Regrowing the spinal cord
Cut nerve fibres do not regrow in the adult spinal cord, so paralysis is usually permanent; stimulation and stem cells give partial gains.
Open in the interactive tree →Nerve fibres in the adult brain and spinal cord rarely regrow after injury. A scar and growth-blocking signals stop them, and surviving fibres may lose their insulation. Rehabilitation and stimulation can retrain surviving circuits, but a real repair would reconnect cut fibres to the right targets.
As of October 2026
WHO's fact sheet puts 15.4 million people worldwide as living with spinal cord injury in 2021. In July 2026 Keio University reported in Nature Medicine the first transplant of stem-cell-derived neural progenitor cells into people with recent injuries (four patients in the trial): no tumours or serious related adverse events over up to four years, and more improvement than a historical comparison group, with a chronic-injury trial expected to start recruiting in 2027. Stimulation is further along: ONWARD's non-invasive ARC-EX is FDA-cleared to improve hand strength and sensation in chronic incomplete injury, and a sham-controlled pivotal trial of its implanted ARC-IM for blood-pressure instability started in the first quarter of 2026 (company reports). In mice, a 2023 gene therapy made cut fibres regrow so that animals with complete injuries walked again, and a 2024 Nature cell atlas from the same Lausanne group maps how injured cord cells change.
What is missing
- Ways to make cut nerve fibres grow across the scar and reconnect to the right targets
- Treatments that work in chronic injury, years after the accident, when most patients are seen
- Cells or drugs that restore insulation and keep surviving fibres alive
- Controlled trials with agreed measures of recovery; many reports rely on historical comparison groups
- Affordable devices and care outside rich countries
Becomes possible once solved
- Standing, walking and hand function after paralysis
- Control of bladder, bowel and blood pressure
- Repair of other damage in the brain and spinal cord
- Less lifelong disability: over 60 percent of adults with spinal cord injury are unemployed, per WHO
Open steps
- Cells for fresh injuries Low AI leverageShow in larger controlled trials that stem-cell-derived progenitors given weeks after injury improve recovery safely.
- Repair years after injury Low AI leverageFind treatments for chronic injury, when the scar is mature and most patients are seen; Keio expects a chronic-injury trial to recruit from 2027.
- Regrow fibres to the right target Medium AI leverageCombine growth programmes in selected neurons, support across the scar and guidance cues so cut fibres reconnect, as done in mice in 2023.
- Smarter stimulation and brain links High AI leverageBuild stimulators and brain-to-spine bridges that adapt to each person, work at home and use AI to decode movement intent.
- Agree how to measure recovery Medium AI leverageSettle on outcome measures and natural-recovery models so trials without large control groups can still show whether a treatment works.
Where AI could help
Medium AI leverage. AI decodes brain signals, tunes stimulation and mines cell atlases, but regrowth and safety need years of animal work and slow trials.
- Decoding movement intent and tuning stimulation for each person
- Mining single-cell and spatial atlases for repair targets
- Designing gene-therapy payloads and delivery vectors
Shown so far
- In 2024 a Lausanne team published in Nature four single-cell and spatial atlases of spinal cord injury in mice, analysed with newly developed machine-learning methods, and used them to design a targeted gene therapy based on the loss of astrocyte response in aged animals. source
- In 2023 an AI algorithm decoded motor intent from brain signals in real time in one man with a spinal cord injury, letting him stand, walk with crutches and climb stairs through a brain-to-spine implant. source