In principle the 90° drill/screwdriver provides allows burr screw holes and insert screws to be burred perpendicular to the bony surface without a direct route for instrumentation.
The procedure diminishes the loading force along the drill bit or screw because the activation is exerted from a remote pivot point over the handle and not in line with the insertion axis.
The drill /screwdriver is a precision-built mechanical instrument analogous to an angled dentist drill that transmits the force of a longitudinal input rotation axis into a smaller output axis and which carries the tool, ie, the drill bit or a screw driver blade.
The drill/ screw driver is construed of several main components:
The back of the handle has a quick coupling connection to attach an electric motor or a handgrip for manual screw insertion. The mechanics inside are continuous to the interface with the shaft.