Disc space sizing devices

A sizing device for measuring and/or adjusting the spacing between two opposing surfaces, comprising:

• first and second distraction members
• cooperatively associated with a distal end of the sizing device,
• adapted for at least partial insertion into a space between two surfaces, and
• movable between a first configuration for insertion into the space in which each distraction member has a height dimension and a second configuration in which each distraction member has a larger height dimension for measuring and/or adjusting the spacing between the two surfaces;
• an actuator associated with the distraction members and movable to change the height dimensions of the distraction members;
• an actuator controller associated with the actuator and movable to move the actuator;
• and
• a force measurement assembly disposed in the sizing device between the actuator controller and the distraction members, and associated with the actuator for measuring a reaction force applied by the two surfaces on the distraction members.

A sizing device for measuring and/or adjusting the spacing between two opposing surfaces, comprising:

• at least one distraction member
• cooperatively associated with a distal end of the sizing device,
• adapted for at least partial insertion into a space between two surfaces, and
• movable between a first configuration for insertion into the space in which the at least one distraction member has a height dimension and a second configuration in which the at least one distraction member has a larger height dimension for measuring and/or adjusting the spacing between the two surfaces;
• an actuator associated with the at least one distraction member and movable to change the height dimension of the at least one distraction member;
• and
• an actuator controller associated with the actuator and movable to move the actuator, wherein the actuator controller is configured such that the amount of force required to be applied to the actuator controller to move the actuator is generally constant throughout the entire range of motion of the actuator.