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: 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.