The mediRod pedicle screw system offers the advantage of pedicle screws to be completed in situ.It has been adapted to the approach of open and percutaneous technique, even when applying polyaxial screw heads to be completed in situ. The „mediRod®“-Tri system offers the possibility of placing the polyaxial head onto the initially inserted cannulated pedicle screw after carrying out the minimal-invasive decompression of spinal canal.