INSTRUMENTS AND SURGICAL TECHNIQUES FOR DISC PREPARATION
A positive stop distractor, and arrays thereof, each instrument adapted with a generally flat/planar paddle and one or more mechanical stops on the planar paddle. And a modular distractor used to provide sustained distraction of a joint space, particularly a spinal disc space, including a distractor handle, a body, and a retrievable shim, and an optional cable for retention and retrieval of the shim.
1 . A modular surgical distractor, comprising:
an elongate body having opposing generally planar faces along a length dimension between proximal and distal ends, a handle portion at the proximal end, and at the distal end a maximum width dimension, and a maximum depth dimension, and a center elongate axis, along the body, the distal end having a generally rectangular cross sectional shape
a shim that is engageable with the elongate body by releasable engagement at the body's distal end, the shim having opposing generally planar faces along a length dimension, and having each of a width dimension and a depth dimension
each of the elongate body and the shim comprising engagement features that form an engagement seat for releasable engagement between the body and the shim between locked and unlocked configurations, the locked configuration actuated by rotation of one of the body and shim from an antiparallel arrangement of the body and shim width dimensions to a parallel arrangement of the body and shim width dimensions.
2 . The modular surgical distractor according to claim 1 , wherein the modular distractor in the locked configuration comprises the body and shim engaged and oriented with their opposing faces aligned as parallel, and in the unlocked configuration comprises the body and shim engaged and oriented with their opposing faces aligned generally antiparallel, and wherein the actuation of locking between the body and the shim comprises rotation in a first direction of one of the body and the shim around the central axis of the elongate body so that the planar faces are essentially perpendicular, and wherein the actuation of unlocking between the body and the shim comprises rotation of one of the body and the shim in a second direction, the shim is disengagable from the body.
3 . The modular surgical distractor according to claim 2 , wherein the actuation of locking between the body and the shim comprises rotation of the body in a counterclockwise direction, and wherein the actuation of unlocking between the body and the shim comprises rotation of the body in a clockwise direction.
4 . The modular surgical distractor according to claim 1 , wherein one or more of the width and depth dimensions of the shim is the same as or greater than the width and depth dimensions of the elongate body.
5 . The modular surgical distractor according to claim 1 , wherein the body tapers from distal to proximal.
6 . The modular surgical distractor according to claim 1 , comprising a removable handle.
7 . The modular surgical distractor according to claim 1 , wherein the shim has at a distal end corners and edges that are radiused or beveled.
8 . The modular surgical distractor according to claim 1 , wherein the body includes at a bottom surface of its distal end a male extension and the shim includes at a top surface at a proximal end a female receiver, the male extension and female receiver engageable by insertion of the male extension into the female receiver in an unlocked state when the width dimensions of each of the body and the shim are other than parallel with each other, each of the male extension and the female receive including engagement features that lock engagement when the body and shim are aligned in parallel.
9 . The modular surgical distractor according to claim 1 , wherein the shim is sized as slightly larger than the body.
10 . The modular surgical distractor according to claim 1 , further comprising a cable that is passable through a conduit in at least one of the body and shim and along the axis of the body.
11 . The modular surgical distractor according to claim 10 , wherein the cable is fixedly engaged with the shim.
12 . The modular surgical distractor according to claim 1 , wherein the body has at its proximal end an engagement feature for releasable engagement with the handle portion.
13 . The modular surgical distractor according to claim 1 , wherein, in use in an intervertebral disc space, the modular distractor is insertable in a first orientation with the body and shim opposing faces aligned in parallel and facing adjacent end plates within the disc space, and the assembled body and shim are rotatable in a first direction around the central axis of the elongate body so that the planar faces are essentially perpendicular with the adjacent vertebral body endplates, and upon rotation of the body in a second direction, the shim is disengagable from the body allowing removal of the body from the disc space and retention of the shim therein.
14 . A positive stop distractor comprising:
an elongate body having a length dimension and a width dimension, and a center elongate axis, the elongate body comprising
a proximal end having a handle, and
a distal end having a generally flat and planar distal paddle that includes one or more mechanical stop features positioned along the paddle above the distal end
wherein, in use in an intervertebral disc space, the instrument is insertable in a first orientation with its opposing planar faces facing adjacent end plates, and is rotatable around the central axis of the elongate body so that the planar faces are essentially perpendicular with the adjacent vertebral body endplates, and
wherein the one or more mechanical stop features is adapted to extend away from one or the other of the planar faces of the paddle so as to interfere with the edge of one or the other of the adjacent vertebral bodies so as to prevent movement of the paddle into the disc space once the mechanical stop has contacted the edge of a vertebral body adjacent to the disc space.
15 . The positive stop distractor according to claim 1 wherein the paddle is flared, having a taper angle from the center axis that originates at the proximal neck, the taper angle from 0 to 10 degrees.
16 . The positive stop distractor according to claim 1 wherein the elongate body has at its proximal end an engagement feature for releasable engagement with the handle.