Intersomatic vertebral cage

• US 5,554,191 A
• Filed: 01/23/1995
• Issued: 09/10/1996
• Est. Priority Date: 01/26/1994
• Status: Expired due to Fees

• Current Assignee: Biomat B.V.
• Original Assignee: Biomat B.V.
• Inventors: Cottin, Philippe, Lahille, Michel
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US08/376,413
• Time in Patent Office: 596 Days
• Field of Search: 623/16, 623/17, 606/61, 606/63, 606/73, 411/49, 411/55, 411/57, 411/71
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30169 Pi-shaped
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• 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 2002/4687 : Mechanical guides for implantation instruments
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0047 : Pi-shaped
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

An intersomatic cage to be inserted from the posterior approach between two vertebrae comprises two substantially parallel branches for contact with the vertebral bodies, a linking portion linking the posterior ends of the branches, and a movable spreader member for angularly spreading the two branches after insertion of the cage between the two vertebrae. The cage allows adjustment of the lordosis angle between the two vertebrae during surgery. Ancillary equipment for insertion of the cage includes a rasp for forming a housing for the cage between the two vertebrae, a cage-holder for inserting the cage into the housing, a screwdriver for turning a screw screwed into the spreader member to spread the two branches of the cage, and a guide for successively guiding the rasp, the cage-holder with the cage, and subsequently the screwdriver.

Claims

1. An intersomatic cage adapted to be inserted between a pair of vertebral bodies, comprising:

(a) two spaced branches having first and second ends, said second branch ends having facing bearing surfaces, said branches defining a longitudinal slot therebetween extending from said second ends of said branches, said slot being enlarged near said first end, thereby to increase the flexibility of said branches, said branches having outside surfaces which are substantially plane and parallel when said intersomatic cage is being inserted between the two vertebral bodies;

(b) a linking portion linking said first ends of said branches and integral with said first branch ends;

(c) a screw having a screw-threaded shank passing through said linking portion and between said branches; and

(d) a spreader member disposed between said facing bearing surfaces of said second branch ends and screwed to said screw-threaded shank of said screw, said spreader member being applied onto said facing bearing surfaces by screwing said screw, thereby spreading said second ends of said branches after having inserted said cage between said vertebral bodies.

3. The cage claimed in claim 1 wherein an end of said screwthreaded shank of said screw comprises stop means for holding said spreader member on said screwthreaded shank.

4. The cage claimed in claim 1 wherein a head of said screw comprises means adapted to be operated by a screwdriver.

5. The cage claimed in claim 1, wherein one side of said linking portion opposite said branches contains a circular screw head receiving bore extending axially and parallel to said branches and crossed perpendicularly by a groove for inserting a corresponding tenon at an end of a cage-holder.

6. The cage claimed in claim 1, substantially parallelepiped-shape.

7. The cage claimed in claim 1 wherein outside surfaces of said branches comprise transverse anchoring means which are divided between smaller teeth at said first branch ends and larger teeth at said second branch ends.

8. The cage claimed in claim 1 wherein said branches comprise oblong openings substantially extending between said first and second branch ends respectively.

9. The cage claimed in claim 1 in combination with a rasp adapted to define a recess between said vertebral bodies, and guide means for inserting said cage within said recess,

(a) said rasp comprising a rasp head having a transverse section analogous to a transverse section of said cage perpendicular to said branches, a longitudinal rasp conduit opening at an end of said rasp head, and a longitudinal outside groove, at least one longitudinal side of said rasp head being provided with teeth and notches, said rasp head being provided with teeth and notches, said notches being located between said teeth and opening into said longitudinal rasp conduit,

(b) said guide means comprising a cylindrical longitudinal guide conduit in which said rasp and said cage are longitudinally slidable, means projecting from a first end of said guide conduit for anchoring said guide in said vertebral bodies and means located at a second end of said guide conduit and projecting radially towards the inside of said guide conduit rasp thereby rotationally positioning said cage in said guide conduit before inserting said cage in said recess between said two vertebral bodies.

10. The combination claimed in claim 9, wherein said rasp has an external abutment located at another end of said rasp opposite said rasp head for abutting against a bearing surface substantially located at said second end of said guide conduit, extending substantially perpendicular to the guide conduit, and facing towards said first end of said guide conduit.

2. An intersomatic cage adapted to be inserted between a pair of vertebral bodies, comprising:

(a) a body member including a pair of generally parallel flexible branch portions having tapered first end inner surfaces forming a generally V-shaped notch, said branch portions having initially parallel outer surfaces, thereby to allow said intersomatic cage to be inserted between the vertebral bodies, said branches being spaced to define a longitudinal slot therebetween, said slot including a narrow first end adjacent said first end inner surfaces and an enlargement adjacent said narrow first end, thereby to increase the flexibility of said cage member;

(b) a linking portion joining second ends of said branch portions, said linking portion containing a longitudinal through-bore;

(c) a screw passing through said through-bore and between said branch portions; and

(d) a spreader member contained within said V-shaped notch connected with said screw and adapted to engage said first end inner surfaces of said branch portions when said screw is turned, thereby to force said branch portion first ends apart after said intersomatic cage has been inserted between the vertebral bodies.