Abstract: A bone fixation device comprises a plurality of brackets (6, 8, 42-48), each defining a surface formed with at least one recess (56, 58). Part of a ball (12-18, 52, 54) is mounted in each recess with an exposed face formed with a groove (24, 26, 52, 54) for receiving a fixation rod or bone screw. The brackets are capable of being brought together such that at least one pair of exposed ball faces are in juxtaposition with the grooves defining a sleeve for a fixation rod or bone screw, and means (10, 50) are included for urging the brackets and the exposed ball faces towards each other to clamp a fixation rod or bone screw between a pair of juxtaposed ball faces. Normally, the recesses and ball parts are arranged such that as the brackets are brought together at least two pairs of ball parts are in juxtaposition, forming two sleeves for fixation rods or bone screws.

Abstract: In a fixation system for controlling the alignment of adjacent vertebra after spinal surgery, aligned fixation rods are held in a mount on each of such vertebra, with their juxtaposed ends received in a sleeve between the mounts. At least one of the rods is movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. In some embodiments, the sleeve can itself be held in a mount installed on one of such vertebra with the aligned fixation rods being capable of relative movement therein. The system allows the spine to grow without the need for further surgery.

Abstract: A bone fixation device comprises a plurality of brackets (6, 8, 42-48), each defining a surface formed with at least one recess (56, 58). Part of a ball (12-18, 52, 54) is mounted in each recess with an exposed face formed with a groove (24, 26, 52, 54) for receiving a fixation rod or bone screw. The brackets are capable of being brought together such that at least one pair of exposed ball faces are in juxtaposition with the grooves defining a sleeve for a fixation rod or bone screw, and means (10, 50) are included for urging the brackets and the exposed ball faces towards each other to clamp a fixation rod or bone screw between a pair of juxtaposed ball faces. Normally, the recesses and ball parts are arranged such that as the brackets are brought together at least two pairs of ball parts are in juxtaposition, forming two sleeves for fixation rods or bone screws.

Abstract: In a fixation system for controlling the alignment of adjacent vertebra after spinal surgery, aligned fixation rods are held in a mount on each of such vertebra, with their juxtaposed ends received in a sleeve between the mounts. At least one of the rods is movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. In some embodiments, the sleeve can itself be held in a mount installed on one of such vertebra with the aligned fixation rods being capable of relative movement therein. The system allows the spine to grow without the need for further surgery.

Abstract: An expansion device is disclosed which, when mounted on an appropriate support, can make controlled advancement relative to the support in response to activation from a remote site. The device comprises first (6) and second (8) elements coupled for relative movement along an axis defined on a support 2. An expandable chamber is defined between the elements, in which chamber is a flexible and elastic membrane (24). A resilient mechanism urges the two elements towards each other to define a minimum volume for the chamber. The chamber can be expanded to separate the elements, and hold mechanisms typically in the form of latches, are provided for selectively restricting movement on the respective elements relative to the support.

Abstract: A bone fixation device has a housing on the exposed head of a screw mounted in a bone part from which it projects. A clamp for a fixation rod is mounted on a plate extending from each of opposite lateral sides of the housing in such a manner that allows the plate to rotate about a lateral axis relative to the housing. Each clamp is itself rotatable on its plate about an axis perpendicular to its respective lateral axis, and thereby provides universal movement relative to the housing. Mechanisms are provided for closing the clamps, for locking each plate against rotation about its lateral axis, and blocking each clamp against rotation about its perpendicular axis. In this way rods can be fixed in the clamps and relative to the device.

Abstract: An expansion device is disclosed which, when mounted on an appropriate support, can make controlled advancement relative to the support in response to activation from a remote site. The device comprises first (6) and second (8) elements coupled for relative movement along an axis defined on a support 2. An expandable chamber is defined between the elements, in which chamber is a flexible and elastic membrane (24). A resilient mechanism urges the two elements towards each other to define a minimum volume for the chamber. The chamber can be expanded to separate the elements, and hold mechanisms typically in the form of latches, are provided for selectively restricting movement on the respective elements relative to the support.

Abstract: In a fixation system for controlling the alignment of adjacent vertebra after spinal surgery, aligned fixation rods are held in a mount on each of such vertebra, with their juxtaposed ends received in a sleeve between the mounts. At least one of the rods is movable in the sleeve relative to the other to allow controlled movement of adjacent vertebra. In some embodiments, the sleeve can itself be held in a mount installed on one of such vertebra with the aligned fixation rods being capable of relative movement therein. The system allows the spine to grow without the need for further surgery.

Abstract: A bone fixation device has a housing on the exposed head of a screw mounted in a bone part from which it projects. A clamp for a fixation rod is mounted on a plate extending from each of opposite lateral sides of the housing in such a manner that allows the plate to rotate about a lateral axis relative to the housing. Each clamp is itself rotatable on its plate about an axis perpendicular to its respective lateral axis, and thereby provides universal movement relative to the housing. Mechanisms are provided for closing the clamps, for locking each plate against rotation about its lateral axis, and blocking each clamp against rotation about its perpendicular axis. In this way rods can be fixed in the clamps and relative to the device. In a particular embodiment, the plates are supported for pivotal movement about their lateral axes, on part-cylindrical surfaces on opposite lateral sides of the housing.

Abstract: Apparatus for cutting an elongate element (2) comprises two lateral devices (6) for gripping the element on either side of a central section. A third device (10) fits between the lateral devices for gripping the central section, and together the gripping devices (6,10) define a common axis along which the element to be cut is aligned. With the devices installed on the element the lateral devices (6) are rotated relative to the third device (10) to twist and shear the central section from the element on either side.

Abstract: A tool for breaking a shaft includes two aligned tubular elements (20, 22), each having an end portion for receiving a contiguous length of the same shaft (2). Means are provided for locking each end portion against rotation relative to the shaft length received therein, and the elements are adapted for rotation relative to one another with the end portions so locked, to relatively twist the shaft lengths and shear the lengths at the interface between them. The element end portions will normally have juxtaposed faces, and it is preferred that the faces are moved towards each other during the relative rotation and as the shaft lengths are twisted relative to each other. This assists in achieving a substantially planar face at the fracture plane. A compressible washer may be disposed between the juxtaposed faces. This can stabilize the moving parts as the shaft is broken, although normally screw threads on the tubular elements will effect the movement of the element.

Abstract: A tool for breaking a shaft includes two aligned tubular elements (20, 22), each having an end portion for receiving a contiguous length of the same shaft (2). Means are provided for locking each end portion against rotation relative to the shaft length received therein, and the elements are adapted for rotation relative to one another with the end portions so locked, to relatively twist the shaft lengths and shear the lengths at the interface between them. The element end portions will normally have juxtaposed faces, and it is preferred that the faces are moved towards each other during the relative rotation and as the shaft lengths are twisted relative to each other. This assists in achieving a substantially planar face at the fracture plane. A compressible washer may be disposed between the juxtaposed faces. This can stabilize the moving parts as the shaft is broken, although normally screw threads on the tubular elements will effect the movement of the element.

Abstract: A cortical bone screw assembly which includes a threaded shaft and a nut.

Abstract: An adjustable two-dimensional joint for use in hip compression screw assemblies, allows for relative alignment of the lag screw and angle plate, even when these components are effectively fitted to the respective bone sections. The joint has first and second elements (2, 4), formed with complementary male and female cylindrical surfaces (10, 12), which define the plane of adjustment. The first element (2) also defines a hinge point (6) at the axis of the male cylindrical surface (10), and the second element (4) includes a fulcrum (8) extending to the axis of the female cylindrical surface (12). A setting device (20) extends between the two elements (2, 4), which can be extended or contracted to alter the angle subtended at the hinge point/fulcrum (6, 8).