Iso-C3D fluoroscopy-based navigation in direct pedicle screw fixation of Hangman fracture: a case report.

Direct pedicle screw fixation of the C2 is rarely performed in trauma owing to the risk of damage to the neurovascular structures. Computed tomography-based navigation has the problem of change in intersegmental anatomy after positioning for surgery. Iso-C-based computer navigation acquires the intraoperative real-time images after patient positioning and thus avoids registration errors and improves accuracy. A Hangman fracture treated by posterior direct pedicle screw fixation using Iso-C computer navigation guidance is reported. Postoperative computed tomographic images confirmed the accurate placement of pedicular screws. Intraoperative fluoroscopy-based computer navigation is advantageous especially in an unstable upper cervical spine injury where the likelihood of change in the intersegmental relationship is maximal before and after positioning for surgery. The Iso-C navigation has the advantages of clarity and accuracy, making safe pedicle fixation of C1 and C2 possible despite fractured posterior elements. To our knowledge, this is the first reported case of displaced Hangman fracture treated successfully using Iso-C fluoroscopic navigation assisted direct pedicle screw osteosynthesis in the literature. Intraoperative acquisition of fluoroscopic images avoids registration-related problems. Three-dimensional fluoroscopic navigation gives excellent accuracy and safety in screw instrumentation of Hangman fracture.