Disc preparation instrument for use in spinal fusion

A disc preparation instrument for use in fusing together a superior vertebra and an inferior vertebra, the superior vertebra including an inferior endplate and a vertebral body, the inferior vertebra including a superior endplate and a vertebral body, the superior and inferior endplates defining a disc space therebetween, the disc preparation instrument comprising:

• an elongate handle having a distal end and a proximal end, and a trial device supported by said handle at the distal end thereof,
• wherein said trial device comprises a trial body of size and configuration approximating the size and configuration of a cage implant for insertion into said disc space, said body having a distal surface, a proximal surface, a top surface and a bottom surface, said top surface having a top opening and said bottom surface having a bottom opening, said body including a movable scoring element having a first portion and a second portion, said scoring element being selectively movable from a first position wherein said first portion and said second portion are disposed interiorly of said device to a second position wherein said first portion extends exteriorly of said body through said top opening for scoring said inferior endplate of said superior vertebra at an upper scored location and said second portion extends exteriorly of said body through said bottom opening for scoring said superior endplate of said inferior vertebra at a lower scored location;
• and
• wherein said handle comprises an elongate shaft extending within said handle, said shaft having a distal end extending into said body and attached to said scoring element, said shaft having an actuator at a proximal end, said actuator being operable to move said shaft and thereby said scoring element at the distal end thereof, said handle supporting a movable depth stop disposed adjacent to the distal end of said handle and being sized and configured to engage an exterior surface of one of said vertebrae when said trial device is disposed in said disc space, said handle having an adjustment knob operable to axially move said depth stop along said handle, said depth stop being spaced axially from said proximal surface of said trial body by a distance that is adjustable upon operation of said adjustment knob, said handle comprising an inner sleeve and an outer sleeve, said inner sleeve being attached to said trial body at a distal end thereof and having a lumen through which said shaft extends, said outer sleeve being movable axially along said inner sleeve and supporting said depth stop at a distal end thereof, said adjustment knob being supported on said outer sleeve for limited axial movement relative to said outer sleeve and said inner sleeve, said adjustment knob being biased axially against said inner sleeve to thereby form in a normal state a releasable lock preventing inadvertent axial movement of said outer sleeve relative to said inner sleeve.