Considering these trials were done on chronic patients, including some with failed backs, you would think that there would have been many follow up double blind placebo trials to confirm the outstanding results from these minimal treatment approaches.
Much more money to be made in open surgery and selling pieces of metal I suppose.
Biochemical injection treatment for discogenic low... [Spine J. 2003 May-Jun] - PubMed result
Treatment of painful advanced internal lumbar disc... [Pain Physician. 2006] - PubMed result