Abstract: A dynamic subsidence plate is described having a first plate member and a second plate member in sliding engagement that may infinitely subside between a first and second assembled position. The plate includes a lock assembly associated with the first and second plate members. The lock assembly includes a ramp portion, an interference portion, and a bearing member situated between the ramp portion and the interference portion. The lock assembly of the plate is configured to allow movement of the first member with respect to the second member in a first direction in an infinite number of positions between a first assembled position and a second assembled position. Further, the lock assembly alternatively prevents movement of the first member with respect to the second member in an opposite second direction between the first and second assembled positions.

Abstract: A method of dilating an incision to provide access to a surgical site. Such method may include the steps of making an incision in the skin of a patient near a predetermined surgical site, inserting into the incision a dilator, inserting at least one shoe horn in juxtaposition or in direct apposition with the dilator, removing the dilator from the incision, inserting a blunt dissector adjacent the at least one shoe horn, removing the at least one shoe horn, inserting a retractor or a tube over the blunt dissector and into the incision such that the retractor or tube is at or adjacent the predetermined surgical site, removing the blunt dissector from the incision, and performing a surgical procedure at the predetermined surgical site through the retractor or tube.

Abstract: A prosthetic intervertebral spacer is disclosed. The spacer preferably includes a body and an interface extending away from the body for use during implantation of the spacer. Methods of implanting the spacer and tools used during such procedure are also disclosed.

Abstract: A spinal implant has a bone plate with a bone contacting surface and an opposite upwardly facing surface and at least one opening with a groove formed around an inner circumference of the opening. The groove has an axially spaced upper and lower surface. A bone-anchor or bone screw is capable of being accommodated in the opening between the groove and the bone contacting surface. A split-ring is mounted in the groove. The split-ring is sized to expand upon insertion of the anchor element into the opening and to come into direct contact with a head of the bone anchor to hold the bone anchor in the opening. The split-ring has an upper surface and a lower surface for respectively engaging the upper and lower surface of said groove, wherein the split-ring has a variable width so as to optimize its flexibility.

Abstract: A dynamic subsidence plate is described having a first plate member and a second plate member in sliding engagement that may infinitely subside between a first and second assembled position. The plate includes a lock assembly associated with the first and second plate members. The lock assembly includes a ramp portion, an interference portion, and a bearing member situated between the ramp portion and the interference portion. The lock assembly of the plate is configured to allow movement of the first member with respect to the second member in a first direction in an infinite number of positions between a first assembled position and a second assembled position. Further, the lock assembly alternatively prevents movement of the first member with respect to the second member in an opposite second direction between the first and second assembled positions.

Abstract: A method of spinal fixation includes inserting a plurality of screws into at least three vertebral bodies of a spine, the three vertebral bodies defining first and second disc spaces therebetween, and providing a spinal rod having first and second segments that exhibit different properties of flexibility. The spinal rod is connected to the plurality of screws such that the first segment is associated with the first disc space and the second segment is associated with the second disc space.

Abstract: A method of inserting an expandable intervertebral implant is disclosed. The implant preferably includes first and second members capable of being expanded upon movement of first and second wedges. The first and second wedges, while being capable of moving with respect to each other and the first and second members are also preferably attached to the first and second members. In addition, the first and second wedges are preferably capable of moving only in a first direction, while movement in a second direction is inhibited. The first and second wedges are also preferably prevented from torsionally moving with respect to the first and second members.

Abstract: A distraction wedge inserting and removing device, the device having an outer member with a handle and a shaft extending therefrom, the shaft having at least one collet formed between a pair of slots extending from a distal end of the shaft toward the handle, the at least one collet having a cammed surface on the interior surface thereof. The device also having an inner member with a roller and a rod extending therefrom from a proximal end of the inner member to a head at a distal end of the inner member, the rod being configured to interact with the handle to advance the rod within the outer member toward the distal end of the outer member, whereby the head interferes with the cammed surface of the at least one collet to move the at least one collet outwardly in a radial direction to secure a distraction wedge.

Abstract: A polyaxial screwdriver for inserting a bone screw in a vertebra. A polyaxial bone screw assembly includes a coupling element. When a screw engaging end of the polyaxial screwdriver is lowered on the head of the bone screw, the complimentary surfaces of the screw engaging end of the screwdriver and the head of the screw self-align. A ratchet mechanism formed in the screwdriver provides progressive and automatic locking of the polyaxial screwdriver to the coupling element and prevents the accidental unthreading from the coupling element. In another embodiment of the polyaxial screwdriver, a collet slides over the outside surface of the upper end of the coupling element and locks on to the coupling element. In yet another embodiment of a polyaxial screwdriver, the outer sleeve of the polyaxial screwdriver has a split end that securely engages the coupling element.

Abstract: An implant has a bone plate with a bone contacting surface and an opposite outwardly facing surface. The plate includes a split-ring receiving recess open to the outwardly facing surface located intermediate first and second bone screw receiving openings in the plate. The first and second bone screw receiving openings each having a slot spaced from the outwardly facing surface towards the bone contacting surface. The slot is formed in a wall of the first and second bone screw receiving openings. The slot is open to the split ring receiving recess. A resilient split-ring has a thickness less than a height of the slots in the first and second bone screw openings when measured along the bone screw receiving opening axis.

Abstract: An expandable intervertebral implant and tool for use in implanting same are disclosed. The tool is useful in retaining the implant in a non-expanded state throughout insert of the implant between adjacent vertebral bodies. Among other elements, the tool includes a rod, a sleeve placed over the rod, and a locking knob attached to the rod and the sleeve to fix them with respect to each other. This construct preferably aids in preventing movement of the various components of the implant, including first and second members and first and second wedges. A method of attaching inserting the implant through the use of the tool and attaching the tool to the implant are also disclosed.

Abstract: A system and method for the stabilization of the human spine using rods or plates having variable shapes and mechanical properties over their length. The rods or plates may be made up of various segments, each having different properties such as different flexibilities.

Abstract: Anatomic points within the body are projected outside the body through the use of extenders. The projected points may then be used for measurement, or to facilitate the selection or configuration of an implant that is to be positioned proximate the anatomic points. Such an implant may be a rod for a posterior spinal fusion system. Pedicle screws may be implanted into pedicles of the spine, and may then serve as anchors for the extenders. The extenders may have rod interfaces that receive the rod in a manner that mimics the geometry of the pedicle screws so that the selected or configured contoured rod will properly fit into engagement with the pedicle screws.

Abstract: A polyaxial screwdriver for inserting a bone screw in a vertebra. A polyaxial bone screw assembly includes a coupling element. When a screw engaging end of the polyaxial screwdriver is lowered on the head of the bone screw, the complimentary surfaces of the screw engaging end of the screwdriver and the head of the screw self-align. A ratchet mechanism formed in the screwdriver provides progressive and automatic locking of the polyaxial screwdriver to the coupling element and prevents the accidental unthreading from the coupling element. In another embodiment of the polyaxial screwdriver, a collet slides over the outside surface of the upper end of the coupling element and locks on to the coupling element. In yet another embodiment of a polyaxial screwdriver, the outer sleeve of the polyaxial screwdriver has a split end that securely engages the coupling element.

Abstract: A compression and distraction shaft assembly applies compression and distraction to bones including vertebrae. Shaft A assembly and shaft B assembly are attached together via a polyaxial fulcrum. The polyaxial fulcrum allows all rotational degrees of freedom between shaft A assembly and shaft B assembly. Such fulcrum, during compression and distraction, does not impart ancillary stresses or motion to vertebrae. An hourglass-shaped bore for engaging pliers is formed in approximately middle of both the shaft A assembly and the shaft B assembly. Distraction pliers having cylindrical tips are used to apply distraction to vertebrae. Once handles are pressed to impart an appropriate amount of distraction to the vertebrae, they are locked in this position. Compression pliers having cylindrical tips are used to apply compression to vertebrae. Once handles are pressed to impart an appropriate amount of compression to the vertebrae, they are locked in this position.

Abstract: A spinal implant insertion guide is disclosed. The insertion guide includes at least one channel suitable for receiving and facilitating movement of a spinal implant into an intervertebral space between two vertebrae and a portion suitable for insertion into the intervertebral space. In embodiments for use with spinal implant having multiple pieces, the pieces of the spinal implant remain in cooperation throughout movement. The guide may further include a plunger for facilitating the movement of the spinal implant.

Abstract: A posterior vertebral stabilizer has a resilient member such as a linear spring, which operates in tension and compression. The resilient member may be kept straight by a stabilization rod extending through the spring, or by a telescoping assembly that encases the resilient member. The ends of the stabilizer are attachable to pedicles of adjacent vertebrae so that the stabilizer adds stiffness to control flexion and extension of the vertebrae. Two such stabilizers may be used, and may be connected together by a crosslink designed to limit relative rotation of the stabilizers. Thus, the stabilizers may restrict axial rotation and lateral bending between the vertebrae, while permitting stiffened flexion and extension. Such stabilizers help provide the stiffness of a healthy intervertebral disc. In the event that fusion of the joint becomes necessary, a set screw or other component may be used to further restrict flexion and extension.

Abstract: A system and method that facilitates minimally invasive spine surgery. The system includes screw preparation instruments that include a targeted guide with a laser attached to a fluoroscope, at least one polyaxial screw and rod guidance instruments that selectively insert the at least one polyaxial screw within the spine. The screw preparation instruments include an awl, a hand-held drill or tap, a ball-tipped probe, a cannulated depth gauge ruler, and a hexagonal screwdriver. Each screw preparation instrument have respective handles marked with a targeting guide oriented along respective central axes of the instruments. The rod guidance instruments include a rod with a tapered tip, a T-handle rod holder, a T-handle alignment guide, an alignment marker sleeve, a flexible alignment marker with a polyaxial head, and a template rod.

Abstract: A method for osteosynthesis of a spinal column using an assembly including a bone anchor, a connector and a ring, the method comprising: inserting an anchoring part of the bone anchor into bone, the bone anchor including the anchoring part and a head, the head positioned to be in contact with the connector and ring; inserting a connecting member into the connector; and applying a force to the connecting member such that the connecting member applies the force against the ring and the bone anchor, wherein the head of the bone anchor contacts the connector, ring and connecting member during the application of the force.

Abstract: A method of inserting and positioning an intervertebral spacer is provided. The spacer includes a longitudinal axis, an on-axis interface coincident with or parallel to the longitudinal axis, and an off-axis interface angled to the longitudinal axis. The spacer's front end may be curved. The method may include inserting the spacer into the disc space utilizing a tool to engage an on-axis interface and then to engage one or more of the off-axis interfaces, which may be used for further modification of the spacer. The tool is moved substantially along a single insertion direction, which may be substantially parallel to a posterior-anterior axis of the disc space. The method may result in the longitudinal axis of the spacer being perpendicular to the insertion direction, or substantially parallel to a medial-lateral axis of the disc space. The spacer may also be positioned in an anterior aspect of the disc space.