US Patent 7794464 Spinal derotation instruments and methods

Derotation instrument assemblies and systems are provided to facilitate positioning one or more vertebrae of a spinal column into a desired alignment. The instrument assemblies and systems include implant holders engageable to respective implants engaged to vertebrae of the spinal column, transverse bridges to connect implant holders associated with a particular vertebra, and inter-level linking assemblies to connect instrument assemblies associated with different vertebrae. Derotation handles can be provided to facilitate application of the alignment forces, while the assemblies distribute the corrective forces to the connected implants and vertebrae.