No one knows how long the therapeutic effects of a stem cell procedure will last. Our surgeons have been using bone marrow stem cells in spine surgery since the 1990s. Our experience is that about 5% of patients have a second stem cell procedure done within two years of the first procedure. Having a second procedure does not in any way increase any risks. Our experience indicates a second procedure often provides the additional relief a patient is seeking. If a patient doesn’t achieve adequate results within three months of the first procedure, a second procedure should be given serious consideration.