Comment by vilhelm_s

They cite this paper which gives the concept: https://www.sciencedirect.com/science/article/pii/S002234681... . The mechanism of injury in spina bifida is that the spinal cord gets exposed and damaged. Current surgery will close the spinal canal to prevent further exposure, but it doesn't do anything to reverse the damage that has already happened. The stem cells integrate into the neural tissue and hopefully help the axons heal.