title: Regional variations in spine surgery: current challenges and potential solutions.
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Elyne N
authors.initials: EN
authors.lastname: Kahn
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Park
authors.affiliation: Department of Health Management and Policy, School of Public Health, University of Michigan, 1415 Washington Heights, SPH II, Rm. M3124, Ann Arbor, MI 48109, USA. Electronic address: amryan@umich.edu.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ryan