Internal ilio-lumbar fixator

Claim 2

An internal ilio-lumbar fixator comprising at least one pedicle screw with a bifurcated head, a pelvic plate and a bent rod having a spinal portion for engagement in the bifurcated head of the pedicle screw and a pelvic portion for engagement with the pelvic plate; in which combination: the pedicle screw has a washer within said bifurcated head to embrace the spinal portion of the bent rod and to be pressed into firm engagement therewith by a grubscrew secured into the bifurcated head, and at least one additional locking screw in a screwthreaded hole through one side of the bifurcated head to engage the spinal portion of the bent rod; the pelvic plate has at least two holes for bone screws, another hole having a non-circular female cross-section, and a locking screw in a screwthreaded hole opening into at least one side of the female hole; and the bent rod having a mating male cross-section along a major part of its pelvic portion affording a close sliding fit in the female hole in the pelvic plate.

Claim 3

A fixator as in claim 1, wherein the pelvic plate has a thicker portion in which is provided the female hole and the screwthreaded hole.

Claim 4

A fixator as in claim 1 or claim 2, wherein the female hole is provided at an end formed on the pelvic plate.

Claim 5

A fixator as in claim 1 or claim 2, wherein the female hole is provided intermediate two ends formed on the pelvic plate.

Claim 6

A fixator as in claim 1 or claim 2, wherein the female hole has a polygonal cross-section.

Claim 7

A fixator as in claim 5, wherein the polygonal cross-section is twelve-sided.

Claim 8

A fixator as in claim 1, wherein the pelvic portion of the bent rod is splined, and the female hole is provided with at least one mating rib.

Claim 9

A fixator as in claim 7, wherein there are twenty splines.

Claim 10

A fixator as in claim 1, wherein the pelvic plate is curved to match an iliac crest formation.

Claim 11

A fixator as in claim 1, wherein the spinal portion of the bent rod is knurled or splined and the face of the washer for engagement therewith provided with a complementary formation.

Claim 12

A fixator as in claim 1, wherein the spinal portion of the bent rod is long enough to enable it to fit within a second pedicle screw of the tulip type screwed into the corresponding pedicle of the next vertebra.

Claim 13

A fixator as in claim 1, wherein the pedicle screws are cannulated so that they can be introduced over a guide wire.

Claim 14

An internal ilio-lumbar fixation comprising at least one pedicle screw with a bifurcated type, a pelvic plate, a bent rod having a spinal portion for engagement in the bifurcated head of the pedicle screw and a pelvic portion for connection to the pelvic plate, and two universal joint members between the pelvic portion of the bent rod and the pelvic plate, in which combination: the pedicle screw has a washer within said bifurcated head to embrace the spinal portion of the bent rod and to be pressed into firm engagement therewith by a grubscrew secured into the bifurcated head, and at least one additional locking screw in a screwthreaded hole through one side of the bifurcated head to engage the spinal portion of the bent rod; the pelvic plate has at least two holes for bone screws and another hole for a screw forming a first lockable pivotal connection with one of the universal joint members; the pelvic portion of the bent rod has a second lockable pivotal connection with the other universal joint member the axis of which is perpendicular to the first lockable pivotal connection; and the universal joint members are joined together by a third lockable pivotal connection the axis of which is perpendicular to the first and second lockable pivotal connections respectively.

Claim 15

An internal ilio-lumbar fixation comprising at least one pedicle screw with a bifurcated type, a pelvic plate, a bent rod having a spinal portion for engagement in the bifurcated head of the pedicle screw and a pelvic portion for connection to the pelvic plate, and two universal joint members between the pelvic portion of the bent rod and the pelvic plate, in which combination: the pedicle screw has a washer within said bifurcated head to embrace the spinal portion of the bent rod and to be pressed into firm engagement therewith by a grubscrew secured into the bifurcated head, and at least one additional locking screw in a screwthreaded hole through one side of the bifurcated head to engage the spinal portion of the bent rod; the pelvic plate has at least two holes for bone screws and another hole for a screw forming a first lockable pivotal connection with one of the universal joint members; the pelvic portion of the bent rod has a second lockable pivotal connection with the other universal joint member the axis of which is perpendicular to the first lockable pivotal connection; and the universal joint members are joined together by a third lockable pivotal connection the axis of which is perpendicular to the first and second lockable pivotal connections respectively.

Claim 16

A fixator as in claim 13, wherein the second lockable pivotal connection is formed by the pelvic portion of the bent rod being screwthreaded and fitting through a hole in its respective universal joint member, with a pair of nuts on the screwthreaded portion to bear against opposite faces of the respective universal joint member.

Claim 17

A fixator as in claim 13, wherein the third lockable pivotal connection is formed by a screw extending from one of the universal joint members through a hole in a lug on the other universal joint member, and a nut screwing on to the screw.

Claim 18

A fixator as in any one of claims 13 to 15, wherein the hole for a screw forming the first lockable pivotal connection is provided at an end formed on the pelvic plate.

Claim 19

A fixator as in any one of claims 13 to 15, wherein the hole for a screw forming the first lockable pivotal connection is provided intermediate two ends formed on the pelvic plate.