Occipito-cervical osteosynthesis instrumentation

• US 5,507,745 A
• Filed: 02/18/1994
• Issued: 04/16/1996
• Est. Priority Date: 02/18/1994
• Status: Expired due to Term

• Current Assignee: Sofamor S.N.C.
• Original Assignee: Sofamor S.N.C.
• Inventors: Marienne, Jean-Luc, Logroscino, Carlo, Jerome, Pierre, Goube, Michel, Bancel, Philippe
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): MARKOW, SCOTT
• Application Number:
  US08/198,986
• Time in Patent Office: 788 Days
• Field of Search: 606/61, 606/60, 606/69, 606/70, 606/71
• US Class Current: 606/261
• CPC Class Codes: A61B 17/7055 connected to sacrum, pelvis or skull
• CPC Class Codes: A61B 17/7056 Hooks with specially-designed bone-contacting part

Abstract

The instrumentation comprises two separate similar parts, namely a right part (1) and a left part (2), each formed by a cervical rod (3) having asperities and an elongate occipital plate (5) forming one piece with the rod and extending it toward the occiput (6) in the position of use, and adjustable means for anchoring the rod to the vertebrae and the plate to the occiput. Each part is so preangulated and shaped as to be adapted to the anatomy of the occipito-cervical connection. Each rod (3) has two rectilinear sections making therebetween an angle of between about 70° and 90°, one of the sections being connected to the occipital plate (5), which is bent so as to correspond to the curvature of the occipital shell. The invention permits conveniently adapting the distance between the rods (3) to the anatomy of the patient and reduces the overall size of the instrumentation, which enables projections under the skin of the occiput to be considerably reduced.

Claims

1. Occipito-cervical osteosynthesis instrumentation comprising:

a) a part formed by a cervical rod and an elongate occipital plate forming one piece with said rod and extending it toward the occiput in the position of use, said occipital plate defining an opening therethrough,

b) a hook having a laminar portion configured to engage the occipito-cervical lamina, and a body having a small height relative to the width of said body, a groove defined in said body for receiving said occipital plate, and a tapped hole defined in said body in facing relation to said plate,

c) a screw for fixing said plate to said hook configured to extend through said opening in said occipital plate and threaded to engage said tapped hole,

d) said part being so preangulated and shaped as to be adapted to the anatomy of the occipito-cervical junction.

2. Instrumentation according to claim 1, wherein:

said oblong openings and said circular openings of said occipital plate each include chamfers defined therearound; and

said screws for fixing said plate to said hook each include heads configured complementary to said chamfers and being so dimensioned as to be flush with a surface of said plate surrounding said oblong openings and said circular openings.

3. Instrumentation according to claim 1, wherein said plate has a thickness and said groove has a depth, wherein said thickness is at least equal to said depth.

4. Instrumentation according to claim 1, further comprising an oblong opening and a circular opening formed in said elongate occipital plate, at least one of said oblong opening and said circular opening configured to receive said screw for fixing said plate to said hook therethrough.

5. Instrumentation according to claim 4, further comprising a bone screw having bone engaging threads configured for threading into the occiput, and a head configured to be received within at least one of said oblong opening and said circular opening.

6. Instrumentation according to claim 5, further comprising a second bone screw having bone engaging threads configured for threading into the occiput, and a head configured to be received within said oblong opening when said head of said bone screw is also received within said oblong opening.

7. Occipito-cervical osteosynthesis instrumentation comprising:

a part formed by a cervical rod and an elongate occipital plate forming one piece with said rod and extending toward the occiput in the position of use;

adjustable anchoring means for anchoring said rod to the vertebrae and said plate to the occiput in the position of use;

said rod having two substantially rectilinear sections, one of said sections being shorter than the other and connected to said occipital plate, said shorter rod section extending along the base of the occiput in the position of use, said sections forming an angle therebetween adapted to the anatomy of the occipito-cervical junction;

wherein said adjustable anchoring means includes hooks having a laminar portion adapted to be inserted at the base of the occipital bone in a foramen opening, said hooks being mounted on said shorter section of said rod which is connected to said occipital plate.

8. A method for mounting an occipito-cervical instrumentation to the occipito-cervical junction, comprising the steps of:

a) providing occipito-cervical instrumentation having a part formed by a cervical rod and an elongated occipital plate which forms one piece with the rod, an oblong opening and a circular opening defined in the plate, the part being so preangulated and shaped as to be adapted to the anatomy of the occipito-cervical junction;

b) forming an opening in the occipital bone;

c) providing a hook having a laminar portion adapted to be received within the opening in the occipital bone, and a head portion configured for receiving the occipital plate therein;

d) inserting the laminar portion of the hook in the opening formed in said occipital bone;

e) placing the occipital plate of the part in the head portion of the hook and fixing the plate thereto; and

f) providing a bone engaging fastener and a connector;

g) fixing the cervical rod to at least one of the vertebrae by the bone engaging fastener connected to the rod by the connector.