Reduction instruments and methods
The present subject disclosure provides a novel design for devices and methods for straightening a curved spine by using a reduction tool to move the spine with respect to an attached bone plate.
1. A spinal reduction device, comprising: a base comprising a top surface, a bottom surface, a first side, a second side, a first end, and a second end, the base further comprising a longitudinal axis extending from the first end to the second end; a vertical post positioned substantially centrally on the base, wherein the vertical post extends upwardly from the base and has a longitudinal axis which is substantially perpendicular to the longitudinal axis of the base; a plurality of arms extending away from the first side of the base in a direction away from the second side of the base and generally parallel to the bottom surface of the base, the plurality of arms adapted to be visible to a user when viewed from above the base, each arm comprising a distal end; a plurality of prongs, wherein each of the plurality of prongs extends downwardly from a distal end of a corresponding one of the plurality of arms, the plurality of prongs adapted to be engaged with corresponding attachment apertures in a bone plate; and a first guide extending upwards from the base adjacent the first end thereof, the first guide comprising a first guide passage with a longitudinal axis, wherein the spinal reduction device further comprises a translation nut adapted to translate along the longitudinal axis of the vertical post, wherein the translation nut has a hexagonal outer geometry which matingly engages with a driver having a hexagonal female geometry, thereby allowing the driver to rotate the translation nut about a threaded shaft.
2. The spinal reduction device of claim 1 , wherein when the plurality of prongs are engaged with corresponding attachment apertures on the bone plate, the first guide passage is aligned such that its longitudinal axis extends directly through a first screw hole positioned in the bone plate.
3. The spinal reduction device of claim 2 , further comprising: a second guide extending upwards from the base adjacent the second end thereof, wherein the second guide has a second guide passage with a longitudinal axis, wherein when the plurality of prongs are engaged with the corresponding attachment apertures in the bone plate, the second guide passage is aligned such that its longitudinal axis extends directly through a second screw hole positioned in the bone plate.
4. The spinal reduction device of claim 1 , wherein the first guide passage has a diameter dimensioned to receive a tap shaft and a length dimensioned to permit the tap shaft to extend a distance below the bottom surface before a tap head engages a proximal end of the guide to prevent further extension of the tap shaft below the bottom plate-facing surface.
5. The spinal reduction spinal reduction device of claim 1 , wherein the first guide comprises a distal end that engages with the base, and a proximal end that has teeth which are adapted to engage with a head of a tap shaft and prevent it from further rotation when the tap shaft is inserted a certain distance into an interior of the guide.