Expandable sizer instrument for spacing vertebral bodies

Patent metadata

Field	Value
Publication number	US-9655740-B1
Application number	US-201615141344-A
Country	US
Kind code	B1
Filing date	Apr 28, 2016
Priority date	Apr 28, 2016
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

An expandable sizer instrument for distracting and spacing opposing vertebral bodies of a spine comprises an elongate hollow shaft defining a longitudinal axis and having opposed distal and proximal ends. An actuator is provided at the proximal end and an expandable distractor is provided at the distal end. An elongate push rod extends within the shaft, a proximal end of the push rod being coupled to the actuator and a distal end being coupled to the expandable distractor. The distractor comprises a lower plate immovably attached to the shaft, and an upper plate coupled to the lower plate by a linkage mechanism fully contained within the perimeter of the distractor and operable to move the upper plate away from the lower plate in an expansion direction substantially parallel to the lower plate. The linkage mechanism comprises two laterally spaced linkage pairs with a middle link disposed therebetween.

First claim

What is claimed is:

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.

2. The expandable sizer instrument of claim 1 , wherein said fifth connecting pin extends transversely across said lower plate and into the elongated slots in said opposite side surfaces of said lower plate.

3. The expandable sizer instrument of claim 2 , wherein said second connecting pin extends transversely across said upper plate and into the elongated slots in said opposite side surfaces of said upper plate.

4. The expandable sizer instrument of claim 1 , wherein said actuator comprises a threaded driving mechanism and a rotatable handle.

5. The expandable sizer instrument of claim 4 , wherein rotation of said handle in one direction moves said push rod in the distal direction to operate said linkage mechanism and move said upper plate in the expansion direction away from said lower plate.

6. The expandable sizer instrument of claim 5 , wherein rotation of said handle in a direction opposite said one direction moves said push rod in the proximal direction to operate said linkage mechanism and move said upper plate in the expansion direction toward said lower plate.

7. The expandable sizer instrument of claim 1 , wherein said third link is generally parallel to said first link, and said middle link is generally parallel to both of said first link and said third link.

8. The expandable sizer instrument of claim 1 , wherein said fourth link is generally parallel to said second link, and wherein said middle link is generally parallel to both of said second link and said fourth link.

Assignees

• Spine Wave Inc

Inventors

• Faulkner Kara Michelle
• Skolnick Edward Charles
• Stuart Mary Elizabeth
• Barbieri Thomas John

Classifications

• A61F2/442

  Intervertebral or spinal discs, e.g. resilient (non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455) · CPC title

• A61F2/4425 Primary

  made of articulated components · CPC title

• A61F2002/4628

  with linear motion along or rotating motion about an axis transverse to the instrument axis or to the implantation direction, e.g. clamping · CPC title

• A61F2002/30556

  for adjusting thickness · CPC title

• A61F2/4684 Primary

  Trial or dummy prostheses · CPC title