2019 Position Statement from the International Society for the Advancement of Spine Surgery on Cervical and Lumbar Disc Replacements Gregory D. Schroeder MD, Alexander R. Vaccaro MD, PhD, MBA, Srikanth N. Divi, MD, Ariana A. Reyes, BS, Dhruv K.C. Goyal, BA, Frank  M Phillips MD, Jack Zigler MD Introduction: Cervical and lumbar degenerative disc disease...