Dr. John Regan during his medical career was one of the key physicians within Texas Back Institute, the first spine specialty clinic in the United States. Over the following years, Dr. Regan was a partner in this physician-owned spine Center of Excellence as it grew quickly from 1986 to 1995 to become the largest and most respected spine center in the world.

In 2001, Cedars Sinai Institute in Southern California recruited Dr. Regan to relocate to Southern California and help the hospital create a similarly respected spine program for the Los Angeles region. For the next four years, as Director of the Cedars Sinai Institute for Spinal Disorders, Dr. Regan helped Cedars Sinai improve their spine program accordingly for the Los Angeles area.