An intervertebral implant may include a shaft having a proximal end, a distal end, a longitudinal axis, a minor diameter, and a helical thread disposed about the shaft along the longitudinal axis between the proximal end and the distal end of the shaft. The helical thread may include a major diameter and a concave undercut surface angled towards one of the proximal end and the distal end of the shaft. The intervertebral implant may be implanted within an intervertebral space between a superior vertebral body and an inferior vertebral body. A ratio of the major diameter to the minor diameter may be less than 1.50. The concave undercut surface may engage the superior vertebral body and the inferior vertebral body and may be shaped to resist at least one force transmitted between the superior vertebral body and the inferior vertebral body to stabilize the intervertebral space.

A bone disunion fastener may include a fastener shaft, a helical thread, and a bone staple. The helical thread may include a concave undercut surface oriented towards one end of the fastener shaft. The bone staple may include a first bone-engaging feature, a second bone-engaging feature, and a middle portion with an opening. The bone disunion fastener may be implanted along a disunion between a first bone portion and a second bone portion. The concave undercut surface may be shaped to resist at least one force transmitted between the first bone portion and the second bone portion to stabilize the disunion. The first bone-engaging feature may engage the first bone portion and the second bone-engaging feature may engage the second bone portion to couple the bone staple to the bone portions and resist at least one force transmitted between the bone portions to stabilize the disunion.

A polyaxial bone anchoring device includes a receiving part having a longitudinal axis, a channel for receiving a rod, and an accommodation space for pivotably holding a head of a bone anchoring element, and a pressure member configured to be positioned in the receiving part and to exert pressure onto the head to lock the head in the receiving part. The pressure member includes a pressure exerting surface and a deformable portion having a free end, wherein the deformable portion is configured to assume at least a first configuration and a second configuration. The polyaxial bone anchoring device further includes a locking member configured to be inserted into the channel and to exert a force onto the deformable portion. When the head and the pressure member and the locking member are in the receiving part, the free end of the deformable portion is supported in the receiving part, and the locking member is movable in the channel along the longitudinal direction in such a manner that the locking member first contacts the deformable portion and exerts a force onto the deformable portion to bring the deformable portion from the first configuration into the second configuration thereby locking the head. Thereafter the locking member comes into contact with the rod and locks the rod.

A bone fixation system comprises a first fastener configured to anchor into a first vertebrae, a second fastener configured to anchor into a second vertebrae, and a set screw to retain the second fastener to the first fastener. The first fastener includes a shaft extending along a longitudinal axis and a head. The shaft includes a first cylindrical body. The head of the first fastener includes a second cylindrical body defining a passageway having an interior surface. The passageway defines a longitudinal axis that is different than the longitudinal axis of the shaft. The first cylindrical body of the shaft and the second cylindrical body of the head are angled relative to each other. A head of the second fastener is configured to engage the interior surface of the passageway of the head of the first fastener. The set screw retains the head of the second fastener in the passageway.

The present invention relates to stable fixation of spine segments, allowing for fusion in, e.g., skeletally mature patients. More particularly, the invention relates to a bone fixation device that can be affixed to vertebrae of a spine to provide reduction (or enlargement) capabilities and allow for fixation in the treatment of various conditions, including, e.g., spondyloslisthesis, degenerative disc disease, fracture, dislocation, spinal tumor, failed previous fusion, and the like, in the spine. The invention also relates to a method for delivering and implanting the bone fixation device.

A bone screw, for drawing first and second bone fragments together, includes a shaft having a distal section and a proximal section. The distal section has a first external male screw thread and a minor diameter. The proximal section has a second external male screw thread. A major diameter of the distal section is larger than a major diameter of the proximal section. The bone screw includes a sleeve that has an internal female screw thread configured to mate with the second male screw thread. A distal portion of the sleeve has an outer diameter. The outer diameter is equal to or smaller than the minor diameter of the distal section of the shaft.

The present invention relates to a system, method, device and kit which utilize a modular pedicle screw implant that does not require the use of a guide wire for implantation and can be assembled in situ. The system, method, device, and kit include a surgical instrument for implanting a modular pedicle screw comprising a cannula coaxially aligned with a modified trocar style instrument or surgical shaft. The surgical shaft contains a first member of a surgical shaft-inner pedicle bone screw member joint, illustrated herein as a locking taper, for securing an inner member of a pedicle screw thereto. The inner member of a pedicle screw is further adapted to couple to an outer pedicle sheath. In combination, the inner member of a pedicle screw and the outer pedicle sheath form a solid modular pedicle screw.

A bone fastener system can comprise a fastener and a first sizing component. The fastener can comprise a shaft that provides an anchoring footprint. The first sizing component can be configured to be connected to the shaft and can include a first anchoring feature, or circumferential bone engaging feature, to increase a size of the anchoring footprint. The first anchoring feature can comprise a sleeve that radially expands a diameter of the threaded shaft. The first anchoring feature can comprise axially extending teeth. The system can further comprise a second sizing component including a second anchoring feature to increase the size of the anchoring footprint, the second anchoring feature being different from the first anchoring feature. The second anchoring feature can expand the diameter of the threaded shaft a greater amount than the first anchoring feature. The second anchoring feature can have a length greater than the first anchoring feature.

Described herein is a pedicle screw for use in the thoracolumbar spine where the height can be adjusted intra-operatively before or after installation member of the longitudinal member. The pedicle screws with adjustable height may be made with a monoaxial or polyaxial configuration. The height of the pedicle screw can be lengthened or shortened.

This disclosure is directed to surgical fixation devices (e.g., staples, screws, etc.) which are able to bring bone fragments into close proximity with each other, generate a compressive load, and maintain that compressive load for a prolonged period of time while healing occurs. The surgical fixations devices are manufactured from a shape memory material (e.g., a material capable of exhibiting superelasticity and/or a temperature-induced shape change).