Bone anchor assemblies are disclosed herein that provide for a single bone anchor assembly that can be utilized across a range of spinal surgical procedures, reduce manufacturing burden and cost, and provide for greater flexibility during a surgical procedure. The bone anchor assemblies disclosed herein include an implantable shank and a receiver member having two spaced apart arms which form a U-shaped seat to receive a rod, among other components. The bone anchor assemblies disclosed herein also provide a number of features to enhance capability and usability. Examples include features to facilitate better implantation of the shank, better coupling of instrumentation to the anchor, better performance in reducing a spinal fixation element, such as a rod, into the receiver member seat, and others.

A screw insertion system has a screw having a threaded shaft and a head. The head has a conically tapered outer surface, the taper increasing in distance from a central longitudinal axis of the screw from a free end of the head towards a larger diameter adjacent the connection between the head and the threaded shaft. The conically tapered head outer surface has preferably two helically extending partially rounded threads. The head has a drive element for engaging a driver. A tubular screw holder has an outer surface and internal bore extending between a leading end and a trailing end for receiving the screw. The leading end having a conically tapered inner threaded portion for engaging the conically tapered outer thread of the screw head. The tubular screw holder outer surface having a diameter less than or equal to the maximum diameter of the conically tapered head.

A method of assembling a receiver assembly includes positioning a retainer and an insert into a through-space of a receiver that extends between a bottom opening and an upper opening, such that a second channel of the insert is in non-alignment with a first channel of the receiver. The through-space includes at least one integral downward facing surface and an integral inward projecting surface. The insert includes side structures for contacting internal surfaces of the through-space of the receiver. The method further includes rotating the insert within the through-space of the receiver so as to align the second channel with the first channel for receiving a rod, to move the side structures of the insert into an overlapping arrangement with the inward projecting surface of the through-space that maintains substantial alignment between the second channel and the first channel, and to move one or more upward facing surfaces of the insert into contact with the one or more integral downward facing surfaces of the receiver that limits the insert from moving towards the upper opening in the receiver.

A surgical guidance device is cannulated for passage of a guidewire or pin and includes a hand grip and differential control assembly for driving the guidewire or pin and differentially driving a screw, such as but not limited to a pedicle screw, into bone. The differential control assembly resides in a housing and includes a differential control assembly for gripping and locking or releasing the guidewire or pin and effecting directional movement (relative to the user holding the surgical guidance device) either distally into the bone or proximally away from bone to thereby drive or retract the guidewire. The differential control assembly also allows distal or proximal drive of a screw, such that one or both the guidewire and screw can be passed proximally or distally alone or together.

Some embodiments provide systems, assemblies, and methods of analyzing patient anatomy, including providing an analysis of a patient's spine, and also analyzing the biomechanical effects of implants. In some embodiments, the systems, assemblies, and/or methods can include obtaining initial patient data, acquiring spinal alignment and contour information, acquiring flexibility and/or biomechanical information, registering patient anatomical landmarks of interest relative to fiducial markers, analyzing databases of measurements and patient data to predict postoperative patient outcomes. Further, in some embodiments, the systems, assemblies, and/or methods can assess localized anatomical features of the patient, and obtain anatomical region data. In some embodiments, the systems, assemblies, and/or methods can also analyze the localized anatomy and therapeutic device location and contouring. Further, the systems, assemblies, and/or methods can output localized anatomical analyses and therapeutic device contouring data and/or imagery on a display according to some embodiments.

Disclosed are devices, systems and methods for inserts for sacroiliac joint arthroplasty, which can include the employment of a longitudinal bone screw and associated threaded cylindrical sleeve, received on a proximal end of the bone screw, with a collet, nut or other securement feature holding the sleeve onto the screw. The sleeve can selectively articulate and/or be immobilized relative to the bone screw, with the system allowing for, at a surgeon's option, motion preservation between bone surfaces in some surgical applications while being utilized as an immobilizing and/or fusion construct between bone surfaces during other surgical applications.