Significance of Facet Fluid Index in Anterior Cervical Degenerative Spondylolisthesis oleh Yunsoo Lee, Jeremy C. Heard, Mark J. Lambrechts, Nathaniel Kern, Bright Wiafe, Perry Goodman, John J. Mangan, Jose A. Canseco, Mark F. Kurd, Ian D. Kaye, Alan S. Hilibrand, Alexander R. Vaccaro, Christopher K. Kepler, Gregory D. Schroeder, Jeffrey A. Rihn