Yamamoto Yu, Nishimura Yusuke, Ishii Motonori, Fukaya Nobuhisa, Tsukamoto Eisuke, Saito Ryuta, Hara Masahito, Takayasu Masakazu
Department of Neurosurgery, Inazawa Municipal Hospital, Inazawa, Japan.
Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Neurospine. 2025 Jun;22(2):514-522. doi: 10.14245/ns.2550110.055. Epub 2025 Jun 30.
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.
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.
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.
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.
椎旁孔螺钉（PVFS）已被研发出来，其拔出强度优于侧块螺钉，且与椎弓根螺钉相比，椎动脉和神经损伤风险更低。虽然最初的方法是使用侧位透视进行置入，但其可靠性可能有限。本报告首次评估了在导航下置入PVFS的准确性。鉴于导航系统存在固有的不准确性，作者提出并评估了一种新的分步置入PVFS的方法，即分步PVFS，重点是实现螺钉尖端的正确位置，以获得良好的皮质骨把持力。
作者对2022年10月至2024年2月期间在O型臂导航下采用分步PVFS进行颈椎固定的12例患者（78枚螺钉）进行了回顾性分析。使用术后计算机断层扫描（CT）评估螺钉置入的准确性。
共为5名男性和7名女性置入了78枚PVFS，平均年龄75岁（范围52 - 85岁）。平均随访期为471天（范围47 - 834天）。没有与螺钉置入相关的不良事件。术后CT显示70枚螺钉（90%）位置理想。在未达到理想位置的8枚螺钉中，4枚有侧向偏移（位于侧块），另外4枚太短。末次随访时没有螺钉松动的情况。
本研究表明，与先前研究报道的传统透视引导下的PVFS相比，导航引导下的分步PVFS方法在PVFS置入方面具有更高的准确性。
