Bone fastener and instrument for insertion thereof

A fastener that can be fixed through an opening between adjacent members each member having a near face and a far face, the fastener comprising:

• first and second fastening members;
• a first connector on the first fastening member;
• a second connector on the second fastening member for connecting with the first connector;
• a positioning member on the first fastening member for interacting with a positioning instrument extending through the second fastening member to position the first fastening member in a fastening position on the far face so that the first and second connectors can be interconnected and the positioning instrument can be removed from the first fastening member while leaving the first and second connectors interconnected;
• wherein the first fastening member is a base with an inner face, and a projection projects from the inner face of the base to engage the far face of at least one of the adjacent members to inhibit rotation of the base relative to the adjacent members.

A fastener that can be fixed through an opening between adjacent members, each member having a near face and a far face, the fastener comprising:

• first and second fastening members;
• a first connector on the first fastening member;
• a second connector on the second fastening member for connecting with the first connector;
• a positioning member on the first fastening member for interacting with a positioning instrument extending through the second fastening member to position the first fastening member in a fastening position on the far face so that the first and second connectors can be interconnected, and the positioning instrument can be removed from the first fastening member while leaving the first and second connectors interconnected;
• the second fastening member comprises a cap having a convex outer face with a recess for engaging a drive member that rotates the cap, and a flat inner face, and the second connector comprises a threaded stud that projects from the inner face of the cap;
• and
• the first fastening member is a base with an inner face, and the first connector comprises a collar that projects from the inner face of the first fastening member, and a plurality of raised barbs project from the inner face of the base in a same direction that the collar projects from the base.

A fastener sustem that can be fixed through an opening between adjacent members, each adjacent member having a near face and a far face, the fastener system comprising:

• first and second fastening members;
• a first connector on the first fastening member;
• a second connector on the second fastening member for connecting with the first connector;
• a projection from the first fastening member for inhibiting rotation of the first fastening member relative to the adjacent members;
• a positioning member on the first fastening member for interacting with a positioning instrument extending from the near face;
• and
• a positioning device, comprising a platform member with a projection that engages the positioning member to maintain the first fastening member in a substantially stationary position on the positioning device.

A fastener that can be fixed through an opening between adjacent members, each adjacent member having a near face and a far face, the fastener comprising;

• first and second fastening members;
• a first threaded connector projecting from the first fastening member;
• a second threaded connector projecting from the second fastening member for engagement with the first threaded connector;
• wherein the first threaded connector is both externally and internally threaded to engage the threads of both the second threaded connector and a threaded portion of a positioning instrument that extends through the second threaded connector.

A fastener, comprising:

• a base having an inner face;
• an externally threaded elongated stud projecting away from the inner face of the base, the elongated stud having an internally threaded bore at a free end of the stud, and a plurality of raised barbs on the inner face of the base around the stud;
• and
• a cap comprising a recess for engaging a fastener instrument and securing the cap to a drive member, and an inner face of the cap from which an internally threaded collar projects for inter-engagement with the externally threaded stud, and an opening through the cap and collar for the fastener instrument to communicate with the internally threaded bore of the stud when the fastener is assembled.

A method of replacing a cranial bone plate following a craniotomy, wherein the craniotomy has been performed by providing a plurality of craniotomy holes through the skull that are subsequently connected by saw lines along a separation border to remove the cranial bone plate, thereby leaving a portion of a hole in the bone plate and a corresponding portion of the hole in a surrounding cranial bone, and the bone plate has internal and external faces that are to be placed substantially co-planar with surrounding internal and external faces of the surrounding cranial bone, with opposing transverse faces of the bone plate and the surrounding bone in apposition along the separation border, and the method comprises the steps of:

• providing a fastener having a first member with an externally threaded stud projecting therefrom, and a second member with an internally threaded collar projecting therefrom, wherein the first and second members are wider than the hole through the skull, the collar fits through the hole, and the combined length of the collar and shank is at least as great as the distance between the internal and external faces of the bone plate;
• after removing the bone plate, placing one of the first or second members beneath the portion of the hole in the surrounding bone, overlapping the separation border;
• replacing the bone plate with the corresponding portion of the hole complementing the portion of the hole in the surrounding bone to reform the hole, with the collar projecting into the hole;
• placing the other of the first or second member over the reformed hole and the external face of the surrounding bone and the bone plate, overlapping the separation border;
• and
• rotating the stud into the collar until the first and second members are brought into frictional engagement with and clamp the bone plate and the surrounding bone to each other.

A method of replacing a cranial bone plate following a craniotomy, wherein the craniotomy has been performed by providing a plurality of craniotomy holes through the skull that are subsequently connected by an osteotomy along a separation border to remove the cranial bone plate, thereby leaving a portion of a hole in the bone plate and a complementary portion of the hole in a surrounding cranial bone, and the bone plate has internal and external faces that are to be placed substantially co-planar with internal and external faces of the surrounding cranial bone to close the craniotomy, with opposing transverse faces of the bone plate and the surrounding bone in apposition along the separation border, and the method comprises the steps of:

• providing a base comprising a disc having an inner face and an outer face, the inner face of the base circumscribing an elongated, externally threaded stud projecting from the inner face, and the base further comprises a plurality of raised barbs on the inner face of the base surrounding the collar;
• providing a cap having an outer face that includes a recess, and an inner face from which an internally threaded collar projects for inter-engagement with the externally threaded stud, and an opening through the cap that communicates with the internally threaded collar, wherein the stud includes an internally threaded bore, the base and cap are each wider than the hole, the collar fits through the hole, and the base and cap are made of a biocompatible material suitable for implantation in the human body;
• after removing the bone plate, placing the inner face of the base against the internal face of the surrounding bone, beneath the portion of the hole in the surrounding bone, overlapping the separation border, with the barbs engaging the internal face of the surrounding bone and the collar projecting through the portion of the hole in the surrounding bone;
• replacing the bone plate with the complementary portion of the hole in the bone plate complementing the portion of the hole in the surrounding bone to reform the hole;
• placing the cap over the reformed hole and against the external face of the surrounding bone and the bone plate, overlapping the separation border;
• and
• providing a fastener instrument comprising a sleeve, a shaft that slides within the sleeve wherein the shaft has a threaded tip, and a prong on the sleeve that fits within the receptacle on the cap to secure the sleeve to the cap;
• inserting the prong into the recess in the cap to secure the sleeve to the cap;
• inserting the threaded tip of the shaft through the opening through the cap and into the internally threaded bore in the shaft, then rotating the threaded tip to screw the threaded tip into the internally threaded bore of the stud;
• rotating the shaft to screw the internally threaded collar of the cap onto the externally threaded stud to bring the cap and base together into frictional engagement, clamping the bone plate and the surrounding bone to each other;
• rotating the shaft to unscrew the threaded tip from the internally threaded bore of the stud.

An instrument for engaging first and second members to each other, comprising:

• a sleeve;
• a shaft that slides within the sleeve;
• an attachment member on the instrument for engaging the first member to the instrument;
• and
• an engagement structure on the shaft that engages the second member and pulls it into engagement with the first member.

An instrument, comprising:

• a sleeve that includes a handle extending from the sleeve;
• a rod that slides within the sleeve;
• a threaded tip on a first end of the rod;
• and
• a handle on a second end of the rod.

A device, comprising:

• an elongated tubular sleeve with a proximal end and a distal end, wherein a handle member extends away from the proximal end of the sleeve, and the distal end includes a plurality of projections;
• an elongated rod that slides within the sleeve, wherein the rod includes a proximal end and a distal end, a handle member attached on the proximal end of the rod, and an externally threaded tip at the distal end of the rod;
• a first fastener member having indentations therein for tightly receiving the plurality of projections and securing the first fastener member to the sleeve, and an opening through the first fastener member through which the rod can slide when the first fastener member is secured to the sleeve, wherein the opening is internally threaded;
• and
• a second fastener member having sharp projections directed toward the first fastener member, and a projection from the second fastener member with internal threads that are complementary to the externally threaded tip of the rod, and external threads that are complementary to the internally threaded opening through the first fastener member.