Posterior expandable fusion cage
First Claim
1. A posterior interbody device that is anteriorly variably expandable;
- said device comprising;
a) a U-shaped body having an upper wall and a bottom wall hingeably joined by rear wall;
said rear wall having a threaded bore, said upper and lower walls having a non-expanded configuration;
b) said upper and lower walls each having an anterior mating region that face each other;
c) an elongate expansion member;
said expansion member being threaded and being operably threadedly received in said rear wall bore;
d) said expansion member having a wedge that is sized, shaped and positioned to engage said upper and lower anterior mating regions as said expansion member is threadedly advanced into said bore such that anterior ends of upper and lower walls are urged into an expanded configuration wherein said upper and lower walls become spaced greater than said non-expanded configuration.
1 Assignment
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Accused Products
Abstract
An interbody device for use between a pair of adjacent vertebrae includes a body and at least one expansion member. The body has upper and lower walls that are joined by a rear wall that functions as a spring hinge. The walls have anterior or distal ends that are supported in a non-expanded configuration by spaced feet that project out from the walls. The expansion member is elongate and has a threaded portion that is threadably received in the rear wall. Each expansion member also includes a head having an anterior wedge portion that engages the anterior ends of the walls and forces the walls apart as the expansion member is screwed into the body. A surface engages the expansion member after expansion and supports the walls during usage. Preferably, the expansion member is only one of a plurality of expansion members found in a kit which vary with respect to the diameter of the head thereof.
440 Citations
16 Claims
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1. A posterior interbody device that is anteriorly variably expandable;
- said device comprising;
a) a U-shaped body having an upper wall and a bottom wall hingeably joined by rear wall;
said rear wall having a threaded bore, said upper and lower walls having a non-expanded configuration;
b) said upper and lower walls each having an anterior mating region that face each other;
c) an elongate expansion member;
said expansion member being threaded and being operably threadedly received in said rear wall bore;
d) said expansion member having a wedge that is sized, shaped and positioned to engage said upper and lower anterior mating regions as said expansion member is threadedly advanced into said bore such that anterior ends of upper and lower walls are urged into an expanded configuration wherein said upper and lower walls become spaced greater than said non-expanded configuration. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 10)
a) said expansion member has an axis of rotation; and
b) said wedge is cylindrical shaped and is coaxial with said axis of rotation.
- said device comprising;
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3. The device according to claim 1 wherein:
a) said body includes a support surface adjacent and anterior of said mating region.
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4. The device according to claim 1 wherein:
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a) said expansion member has an axis of rotation;
b) said expansion member has a threaded region near a posterior end thereof that is screwable into a thread in said rear wall bore;
c) said expansion member has a head near an anterior end thereof;
said head including said wedge in the shape of a cylinder;
said body including a supporting surface anterior of said mating region that is sized, shaped and positioned to engage and support said upper and lower walls when said expansion member is fully inserted into said body;
so that as said expansion member is threadedly advanced into said body, said wedge engages said upper and lower wall wedge mating regions and vertically spreads the anterior ends of said upper and lower walls while said walls hinge at a posterior end thereof and, thereafter said support surface engages and supports anterior ends of said upper and lower walls in a preselected anterior spaced configuration.
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5. The device according to claim 4 wherein:
a) said expansion member includes a stop located to limit advancement of said expansion member into said body and to position said expansion member in said body.
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7. The device according to claim 1 wherein:
a) said upper and lower walls each include a window positioned to allow growth of bone therethrough during usage.
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8. The device according to claim 1 wherein:
a) said upper and lower walls have anterior surfaces that engage under load when in a non-expanded configuration such that said device is adapted to be utilized alternatively as an expanded or non-expanded fusion cage.
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9. The device according to claim 1 wherein:
a) said upper and lower walls each include an anterior pair of spaced legs that respectively engage and rest against legs of the opposite wall when in the non-expanded configuration and when under a load that urges the legs toward one another.
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10. The device according to claim 1 wherein:
a) when fully inserted, said expansion member extends longitudinally through said body from a posterior end thereof in said threaded bore to near an anterior end thereof.
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6. The device according to claim 6 wherein:
a) said stop is adjacent and posterior to said threaded region of said expansion member and has a greater diameter than said threaded region.
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11. A posterior interbody device that is anteriorly variably expandable;
- said device comprising;
a) a U-shaped body having an upper wall and a bottom wall hingeably joined by a rear wall;
said rear wall having a threaded bore, said upper and lower walls having a non-expanded configuration;
b) said upper and lower walls each having an anterior mating region that face each other;
c) first and second elongate expansion members;
each of said expansion member being threaded and being operably threadedly received in said rear wall bore;
d) each of said expansion members having a wedge that is sized, shaped and positioned to engage said upper and lower anterior mating regions as a respective expansion member is threadedly advanced into said bore such that anterior ends of upper and lower walls are urged into an expanded configuration wherein said upper and lower walls become spaced greater than said non-expanded configuration;
e) said body including a support surface adjacent to and anterior of said mating region; and
f) including said first and second expansion members being incorporated in a set wherein said first and second expansion members have respective cylindrical surfaces of different diameters so that said first and second expansion members can be selectively individually used with said body to produce different degrees of expansion of the anterior end of said body.
- said device comprising;
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12. A posterior interbody device that is anteriorly variably expandable;
- said device comprising;
a) a U-shaped body having an upper wall and a bottom wall hingeably joined by a rear wall;
said rear wall having a threaded bore, said upper and lower walls having a non-expanded configuration;
b) said body being generally rectangular in cross section;
c) said upper and lower walls each having an anterior mating region that face each other;
d) an elongate expansion member;
said expansion member being threaded and being operably threadedly received in said rear wall bore; and
e) said expansion member having a wedge that is sized, shaped and positioned to engage said upper and lower anterior mating regions as said expansion member is threadedly advanced into said bore such that anterior ends of upper and lower walls are urged into an expanded configuration wherein said upper and lower walls become spaced greater than said non-expanded configuration.
- said device comprising;
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13. In an expandable posterior interbody fusion cage;
- the improvement comprising;
a) said cage having a U-shaped body having upper and lower walls each with anterior mating regions near an anterior end thereof; and
b) an elongate expansion member that is threadedly received in said body;
said expansion member having a head with an anterior wedge for operably engaging said body mating regions and expanding an anterior end of said cage as said expansion member advances into said body.
- the improvement comprising;
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14. In a posterior expandable fusion cage having an expansion member;
- the improvement comprising;
a) wherein said expansion member is a first expansion member and including in an expansion kit a second expansion member that is interchangeable with said first expansion member;
each of said first and second expansion members being cooperatively mateable with said cage to provide a different degree of anterior expansion of said cage and operably producing a different degree of expansion in said fusion cage.
- the improvement comprising;
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15. In a posterior expandable fusion cage having an expansion member;
- the improvement comprising;
a) wherein said expansion member is a first expansion member and including in an expansion kit a second expansion member that is interchangeable with said first expansion member;
each of said first and second expansion members being cooperatively mateable with said cage to provide a different degree of anterior expansion of said cage; and
b) said kit including a non-expansion plug. - View Dependent Claims (16)
a) at least one of said non-expansion plug and expansion members includes a threaded region for being threaded into a bore in a rear wall of said cage and said threaded region includes a passageway therethrough to allow insertion of matrix material into said cage after installation of said one of said non-expansion plug and expansion members.
- the improvement comprising;
Specification