surgery could affect the independence of someone living in the community without the supports that exist in in-patient rehabilitation. There needed to be more preparation to accommodate the losses in function he experienced. Considering his rehabilitation, he says, “…you’re on your own so I think it would be better if there was something more – like a program that you do for three months after the surgery”.

Three years after the surgery, the numbness and pain from right after surgery have improved, but the losses in strength have persisted. Dan says, “I still have difficulty doing some things that I used to do before the surgery, but not too much.” That said, he has gained the ability to open and extend his fingers and has enough grip to squeeze the hand brakes of the electric bike attachment on his wheelchair.

Overall, the research on nerve transfer surgeries suggests that it can improve arm/hand muscle function and independence for people with cervical SCI, and that the procedure is safe. However, this is an invasive procedure, so the evidence is limited because it is usually not possible to have randomization or a control group to experimentally demonstrate the benefits.

Extensive assessments are required to determine whether a nerve transfer could work for you. It is important to keep in mind that it may take years of physical/occupational therapy to see the full results of the treatment. There are also external factors to consider, including if you can take time off work/school for recovery, if you have adequate care and support, if you are mentally well enough to have surgery, and what your personal goals are for function. If you are interested in nerve transfer, speak to your health care provider to determine if it’s the right fit for your goals and your injury.

For a review of how we assess evidence at SCIRE Community and advice on making decisions, please see SCIRE Community Evidence.

Nerve and Tendon Transfers to Improve Upper Limb Function in Cervical Spinal Cord Injury (video)

SCIRE Professional “Upper Limb” Module

Evidence for “What is nerve transfer surgery?” is based on:

Ahuja, C. S., Wilson, J. R., Nori, S., Kotter, M. R. N., Druschel, C., Curt, A., & Fehlings, M. G. (2017). Traumatic spinal cord injury. Nature Reviews Disease Primers, 3(1), 17018. https://doi.org/10.1038/nrdp.2017.18

Hill, E. J. R., & Fox, I. K. (2019). Current Best Peripheral Nerve Transfers for Spinal Cord Injury. Plastic & Reconstructive Surgery, 143(1), 184e–198e. https://doi.org/10.1097/PRS.0000000000005173

Evidence for “What can nerve transfers help with?” is based on:

Mahar, M., & Cavalli, V. (2018). Intrinsic mechanisms of neuronal axon regeneration. Nature Reviews Neuroscience, 19(6), 323–337. https://doi.org/10.1038/s41583-018-0001-8

Bazarek, S., & Brown, J. M. (2020). The evolution of nerve transfers for spinal cord injury. Experimental Neurology, 333, 113426. https://doi.org/10.1016/j.expneurol.2020.113426

Bunketorp-Käll, L., Reinholdt, C., Fridén, J., & Wangdell, J. (2017). Essential gains and health after upper-limb tetraplegia surgery identified by the International classification of functioning, disability and health (ICF). Spinal Cord, 55(9), 857–863. https://doi.org/10.1038/sc.2017.36

Evidence for Table 1 is based on:

Bazarek, S., & Brown, J. M. (2020). The evolution of nerve transfers for spinal cord injury. Experimental Neurology, 333, 113426. https://doi.org/10.1016/j.expneurol.2020.113426

Galea, M., Messina, A., Hill, B., Cooper, C., Hahn, J., & van Zyl, N. (2020). Reanimating hand function after spinal cord injury using nerve transfer surgery. Advances in Clinical Neuroscience & Rehabilitation, 20(2), 17–19. https://doi.org/10.47795/CQZF2655

Evidence for “Who is suitable for a nerve transfer?” is based on:

Khalifeh, J. M., Dibble, C. F., Van Voorhis, A., Doering, M., Boyer, M. I., Mahan, M. A., Wilson, T. J., Midha, R., Yang, L. J. S., & Ray, W. Z. (2019a). Nerve transfers in the upper extremity following cervical spinal cord injury. Part 1: Systematic review of the literature. Journal of Neurosurgery: Spine, 31(5), 629–640. https://doi.org/10.3171/2019.4.SPINE19173

Dengler, J., Mehra, M., Steeves, J. D., Fox, I. K., Curt, A., Maier, D., Abel, R., Weidner, N., Rupp, R., Vidal, J., Benito, J., Kalke, Y.-B., Curtin, C., Kennedy, C., Miller, A., Novak, C., Ota, D., & Stenson, K. C. (2021). Evaluation of Functional Independence in Cervical Spinal Cord Injury: Implications for Surgery to Restore Upper Limb Function. The Journal of Hand Surgery, 46(7), 621.e1-621.e17. https://doi.org/10.1016/j.jhsa.2020.10.036

Kirshblum, S. C., Burns, S. P., Biering-Sorensen, F., Donovan, W., Graves, D. E., Jha, A., Johansen, M., Jones, L., Krassioukov, A., Mulcahey, M. J., Schmidt-Read, M., & Waring, W. (2011). International standards for neurological classification of spinal cord injury (Revised 2011). The Journal of Spinal Cord Medicine, 34(6), 535–546. https://doi.org/10.1179/204577211X13207446293695

Javeed, S., Dibble, C. F., Greenberg, J. K., Zhang, J. K., Khalifeh, J. M., Park, Y., Wilson, T. J., Zager, E. L., Faraji, A. H., Mahan, M. A., Yang, L. J., Midha, R., Juknis, N., & Ray, W. Z. (2022). Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia. JAMA Netw Open, 5(11), e2243890-. https://doi.org/10.1001/jamanetworkopen.2022.43890

Khalifeh, J. M., Dibble, C. F., Van Voorhis, A., Doering, M., Boyer, M. I., Mahan, M. A., Wilson, T. J., Midha, R., Yang, L. J. S., & Ray, W. Z. (2019b). Nerve transfers in the upper extremity following cervical spinal cord injury. Part 2: Preliminary results of a prospective clinical trial. Journal of Neurosurgery: Spine, 31(5). https://doi.org/10.3171/2019.4.SPINE19399

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Stanley, E. A., Hill, B., McKenzie, D. P., Chapuis, P., Galea, M. P., & N, van Z. (2022). Predicting strength outcomes for upper limb nerve transfer surgery in tetraplegia. J Hand Surg Eur Vol, 47(11), 1114–1120. https://doi.org/10.1177/17531934221113739

Berger, M. J., Dengler, J., Westman, A., Curt, A., Schubert, M., Abel, R., Weidner, N., Röhrich, F., & Fox, I. K. (2023). Nerve transfer after cervical spinal cord injury: Who has a “time sensitive” injury based on electrodiagnostic findings? Archives of Physical Medicine and Rehabilitation. https://doi.org/10.1016/j.apmr.2023.11.003

Bryden, A. M., Hoyen, H. A., Keith, M. W., Mejia, M., Kilgore, K. L., & Nemunaitis, G. A. (2016). Upper Extremity Assessment in Tetraplegia: The Importance of Differentiating Between Upper and Lower Motor Neuron Paralysis. Archives of Physical Medicine and Rehabilitation, 97(6), S97–S104. https://doi.org/10.1016/j.apmr.2015.11.021

Castanov, V., Berger, M., Ritsma, B., Trier, J., & Hendry, J. M. (2021). Optimizing the Timing of Peripheral Nerve Transfers for Functional Re-Animation in Cervical Spinal Cord Injury: A Conceptual Framework. Journal of Neurotrauma, 38(24), 3365–3375. https://doi.org/10.1089/neu.2021.0247

Hill, E. J. R., & Fox, I. K. (2019). Current Best Peripheral Nerve Transfers for Spinal Cord Injury. Plastic & Reconstructive Surgery, 143(1), 184e–198e. https://doi.org/10.1097/PRS.0000000000005173

Jain, N. S., Hill, E. J. R., Zaidman, C. M., Novak, C. B., Hunter, D. A., Juknis, N., Ruvinskaya, R., Kennedy, C. R., Vetter, J., Mackinnon, S. E., & Fox, I. K. (2020). Evaluation for Late Nerve Transfer Surgery in Spinal Cord Injury: Predicting the Degree of Lower Motor Neuron Injury. J Hand Surg Am, 45(2), 95–103. https://doi.org/10.1016/j.jhsa.2019.11.003

Fox, I. K., Novak, C. B., Krauss, E. M., Hoben, G. M., Zaidman, C. M., Ruvinskaya, R., Juknis, N., Winter, A. C., & Mackinnon, S. E. (2018). The Use of Nerve Transfers to Restore Upper Extremity Function in Cervical Spinal Cord Injury. PM&R, 10(11), 1173. https://doi.org/10.1016/j.pmrj.2018.03.013

Evidence for “What is the process for a nerve transfer?” is based on:

Dengler, J., Steeves, J. D., Curt, A., Mehra, M., Novak, C. B., & Fox, I. K. (2022). Spontaneous Motor Recovery after Cervical Spinal Cord Injury: Issues for Nerve Transfer Surgery Decision Making. Spinal Cord, 60(10), 922–927. https://doi.org/10.1038/s41393-022-00834-6

Hill, E. J. R., & Fox, I. K. (2019). Current Best Peripheral Nerve Transfers for Spinal Cord Injury. Plastic & Reconstructive Surgery, 143(1), 184e–198e. https://doi.org/10.1097/PRS.0000000000005173

Kane, N. M., & Oware, A. (2012). Nerve conduction and electromyography studies. Journal of Neurology, 259(7), 1502–1508. https://doi.org/10.1007/s00415-012-6497-3

Berger, M. J., Dengler, J., Westman, A., Curt, A., Schubert, M., Abel, R., Weidner, N., Röhrich, F., & Fox, I. K. (2023). Nerve transfer after cervical spinal cord injury: Who has a “time sensitive” injury based on electrodiagnostic findings? Archives of Physical Medicine and Rehabilitation. https://doi.org/10.1016/j.apmr.2023.11.003

Bersch, I., & Fridén, J. (2020). Upper and lower motor neuron lesions in tetraplegia: implications for surgical nerve transfer to restore hand function. J Appl Physiol (1985), 129(5), 1214–1219. https://doi.org/10.1152/japplphysiol.00529.2020

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Fox, I. K., Miller, A. K., & Curtin, C. M. (2018). Nerve and Tendon Transfer Surgery in Cervical Spinal Cord Injury: Individualized Choices to Optimize Function. Topics in Spinal Cord Injury Rehabilitation, 24(3), 275–287. https://doi.org/10.1310/sci2403-275

Kahn, L. C., Evans, A. G., Hill, E. J. R., & Fox, I. K. (2022). Donor activation focused rehabilitation approach to hand closing nerve transfer surgery in individuals with cervical level spinal cord injury. Spinal Cord Ser Cases, 8(1), 47. https://doi.org/10.1038/s41394-022-00512-y

Aguirre-Güemez, A. V, Mendoza-Muñoz, M., Jiménez-Coello, G., Rhoades-Torres, G. M., Pérez-Zavala, R., Barrera-Ortíz, A., & Quinzaños-Fresnedo, J. (2021). Nerve transfer rehabilitation in tetraplegia: Comprehensive assessment and treatment program to improve upper extremity function before and after nerve transfer surgery, a case report. J Spinal Cord Med, 44(4), 621–626. https://doi.org/10.1080/10790268.2019.1660841

Javeed, S., Dibble, C. F., Greenberg, J. K., Zhang, J. K., Khalifeh, J. M., Park, Y., Wilson, T. J., Zager, E. L., Faraji, A. H., Mahan, M. A., Yang, L. J., Midha, R., Juknis, N., & Ray, W. Z. (2022). Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia. JAMA Netw Open, 5(11), e2243890-. https://doi.org/10.1001/jamanetworkopen.2022.43890

Larocerie-Salgado, J., Chinchalkar, S., Ross, D. C., Gillis, J., Doherty, C. D., & Miller, T. A. (2022). Rehabilitation Following Nerve Transfer Surgery. Techniques in Hand & Upper Extremity Surgery, 26(2), 71–77. https://doi.org/10.1097/BTH.0000000000000359

Opsommer, E., Chevalley, O., & Korogod, N. (2020). Motor imagery for pain and motor function after spinal cord injury: a systematic review. Spinal Cord, 58(3), 262–274. https://doi.org/10.1038/s41393-019-0390-1

Evidence for “How do nerve transfers compare to tendon transfers?” is based on:

Bazarek, S., & Brown, J. M. (2020). The evolution of nerve transfers for spinal cord injury. Experimental Neurology, 333, 113426. https://doi.org/10.1016/j.expneurol.2020.113426

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Evidence for Table 2 is based on:

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Aguirre-Güemez, A. V, Mendoza-Muñoz, M., Jiménez-Coello, G., Rhoades-Torres, G. M., Pérez-Zavala, R., Barrera-Ortíz, A., & Quinzaños-Fresnedo, J. (2021). Nerve transfer rehabilitation in tetraplegia: Comprehensive assessment and treatment program to improve upper extremity function before and after nerve transfer surgery, a case report. J Spinal Cord Med, 44(4), 621–626. https://doi.org/10.1080/10790268.2019.1660841

Kahn, L. C., Evans, A. G., Hill, E. J. R., & Fox, I. K. (2022). Donor activation focused rehabilitation approach to hand closing nerve transfer surgery in individuals with cervical level spinal cord injury. Spinal Cord Ser Cases, 8(1), 47. https://doi.org/10.1038/s41394-022-00512-y

Bunketorp-Käll, L., Reinholdt, C., Fridén, J., & Wangdell, J. (2017). Essential gains and health after upper-limb tetraplegia surgery identified by the International classification of functioning, disability and health (ICF). Spinal Cord, 55(9), 857–863. https://doi.org/10.1038/sc.2017.36

Fox, I. K., Miller, A. K., & Curtin, C. M. (2018). Nerve and Tendon Transfer Surgery in Cervical Spinal Cord Injury: Individualized Choices to Optimize Function. Topics in Spinal Cord Injury Rehabilitation, 24(3), 275–287. https://doi.org/10.1310/sci2403-275

Dunn, J. A., Sinnott, K. A., Rothwell, A. G., Mohammed, K. D., & Simcock, J. W. (2016). Tendon Transfer Surgery for People With Tetraplegia: An Overview. Archives of Physical Medicine and Rehabilitation, 97(6), S75–S80. https://doi.org/10.1016/j.apmr.2016.01.034

Javeed, S., Dibble, C. F., Greenberg, J. K., Zhang, J. K., Khalifeh, J. M., Park, Y., Wilson, T. J., Zager, E. L., Faraji, A. H., Mahan, M. A., Yang, L. J., Midha, R., Juknis, N., & Ray, W. Z. (2022). Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia. JAMA Netw Open, 5(11), e2243890-. https://doi.org/10.1001/jamanetworkopen.2022.43890

Evidence for “What are the risks of nerve transfers?” is based on:

Francoisse, C. A., Russo, S. A., Skladman, R., Kahn, L. C., Kennedy, C., Stenson, K. C., Novak, C. B., & Fox, I. K. (2022). Quantifying Donor Deficits Following Nerve Transfer Surgery in Tetraplegia. J Hand Surg Am, 47(12), 1157–1165. https://doi.org/10.1016/j.jhsa.2022.08.014

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Bertelli, J. A., & Ghizoni, M. F. (2017). Nerve transfers for restoration of finger flexion in patients with tetraplegia. Journal of Neurosurgery: Spine, 26(1), 55–61. https://doi.org/10.3171/2016.5.SPINE151544

Wilson, T. J. (2019). Novel Uses of Nerve Transfers. Neurotherapeutics, 16(1), 26–35. https://doi.org/10.1007/s13311-018-0664-x Khalifeh, J. M., Dibble, C. F., Van Voorhis, A., Doering, M., Boyer, M. I., Mahan, M. A., Wilson, T. J., Midha, R., Yang, L. J. S., & Ray, W. Z. (2019a). Nerve transfers in the upper extremity following cervical spinal cord injury. Part 1: Systematic review of the literature. Journal of Neurosurgery: Spine, 31(5), 629–640. https://doi.org/10.3171/2019.4.SPINE19173

Mooney, A., Hewitt, A. E., & Hahn, J. (2021). Nothing to lose: a phenomenological study of upper limb nerve transfer surgery for individuals with tetraplegia. Disabil Rehabil, 43(26), 3748–3756. https://doi.org/10.1080/09638288.2020.1750716

Hill, E. J. R., & Fox, I. K. (2019). Current Best Peripheral Nerve Transfers for Spinal Cord Injury. Plastic & Reconstructive Surgery, 143(1), 184e–198e. https://doi.org/10.1097/PRS.0000000000005173

Evidence for “What are the limitations of nerve transfers?” is based on:

Mooney, A., Hewitt, A. E., & Hahn, J. (2021). Nothing to lose: a phenomenological study of upper limb nerve transfer surgery for individuals with tetraplegia. Disabil Rehabil, 43(26), 3748–3756. https://doi.org/10.1080/09638288.2020.1750716

Hill, E. J. R., & Fox, I. K. (2019). Current Best Peripheral Nerve Transfers for Spinal Cord Injury. Plastic & Reconstructive Surgery, 143(1), 184e–198e. https://doi.org/10.1097/PRS.0000000000005173

Heredia Gutiérrez, A., Cachón Cámara, G. E., González Carranza, V., Torres García, S., & Chico Ponce de León, F. (2020). Phrenic nerve neurotization utilizing half of the spinal accessory nerve to the functional restoration of the paralyzed diaphragm in high spinal cord injury secondary to brain tumor resection. Child’s Nervous System, 36(6), 1307–1310. https://doi.org/10.1007/s00381-019-04490-9

Bazarek, S., & Brown, J. M. (2020). The evolution of nerve transfers for spinal cord injury. Experimental Neurology, 333, 113426. https://doi.org/10.1016/j.expneurol.2020.113426

Evidence for “Are nerve transfers effective?” is based on:

Javeed, S., Dibble, C. F., Greenberg, J. K., Zhang, J. K., Khalifeh, J. M., Park, Y., Wilson, T. J., Zager, E. L., Faraji, A. H., Mahan, M. A., Yang, L. J., Midha, R., Juknis, N., & Ray, W. Z. (2022). Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia. JAMA Netw Open, 5(11), e2243890-. https://doi.org/10.1001/jamanetworkopen.2022.43890

Khalifeh, J. M., Dibble, C. F., Van Voorhis, A., Doering, M., Boyer, M. I., Mahan, M. A., Wilson, T. J., Midha, R., Yang, L. J. S., & Ray, W. Z. (2019b). Nerve transfers in the upper extremity following cervical spinal cord injury. Part 2: Preliminary results of a prospective clinical trial. Journal of Neurosurgery: Spine, 31(5). https://doi.org/10.3171/2019.4.SPINE19399

Stanley, E. A., Hill, B., McKenzie, D. P., Chapuis, P., Galea, M. P., & N, van Z. (2022). Predicting strength outcomes for upper limb nerve transfer surgery in tetraplegia. J Hand Surg Eur Vol, 47(11), 1114–1120. https://doi.org/10.1177/17531934221113739

van Zyl, N., Hill, B., Cooper, C., Hahn, J., & Galea, M. P. (2019). Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series. Lancet, 394(10198), 565–575. https://doi.org/10.1016/S0140-6736(19)31143-2

Image credits

  1. Nerve Transfer by SCIRE
  2. Elbow Extension by SCIRE
  3. Wrist Extension by SCIRE
  4. Finger Extension by SCIRE
  5. Finger Flexion and Pinch by SCIRE
  6. Nerve and Tendon Transfers to Improve Upper Limb Function in Cervical Spinal Cord Injury (video)
  7. Nerve Transfer Level of Injury by SCIRE
  8. Time Sensitive Nerve Transfers by SCIRE
  9. Nerve Transfer Timeline by SCIRE
  10. Tendon Transfer by SCIRE
  11. Photo provided by participant (Caleb)
  12. Photo provided by participant (Ainsley)
  13. Photo provided by participant (Dan)

 

Disclaimer: This document does not provide medical advice. This information is provided for educational purposes only. Consult a qualified health professional for further information or specific medical advice. The SCIRE Project, its partners and collaborators disclaim any liability to any party for any loss or damage by errors or omissions in this publication.

Epidural Stimulation

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Authors: Dominik Zbogar and Sharon Jang | Reviewer: Susan Harkema | Published: 14 February 2022 | Updated: ~

Key Points

  • Epidural stimulation is a treatment that sends electrical signals to the spinal cord.
  • Epidural stimulation requires a surgical procedure to implant electrodes close to the spinal cord.
  • One of the ways epidural stimulation works is by replacing the signals that would normally be sent from the brain to the spinal cord before spinal cord injury (SCI).
  • Epidural stimulation affects numerous systems. Stimulation aimed at activating leg muscles may potentially also affect bowel, bladder, sexual, and cardiovascular function.
  • Studies of epidural stimulation in spinal cord injury (SCI) generally do not include a comparison group without stimulation. The benefits of epidural stimulation that have been reported have been in small numbers of participants. So, while reports thus far are encouraging, more research is necessary.
  • Because it is in the research and development phase, epidural stimulation for spinal cord injury is not part of standard care nor is it a readily available treatment.

Neuromodulation is a general term for any treatment that changes or improves nerve pathways. Different types of neuromodulation can work at different sites along the nervous system (e.g., brain, nerves, spinal cord) and may or may not be invasive (i.e., involve surgery). Epidural stimulation (also known as epidural spinal cord stimulation or direct spinal cord stimulation) is a type of invasive neuromodulation that stimulates the spinal cord using electrical currents. This is done by placing an electrode on the dura (the protective covering around the spinal cord).

To read more about other types of neuromodulation used in SCI, access these SCIRE Community articles: Functional Electrical Stimulation (FES), Transcutaneous Electrical Nerve Stimulation (TENS), sacral nerve stimulation, and intrathecal Baclofen.

Watch our neuromodulation series videos! Our experts explain experimental to more commonplace applications, and individuals with SCI describe how neuromodulation has affected their lives.

 

 

 

What is “an Epidural”?

Epi- is a prefix and means “upon”, and the dura (full name: dura mater) is a protective covering of the spinal cord. So epidural means “upon the dura”, and in the context of epidural stimulation, this is where the electrodes that stimulate the spinal cord are placed. Yes, it is also possible to have sub-dural (under the dura) or endo-dural (within the dura) electrode placement. And, there are more layers between the dura and the spinal cord, not to mention the spinal cord itself where electrodes could be placed in what is called intraspinal microstimulation. The benefit of being beneath the dura and closer to the spinal cord is that there is a more direct stimulation. Having the electrode closer to the spinal cord allows more precision with the signal going more directly to the neurons.

The drawback is that more complications can arise with closer placement because the electrodes are in the spinal cord tissue. Such placement is currently rare, experimental, or non-existent but that will change as the technology advances. Intraspinal microstimulation has been tested in animal models and is in the process of being translated to humans.

You are probably familiar with the term “epidural” already, as it is often mentioned in relation to childbirth. If a new mother says she had an epidural, what she usually means is that she had pain medication injected into the epidural space for the purpose of managing pain during birth.

We specifically discuss epidural spinal cord stimulation in this article. Spinal cord stimulation can also be applied transcutaneously. This type of spinal cord stimulation is non-invasive as the stimulating electrodes are placed on the skin. With transcutaneous stimulation, the signal has to travel a greater distance through muscle, fat, and other tissues, which means the ability to be precise with stimulation is hampered. However, it does allow for more flexibility in electrode placement and does not require surgery. There is research published or underway investigating the impact of transcutaneous stimulation in some of the areas discussed above, including hand, leg, and cardiovascular function.

Normally, input from your senses travels in the form of electrical signals through the nerves, up the spinal cord, and reaches the brain. The brain then tells the muscles or organs what to do by sending electrical signals back down the spinal cord. After a spinal cord injury, this pathway is disrupted, preventing electrical signals from traveling below the level of injury to reach where they need to go. However, the nerves, muscles, and organs can still respond below the injury to electrical signals.

Epidural stimulation works by helping the network of nerves in the spinal cord below the injury function better and take advantage of any leftover signals from the spinal cord. To do so, the stimulation must be fine-tuned to make sure the amount of stimulation is optimal for each person and a specific function, such as moving the legs.

Recent studies of the role of epidural stimulation on standing and walking have noted unexpected beneficial changes in some participants’ bowel, bladder, sexual, and temperature regulation function. This highlights both the potential for epidural stimulation to improve quality of life in multiple ways and that much research remains to be done to understand how epidural stimulation affects the body.


There may still be spared connections in the spinal cord with a complete injury.

How can someone with a complete injury regain movement control with epidural stimulation?

Being assessed with a complete injury implies that there is no spared function below the injury. However, scientists are finding that this may not be the case. Studies have found that even with a complete loss of sensory and motor function, there may be some inactive connections that are still intact across the injury site. These remaining pathways may be important for regaining movement or other functions. Another hypothesis is that epidural stimulation in combination with training may encourage stronger connections across the level of injury. Although these pathways may provide some substitution for the injured ones, they are not as effective as non-injured pathways across the injury level.

When it is decided that an individual will receive epidural stimulation, a health professional, such as a neurosurgeon, will perform an assessment of the spinal cord using magnetic resonance imaging (MRI) to determine the best place to implant the electrodes.

In most of the studies mentioned in this article, the electrodes were placed between the T9-L1 levels, though researchers are investigating the impact of epidural stimulation on hand function.


Xray image of wires connecting power and signal to electrodes (red circle) placed on a spinal cord.

There are two possible procedures. One approach is to have two surgeries. During the initial surgery, a hollow needle is inserted through the skin into the epidural space, guided using fluoroscopy, a type of X-ray that allows the surgeon to see where the needle is in real time. Potential spots on the spinal cord are tested using a stimulator. A clinician will look to see if stimulation over those areas of the spinal cord leads to a desired response. Once found, the electrode array is properly positioned over the dura and the surgery is completed. This begins a trial period where the response to epidural stimulation is monitored. During this time the electrode array is attached to an electrical generator and power supply, which is worn on a belt outside of the body. When it is shown that things are working as desired, the generator is implanted underneath the skin in the abdomen or buttocks. The generator can be rechargeable or non-rechargeable. A remote control allows one to turn the generator on or off and control the frequency and intensity of stimulation.

The second method is to only have one surgery and no trial period. This is possible due to increased knowledge in how to stimulate the spinal cord. Soon after surgery, the individual will be taught how and when to use the epidural stimulation system at home. If needed, the frequency (how often) and intensity (how strong) of the stimulation will be adjusted at follow-up appointments with the physician. In other cases, many practice sessions of learning the right way to stimulate may be needed before a person can stimulate at home.

If the epidural stimulation is used for leg control, movement training, standing, and stepping will be required to learn how to coordinate and control movement during stimulation. This is required for the recovery of voluntary movements, standing and/or walking.

Epidural stimulation can be used in all people with SCI, regardless of the level or completeness of injury. However, certain situations can make it an unsafe treatment in some. It is important to speak to a health professional about your health history before beginning any new treatment.

Epidural stimulation should not be used in the following situations:

  • By people with implanted medical devices like cardiac pacemakers
  • By people who are unable to follow instructions or provide accurate feedback
  • By people with an active infection
  • By people with psychological or psychiatric conditions (e.g., depression, schizophrenia, substance abuse)
  • By people who are unable to form clots (anticoagulopathy)
  • Near areas of spinal stenosis (narrowing of the spinal canal)

Epidural stimulation should be used with caution in the following situations:

  • By children or pregnant women
  • By people who require frequent imaging tests like ultrasound or MRI (some epidural stimulation systems are compatible)
  • By people using anticoagulant medications (blood thinners)

Epidural stimulation is generally well-tolerated, but there is a risk of experiencing negative effects.

The most common risks and side effects of epidural stimulation include:

  • Technical difficulties with equipment, such as malfunction or shifting of the electrodes that may require surgery to fix
  • Unpleasant sensations of jolting, tingling, burning, stinging, etc. (from improper remote settings)

Other less common risks and side effects of epidural stimulation include:

  • Damage to the nervous system
  • Leakage of cerebrospinal fluid
  • Increased pain or discomfort
  • Broken bones
  • Masses/lumps growing around the site of the implanted electrode

Risks specific to the surgery which involves the removal of part of the vertebral bone (laminectomy) include:

  • bleeding and/or infection at the surgical site
  • spinal deformity and instability

Proper training on how to use the equipment and using the stimulation according to the directions of your health provider can help decrease the risks of experiencing these side effects.

Neuromodulation methods to manage bladder function have usually involved stimulation of the sacral nerves (which are outside of the spinal cord), not with epidural spinal cord stimulation. This is reflected in the fact that almost no research exists regarding the effects of epidural stimulation on bowel and bladder function in the previous century.

New information on epidural stimulation relating to bladder function is coming. In the last several years, several studies (weak evidence) from a very small group of participants of participants (who were AIS A or B) have found consistent improvements in bladder function. Participants in these reports were fitted with epidural stimulators for reactivation of paralyzed leg muscles for walking and reported additional benefits of improvements in bladder and/or bowel function. However, other studies have shown small changes to bladder function and no changes to bowel function. Negative changes, such as decreased control over the bladder, have even been noticed by some participants in another study. These findings suggest that epidural stimulation may improve quality of life by safely increasing the required time between catheterizations. Fewer catheterizations and reduced pressure in the bladder would preserve lower and upper urinary tract health. More research is required, especially with respect to bowel function. It must be noted that walk training alone has been shown to improve bladder and bowel function. Epidural stimulation may provide additional improvement to bladder function in comparison to walk training alone. Neuromodulation methods to manage bladder function have usually involved stimulation of the sacral nerves (which are outside of the spinal cord), not with epidural spinal cord stimulation. This is reflected in the fact that almost no research exists regarding the effects of epidural stimulation on bowel and bladder function in the previous century.

For more information, visit our pages on Bowel and Bladder Changes After SCI!

Why does walk/stand training alone have a beneficial effect on bladder, bowel, and sexual function?

Relationships between the leg movement and nerves in the low back regions have been identified.

Some evidence suggests that walk/step training alone can create improvements in bladder/bowel function. Researchers hypothesize that the sensory information created through walking or standing provides stimulation to the nerves in the low back region, which contains the nerves to stimulate bowel, bladder, and sexual function. Research has shown that bending and straightening the legs can be enhanced by how full the bladder is and the voiding of urine.

One of the consequences of SCI is the loss of muscle mass below the injury and a tendency to accumulate fat inside the abdomen (abdominal fat or visceral fat) and under the skin (subcutaneous fat). These changes and lower physical activity after SCI increase the risk for several diseases.

A single (weak-evidence) study measured body composition in four young males with complete injuries. Participants underwent 80 sessions of stand and step training without epidural stimulation, followed by another 160 sessions of stand/step training with epidural stimulation. This involved one hour of standing and one hour of stepping five days a week. After all, training was complete, all four participants had a small reduction in their body fat, and all participants but one experienced an increase in their fat free body mass (i.e., the weight of their bones, muscles, organs, and water in the body) in comparison to their initial values prior to stimulation. While all participants experienced a reduction of fat, the amount of fat loss was minimal, ranging from 0.8 to 2.4 kg over a period of a year.

The first use of epidural stimulation was as a treatment for chronic pain in the 1960s. Since then, it has been widely used for chronic pain management in persons without SCI. However, it is important to recognize that the chronic pain experienced by those without SCI is different from the chronic neuropathic pain experienced after SCI. This may explain, to some extent, why epidural stimulation has not been as successful in pain treatment for SCI. The mechanism by which electrical stimulation of the spinal cord can help with pain relief is unclear. Some research suggests that special nerve cells that block pain signals to the brain may be activated by epidural stimulation.

There are a few studies focused on the role of epidural stimulation in managing pain after SCI. A number of other studies included a mix of different people with and without SCI. Because chronic neuropathic pain after SCI may not be the same as the chronic pain others experience, studies that do not separate mixed groups raise questions about the validity of findings. The number of individuals with SCI in these studies is often small, most were published in the 1980s and 1990s and so are quite dated, and the research is classified as weak evidence.

The results of this body of research show that some people may receive some pain reduction. Those who saw the most reduction in pain were individuals with an incomplete SCI. Also, satisfaction with pain reduction drops off over time. One study showed only 18% were satisfied 3 years after implantation. A different study looking at the long-term use of epidural stimulation for pain reduction found seven of nine individuals stopped using this method.

In the only recent study in this area, one woman with complete paraplegia (weak evidence) experienced a reduction in neuropathic pain frequency and intensity, and a reduction in average pain from 7 to 4 out of 10, with 0 being no pain and 10 being the worst imaginable pain. This improvement remained up to three months later after implantation of the epidural stimulation device.

It should be noted that the studies for pain place electrodes in different parts of the spinal cord compared to the more recent studies for voluntary movement, standing and stepping.

Refer to our article on Pain After SCI for more information!

Using epidural stimulation to improve respiratory function is useful because it contracts the diaphragm and other muscles that help with breathing. Also, these muscles are stimulated in a way that imitates a natural pattern of breathing, reducing muscle fatigue. More common methods of improving respiratory function do not use epidural stimulation, but rather, directly stimulate the nerves that innervate the respiratory muscles. While such methods significantly improve quality of life and function in numerous ways, they are not without issues, including muscle fatigue from directly stimulating the nerves.

To date, most research into using epidural stimulation to improve respiratory function has been done in animals. Recently, research has been done in humans and weak evidence suggests that epidural stimulation may:

  • help produce a cough strong enough to clear secretions independently.
  • reduce frequency of respiratory tract infections.
  • reduce the time required caregiver support.
  • help individuals project their voice better and communicate more effectively.

Long term use of epidural stimulation shows that improvements remain over years and that minimal supervision is needed, making it suitable for use in the community.

Refer to our article on Respiratory Changes After SCI for more information!

The impact of epidural stimulation on sexual function has been a secondary focus in research studies looking at standing and walking. Currently, there are reports from one male and two females.

After a training program of walk training with epidural stimulation, one young adult male reported stronger, more frequent erections and the ability to reach full orgasm occasionally, which was not possible before epidural stimulation. However, this study looked at the effects of walk training and epidural stimulation together, which took place after several months of walk training without stimulation. Because the researchers did not describe what the individual’s sexual function was like after walk training, it is difficult to say how much benefit is attributed to epidural stimulation versus walk training.

In another study with two middle-aged females 5-10 years post-injury, one reported no change in sexual function and the other reported the ability to experience orgasms with epidural stimulation, which was not possible since her injury.

Refer to our article on Sexual Health After SCI for more information!

Botulinum toxin (Botox) injections and surgically implanted intrathecal Baclofen pumps are the most common ways to manage spasticity. Baclofen pumps are not without issues, however. Many individuals do not qualify for this treatment if they have seizures or blood pressure instability, and pumps require regular refilling.

Research in the 80s and 90s on the use of epidural stimulation for spasticity did not report very positive findings. It was noted that greater benefits were found in those with incomplete injury compared to those who were complete. Another paper concluded that (weak evidence) the beneficial effects of epidural stimulation on spasticity may subside for most users over a short period of time. This, combined with the potential for equipment failure and adverse events, suggested that epidural stimulation was not a feasible approach for ongoing management of spasticity.

More recently, positive results with epidural stimulation have been observed (weak evidence). This is likely due to improvements in technology, electrode placement, and stimulation parameters. Positive findings show that participants:

  • reported fewer spasms over 2 years
  • reported a reduction in severe spasms over 2 years
  • reported a reduction in spasticity
  • reported an improvement in spasticity over 1 year
  • were able to stop or reduce the dose of antispastic medication

For more information, visit our page on Botulinum Toxin and Spasticity!

In a study with a single participant (weak evidence) investigating walking, an individual implanted with an epidural stimulator also reported improvement in body temperature control, however details were not provided. More research is required to understand the role of epidural stimulation for temperature regulation.

In severe SCI, individuals may suffer from chronic low blood pressure and orthostatic hypotension (fall in blood pressure when moving to more upright postures). These conditions can have significant effects on health and quality of life. Some recent studies have looked at how epidural stimulation affects cardiovascular function to improve orthostatic hypotension. Overall, they show (weak evidence) that epidural stimulation immediately increases blood pressure in individuals with low blood pressure while not affecting those who have normal blood pressure. They also showed that there is a training effect with repeated stimulation. This means that after consistently using stimulation for a while, normal blood pressure can occur even without stimulation when moving from lying to sitting.

Moreover, researchers are starting to believe that changes in orthostatic hypotension and blood pressure can promote changes in the immune system (Bloom et al., 2020). In the body, the blood helps to circulate immune cells so they are able to fight infections in various areas. One case study found that after 97 sessions of epidural stimulation, the participant had fewer precursors for inflammation and more precursors for immune responses. Although these changes are exciting, researchers are still unsure why this happens, and whether these effects occur with all people who are implanted with an epidural stimulator.

Refer to our article on Orthostatic Hypotension for more information!

For individuals with tetraplegia, even some recovery of hand function can mean a big improvement in quality of life. Research into using epidural stimulation to improve hand function consists of one case study (weak evidence) involving two young adult males who sustained motor complete cervical spinal cord injury over 18 months prior.

The researchers reported improvements in voluntary movement and hand function with training while using epidural stimulation implanted in the neck. Training involved grasping and moving a handgrip while receiving stimulation. For 2 months, one man engaged in weekly sessions while the other trained daily for seven days. One participant was tested for a longer time as a permanent electrode was implanted, while the other participant only received a temporary implant. Both participants increased hand strength over the course of one session. Additional sessions brought additional gradual improvements in hand strength as well as hand control (i.e., the ability to move the hand precisely). These improvements carried over to everyday activities, such as feeding, bathing, dressing, grooming, transferring in and out of bed and moving in bed. Notably, these improvements were maintained when participants were not using epidural stimulation.

Being able to control your trunk (or torso) is important for performing everyday activities such as picking things up or reaching for items. One study found that using epidural stimulation can increase the amount of distance you are able to lean forward. The improvement in forward reach occurred immediately when the stimulation was turned on. The two participants in this study were also able to reach more side to side as well, but the improvement was minor.

Learning to make voluntary movements

Voluntary movements (i.e., being able to move your body when you want to) of affected limbs can occur with the use of epidural stimulation. Researchers are still unsure of the right training regimen to optimize results. For example, one study found that many sessions of step training with epidural stimulation are required for participants to slowly regain voluntary movement of the leg and foot with epidural stimulation when lying down. However, another study found that participants were able to voluntarily move their legs with stimulation and no stand training.

Voluntary movements (i.e., being able to move your body when you want to) of affected limbs can occur with the use of epidural stimulation. Researchers are still unsure of the right training regimen to optimize results. For example, one study found that many sessions of step and stand training with epidural stimulation are required for participants to slowly regain voluntary movement of the leg and foot with epidural stimulation when lying down. However, another study found that participants were able to voluntarily move their legs with stimulation and no stand training though the amount each participant was able to move their legs with epidural stimulation varied greatly. For example, one participant was able to voluntarily move their leg without any stimulation after over 500 hours of stand training with epidural stimulation while another participant from the same study was not able to voluntarily move their leg without stimulation after training. Overall, more than 25 people can move some or all of their leg joints voluntarily from the first time they receive epidural stimulation.

More recently, research shows that some with epidural stimulators can produce voluntary movements without stimulation on and without any intensive training program. In one study, participants did not do a consistent intensive training program, although many of them attended out-patient therapy or did therapy at home. Over the period of a year, 3 of 7 participants were able to voluntarily bend their knee, and bend and straighten their hips. Additionally, of those 3 participants, 2 were able to point their toes up and down. While the number of people able to make voluntary movements without stimulation is small, many more studies are underway.

Recent research indicates that epidural stimulation can influence walking function in individuals with limited or no motor function. While these findings are exciting, researchers are still learning how to use stimulation effectively to produce walking motions. Before being able to walk again, people must be able to make voluntary movements and be able to stand.

Learning to stand

Some studies have also found that with extensive practice (e.g., 80 sessions), independent standing (i.e., standing without the help of another person, but holding onto a bar) may be achieved without epidural stimulation. Gaining the ability to stand may also occur with stand training combined with epidural stimulation. However, the findings with regard to the effect of stand training with epidural stimulation have been mixed. For example, one study showed that stand training for 5 days a week over a 4 month period with epidural stimulation resulted in independent standing for up to 10 minutes in an individual with a complete C7 injury, while another study has suggested that independent standing for 1.5 minutes can be achieved with epidural stimulation and 2 weeks of non-step specific training in an individual with complete T6 injury.

Learning to walk

Earlier research has found that epidural stimulation can help with the development of walking-like movements, but these movements do not resemble “normal” walking. Instead, they resemble slight up and down movements of the leg. Recent studies have shown that with 10 months of practicing activities while lying down on the back and on the side, in addition to standing and stepping training, people are able to take a step without assistance from another person or body weight support. While some individuals in these studies have been able to regain some walking function, they are walking at a very slow pace, ranging from 0.19 meters per second to 0.22 meters per second. This is much slower than the 0.66 meters per second required for community walking. For example, of the 4 participants in one study, two were able to walk on the ground with a walker, one was only able to walk on a treadmill, and one was able to walk on the ground while holding the hands of another person. These differences in walking abilities gained by participants were not expected.

In late 2018, one researcher demonstrated that constant epidural stimulation was interfering with proprioception, or the body’s ability to know where your limbs are in space, which ultimately hinders the walking relearning process. The solution to this problem involves activating the stimulation in a specific sequence, rather than having it continuously on. With this method and a year’s worth of training, participants were able to begin walking with an assistive device (such as a walker or poles) without stimulation. However, these individuals had to intensively practice standing and walking with stimulation for many months to produce these results. In these studies, one case of injury was reported where a participant sustained a hip fracture during walking with a body weight support. Further studies on how to individualize therapy will be necessary as the response to treatment in these studies varied greatly from person to person depending on the frequency and intensity of the stimulation.

Is it the training or the epidural stimulation?

Most of the stand/walk training conducted in the studies is with the use of a body weight support treadmill.


Arm and leg movement and blood pressure have been seen to improve with epidural stimulation, but the role of rehabilitation in these recoveries is unclear. Rehabilitation techniques can have an effect on regaining motor function. For example, step/walk training alone can help improve the ability to make voluntary movements, walking and blood pressure among individuals with incomplete injuries.  In much of the current research, epidural stimulation is paired with extensive training (typically around 80 sessions) before and after the epidural stimulator is implanted. Furthermore, these studies do not compare the effects of epidural stimulation to a control group who receives a fake stimulation (a placebo) which would help to see if stimulation truly has an effect. Without this comparison, we are unable to clearly understand the extent of recovery that is attributable to epidural stimulation versus the effects of training. However, evidence now shows that voluntary movement and cardiovascular function can be improved from the first time epidural stimulation is used, if the stimulation parameters are specific for the function and person, which supports the role of epidural stimulation in improving function.

Access to new medical treatment for those requiring it cannot come soon enough. Experimental therapies are typically expensive and not covered by health care. Rigorous and sufficient testing is required before treatments become standard practice and receive health care coverage. Epidural stimulation for improving function in SCI is a unique example because epidural stimulation technology has been used widely to treat intractable back pain in individuals without SCI. The benefit of this is that, if/when epidural stimulation for individuals with SCI is shown to be safe and effective, the move from experimental clinical practice could happen relatively quickly as a number of hurdles from regulatory bodies have already been overcome. That said, current barriers to accessing epidural stimulation noted in a survey study of doctors include a lack of strong evidence research showing benefits, a lack of guidelines for the right stimulation settings, and an inability to determine who will benefit from it.

In Canada, the cost for an institution to install an epidural stimulation system for back pain in those without spinal cord injury, which is a common procedure, was $21,595 CAD. The cost incurred by a Canadian citizen undergoing implantation in Canada is $0 as it is covered by publicly funded health care.

 

In the United States, the cost for an institution to install an epidural stimulation system for back pain in those without spinal cord injury ranged between $32,882 USD (Medicare) and $57,896 USD (Blue Cross Blue Shield). The cost incurred for American citizens in the US will vary widely depending on their insurance coverage.

In contrast, for individuals with SCI, an epidural stimulation system is reported to cost over $100,000 USD in Thailand, and higher in other countries. Prospective clients should be aware that the epidural stimulation offered by these clinics may not be the same as that in the research reported in this article.

The recommended course for those wishing to try epidural stimulation is to register in a clinical trial. Regardless, persons interested in pursuing surgery at a private clinic or registering for clinical trials will find it useful to refer to the clinical trial guidelines published by ICORD (https://icord.org/research/iccp-clinical-trials-information/) for information on what they should be aware of when considering having an epidural stimulator implanted. Research studies that involve epidural stimulation can be found by searching the clinicaltrials.gov database.

Overall, there is evidence that epidural stimulation can improve function and health after SCI in numerous ways. However, because of the invasive nature of epidural stimulator implantation, research in this area involves few participants, no control groups, and no randomization, so it is classified as weak evidence. It is therefore important to keep in mind that while these recent reports are encouraging, more rigorous studies with more participants are needed to confirm the benefits and risks of this treatment to determine its place in SCI symptom management.

Epidural stimulation is not “plug and play” technology. Each implanted device needs to be tailored to the spine of the recipient. Some individuals respond to certain stimulation settings while others may respond better to other settings. Furthermore, over time, the need to change stimulation settings or even reposition the implant to maintain effectiveness may be required. Extensive physical training appears to be required for epidural stimulation to be most effective in improving standing or walking. The additional benefit of epidural stimulation to walk training is not always clear from the literature.

For a review of how we assess evidence at SCIRE Community and advice on making decisions, please see SCIRE Community Evidence.


Parts of this page have been adapted from the SCIRE Project (Professional) “Spasticity”, “Bladder Management”, and “Pain Management” chapters:

Hsieh JTC, Connolly SJ, McIntyre A, Townson AF, Short C, Mills P, Vu V, Benton B, Wolfe DL (2016). Spasticity Following Spinal Cord Injury. In Eng JJ, Teasell RW, Miller WC, Wolfe DL, Townson AF, Hsieh JTC, Connolly SJ, Curt A, Mehta S, Sakakibara BM, editors. Spinal Cord Injury Rehabilitation Evidence. Version 6.0.

Available from: scireproject.com/evidence/rehabilitation-evidence/spasticity/

Hsieh J, McIntyre A, Iruthayarajah J, Loh E, Ethans K, Mehta S, Wolfe D, Teasell R. (2014). Bladder Management Following Spinal Cord Injury. In Eng JJ, Teasell RW, Miller WC, Wolfe DL, Townson AF, Hsieh JTC, Connolly SJ, Noonan VK, Loh E, McIntyre A, editors. Spinal Cord Injury Rehabilitation Evidence. Version 5.0: p 1-196.

Available from: scireproject.com/evidence/rehabilitation-evidence/bladder-management/

Mehta S, Teasell RW, Loh E, Short C, Wolfe DL, Benton B, Hsieh JTC (2016). Pain Following Spinal Cord Injury. In Eng JJ, Teasell RW, Miller WC, Wolfe DL, Townson AF, Hsieh JTC, Connolly SJ, Loh E, McIntyre A, Querée M, editors. Spinal Cord Injury Rehabilitation Evidence. Version 6.0: p 1-92.

Available from: scireproject.com/evidence/rehabilitation-evidence/pain-management/


Evidence for “What is epidural stimulation” is based on the following studies:

International Neuromodulation Society. (2010). Neuromodulation: An Emerging Field.

Toossi, A., Everaert, D. G., Azar, A., Dennison, C. R., & Mushahwar, V. K. (2017). Mechanically Stable Intraspinal Microstimulation Implants for Human Translation. Annals of Biomedical Engineering, 45(3), 681–694. Retrieved from http://link.springer.com/10.1007/s10439-016-1709-0

Evidence for “How does epidural stimulation work?” is based on the following studies:

Evidence for “How are epidural stimulation electrodes implanted?” is based on the following studies:

Lu, D. C., Edgerton, V. R., Modaber, M., AuYong, N., Morikawa, E., Zdunowski, S., … Gerasimenko, Y. (2016a). Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients. Neurorehabilitation & Neural Repair, 30(10), 951–962. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/27198185

Lu, D. C., Edgerton, V. R., Modaber, M., AuYong, N., Morikawa, E., Zdunowski, S., … Gerasimenko, Y. (2016b). Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients. Neurorehabilitation & Neural Repair, 30(10), 951–962.

Evidence for “Are there restrictions or precautions for using epidural stimulation?” is based on the following studies:

Moore, D. M., & McCrory, C. (2016). Spinal cord stimulation. BJA Education, 16(8), 258–263. Retrieved from https://linkinghub.elsevier.com/retrieve/pii/S2058534917300975

Wolter, T. (2014). Spinal cord stimulation for neuropathic pain: current perspectives. Journal of Pain Research, 7, 651–663.

Evidence for “Are there risks and side effects of epidural stimulation?” is based on the following studies:

Eldabe, S., Buchser, E., & Duarte, R. V. (2015). Complications of Spinal Cord Stimulation and Peripheral Nerve Stimulation Techniques: A Review of the Literature. Pain Medicine, 17(2), pnv025. Retrieved from https://academic.oup.com/painmedicine/article-lookup/doi/10.1093/pm/pnv025

Taccola, G., Barber, S., Horner, P. J., Bazo, H. A. C., & Sayenko, D. (2020). Complications of epidural spinal stimulation: lessons from the past and alternatives for the future. Spinal Cord, 58(10), 1049–1059. Retrieved from http://dx.doi.org/10.1038/s41393-020-0505-8

Evidence for “Epidural stimulation and bladder and bowel function” is based on the following studies:

Herrity, A. N., Williams, C. S., Angeli, C. A., Harkema, S. J., & Hubscher, C. H. (2018). Lumbosacral spinal cord epidural stimulation improves voiding function after human spinal cord injury. Scientific Reports, 8(1), 1–11. Retrieved from http://dx.doi.org/10.1038/s41598-018-26602-2

Herrity, April N., Aslan, S. C., Ugiliweneza, B., Mohamed, A. Z., Hubscher, C. H., & Harkema, S. J. (2021). Improvements in Bladder Function Following Activity-Based Recovery Training With Epidural Stimulation After Chronic Spinal Cord Injury. Frontiers in Systems Neuroscience, 14(January), 1–14.

Hubscher, C. H., Herrity, A. N., Williams, C. S., Montgomery, L. R., Willhite, A. M., Angeli, C. A., & Harkema, S. J. (2018). Improvements in bladder, bowel and sexual outcomes following task-specific locomotor training in human spinal cord injury. Plos One, 1–26.

Darrow, D., Balser, D., Netoff, T. I., Krassioukov, A., Phillips, A., Parr, A., & Samadani, U. (2019). Epidural Spinal Cord Stimulation Facilitates Immediate Restoration of Dormant Motor and Autonomic Supraspinal Pathways after Chronic Neurologically Complete Spinal Cord Injury. Journal of Neurotrauma, 2336, neu.2018.6006. Retrieved from https://www.liebertpub.com/doi/10.1089/neu.2018.6006

Beck, L., Veith, D., Linde, M., Gill, M., Calvert, J., Grahn, P., … Zhao, K. (2020). Impact of long-term epidural electrical stimulation enabled task-specific training on secondary conditions of chronic paraplegia in two humans. Journal of Spinal Cord Medicine, 0(0), 1–6. Retrieved from https://doi.org/10.1080/10790268.2020.1739894

Evidence for “Epidural stimulation and body composition” is based on the following studies:

Terson de Paleville, D. G. L., Harkema, S. J., & Angeli, C. A. (2019). Epidural stimulation with locomotor training improves body composition in individuals with cervical or upper thoracic motor complete spinal cord injury: A series of case studies. The Journal of Spinal Cord Medicine, 42(1), 32–38.

Evidence for “Epidural stimulation and pain” is based on the following studies:

Guan, Y. (2012). Spinal cord stimulation: neurophysiological and neurochemical mechanisms of action. Current Pain and Headache Reports, 16(3), 217–225.

Marchand, S. (2015). Spinal cord stimulation analgesia. PAIN, 156(3), 364–365.

Tasker, R. R., DeCarvalho, G. T., & Dolan, E. J. (1992). Intractable pain of spinal cord origin: clinical features and implications for surgery. Journal of Neurosurgery.

Cioni, B., Meglio, M., Pentimalli, L., & Visocchi, M. (1995). Spinal cord stimulation in the treatment of paraplegic pain. Journal of Neurosurgery, 82(1), 35–39.

Warms, C. A., Turner, J. A., Marshall, H. M., & Cardenas, D. D. (2002). Treatments for chronic pain associated with spinal cord injuries: many are tried, few are helpful. Clinical Journal of Pain, 18(3), 154–163.

Reck, T. A., & Landmann, G. (2017). Successful spinal cord stimulation for neuropathic below-level spinal cord injury pain following complete paraplegia: a case report. Spinal Cord Series and Cases, 3, 17049.

Evidence for “Epidural stimulation and respiratory function” is based on the following studies:

Hachmann, J. T., Grahn, P. J., Calvert, J. S., Drubach, D. I., Lee, K. H., & Lavrov, I. A. (2017). Electrical Neuromodulation of the Respiratory System After Spinal Cord Injury. Mayo Clinic Proceedings, 92(9), 1401–1414. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/28781176

DiMarco, A. F., Kowalski, K. E., Geertman, R. T., & Hromyak, D. R. (2006). Spinal cord stimulation: a new method to produce an effective cough in patients with spinal cord injury. American Journal of Respiratory and Critical Care Medicine, 173(12), 1386–1389.

DiMarco, A. F., Kowalski, K. E., Geertman, R. T., & Hromyak, D. R. (2009). Lower thoracic spinal cord stimulation to restore cough in patients with spinal cord injury: results of a National Institutes of Health-sponsored clinical trial. Part I: methodology and effectiveness of expiratory muscle activation. Archives of Physical Medicine & Rehabilitation, 90(5), 717–725.

Harkema, S. J., Wang, S., Angeli, C. A., Chen, Y., Boakye, M., Ugiliweneza, B., & Hirsch, G. A. (2018). Normalization of Blood Pressure With Spinal Cord Epidural Stimulation After Severe Spinal Cord Injury. Frontiers in Human Neuroscience, 12, 83.

DiMarco, A. F., Kowalski, K. E., Hromyak, D. R., & Geertman, R. T. (2014). Long-term follow-up of spinal cord stimulation to restore cough in subjects with spinal cord injury. The Journal of Spinal Cord Medicine, 37(4), 380–388.

Evidence for “Epidural stimulation and sexual function” is based on the following studies:

Harkema, S., Gerasimenko, Y., Hodes, J., Burdick, J., Angeli, C., Chen, Y., … Edgerton, V. R. (2011). Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: A case study. The Lancet, 377(9781), 1938–1947.

Darrow, D., Balser, D., Netoff, T. I., Krassioukov, A., Phillips, A., Parr, A., & Samadani, U. (2019). Epidural Spinal Cord Stimulation Facilitates Immediate Restoration of Dormant Motor and Autonomic Supraspinal Pathways after Chronic Neurologically Complete Spinal Cord Injury. Journal of Neurotrauma, 2336, neu.2018.6006. Retrieved from https://www.liebertpub.com/doi/10.1089/neu.2018.600

Evidence for “Epidural stimulation and spasticity” is based on the following studies:

Nagel, S. J., Wilson, S., Johnson, M. D., Machado, A., Frizon, L., Chardon, M. K., … Howard, M. A. 3rd. (2017). Spinal Cord Stimulation for Spasticity: Historical Approaches, Current Status, and Future Directions. Neuromodulation: Journal of the International Neuromodulation Society, 20(4), 307–321.

Dekopov, A. V., Shabalov, V. A., Tomsky, A. A., Hit, M. V., & Salova, E. M. (2015). Chronic spinal cord stimulation in the treatment of cerebral and spinal spasticity. Stereotactic and Functional Neurosurgery.

Dimitrijevic, M. R., Illis, L. S., Nakajima, K., Sharkey, P. C., & Sherwood, A. M. (1986). Spinal cord stimulation for the control of spasticity in patients with chronic spinal cord injury: II. Neurophysiologic observations. Central Nervous System Trauma, 3(2), 145–152. Retrieved from http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med2&AN=3490313

Midha, M., & Schmitt, J. K. (1998). Epidural spinal cord stimulation for the control of spasticity in spinal cord injury patients lacks long-term efficacy and is not cost-effective. Spinal Cord, 36(3), 190–192. Retrieved from https://www.nature.com/articles/3100532

Barolat, G., Singh-Sahni, K., Staas, W. E. J., Shatin, D., Ketcik, B., & Allen, K. (1995). Epidural spinal cord stimulation in the management of spasms in spinal cord injury: a prospective study. Stereotactic & Functional Neurosurgery, 64(3), 153–164.

Dekopov, A. V., Shabalov, V. A., Tomsky, A. A., Hit, M. V., & Salova, E. M. (2015). Chronic spinal cord stimulation in the treatment of cerebral and spinal spasticity. Stereotactic and Functional Neurosurgery.

Pinter, M. M., Gerstenbrand, F., & Dimitrijevic, M. R. (2000). Epidural electrical stimulation of posterior structures of the human lumbosacral cord: 3. Control Of spasticity. Spinal Cord, 38(9), 524–531. Retrieved from https://www.nature.com/articles/3101040

Evidence for “Epidural stimulation and temperature regulation” is based on the following studies:

Edgerton, V. R., & Harkema, S. (2011). Epidural stimulation of the spinal cord in spinal cord injury: current status and future challenges. Expert Review of Neurotherapeutics, 11(10), 1351–1353. Retrieved from http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med7&AN=21955190

Harkema, S. J., Gerasimenko, Y., Hodes, J., Burdick, J., Angeli, C., Chen, Y., … Edgerton, V. R. (2011). Supplementary index: Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: A case study. The Lancet, 377(9781), 1938–1947. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21601270

Evidence for “Epidural stimulation and cardiovascular function” is based on the following studies:

Bloom, O., Wecht, J. M., Legg Ditterline, B. E., Wang, S., Ovechkin, A. V., Angeli, C. A., … Harkema, S. J. (2020). Prolonged Targeted Cardiovascular Epidural Stimulation Improves Immunological Molecular Profile: A Case Report in Chronic Severe Spinal Cord Injury. Frontiers in Systems Neuroscience, 14(October), 1–11.

Evidence for “Epidural stimulation and hand function” is based on the following study:

Lu, D. C., Edgerton, V. R., Modaber, M., AuYong, N., Morikawa, E., Zdunowski, S., … Gerasimenko, Y. (2016a). Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients. Neurorehabilitation & Neural Repair, 30(10), 951–962. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/27198185

Evidence for “Epidural stimulation and movement: trunk control” is based on the following studies:

Evidence for “Epidural stimulation and movement: voluntary movements” is based on the following studies:

Rejc, E., Angeli, C. A., Bryant, N., & Harkema, S. J. (2017). Effects of Stand and Step Training with Epidural Stimulation on Motor Function for Standing in Chronic Complete Paraplegics. Journal of Neurotrauma, 34, 1787–18023. Retrieved from www.liebertpub.com

Angeli, C. A., Edgerton, V. R., Gerasimenko, Y. P., & Harkema, S. J. (2014). Altering spinal cord excitability enables voluntary movements after chronic complete paralysis in humans. Brain, 137(Pt 5), 1394–1409. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999714/

Peña Pino, I., Hoover, C., Venkatesh, S., Ahmadi, A., Sturtevant, D., Patrick, N., Freeman, D., Parr, A., Samadani, U., Balser, D., Krassioukov, A., Phillips, A., Netoff, T. I., & Darrow, D. (2020). Long-Term Spinal Cord Stimulation After Chronic Complete Spinal Cord Injury Enables Volitional Movement in the Absence of Stimulation. Frontiers in systems neuroscience14, 35. https://doi.org/10.3389/fnsys.2020.00035

Evidence for “Epidural stimulation and movement: walking and standing” is based on the following studies:

Grahn, P. J., Lavrov, I. A., Sayenko, D. G., Straaten, M. G. Van, Gill, M. L., Strommen, J. A., … Lee, K. H. (2017). Enabling Task-Specific Volitional Motor Functions via Spinal Cord Neuromodulation in a Human with Paraplegia. Mayo Clinic Proceedings, 92(4), 544–554. Retrieved from http://dx.doi.org/10.1016/j.mayocp.2017.02.014

Harkema, S. J., Gerasimenko, Y., Hodes, J., Burdick, J., Angeli, C., Chen, Y., … Edgerton, V. R. (2011). Supplementary index: Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: A case study. The Lancet, 377(9781), 1938–1947. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21601270

Rejc, E., Angeli, C. A., Atkinson, D., & Harkema, S. J. (2017). Motor recovery after activity-based training with spinal cord epidural stimulation in a chronic motor complete paraplegic. Scientific Reports, 7(1), 13476. Retrieved from www.nature.com/scientificreports

Rejc, E., Angeli, C., & Harkema, S. (2015). Effects of Lumbosacral Spinal Cord Epidural Stimulation for Standing after Chronic Complete Paralysis in Humans. PLoS ONE [Electronic Resource], 10(7), e0133998. Retrieved from http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med8&AN=26207623

Grahn, P. J., Lavrov, I. A., Sayenko, D. G., Straaten, M. G. Van, Gill, M. L., Strommen, J. A., … Lee, K. H. (2017). Enabling Task-Specific Volitional Motor Functions via Spinal Cord Neuromodulation in a Human with Paraplegia. Mayo Clinic Proceedings, 92(4), 544–554. Retrieved from http://dx.doi.org/10.1016/j.mayocp.2017.02.014

Gill, M. L., Grahn, P. J., Calvert, J. S., Linde, M. B., Lavrov, I. A., Strommen, J. A., … Zhao, K. D. (2018). Neuromodulation of lumbosacral spinal networks enables independent stepping after complete paraplegia. Nature Medicine, 24(11), 1677–1682. Retrieved from https://doi.org/10.1038/s41591-018-0175-7

Angeli, C. A., Boakye, M., Morton, R. A., Vogt, J., Benton, K., Chen, Y., … Harkema, S. J. (2018). Recovery of Over-Ground Walking after Chronic Motor Complete Spinal Cord Injury. New England Journal of Medicine, 379(13), 1244–1250. Retrieved from http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=medl&AN=30247091

van de Port, I. G., Kwakkel, G., & Lindeman, E. (2008). Community ambulation in patients with chronic stroke: How is it related to gait speed? Journal of Rehabilitation Medicine, 40(1), 23–27.

Wagner, F. B., Mignardot, J.-B., Le Goff-Mignardot, C. G., Demesmaeker, R., Komi, S., Capogrosso, M., … Courtine, G. (2018). Targeted neurotechnology restores walking in humans with spinal cord injury. Nature, 563(7729), 65–71. Retrieved from http://www.nature.com/articles/s41586-018-0649-2

Angeli, C. A., Edgerton, V. R., Gerasimenko, Y. P., & Harkema, S. J. (2014). Altering spinal cord excitability enables voluntary movements after chronic complete paralysis in humans. Brain, 137(Pt 5), 1394–1409. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999714/

Carhart, M. R., He, J., Herman, R., D’Luzansky, S., & Willis, W. T. (2004). Epidural spinal-cord stimulation facilitates recovery of functional walking following incomplete spinal-cord injury. IEEE Transactions on Neural Systems & Rehabilitation Engineering, 12(1), 32–42. Retrieved from http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=med5&AN=15068185

Harkema, S. J., Wang, S., Angeli, C. A., Chen, Y., Boakye, M., Ugiliweneza, B., & Hirsch, G. A. (2018). Normalization of Blood Pressure With Spinal Cord Epidural Stimulation After Severe Spinal Cord Injury. Frontiers in Human Neuroscience, 12, 83.

Legg Ditterline, B. E., Aslan, S. C., Wang, S., Ugiliweneza, B., Hirsch, G. A., Wecht, J. M., & Harkema, S. (2020). Restoration of autonomic cardiovascular regulation in spinal cord injury with epidural stimulation: a case series. Clinical Autonomic Research, (0123456789), 2–5. Retrieved from https://doi.org/10.1007/s10286-020-00693-2

Evidence for “Costs and availability of epidural stimulation” is based on the following studies:

Solinsky, R., Specker-Sullivan, L., & Wexler, A. (2020). Current barriers and ethical considerations for clinical implementation of epidural stimulation for functional improvement after spinal cord injury. Journal of Spinal Cord Medicine, 43(5), 653–656.

Kumar, K., & Bishop, S. (2009). Financial impact of spinal cord stimulation on the healthcare budget: a comparative analysis of costs in Canada and the United States. Journal of Neurosurgery: Spine.

Image credits
  1. Image by SCIRE Community Team
  2. Image by SCIRE Community Team
  3. Image by SCIRE Community Team
  4. Image by SCIRE Community Team
  5. Adapted from image made by Mysid Inkscape, based on plate 770 from Gray’s Anatomy (1918, public domain).
  6. Pregnant woman holding tummy. [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)] via Google Images.
  7. Edited from Nervous system, Musculature. ©Servier Medical Art. CC BY 3.0.
  8. Neurons ©NIH Image Gallery. CC BY-NC 2.0.
  9. Image by SCIRE Community
  10. bladder by fauzan akbar from the Noun Project
  11. Large Intestine by BomSymbols from the Noun Project
  12. Feet by Matt Brooks from the Noun Project
  13. hip by priyanka from the Noun Project
  14. visceral fat by Olena Panasovska from the Noun Project
  15. Lightning by FLPLF from the Noun Project
  16. Lungs by dDara from the Noun Project
  17. Love by Jake Dunham from the Noun Project
  18. Male by Centis MENANT from the Noun Project
  19. Female by Centis MENANT from the Noun Project
  20. Image by SCIRE Community
  21. Temperature by Adrien Coquet from the Noun Project
  22. Heart by Nick Bluth from the Noun Project
  23. Image by SCIRE Community
  24. Hand by Sergey Demushkin from the Noun Project
  25. Torso by Ronald Vermeijs from the Noun Project
  26. Yoga posture by Gan Khoon Lay from the Noun Project
  27. Standing by Rafo Barbosa from the Noun Project
  28. Walking by Samy Menai from the Noun Project
  29. Image by SCIRE Community
  30. Canada by Yohann Berger from the Noun Project
  31. United States of America by Yohann Berger from the Noun Project

 

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