Patch or Surgery? Comparing Two Paths Toward Spinal Cord Injury Recovery

By Catherine Feng

Most of us move through our day without thinking twice about it: reaching for our phone, walking to work, grabbing a coffee. The body just cooperates, and we rarely stop to appreciate it. But approximately 15.4 million people worldwide are living with a spinal cord injury (World Health Organization, 2024), and for every one of them, some part of that cooperation is gone. Many movements that once required no thought now require everything. Sometimes it starts in a split second: a car crash, a bad fall, a dive into shallow water. Other times it creeps in slowly: a tumour, a degenerative disease, a condition damaging the spinal cord over time.

Depending on where the injury occurs along the spine, a person might lose the ability to walk, to use their hands, to feel a hot stove or a hug, to control their bladder, or to breathe independently. Beyond the physical, there is a ripple effect: adapting a home, relearning daily routines from scratch, depending on others for things you once did automatically. For a long time, medicine had no real answer to offer. The damage was done, the limits were set, and the goal became adaptation rather than recovery. But researchers are now challenging that story, and a technology called electrical spinal cord stimulation is at the centre of it all.

Silent, Not Gone

Your spinal cord isn’t just a passive cable carrying messages from your brain to your muscles. It’s made of millions of nerve cells, called neurons, that pass signals to each other like a relay team handing off a baton. When groups of neurons are wired together to perform a specific task, scientists call them neural circuits. Some of the neural circuits in your spinal cord specialize in rhythmic movements like walking. They know how to alternate your left and right legs, and when to bend and straighten each joint. The brain gives the command, and these circuits handle the execution.

After a spinal cord injury, the connection between the brain and its neural circuits is damaged. The baton stops reaching the runners below the injury. But the runners are often still there. The circuits aren’t necessarily destroyed; they’re just not getting the command they need to execute their task. In many cases, some neurons survive the injury and still carry faint messages from the brain. Those messages are too weak to get through on their own, and get lost on the way.

This is where electrical spinal cord stimulation comes in. Small electrical pulses are delivered to the spinal cord, usually below the injury. They don’t carry the baton themselves, and they don’t tell the legs what to do. Instead, they make the circuits below the injury more responsive, so it takes less of a signal to switch them on. Now, even the weak messages that make it past the injury can be strong enough to produce movement. When the stimulation is turned off, those messages usually go back to being too weak to have an effect.

For people with spinal cord injuries, this began to shift the goal from adaptation to recovery. When electrical stimulation is used repeatedly over months, usually alongside exercises like standing, stepping, or hand training, the effects can start to last. Repeated practice strengthens the connections that survived the injury. Over time, some people have regained movement that stays even after the stimulation is turned off, and some have noticed improvements in sensation, such as feeling touch in areas that had been numb (Wagner et al., 2018; Moritz et al., 2024). With enough time, stimulation could help the spinal cord relearn how to function again.

Patch vs. Surgery

Stimulation can be delivered in two ways: one goes under the skin, and the other sits on top of it (see Figure 1). The first, epidural stimulation, requires surgery to place a thin strip of electrodes in the epidural space, outside the dura mater (the protective membrane surrounding the spinal cord). A small battery is placed under the skin, much like a pacemaker. It means general anaesthesia, a hospital stay, and time to recover, but the electrodes sit right next to their target. This is the approach behind the 2018 studies in which people walked again with support, though these included only eight participants in total, and not all of them regained walking (Angeli et al., 2018; Gill et al., 2018; Wagner et al., 2018).

The second, transcutaneous stimulation (meaning “through the skin”), skips surgery entirely. Electrodes are placed on the skin over the spine, and the current travels through skin, muscle, and bone to reach the cord. It’s cheaper, far more accessible, and can be added to a regular therapy session. The trade-off is that the signal has more to travel through, so it’s less focused by the time it arrives. Even so, in a 2024 trial of 60 people with long-standing neck-level injuries, 72% meaningfully improved both arm and hand strength and function when it was paired with therapy (Moritz et al., 2024).

Figure 1. Epidural stimulation (left) deliPvers current through electrodes implanted beside the spinal cord, keeping it focused. Transcutaneous stimulation (right) uses electrodes placed on the skin, avoiding surgery, but the current spreads out on its way to the cord. Diagram by the author using illustration elements from Canva.

So which works better? Nobody fully knows yet. Because the implanted electrodes sit so close to the cord, epidural stimulation tends to produce stronger responses; in one study, it boosted muscle responses more than the patch did (Murray et al., 2025). But more intense doesn’t automatically mean better recovery. Researchers still don’t know whether recovery depends more on precise stimulation or on activating a wider part of the spinal network, which a patch does naturally. A recent review found that epidural stimulation helped people across all injury severities, while the patch mainly helped those with incomplete injuries. Still, without head-to-head trials, the field can’t say for certain who each method suits best (Bhatia et al., 2026).

Who Gets to Recover?

If I had to pick a side, I’d say the patch deserves more attention than it gets. Epidural stimulation has produced the headlines, and for some people with the most severe injuries, it may remain the better option. But a treatment only helps the people who can get it. Surgery needs a neurosurgeon, an implanted device, and a specialized centre. A patch needs a therapist and a clinic. Access is already uneven: worldwide, as few as 5–35% of people can get a wheelchair (World Health Organization, 2024). If basic mobility aids are out of reach for most, an implanted neurotechnology will be even further out of reach. If transcutaneous stimulation can deliver even part of the same benefit, it could reach far more people. What we need now are studies that compare the two directly, in the same patients, over years rather than months.

Stimulation suggests the injured spinal cord can recover more than we once believed, though much remains to be tested. The next challenge is access: a therapy confined to surgical centres is a scientific triumph; one available in any clinic would be a public health triumph.       

References

Angeli, C. A., Boakye, M., Morton, R. A., Vogt, J., Benton, K., Chen, Y., Ferreira, C. K., & 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. https://doi.org/10.1056/NEJMoa1803588

Bhatia, S., de Freitas, R. M., Kanter, J. H., Buell, T. J., Okonkwo, D. O., Pirondini, E., Prat-Ortega, G., Capogrosso, M., & Gerszten, P. C. (2026). Epidural versus transcutaneous spinal cord stimulation for motor recovery after spinal cord injury: A comparative analysis [Preprint]. medRxiv. https://doi.org/10.64898/2026.06.22.26356277

Gill, M. L., Grahn, P. J., Calvert, J. S., Linde, M. B., Lavrov, I. A., Strommen, J. A., Beck, L. A., Sayenko, D. G., Van Straaten, M. G., Drubach, D. I., Veith, D. D., Thoreson, A. R., Lopez, C., Gerasimenko, Y. P., Edgerton, V. R., Lee, K. H., & Zhao, K. D. (2018). Neuromodulation of lumbosacral spinal networks enables independent stepping after complete paraplegia. Nature Medicine, 24(11), 1677–1682. https://doi.org/10.1038/s41591-018-0175-7

Moritz, C., Field-Fote, E. C., Tefertiller, C., van Nes, I., Trumbower, R., Kalsi-Ryan, S., Purcell, M., Janssen, T. W. J., Krassioukov, A., Morse, L. R., Zhao, K. D., Guest, J., Marino, R. J., Murray, L. M., Wecht, J. M., Rieger, M., Pradarelli, J., Turner, A., D’Amico, J., … Courtine, G. (2024). Non-invasive spinal cord electrical stimulation for arm and hand function in chronic tetraplegia: A safety and efficacy trial. Nature Medicine, 30(5), 1276–1283. https://doi.org/10.1038/s41591-024-02940-9

Murray, L. M., McIntosh, J. R., Goldsmith, J. A., Wu, Y.-K., Liu, M., Sanford, S. P., Joiner, E. F., Mandigo, C., Virk, M. S., Tyagi, V., Carmel, J. B., & Harel, N. Y. (2025). Timing-dependent synergies between noninvasive motor cortex and spinal cord stimulation in chronic cervical spinal cord injury. Clinical Neurophysiology, 180, Article 2111372. https://doi.org/10.1016/j.clinph.2025.2111372

Wagner, F. B., Mignardot, J.-B., Le Goff-Mignardot, C. G., Demesmaeker, R., Komi, S., Capogrosso, M., Rowald, A., Seáñez, I., Caban, M., Pirondini, E., Vat, M., McCracken, L. A., Heimgartner, R., Fodor, I., Watrin, A., Seguin, P., Paoles, E., Van Den Keybus, K., Eberle, G., … Courtine, G. (2018). Targeted neurotechnology restores walking in humans with spinal cord injury. Nature, 563(7729), 65–71. https://doi.org/10.1038/s41586-018-0649-2

World Health Organization. (2024, April 16). Spinal cord injury [Fact sheet]. https://www.who.int/news-room/fact-sheets/detail/spinal-cord-injury