A fusion implant apparatus for facilitating fusion of adjacent bone
structures includes a threadless implant member which is positioned
between adjacent opposed bone structures. The implant member defines a
longitudinal axis and first and second longitudinal ends and has an outer
wall which is dimensioned to engage the opposed bone structures upon
positioning therebetween in supporting relation therewith. The outer wall
defines an internal cavity for the reception of bone growth inducing
substances and includes a plurality of apertures which extend
therethrough in communication with the internal cavity to permit fusion
of vertebral bone tissue. The implant member also includes an
intermediate portion which defines a cross-sectional dimension transverse
to the longitudinal axis which is greater than the respective
cross-sectional dimensions of the first and second longitudinal ends of
the implant member.
