I prefer to invest in biotechs where there is no significant risk that the mechanism-of-action doesn't work.
With this in mind, you might want to drill down some on NVIV. Their first product is neuro-scaffolding that apparently works quite well and is simply the first step and foundation for what might be a whole new paradigm in SCI treatment that might include insertion of stem cells and/or olfactory sheathing cells autologously harvested from the patients to increase the likelihood of new cell generation.
More on Olfactory ensheathing cells can be found in the following NYer article: