Objective
Paravertebral foramen screws (PVFSs) have been developed for better pullout strength than lateral mass screws do and lower the risk of vertebral artery and nerve injury than do pedicle screws. While the original method involves insertion using lateral fluoroscopy, its reliability may be limited. This report is the first to assess the accuracy of PVFS insertion under navigation. Given the inherent inaccuracies associated with navigation systems, the authors propose and evaluate a novel stepwise method of inserting PVFSs, called stepwise PVFS with a focus on achieving the correct screw tip location for good cortical bone purchase.
Methods
The authors conducted a retrospective analysis of 12 patients (78 screws) who underwent cervical spine fixation with stepwise PVFS under O-arm navigation between October 2022 and February 2024. The accuracy of screw placement was evaluated using postoperative computed tomography (CT) scans.
Results
A total of 78 PVFSs were inserted in 5 men and 7 women, with an average age of 75 years (range, 52–85 years). The mean follow-up period was 471 days (range, 47–834 days). There were no adverse events related to screw insertion. Postoperative CT scans revealed that 70 screws (90%) were placed in the ideal position. Among the 8 screws that did not achieve the ideal position, 4 had lateral deviation (located in a lateral mass), whereas the other 4 were too short. There were no cases of screw loosening at the final follow-up.
Conclusion
The present study demonstrates that the stepwise PVFS method under navigation guidance achieves higher accuracy in PVFS placement compared with conventional fluoroscopy-guided PVFS, as reported in previous studies.

Objective
The purpose of this study is to find the clinical and radiographic characteristics of traumatic craniocervical junction (CCJ) injuries requiring occipitocervical fusion (OC fusion) for early diagnosis and surgical intervention.
Methods
We retrospectively reviewed 12 patients with CCJ injuries presenting to St. Michaels Hospital in Toronto who underwent OC fusion and looked into the following variables; (1) initial trauma data on emergency room arrival, (2) associated injuries, (3) imaging characteristics of computed tomography (CT) scan and magnetic resonance imaging (MRI), (4) surgical procedures, surgical complications, and neurological outcome.
Results
All patients were treated as acute spinal injuries and underwent OC fusion on an emergency basis. Patients consisted of 10 males and 2 females with an average age of 47 years (range, 18–82 years). All patients sustained high-energy injuries. Three patients out of 6 patients with normal BAI (basion-axial interval) and BDI (basion-dens interval) values showed visible CCJ injuries on CT scans. However, the remaining 3 patients had no clear evidence of occipitoatlantal instability on CT scans. MRI clearly described several findings indicating occipitoatlantal instability. The 8 patients with normal values of ADI (atlantodens interval interval) demonstrated atlantoaxial instability on CT scan, however, all MRI more clearly and reliably demonstrated C1/2 facet injury and/or cruciate ligament injury.
Conclusion
We advocate measures to help recognize CCJ injury at an early stage in the present study. Occipitoatlantal instability needs to be carefully investigated on MRI in addition to CT scan with special attention to facet joint and ligament integrity.