PMC8769478_01
(a) CT scan of the cervical spine showing a dislocation fracture at the C4-C5 level. (b) Preoperative CT angiogram showing no bilateral VA injuries. (c) Postoperative CT scan showing a left C4 pedicle screw perforating the transverse foramen. (d) Postoperative CT angiogram showing no visualization of the left VA from the origin to the distal side of the screw. (e) Right VA angiogram showing the left posterior inferior cerebellar artery retrogradely (arrow). (f) Left subclavian artery angiogram showing the left VA suspected to be occluded at the origin (arrow). (g) The microcatheter could be navigated distal to the screw through the ipsilateral approach without much resistance. Circle, position of the microcatheter tip. (h) Coil embolization. CT: computed tomography, VA: vertebral artery.
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C4/C5 dislocation fracture (Fig. 1a). CT angiography revealed no apparent damage to the bilateral VAs and similar diameters on both sides (Fig. 1b). CT scan on the third day after the operation revealed that the left C5 pedicle screw had perforated the transverse foramen (Fig. 1c). CT angiography did not visualize the VA from the origin to the distal side of the screw (Fig. 1d). Right vertebral angiography visualized the left posterior inferior cerebellar artery retrogradely (Fig. 1e). Left subclavian angiography revealed only the origin of the left VA (Fig. 1f). Tokyo, Japan) was placed in the origin of the left VA, and an Excelsior SL-10 microcatheter (Stryker, Kalamazoo, MI, USA) could be guided to the cranial side of the screw by pushing without much resistance (Fig. 1g). The left VA was embolized with coils from the cranial side to the caudal side of the stenosed site (Fig. 1h).
PMC8769478_02
(a) Magnetic resonance image of the cervical spine showing cervical spondylosis. Posterior fusion was performed. (b) Postoperative CT scan showing the right C3 pedicle screw perforating the transverse foramen. (c) Postoperative CT angiogram showing a right VA stenosis at the screw insertion site. The left VA was larger in diameter than the right VA. (d) It was difficult to judge from axial image of CT angiogram whether the screw had caused intima damage. (e) Right VA angiogram showing a 70% stenosis at the screw insertion site (arrow). (f) Coil embolization. CT: computed tomography, VA: vertebral artery.
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A 50-year-old male with cervical spondylosis underwent posterior decompression and interbody fusion from C3 to C6 (Fig. 2a). However, postoperative CT revealed a perforation of the right C3 transverse foramen by a pedicle screw (Fig. 2b). On CT angiography, the stenosis of right VA was at the C3 pedicle screw insertion site (Fig. 2c). It was difficult to judge from CT angiography whether the screw had caused intima damage (Fig. 2d). Right vertebral angiography revealed that the antegrade blood flow was maintained, but 70% stenosis was observed at the C3 pedicle screw insertion site (Fig. 2e). Aichi, Japan). After a balloon occlusion test, the right VA was embolized with coils from the cranial side to the caudal side of the stenosed site (Fig. 2f). After embolization, the neurological findings did not worsen, and the MRI revealed no acute infarction.