Apparatus and methods for inserting facet screws

An apparatus, comprising:

• a first shaft having an engagement portion configured to engage a first rotatable member of a bone fixation device;
• a second shaft having an engagement portion configured to engage a second rotatable member of the bone fixation device when the second rotatable member is coupled to the first rotatable member, at least a portion of the second shaft disposed within and coupled to the first shaft such that the first shaft is configured to move a predetermined axial distance relative to the second shaft when the first shaft rotates about the second shaft;
• and
• a locking mechanism configured to selectively allow rotation of the first shaft about the second shaft.

An apparatus, comprising:

• a first shaft having a proximal end portion and a distal end portion, the distal end portion of the first shaft configured to engage a nut;
• a second shaft having a proximal end portion and a distal end portion, the distal end portion of the second shaft configured to engage a screw, at least a portion of the distal end portion of the second shaft disposed within the first shaft;
• and
• a locking mechanism having a first configuration and a second configuration, the locking mechanism configured to limit the rotation of the second shaft relative to the first shaft when in the first configuration, the locking mechanism configured to allow rotation of the second shaft relative to the first shaft when in the second configuration, the locking mechanism including a biasing member configured to bias the locking mechanism in the first configuration.

An apparatus, comprising:

• a first shaft having a proximal end portion and a distal end portion, the distal end portion of the first shaft configured to engage a nut;
• a second shaft having a proximal end portion and a distal end portion, the distal end portion of the second shaft configured to engage a screw, at least a portion of the distal end portion of the second shaft disposed within the first shaft;
• a locking mechanism configured to limit the rotation of the second shaft relative to the first shaft when the locking mechanism is in a first configuration, the locking mechanism configured to allow the rotation of the second shaft relative to the first shaft when the locking mechanism is in a second configuration;
• and
• an actuator configured to move the locking mechanism between the first configuration and the second configuration, the actuator configured to rotate about a longitudinal axis of the second shaft.