Abstract: A method and apparatus for defining the location of a medical instrument relative to features of a medical workspace including a patient's body region are described. Pairs of two-dimensional images are obtained, preferably by means of two video cameras making images of the workspace along different sightlines which intersect. A fiducial structure is positioned in the workspace for defining a three dimensional coordinate framework, and a calibration image pair is made. The calibration image pair comprises two 2D projections from different locations of the fiducial structure. After the calibration image pair is made, the fiducial structure is removed. A standard projection algorithm is used to reconstruct the 3D framework of the fiducial structure from the calibration image pair. Appropriate image pairs can then be used to locate and track any other feature such as a medical instrument, in the workspace, so long as the cameras remain fixed in their positions relative to the workspace.

Abstract: A spinal distraction device is provided that includes a body, a rack and a pinion-locking member. The body has a vertebral endplate engagement end and an opposite end. The body defines a chamber along its length and an opening at the opposite end in communication with the chamber. A gear bore is defined in communication with the chamber and has an axis perpendicular to the length. The rack is slidably disposed through the opening and within the chamber. The rack is slidable between a retracted position with the first end of the rack adjacent the vertebral engaging end of the body and the foot adjacent the opposite end of the body and a number of extended positions wherein the foot is at a distance from the opposite end of the body. The rack defines an engagement member with an engagement surface exposed to the gear bore. The pinion-locking member is rotatable within the gear bore to mesh with the engagement surface to convert rotary motion of the member to reciprocating motion of the rack.

Abstract: A tool for driving a screw having two threaded shanks separated by an intermediate portion. The tool includes a rod having a tapped end portion adapted to engage one of the threaded shanks. The tool also includes a cage adapted to receive the intermediate portion of the screw therein. The cage is provided with at least one opening containing a rolling member configured to be applied against a surface of the intermediate portion of the screw. The tool additionally includes a tube surrounding the rod and the cage. The tube includes an inner wall having a profile configured such that as the tube is rotated about the longitudinal axis, the inner surface applies a radial force to the rolling member, causing the rolling member to be radially displaced through the opening in the cage and placing it in abutment with the intermediate portion of the screw.

Abstract: An intervertebral joint prosthesis having a ball component (22) for engagement with a first vertebra (26) and a trough component (24) for engagement with a second vertebra (27) adjacent to the first vertebra is disclosed. The trough component (24) includes a generally concave surface (50) having a substantially flat portion (52). When the ball component (22) and the trough component (24) are engaged to their respective vertebrae, the ball component (72) and the trough component (24) engage each other, permitting rotation and translation of the vertebrae with respect to each other. Both components include a flange (34,56) for engaging a vertebra. The invention also contemplates a method for and a tool for use in implanting a two-piece intervertebral joint prosthesis.

Abstract: A vertebral rod for fixation of a spine, the rod defining an outer cross section and including a detachable end portion also defining the same outer cross section. In one embodiment, the detachable end portion is connected to the remainder of the rod by a region of reduced strength. The region of reduced strength forms a fracture initiator defining an area of reduced outer cross section so that the detachable end portion can be broken off. In another embodiment, the rod defines a threaded opening and a threaded spigot, each extending along the longitudinal axis of the rod. The spigot threadedly engages the opening to releasably connect the detachable end portion to the remainder of the rod. In either embodiment, the detachable end portion is configured to receive a driving tool for removing the detachable end portion from the remainder of the rod.

Abstract: A vertebral rod for fixation of a spine, the rod formed of a first material and defining a passage extending at least partially therethrough, the passage at least partially filled with a second material different from the first material to thereby enable the stiffness of the rod to be varied along its length. The first and second materials are either a metallic material or a biocompatible material such as plastic. The rod may be formed of at least three layers of material, with the layers composed of at least two different materials.

Abstract: Bone screw for osteosynthesis devices comprising a screwing head and a screw-threaded shank having a transition portion having a variable profile between two shank parts of different profiles. The threading has a constant pitch and a constant outside diameter, and includes cutting crests throughout its length, including in the transition region. According to one method for manufacturing this screw, there are machined on the transition portion of the shank threads of decreasing depth up to the end of this transition region, the threads along the transition portion defining truncated, non-cutting crests. There is removed from the threads on the transition portion a sufficient amount of material for converting the non-cutting crests into sharp, cutting crests. This method provides a screw with bone anchorage capability throughout the length of the thread.

Abstract: This instrumentation comprises valves (2) for shifting aside tissues and vessels, pins for fixing each valve (2) to the spine, each valve (2) comprising for this purpose sleeves (6) in which the pin (5) is slidable; the instrumentation further comprises, for each valve (2), an articulated device (7) comprising a clamp (12) for clamping a rod (13) fixed to the valve (2); the clamp (12) may be articulated to a ball and oriented in all directions in space while the rod (13) and the valve (2) are adjustable in translation in the clamp (12); the articulated devices (7) are adjustably slidably mounted on a support frame (8). The instrumentation further comprises a push member which is capable of bearing against the valves (2) and preventing them from slipping on the surface of the spine while they are being placed in position. This device permits conveniently orienting the valves (2) in all directions and in translation.

Abstract: A fastener with a recessed drive socket and a driving tool with a cooperable driving head. The socket having a cylindrical interior wall interrupted by a plurality of driving corners. The driver having a tapered driving head including a plurality of sharpened driving edges adapted to engage the driving corners. The tapered driving end may be axially forced into the driving socket such that the plurality of driving edges frictionally engage the driving corners to hold the fastener on the driver and to enhance torque transmission. The cylindrical walls of the socket and the walls of the driver bit between the driving edges cooperate to define a fluid channel for passage of fluid around the driving head during positioning within the socket.

Abstract: The body (4) of the hook (1) has a passage (6) for receiving a transverse bar, which passage terminates in an aperture (7) and extends throughout the length of the body. The hook (1) includes a curved strip portion (5) for retaining an osteosynthesis rod which is connected to the body (4) in a region of said aperture (7). The height of the aperture (7) exceeds the thickness of the bar. The strip portion (5) has a width substantially equal to the width of the body (4) and edge portions (9) of the passage (6) are so shaped as to define sliding ramps for the rod which are inclined toward the interior of the strip portion (5). The arrangement of the hook ensures a trapping of the rod which improves the safety of the device in use and reduces the overall size of the hook.

Abstract: The instrumentation comprises for each lumbar vertebra two pedicular screws having two screw threads, one of the screw threads corresponding to the region of penetration of the screw in the pedicle, two rods having asperities respectively associated with a pedicular screw and secured to the latter by connection elements provided with elements for clamping the rods. Each connection element is in one piece and the screw thread corresponding to the region of penetration of the screw in the pedicle terminates in an annular shoulder against which the connection element bears which is separated by a smooth part from the screw thread outside the region of penetration in the pedicle.

Abstract: A biocompatible cranioplasty plate structure, and method of its installation, for use in the surgical repair and recontour of large cranial defects of the human skull created or caused by injury, surgical intervention for tumor removal, or congenital anomaly or disease. The plate structure is formed from a sheet of pliable perforated metallic material, particularly commercially pure titanium or titanium alloy material, and is of generally elliptical configuration with a central preformed arcuate and convex area matching the compound and complex curvature of the forehead, side or rear areas of the typical human adult skull. The plate structure includes adjustable peripheral panels for bending fitment and close adaptation of the plate structure to intact cranial bone of the skull adjacent to and surrounding the defect and for attachment of the plate structure to intact bone by bone screws having low profile heads and applicable through perforations of the peripheral panels.

Abstract: The present invention discloses a spinal fusion implant that is at least partially cylindrical, made of material appropriate for human implantation and having preferably, but not necessarily, one closed end and one end capable of being closed, such that an internal chamber can be filled and hold any natural or artificial osteoconductive, osteoinductive, osteogenic, or other fusion enhancing material. The partially cylindrical implant directly participates and is incorporated in the ensuing fusion. In the preferred embodiment, the implant of the present invention relies on surface roughenings of the outer surface to enhance its stability and resist dislodgement from within the disc space between two adjacent vertebrae. The implant of the present invention incorporates at its rear end, an engagement means to facilitate insertion or extraction of the implant. The implant may be filled with, coated with, and/or composed of, fusion promoting substances.

Abstract: A spinal implant for promoting fusion between adjacent vertebrae consisting of an integral, generally rectangular member having a plurality of openings for promoting ingrowth. In the preferred embodiment, the implant has an interior enclosed chamber, accessible from the outside through an opening in one wall, and a cap for covering said opening in the wall.

Abstract: Prosthetic apparatus for promoting and supporting guided bone tissue regeneration in at least missing or excised portions of the human mandible or maxilla and in bony defects of the mandible and maxilla. The apparatus includes a bone attachment tray formed of tissue-biocompatible titanium sheet material having perforations therethrough for receiving bone screws to affix the tray to stump portions and ridge sections of the mandible or maxilla proximate the missing or excised stump portions or ridge sections and one or more tissue-biocompatible metallic dental tooth root replacement implants which are releasably affixed at one end to the inner surface of the tray and which depend from the tray into the missing or excised portions or bone defects of the mandible or maxilla for incorporation and support in bone tissue regenerated within the tray.

Abstract: A medical/dental apparatus utilizing the properties of shape memory materials to variably control the spatial relationship between two or more elements having portions which are proximately disposed and overlapping relative to one another. Another portion of each element is connectable to part of a patient's body.

Abstract: An instrument including a guide needle (1), at least two nesting concentric tubes (2-6) placed over the guide needle, and an outer working tube (7) concentric with said tubes. The tip of the outer tube (7) is provided with a device (11) for spacing apart the bodies of vertebrae adjacent to the disk and keeping them apart during surgery, while its proximal end is provided with a hand grip (8). Anterior percutaneous nuclear incision performed with said instrument enables puncture of the disk, and particularly excision of the nucleus, to be performed easily, more quickly and more effectively than with the conventional posterolateral approach, while avoiding any damage to the anatomical environment of the patient.

Abstract: The body (4) of the hook (1) has a passage (6) for receiving a transverse bar, which passage terminates in an aperture (7) and extends throughout the length of the body. The hook (1) includes a curved strip portion (5) for retaining an osteosynthesis rod which is connected to the body (4) in a region of said aperture (7). The height of the aperture (7) exceeds the thickness of the bar. The strip portion (5) has a width substantially equal to the width of the body (4) and edge portions (9) of the passage (6) are so shaped as to define sliding ramps for the rod which are inclined toward the interior of the strip portion (5). The arrangement of the hook ensures a trapping of the rod which improves the safety of the device in use and reduces the overall size of the hook.

Abstract: Four versions of clamps originally slidable along two generally parallel spinal rods are swivel connected to three versions of transverse connectors located between the rods. Set screws lock the transverse connectors to the clamps. Two of the clamp versions use interfitting rotational index locking detents at the swivel connections to fix the final orientation of the transverse connector relative to the spinal rods. The other two clamp versions use locking tapers to lock the rotational index positions at the swivel connections to fix the final orientation of the transverse connector relative to the spinal rods. One clamp version uses a separate set screw to fix the clamp on the spinal rod. One transverse connector has an open clamping head for installation directly onto the spinal rod without sliding it onto the rod from one end or the other.