After traumatic SCI, secondary neurologic injury happens in large part because of cellular-level events including demyelination and axonal degeneration. Bone marrow, with its associated pluripotent stem cells, is purported to enhance the cellular milieu for neuronal regrowth. This therapeutic option has an undeniable theoretical appeal. To date, a very limited number of human studies have been performed with mixed results. Generally, stem cell therapy enjoys a wide and sometimes over-enthusiastic public profile in terms of clinical therapeutic potential, and these studies should help contextualize the current level of efficacy in traumatic SCI.
One prospective randomized controlled trial in human subjects has been performed for acute stem cell transplantation after SCI. In their pilot study, Chhabra et al. (2016) recruited 21 individuals who had undergone surgical stabilization and/or decompression for AIS A injuries. They performed either intralesional, intrathecal, or no injection of autologous stem cells. Notably, stem cell transplantation was performed as a second procedure, at 10-14 days post injury, after the primary surgery had been performed. In this study, there was a similar safety profile between groups, with no differences in complications, and similar improvements in functional status measured in each group. There was no difference in neurological recovery, electrophysiological data, functional status or urodynamic profiles between groups at 6 or 12 months.
An additional case series from China (Akbary & Arora 2014) reported on the simultaneous transplantation of autologous bone marrow at the time of the primary surgery in ten AIS A individuals. At six-week follow-up, two individuals demonstrated some improvement in AIS sensory scores, but no individual demonstrated any motor or functional improvement at 6 weeks or 3 months.
There is level 1b evidence based on one randomized controlled trial (Chhabra et al. 2016) and one pre-post study (Akbary & Arora 2014) that autologous bone marrow transfer is not effective in promoting neurological or functional recovery in individuals with traumatic SCI.