Abstract: Devices and methods for selectively converting polyaxial bone screws into monoaxial screws are described herein. In one embodiment, a spinal screw extension instrument is provided having an outer component configured to engage a receiving member of a polyaxial screw. The instrument further includes an inner component disposed within an inner lumen of the outer component and configured to translate longitudinally relative to the outer component such that the inner component can apply a distal force to a compression member of the polyaxial screw disposed within a distal portion of the receiving member to thereby convert the polyaxial screw to a monoaxial screw.

Abstract: Various exemplary methods and devices are provided for fixing bone anchors to bone. In general, the methods and devices can allow for a bone anchor to be fixed to a bone at a desired angle to a receiver member. In an exemplary embodiment, a bone anchor assembly is provided that includes a bone anchor configured to engage bone, a receiver member that polyaxially seats a spherical head of the bone anchor, and a compression member seated within the receiver member, proximally of the head of the bone anchor. The compression member can have a distal end with gripping features thereon configured to create at least one line contact and/or one band contact with the head of the bone anchor, thus providing a firm grip on the head of the bone anchor and reducing a risk of slippage of the bone anchor with respect to the receiver member.

Abstract: Various methods and devices for inserting a guidewire into the body are provided. In one embodiment, a guidewire insertion device is provided and includes and outer sheath having an outer surface and an inner lumen extending therethrough, and a dilator having an inner lumen extending therethrough and having a length greater than a length of the outer sheath. A guidewire can be configured to extend through the inner lumen of the dilator such that the guidewire is removably and replaceably disposable within the dilator and coupled thereto. A locking mechanism can be effective to selectively configure the guidewire between a locked position in which the guidewire is stationary relative to the dilator and an unlocked position in which the guidewire is movable relative to the dilator.

Abstract: A bone anchor assembly includes a bone anchor, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, a compression member positioned within the receiver member, and a closure mechanism including an outer set screw and an inner set screw. The outer set screw delivers a distal force to the compression member to fix the bone anchor relative to the receiver member. The proximal surface of the compression member has a shape configured to restrict deformation of the compression member arms including motion of the compression member arms relative to each other. The distal surface of the outer set screw has a shape that is complementary to the shape of the proximal surface of the compression member.

Abstract: Various methods and devices for inserting a guidewire into the body are provided. In one embodiment, a guidewire insertion device is provided and includes and outer sheath having an outer surface and an inner lumen extending therethrough, and a dilator having an inner lumen extending therethrough and having a length greater than a length of the outer sheath. A guidewire can be configured to extend through the inner lumen of the dilator such that the guidewire is removably and replaceably disposable within the dilator and coupled thereto. A locking mechanism can be effective to selectively configure the guidewire between a locked position in which the guidewire is stationary relative to the dilator and an unlocked position in which the guidewire is movable relative to the dilator.

Abstract: A reamer for preparing a spinal upper facet to facilitate insertion of combined screw/washer implant, preventing bone damage and facet weakening, and also allowing possibility to place grafting so as to maximize implant stabilization. The reamer has shallow outer cutting surfaces to cut a groove for spike insertion; deep inner cutting surfaces to cut a cortical-penetrating bore for insertion of the screw, and a flat therebetween to limit penetration of these cutting surfaces.

Abstract: An assembly for connecting a support element to a bone. The assembly comprises: a bone screw having a head at one end of a threaded shaft; and a clamp comprising: a base at a first end of the clamp delimiting an opening for receiving the head of the bone screw; and at least two side members extending from the base towards a second end of the clamp. The head of the bone screw and the clamp are configured to allow the head of the bone screw to be inserted into the base from the direction of the first end at a first orientation of the base to the bone screw, and to retain an inserted bone screw within the base at a second orientation of the base relative to the bone screw. This allows the screw to be inserted into the bone without requiring prior assembly of the screw and clamp. It also allows later revision whereby the clamp can be removed from the screw without requiring an implanted screw to be removed from the bone.

Abstract: A bone anchor assembly includes a bone anchor, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, and a closure mechanism. The closure mechanism is positionable between the arms of the receiver member to capture a spinal fixation element within the receiver member and fix the spinal fixation element with respect to the receiver member. The closure mechanism includes an outer thread engageable with an inner thread on the arms of the receiver member. The inner thread and the outer thread have a thread angle between 5° and 25°.

Abstract: A connector for connecting a second bone anchor to a first bone anchor includes a first component engageable to the first bone anchor and rotatably adjustable relative to the first bone anchor, a second component connected to the first component and forming a socket to receive the second bone anchor in a plurality of angular orientations, and a closure mechanism engageable with the second component to fix the second bone anchor at a selected angular orientation relative to the second component.

Abstract: A cannulated bone anchor assembly includes a bone anchor, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, and a closure mechanism to fix the spinal fixation element with respect to the receiver member. The bone anchor includes a distal shaft having a first threaded section proximal a proximal head, a second threaded section proximal to and adjacent the first threaded section, and a third threaded section proximal to and adjacent the second threaded section. The first threaded section having a constant major and minor diameter. The second threaded section having a tapering major and minor diameter. The third threaded section having a tapering major diameter and a constant minor diameter.

Abstract: A method of manufacturing a medical implant comprising a radiopaque marker is described. The method comprises manufacturing a medical implant using stereolithography, wherein the medical implant has an external surface that delimits an opening to a channel. A curable mixture of a biocompatible polymer and a radiopaque material is then inserted into the channel while in a liquid state and cured in the channel so that it solidifies in the channel. The combination of an implant manufactured by stereolithography and a radiopaque marker which is inserted into the channel in a liquid state enables complex internal structures to be formed in the implant for the radiopaque marker and for the marker to take on those complex forms more easily. This allows a better visualisation of the marker under X-Ray or other medical imaging technique.

Abstract: Various methods and devices for inserting a guidewire into the body are provided. In one embodiment, a guidewire insertion device is provided and includes and outer sheath having an outer surface and an inner lumen extending therethrough, and a dilator having an inner lumen extending therethrough and having a length greater than a length of the outer sheath. A guidewire can be configured to extend through the inner lumen of the dilator such that the guidewire is removably and replaceably disposable within the dilator and coupled thereto. A locking mechanism can be effective to selectively configure the guidewire between a locked position in which the guidewire is stationary relative to the dilator and an unlocked position in which the guidewire is movable relative to the dilator.

Abstract: A reamer for preparing a spinal upper facet to facilitate insertion of combined screw/washer implant, preventing bone damage and facet weakening, and also allowing possibility to place grafting so as to maximize implant stabilization. The reamer has shallow outer cutting surfaces to cut a groove for spike insertion; deep inner cutting surfaces to cut a cortical-penetrating bore for insertion of the screw, and a flat therebetween to limit penetration of these cutting surfaces.

Abstract: An assembly for connecting a support element to a bone. The assembly comprises: a bone screw having a head at one end of a threaded shaft; and a clamp comprising: a base at a first end of the clamp delimiting an opening for receiving the head of the bone screw; and at least two side members extending from the base towards a second end of the clamp. The head of the bone screw and the clamp are configured to allow the head of the bone screw to be inserted into the base from the direction of the first end at a first orientation of the base to the bone screw, and to retain an inserted bone screw within the base at a second orientation of the base relative to the bone screw. This allows the screw to be inserted into the bone without requiring prior assembly of the screw and clamp. It also allows later revision whereby the clamp can be removed from the screw without requiring an implanted screw to be removed from the bone.

Abstract: A hook for joining a vertebra and a rod, comprising a main body (4) with a channel portion (10) and a hook portion (8). The channel portion (10) is for receiving a spinal support rod, and the hook portion (8) is for receiving vertebral tissue. The hook incorporates a clamp (6) which rotates about an axis so that a sharp tip of the clamp (6) can move towards and away from the free end of the hook portion, allowing a bone to be gripped within the hook portion (8) by the clamp (6).