The invention provides compounds of formula :wherein:m is 0, 1 or 2;X is O, S or N\u2014CN;R is F, Cl or CN;A is a C3-6 cycloalkylene group optionally substituted with a C1-4 alkyl group; andB is a single bond or a C1-2 alkylene group;or a pharmaceutically acceptable salt, solvate, polymorph or prodrug thereof. In one form of the invention, an implant includes a load bearing elastic body surrounded in the disc space by an anchoring, preferably resorbable, outer shell. The layout engine identifies a video layer.