Cutter for preparing intervertebral disc space

• US 20070260270A1
• Filed: 02/28/2007
• Published: 11/08/2007
• Est. Priority Date: 02/16/2000
• Status: Abandoned Application

• Current Assignee: TranS1 Incorporated (Baxano Surgical, Inc.)
• Original Assignee: TranS1 Incorporated (Baxano Surgical, Inc.)
• Inventors: Arthurs, Brandon, Assell, Robert, Ainsworth, Stephen, Cragg, Andrew, Dickhudt, Eugene, Wessman, Bradley, Barnhouse, Michael
• Application Number:
  US11/712,548
• Publication Number:
  US 20070260270A1
• Time in Patent Office: Days
• US Class Current: 606/171
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/1617 with mobile or detachable parts
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/320016 Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes A61B10/0233, A61B17/29, A61B17/3207 take precedence
• CPC Class Codes: A61B 17/32002 with continuously rotating, oscillating or reciprocating cutting instruments
• CPC Class Codes: A61B 17/3421 Cannulas
• CPC Class Codes: A61B 17/7055 connected to sacrum, pelvis or skull
• CPC Class Codes: A61B 17/7082 for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws driving other bone screws A61B17/8875
• CPC Class Codes: A61B 17/8897 Guide wires or guide pins
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/3445 used as instrument channel for multiple instruments catheters A61B2017/22072
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30327 : differing in diameter
• CPC Class Codes: A61F 2002/30405 : made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30495 : using a locking ring
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3055 : for adjusting length
• CPC Class Codes: A61F 2002/30563 : having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30566 : Helical springs
• CPC Class Codes: A61F 2002/30581 : having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30588 : filled with solid particles
• CPC Class Codes: A61F 2002/30601 : telescopic
• CPC Class Codes: A61F 2002/30649 : Ball-and-socket joints
• CPC Class Codes: A61F 2002/30665 : Dual arrangement of two adjacent ball-and-socket joints
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30859 : having threaded portions of different pitches
• CPC Class Codes: A61F 2002/30863 : the entry end surface having flutes, relief grooves, starter notches or bevelled indentations
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2210/0061 : swellable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0039 : differing in diameter

Abstract

Cutter assemblies for use with cutter blades made of shape memory materials. The cutter blades may be deployed in the interior of an intervertebral disc space and rotated relative to a central axis of the cutter assembly to cut the material present for removal from the intervertebral disc space. Cutter blades with different attributes (such as throw length, cutter blade angle, type and location of blade edges) are adapted to achieve different objectives within the intervertebral disc space. Some cutter blades are adapted to promote bleeding of cartilage and vertebral body endplates and some cutter blades are adopted to avoid causing such bleeding. Closed loop cutter blades are described which have certain desirable attributes including the ability to remove the entire cutter blade from the intervertebral disc space after a break in the blade. Serration patterns are disclosed including a serration pattern that makes use of trapezoidal serrations.

Claims

1. A cutter, for disrupting material in an intervertebral space between two vertebral body endplates, the cutter adapted to extend through an axial channel with a centerline axis, the axial channel including at least one vertebral body endplate and extending into the intervertebral space,

the cutter comprising:

a cutter blade made from a shape memory material;

a first side surface on the cutter blade generally facing one of the vertebral body endplates when the cutter blade is oriented generally transverse to the centerline axis;

a second side surface on the cutter blade, separated from the first side surface by a blade thickness;

a clockwise side on the cutter blade that is the leading side when the cutter is rotated clockwise within the axial channel;

a counterclockwise side on the cutter blade that is the trailing side when the cutter is rotated clockwise within the axial channel; and

at least one cutting edge on at least one of the clockwise and counterclockwise sides.

2. A cutter blade for use in an intervertebral disc space, the cutter blade created from a shape memory material and comprising:

a first longitudinal portion of the cutter blade with a cutter blade hole for use in affixing the closed loop cutter blade to a cutter assembly;

a second longitudinal portion with a cutter blade slot for use in connecting the second longitudinal portion to the cutter assembly through a slotted connection that allows a limited range of motion of the second longitudinal portion; and

the closed loop cutter blade being retractable and extendible from a cutter sheath comprising part of the cutter assembly.

3. The closed loop cutter blade of claim 2 wherein the extended closed loop cutter blade defines a closed loop bounded when connected to the cutter assembly by a connection point running through the first longitudinal portion and the second longitudinal portion, the closed loop having an inner perimeter and an outer perimeter.

4. The closed loop cutter blade of claim 3 wherein all cutting edges are recessed from the outer perimeter.

5. The closed loop cutter blade of claim 3 wherein all cutting edges are along the inside perimeter of the closed loop.

6. The closed loop cutter blade of claim 2 wherein the closed loop cutter blade has two faces, a first face and a second face such that when the closed loop cutter blade is affixed to a cutter assembly that is rotated in a first direction, the first face is a leading face and the second face is a trailing face, and the closed loop cutter blade has a cutting edge on at least a portion of the first face and a blunt side on the second face.

7. The closed loop cutter blade of claim 2 wherein a the closed loop cutter blade has two faces, a first face and a second face such that when the closed loop cutter blade is affixed to a cutter assembly that is rotated in a first direction, the first face is a leading face and the second face is a trailing face, and the closed loop cutter blade has a cutting edge on at least a portion of the first face and has a cutting edge on at least a portion of the second face.

8. The closed loop cutter blade of claim 7 wherein the cutting edge on the first face uses a serrated cutting edge with a first pattern and the cutting edge on the second face is different from the cutting edge on the first face.

9. The closed loop cutter blade of claim 7 wherein the cutting edge on the first face uses a serrated cutting edge with a first pattern and the cutting edge on the second face uses a serrated cutting edge with a pattern different from the first pattern.

10. The closed loop cutter blade of claim 7 wherein the cutting edge on the first face uses a serrated cutting edge and the cutting edge on the second face does not.

12. The closed loop cutter blade of claim 2 wherein the closed loop cutter blade has two faces, a first face and a second face such that when the closed loop cutter blade is affixed to a cutter assembly that is rotated in a first direction, the first face is a leading face and the second face is a trailing face, and the closed loop cutter blade has a cutting edge on at least a portion of the first face and the first face has a series of four-sided pyramids with the apexes of the pyramids aligned at about halfway between the outer perimeter of the closed loop and the inner perimeter of the closed loop.

13. The closed loop cutter blade of claim 2 wherein the closed loop includes a cutting edge on a proximal portion of the cutter blade and the angle between the proximal portion of the cutter blade when in the extended position and the first longitudinal portion is between about 25 degrees and about 90 degrees.

14. The closed loop cutter blade of claim 2 wherein the closed loop includes a cutting edge on a proximal portion of the cutter blade and the angle between the proximal portion of the cutter blade when in the extended position and the first longitudinal portion is between about 90 degrees and about 155 degrees.

15. The closed loop cutter blade of claim 2 wherein the closed loop includes a cutting edge on a proximal portion of the cutter blade and the angle between the proximal portion of the cutter blade when in the extended position and the first longitudinal portion is between about 80 degrees and about 100 degrees.

16. A closed loop cutter blade for use in an intervertebral disc space, the closed loop cutter blade having shape memory of an extended position, the closed loop cutter blade having:

an inner surface which forms at least a portion of the inner perimeter of the closed loop;

an outer surface which forms at least a portion of the outer perimeter of the closed loop;

a first face on an exterior of the closed loop cutter blade between the inner surface and the outer surface, the first face being a leading face when the closed loop cutter blade is attached to a cutter assembly and rotated in a first direction around a long axis of the cutter assembly;

a second face on the exterior of the closed loop cutter blade between the inner surface and the outer surface, the second face being a trailing face when the closed loop cutter blade is attached to the cutter assembly and rotated in the first direction around the long axis of the cutter assembly; and

at least a portion of the first face having a cutting edge with a set of serrations.

26. The closed loop cutter blade of claim 16 wherein the set of serrations includes a set of trapezoids.

27. The closed loop cutter blade of claim 16 wherein the set of serrations is cut at an angle across the first face so that the depth of the of serrations ranges from the thickness of the first face to zero.

17. The closed loop cutter blade of 16 wherein the first face has a first set of serrations that extend into the outer surface and a second set of serrations that extend into the inner surface.

18. The closed loop cutter blade of 17 wherein first set of serrations have serration teeth tips and the second set of serrations have serrations teeth tips that do not align with the serration teeth tips of the first set.

19. The closed loop cutter blade of 18 wherein the first set of serrations have serration pattern and the second set of serrations have the same serration pattern but offset so that the teeth tips do not align.

20. The closed loop cutter blade of 18 wherein the first set of serrations have first serration pattern and the second set of serrations have a second serration pattern different from the first serration pattern but offset so that the teeth tips do not align.

21. The closed loop cutter blade of 18 wherein the first face has valley between a serration tooth on the outer surface and a serration tooth on the inner surface.

11. The closed loop cutter blade of claim 21 wherein the closed loop cutter blade has two faces, a first face and a second face such that when the closed loop cutter blade is affixed to a cutter assembly that is rotated in a first direction, the first face is a leading face and the second face is a trailing face, and the closed loop cutter blade has a cutting edge on at least a portion of the first face and the cutting edge on the first face is formed by a pattern imposed on the a portion of the first face and a corresponding portion of the inside perimeter of the closed loop and a repetition of the pattern imposed on a portion of the first face and a corresponding portion of the outside perimeter of the closed loop.

22. The closed loop cutter blade of 21 wherein the valley contains a V formed by an acute angle.

23. The closed loop cutter blade of 16 wherein the set of serrations includes round serrations.

24. The closed loop cutter blade of 16 wherein the set of serrations includes beveled round serrations.

25. The closed loop cutter blade of 16 wherein the set of serrations includes a set of polygons.

28. A cutter, for disrupting material in an intervertebral space between an endplate on a distal vertebral body and an endplate on a proximal vertebral body, the cutter adapted to extend through an bore along an axis extending through at least the proximal vertebral body endplate to position one end of the cutter into the intervertebral space, the cutter comprising:

a cutter shaft;

a cutter sheath surrounding at least a portion of the cutter shaft;

a cutter blade;

the cutter the cutter configured to be retracted into and extended from the cutter sheath, the cutter blade having a shape memory of the extended position, the extended cutter blade significantly transverse to the long axis of the cutter shaft;

a distal side surface on the cutter blade on the side of the extended cutter blade that is adapted to be closer to the endplate on the distal vertebral body than to the endplate on the proximal vertebral body when the cutter blade is extended in the intervertebral space;

a proximal side surface on the cutter blade on the side of the inserted extended cutter blade that is adapted to be closer to the endplate on the proximal vertebral body than to the endplate on the distal vertebral body when the cutter blade is extended in the intervertebral space;

a first edge on the cutter blade that would be the leading edge of the cutter blade when the extended cutter blade is rotated in a first direction around the long axis of the cutter shaft;

a second edge on the cutter blade that would be the leading edge of the cutter blade when the extended cutter blade is rotated in a second direction around the long axis of the cutter shaft, the second direction opposite to the first direction; and

at least one cutting edge on at least one of the first or second edges, the cutting edge recessed relative to the distal side surface of the cutter blade.

29. The cutter of claim 28 wherein the cutting edge is recessed relative to the proximal side surface of the cutter blade.

30. The cutter of claim 28 wherein the cutter blade includes a loop extending from a portion of the cutter blade connected to the cutter shaft, such that a first portion of the loop contains the distal side surface and a second portion of the loop contains the proximal side surface, the loop also including a loop tip connecting the first portion and the second portion, the loop defining an open area such that when the cutter blade is rotated around the long axis of the cutter shaft.

31. The cutter of claim 28 wherein the cutter blade includes a loop extending from a portion of the cutter blade connected to the cutter shaft, such that a first portion of the loop contains the distal side surface and a second portion of the loop contains the proximal side surface, the loop also including a loop tip connecting the first portion and the second portion, the loop defining an open area such that when the cutter blade is rotated around the long axis of the cutter shaft, material may pass through the open area.

32. The cutter of claim 28 wherein the extended cutter blade significantly transverse to the long axis of the cutter shaft is positioned to be between about 25 degrees to about 155 degrees off of the long axis of the cutter shaft.

33. The cutter of claim 28 where the distal portion of the cutter blade is substantially parallel to the proximal portion of the cutter blade.

34. The cutter of claim 28 where a projection of the distal portion of the cutter blade intersects a projection of the proximal portion of the cutter blade to form an acute angle.

35. The cutter of claim 28 wherein a cutting edge on the first edge of the cutter blade is serrated.

36. The cutter of claim 35 wherein cutter blade has a series of teeth and the teeth are substantially the same height.

37. The cutter of claim 35 wherein cutter blade has a series of teeth, with a set of teeth at a first tooth height, and a set of teeth at a second tooth height, the second tooth height being greater than the first tooth height.

38. The cutter of claim 35 where the cutter blade has a serration pattern with valleys in the serration pattern having acute angles.

39. The cutter of claim 35 wherein the distal side surface and the proximal side surface are joined by a loop tip so that the cutter with a cutter blade in an extended position forms a closed loop and a cutting edge on a first edge of the cutter blade has a serration pattern along the loop tip that is different from the serration pattern found on another part of the first edge.

40. The cutter of claim 35 wherein a cutting edge on the second edge of the cutter blade is not serrated.

41. A cutter, for disrupting material in an intervertebral space between an endplate on a distal vertebral body and an endplate on a proximal vertebral body, the cutter adapted to extend through an axial bore along an axis extending through at least the proximal vertebral body endplate to position one end of the cutter into the intervertebral space, the cutter comprising:

a cutter shaft having a long axis;

a cutter sheath surrounding at least a portion of the cutter shaft;

a cutter blade;

the cutter the cutter configured to be retracted into and extended from the cutter sheath the cutter blade extended generally transverse to the long axis of the cutter shaft;

a distal side surface on the cutter blade on the side of the extended cutter blade that is adapted to be closer to the endplate on the distal vertebral body than to the endplate on the proximal vertebral body when the cutter blade is extended in the intervertebral space;

a proximal side surface on the cutter blade on the side of the inserted extended cutter blade that is adapted to be closer to the endplate on the proximal vertebral body than to the endplate on the distal vertebral body when the cutter blade is extended in the intervertebral space;

the distal side surface and the proximal side surface are joined by a loop tip so that the cutter with a cutter blade in an extended position forms a closed loop; and

the cutter shaft having extensions so that a portion of an extended cutter blade that is generally transverse the long axis of the cutter shaft is located between the cutter shaft extensions.

42. A kit for preparing an intervertebral disc space for a therapeutic procedure, the kit comprising:

a cutter assembly with radial cutter blade of a first throw length;

a cutter assembly with a cutter blade having a blade angle of less than 90 degrees and the first throw length;

a cutter assembly with a radial cutter blade of a second throw length, longer than the first throw length; and

a cutter assembly with a cutter blade having a blade angle of less than 90 degrees and the second throw length.

43. The kit of claim 42 including:

a cutter assembly with a radial cutter blade of a third throw length, longer than the second throw length; and

a cutter assembly with a cutter blade having a blade angle of less than 90 degrees and the third throw length.

44. The kit of 42 wherein the blade angle for the cutter assembly with a cutter blade having a blade angle of less than 90 degrees and the first throw length is about 45 degrees.