CD HORIZON® SEXTANT™ is a "percutaneous" (through the skin) pedicle screw and rod insertion system. It enables the surgeon to precisely implant the screws and rods in a minimally invasive fashion. Once the METRx tubes have been removed, the SEXTANT™ screws are placed through the same small (one-inch) incisions. The rods are percutaneously inserted through tiny openings (approximately one-fourth of an inch long) in the skin. This system helps to immobilize the spine (internal fixation) so the bone grafts can heal and fuse the vertebrae together.