Indexed on: 31 May '14Published on: 31 May '14Published in: Spine
Study Design. Case series and description of technique.Objective. The purpose of this study was to evaluate the feasibility and accuracy of inserting pedicle screws in unstable Hangman's fracture cases by using intraoperative CT (O-arm) based navigation.Summary of Background Data. Hangman's fracture, also known as traumatic spondylolisthesis of the C2, is defined as a fracture involving the lamina, articular facets, pedicles, or pars of the axis vertebra. Opinions vary regarding the optimal treatment of unstable Hangman's fractures. Some authors have recommend the use of rigid orthosis, while others have recommended surgical stabilization. The peculiar anatomy of the upper cervical spine is highly variable and the presence of surrounding neurovascular structures make pedicle screw fixation even more technically challenging. The advent of intraoperative 3D navigation systems permit safe and accurate instrumentation of the cervical spine.Methods. Ten patients with unstable Hangman's fracture, with age ranging from 17 years to 81 years, were operated under O-Arm based navigation and screw position was confirmed with intra op CT scan.Results. Total 52 screws were inserted under O arm guidance: 20 in C2 pedicle, 20 in C3 lateral mass and rest in C4 lateral mass. Screw misplacement was seen in only one C2 pedicle screw (1 out of 20, 5%). No new onset neurological deficit developed in any of the patients. Follow up ranged from 3 months to 21 months. Bony fusion was achieved in all. Full rotation was preserved at C1 C2 joint. All the patients (50%) with neurological deficits before surgery improved following surgery.Conclusion. This series demonstrates that C2 pedicle screws can be put with precision under O-Arm guided navigation and intraoperative CT scan can confirm position of screws. Patients can be operated and mobilized early with negligible risk of screw misplacement with preservation of motion at the C1 C2 joint.