Preferred Angle

The tops of the screws have a tulip. The tulip is typically polyaxial such that the rotation allows capture of the rod. In the picture below, the tulip is silver and blue part that does not have treads. If you look at the screw, the silver collar that rotates has a notch. This notch allows

Pedicle Angulation

Today’s post is a short post on pedicle angulation. In general the pedicles have a “textbook” angle in how to align the screw to obtain the proper trajectory through the pedicle without violating the walls and possibly injuring nearby structures. The angles are a general heuristic. However studying preoperative imaging can aid in refining plan

Fixed angle screws vs variable angle screws

What the heck? What’s the difference, can’t I angle both screws? The below discussion is with regards to the anterior cervical instrumentation. Fixed angle screws and variable screws are used to hold an anterior cervical plate in place. These screws have a limitation on the amount of angulation that is “allowed” because placing them at