Rotation shaft for a rod reducer

A system for reducing a spinal rod comprising:

• a rotation shaft configured to couple with a rod reducer, the rotation shaft including:
• a body including a threaded portion disposed along an inner surface of a longitudinal throughhole;
• a rod including a distal end and threads configured to engage the threaded portion;
• an anvil coupled to the distal end of the threaded rod;
• a linkage coupled to the anvil;
• and
• a biasing member partially disposed about the linkage distal of the anvil,
• wherein rotation of the threaded rod translates into linear movement of the linkage relative to the body;
• and
• a rod reducer configured to couple with a bone screw and reduce a spinal rod therein, the rod reducer including:
• a housing having a shaft slidably disposed therethrough;
• the shaft defining a head at a proximal end thereof configured to engage the linkage of the rotation shaft;
• an anvil coupled to a distal end of the shaft, the anvil configured to engage a spinal rod;
• and
• a first arm member and a second arm member operably coupled to the anvil and the housing, first and second arm members transitionable between a first orientation, coupled with a bone screw, and a second orientation, uncoupled from a bone screw,
• wherein proximal and distal translation of the shaft with respect to the housing transitions first and second arm members between the first and second orientations.

A method of reducing a spinal rod comprising:

• coupling a first rod reducer to a first bone screw;
• positioning a spinal rod between an anvil of the first rod reducer and a screw housing of the first bone screw;
• coupling a first rotation shaft to the first rod reducer such that a linkage of the first rotation shaft is coupled to a shaft of the first rod reducer;
• rotating a threaded rod of the first rotation shaft such that the linkage translates distally with respect to a body of the first rotation shaft, wherein the linkage drives the shaft of the first rod reducer distally with respect to a housing of the first rod reducer such that the anvil of the first rod reducer is brought into contact with an outer surface of the spinal rod;
• biasing the linkage, the shaft of the first rod reducer, and the anvil of the first rod reducer distally, via a biasing member partially disposed about the linkage, against the outer surface of the spinal rod;
• and
• translating the anvil of the first rod reducer distally via rotation of the threaded rod of the first rotation shaft.