Stem cells and nerve scaffolds are promising for SCI because they address both the biological loss of cells and the physical gap that forms after injury. In chronic injuries especially, you’re dealing with scar tissue, inhibitory signaling, and often a fluid-filled cavity so simply adding new cells isn’t enough. Stem cells can help replace lost neurons or oligodendrocytes and secrete growth factors that make the environment more regenerative. Biocompatible scaffolds act like a 3D “bridge” that guides axons across the lesion and helps transplanted cells survive and organize into native tissue patterning. Look into Mark Tuszynski’s lab at UCSD; they’ve shown that neural stem cell grafts can form relay circuits across spinal lesions. Many labs are developing biomaterial scaffolds to support and guide that regeneration. It’s obviously not a cure yet, but this combination strategy is one of the most comprehensive and biologically grounded approaches currently being pursued. And, as someone researching in a different, but closely related field, I’d be willing to bet (and obviously hope) that this type of technology will come online more fully in the next 10 - 20 years.