Intraoperative three-dimensional fluoroscopy assessment of iliosacral screws and lumbopelvic implants stabilizing fractures of the os sacrum

Abstract

Percutaneous iliosacral screw fixation of unstable sacrum fractures has gained popularity since its introduction in the 1990s. The combination with lumbopelvic implants allows the application even in situations of higher instability. Both manual and navigated screw insertion in the sacrum and vertebra bodies shows unchanged relevant malpositions. The current standard to control the screw position is postoperative computed tomography. The study presents the results of assessment of these implants by intraoperative three-dimensional fluoroscopy. From January 2008 through March 2009, 14 patients had stabilization of the dorsal pelvic ring with iliosacral screws alone or in combination with lumbopelvic implants. Intraoperative 3D fluoroscopy was performed to evaluate the position of the implants stabilizing the posterior pelvic ring. Fourteen iliosacral screws and eight pedicle screws were depicted. In all patients, we were able to adequately evaluate the placement of iliosacral screws, lumbar pedicle screws and iliacal screws. As a consequence of intraoperative 3D scan a lumbar pedicle screw was corrected. The entire scanning procedure required 5 min. The time for analyzing the 3D scan took 3 min. Intraoperative 3D fluoroscopy is a valuable tool for intraoperative assessment of iliosacral screws and lumbopelvic implants. The technique should help us to detect intraoperative malplacement of the screws more reliably than conventional fluoroscopy and allows an immediate correction of malplaced implants. Therefore, a postoperative computed tomography to control the position of implants is dispensable.