ISO-C-3D-assisted navigated implantation of pedicle screws in the thoracic and lumbar spine

The mobile Siremobil Iso-C-3D C-arm (Siemens AG, Medical Solutions, Erlangen) is the first device that permits the intraoperative three-dimensional (3D) representation of bone structures. A high-resolution isotropic 3D data cube in the isocenter with an edge length of approximately 12 cm is calculated simultaneously. The Siremobil ISO-C-3D is linked to navigation with the integrated NaviLink interface (Siemens AG, Medical Solutions, Erlangen). This makes it possible to transfer the generated 3D data directly to the linked navigation system Surgigate (Medivision, Oberndorf,Switzerland). In this prospective clinical trial we evaluated the accuracy of pedicle screw placement using the Siremobil ISO-C-3D C-arm. The results were compared to the conventional approach and other computer-assisted procedures (CT-based navigation, C-arm-based 2D navigation) in historical control groups. A total of 141 pedicle screws were placed in 30 patients (70 thoracic spine, 71 lumbar spine). Only in one single case was misplacement shown in the postoperative control CT scan (0.71%),the lowest rate of incorrect placements of all techniques. Also the lowest average fluoroscopy time (1.28 +/- 0.56 min) was achieved during the placement of pedicle screws on the spine with Iso-C-3D navigation at a comparable average OR duration (103.26 +/- 23.3 min). There were no postoperative neurological complications in all 30 patients. From these data we conclude that Iso-C-3D navigation of pedicle screws is a very accurate method in the correct placement of pedicle screws.