Optimized epidural stimulation restored volitional hand function in two individuals with severe chronic cervical spinal cord injury.

This early-phase trial represents the first human implantation of a 32-contact cervical epidural paddle array in two individuals with severe chronic cervical spinal cord injury. The procedure utilized location-, intensity-, and frequency-optimized stimulation guided by individualized motor pool recruitment maps, administered in home and community settings over several months of autonomous use. No explicit control group was reported, and the comparator was previously unattainable function.

Primary outcomes demonstrated the restoration of volitional hand opening, closing, and coordinated upper-limb movements. Specifically, complex reach-grasp-lift-release sequences were restored with a success rate greater than 91%. Secondary outcomes included substantial gains in range of motion, grip strength, and pinch strength, though absolute numbers and statistical measures were not reported.

Safety data were not reported regarding adverse events, serious adverse events, discontinuations, or specific tolerability metrics. Key limitations include the very small sample size of two participants and the absence of a control group, which precludes definitive causal conclusions. Funding sources and conflicts of interest were not reported. The study establishes a mechanistically grounded and translational framework for restoring upper-limb function after chronic severe spinal cord injury, but generalizability beyond these two individuals and long-term durability beyond several months remain uncertain.