US Patent 10022172 Minimally invasive posterolateral fusion

A percutaneous system in which tubular retractors are utilized as a means of access, visualization, and a controlled orientation for preparation of posterior spinal elements and delivery of graft material for posterior spinal fusion. The tubular retractors are affixed to screw extensions to rotate and articulate relative to multi-axial screws percutaneously inserted into respective pedicles of vertebral bodies. The procedure is done bilaterally, although it could be performed unilaterally in cases where the anatomy or surgeon preference dictates. A number of different deployable graft concepts are disclosed, the primary features being to allow for creation of a graft space volume and a means for delivery of the graft material preferred by the surgeon.