A surgical instrument comprises a first portion defining a cavity configured for disposal of a first implant support member. A second portion defines at least one passageway aligned with the cavity and including a guide engageable with a second implant support member to orient the second implant support member with the at least one passageway such that the second implant support member is connectable with the first implant support member. Systems, spinal constructs, spinal implants and methods are disclosed.

A pivotal bone anchor assembly includes a shank with a head and an anchor portion, and a receiver with a channel for receiving a rod and a lower portion of an axial bore for receiving the shank head, with the axial bore including a stop structure and a downwardly-facing surface beneath a helically wound thread. The assembly also includes an insert having an upwardly-facing seat, a lower surface for engaging the shank head, a side structure for engaging the stop structure, and an upwardly-facing surface positioned radially outward from the upwardly-facing seat, with the insert being installed into the axial bore in a first angular position. Subsequent rotation of the insert within the axial bore moves the upwardly-facing surface under the downwardly-facing surface to inhibit upward movement of the insert within the axial bore, with further rotation being inhibited by the side structure coming into engagement with the stop structure.

Enzymatic and non-enzymatic detectors and associated membrane apparatus, and methods of use, such as within a fully implantable sensor apparatus. In one embodiment, detector performance is controlled through selective use of membrane configurations and enzyme region shapes, which enable accurate detection of blood glucose level within the solid tissue of the living host for extended periods of time. Isolation between the host's tissue and the underlying enzymes and reaction byproducts used in the detectors is also advantageously maintained in one embodiment via use of a non-enzyme containing permeable membrane formed of e.g., a biocompatible crosslinked protein-based material. Control of response range and/or rate in some embodiments also permits customization of sensor elements. In one variant, heterogeneous detector elements are used to, e.g., accommodate a wider range of blood glucose concentration within the host. Methods of manufacturing the membranes and detectors, including methods to increase reliability, are also disclosed.

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.

Embodiments disclosed herein provide compression/distraction methods and tools useful for fitting a spinal stabilization system in a patient through minimally invasive surgery. The spinal stabilization system may comprise screws anchored in vertebrae. The vertebrae may need to be compressed or distracted. One embodiment of an instrument disclosed herein may comprise a shaft for engaging one of the screws through an extender sleeve. A driver may engage another screw through an opening of the instrument. Through this engagement, a surgeon may use the rack and pinion of the instrument to compress or distract one or more levels of the vertebrae in a parallel motion, which can be advantageous clinically in certain situations.

This invention relates to a transdiscal screw capable of following a non-linear trajectory. The screw assembly includes a first screw and second screw coupled at a poly-axial joint. The first screw and the second screw capable of rotating independently of each other. The screw can also include a third screw coupled to the second screw at a poly-axial joint such that the first screw, second screw and third screw can rotate independently of each other.

Bone anchor assemblies are disclosed herein that include one or more features for indicating the relative positioning of the receiver member and the shank, or for selectively maintaining the receiver member and the shank in a fixed relative position. For example, the head of the shank can include a surface feature that interacts with a drag ring to provide tactile or audible feedback when the shank is positioned at a particular orientation with respect to the receiver member. By way of further example, the head of the shank and a compression cap disposed in the receiver member can each include engagement features that cooperate to allow for selective locking of the orientation of the shank with respect to the receiver member.

A bone anchor implant assembly configured for surgical implantation into a bone of a patient. The bone anchor implant assembly includes an elongate rod, a separate shank and head, and a closure mechanism configured as a one-part closure or two-part closure. The one-part closure and two-part closure are configured to be interchangeable with each other for closing a channel of the head and locking the assembly and the elongate rod between arms of the head with the closure mechanism.

A spinal fixation construct for aligning vertebral bodies includes a bone screw, a spinal rod, a flexible member, and a fixation member. The spinal rod is disposed within a saddle portion of a housing of the bone screw, and includes an elongated body having a first end and a second end. The spinal rod is formed from a first material having a first modulus of elasticity. The flexible member is coupled to the spinal rod, and includes an elongated body having a first end portion and a second end portion. The flexible member is formed from a second material having a second modulus of elasticity that is different from the first modulus of elasticity. The fixation member includes a threaded body portion and a head portion defining a hole therethrough. A portion of the flexible member extends through the hole of the head portion.

Spinal fixation apparatus with a first end for selectively flexing to expand in diameter when receiving a head of an engagement member, the engagement member for coupling to a portion of a spine and a flexible sidewall between the first end and a second end, the flexible sidewall to selectively expand in length, between the first end and the second end, when the first end is not in receipt of the head of an engagement member and alternatively to contract in length when the first end is in receipt of the head of the engagement member.