Patent ID: 9655740
Date: 2017-05-23
CPC Classifications: A61B,A61F

Claim:
1. An expandable sizer instrument for distracting and spacing opposing vertebral bodies of a spine, comprising: an elongate hollow shaft defining a longitudinal axis and having a distal end and a proximal end; an actuator at the proximal end of said elongate hollow shaft; an expandable elongate distractor having a distal end and a proximal end, said elongate distractor being disposed at the distal end of said elongate hollow shaft; an elongate push rod extending within said hollow shaft, a proximal end of said push rod being coupled to said actuator and a distal end of said push rod being coupled to said expandable distractor; said elongate expandable distractor comprising: a lower plate immovably attached at its proximal end to said hollow shaft, an upper plate coupled to said lower plate by a first linkage pair operable to move said upper plate away from and toward said lower plate in an expansion direction substantially orthogonal to said longitudinal axis while maintaining the upper plate to be substantially parallel to said lower plate in a manner to selectively and lockably increase or decrease a maximum height of said expandable elongate distractor, said lower plate comprising an upper surface and an opposing lower surface configured to contact one of the opposing vertebral bodies, and a pair of opposite side surfaces connecting the upper and opposing lower surfaces of the lower plate to each other, the distal end of said lower surface of said lower plate tapering relatively smoothly upwardly toward the opposing upper surface of said lower plate, said upper plate comprising an upper surface configured to contact the other one of the opposing vertebral bodies and an opposing lower surface, and a pair of opposite side surfaces connecting the upper and opposing lower surfaces of the lower plate to each other, the distal end of said upper surface of said upper plate tapering relatively smoothly downwardly toward the opposing lower surface of said upper plate, at least one slot extending through said upper surface and said lower surface of said upper plate, an outside perimeters of said upper plate and said lower plate defining a perimetric boundary of said elongate expandable distractor, said first linkage pair being fully contained within the perimetric boundary of said distractor, said first linkage pair comprising a first link and a second link each having opposite ends respectively, said first link and said second link being pivotally joined to each other at intermediate portions between said opposite ends by a first connecting pin, wherein one end of said first link is pivotally attached to said lower plate by a second connecting in extending through openings in said pair of opposite side surfaces of said lower plate and said opposite end of said first link is pivotally and movably attached to said upper plate by a third connecting pin extending through elongated slots in said pair of opposite side surfaces of said upper plate aligned with the longitudinal axis, and wherein one end of said second link is pivotally attached to said upper plate by a fourth connecting pin extending through openings in said pair of opposite side surfaces of said upper plate with said one end of said second link being accommodated in and fully contained within said at least one slot and disposed interiorly of the perimetric boundary of said distractor, and wherein said opposite end of said second link is pivotally and movably attached to said lower plate by a fifth connecting pin extending through elongated slots in said pair of opposite side surfaces of said lower plate aligned with the longitudinal axis, said distal end of said push rod being attached to said fifth connecting pin, such that axial movement of the push rod relative to the hollow shaft selectively and lockably increases and decreases the maximum height of said elongate distractor; a second linkage pair cooperative with said first linkage pair, said second linkage pair being fully contained within said perimetric boundary of said distractor and being spaced laterally from said first linkage pair relative to said longitudinal axis thereby defining a space between said first linkage pair and said second linkage pair, said second linkage pair comprising a third link and a fourth link each having opposite ends respectively, said third link and said fourth link being pivotally joined to each other at intermediate portions between said opposite ends by said first connecting pin, wherein one end of said third link is pivotally attached to said lower plate by said second connecting pin and said opposite end is pivotally and movably attached to said upper plate by said third connecting pin, and wherein one end of said fourth link is pivotally attached to said upper plate by said fourth connecting pin with said one end of said fourth link being accommodated in and fully contained within said at least one slot and disposed interiorly of the perimetric boundary of said distractor, and wherein said opposite end of said fourth link is pivotally and movably attached to said lower plate by said fifth connecting pin; a middle link disposed within said space defined between said first and second linkage pairs, said middle link being pivotally joined to said first linkage pair and said second linking pair at an intermediate portion between opposite ends of said middle link by said first connecting pin, one end of said opposite ends of said middle link being pivotally attached to said upper plate by said fourth connecting in and the other end of the opposite ends being pivotally attached to said lower plate by said fifth connecting pin, said middle link being generally parallel to one of said first link or said second link; and wherein the first and second linkage pairs and the middle link are fully contained within the elongated distractor between the opposite side surfaces of the upper and lower plates and between the upper surface of the upper plate and the lower surface of the lower plate.