A Quantitative Comparison of the Vertebral Artery and Transverse Foramen Using CT Angiography

Object The purpose of this retrospective study was to quantify the anatomical relationship between the vertebral artery (VA), the cervical pedicle, and its surrounding structures, including the incidence of irregularities. Additionally, data delineating a “safe zone,” and these data's application during instrumentation with transpedicular cervical screw fixation were considered. The anatomical proximity of the VA to the cervical pedicle prevents spine surgeons from preferring cervical pedicle screws (CPSs) over lateral mass screws at levels C3–6. Accurate placement of CPSs is often difficult to determine, because this definition can vary between 1 and 4 mm of lateral “noncritical” and “critical” pedicle breaches. No previous study in a western population has investigated the VA's proximity to the cervical pedicle, its percentage of occupancy in the transverse foramen (TF), and the incidence of irregular VA pathways. Methods One hundred twenty-seven consecutive patients who underwent CT angiography of the neck were enrolled in this study. The measurements included the following: medial pedicle border to VA; lateral pedicle border to VA; pedicle diameter (PD); sagittal diameter of the VA; coronal diameter of the VA; sagittal diameter of the TF; and coronal diameter of the TF. The cross-sections of the VA and the TF were measured to determine the occupation ratio of the VA. In addition, a safe zone was defined based on all lateral pedicle border to VA measurements in which the VA was within the TF. The level of entry of the VA into the TF as well as irregularities of the VA and the cervical pedicles were recorded. Results Vertebral artery dominance on the left side was seen in 69.3% of cases. The mean PD increased from 4.9 to 6.5 mm (from C-3 to C-7, respectively). Statistically significantly bigger PDs were seen in males. The mean PD at C-2 was 5.6 mm. Entry of the VA at C-6 was seen in approximately 80% of cases. The TF occupation ratio of the VA was found to be the greatest in C-4 and C-7 (37.1 and 74.2%, respectively). The safe zone increased from C-2 to C-6 (1.1 to 1.7 mm, respectively), but was only 0.65 mm at C-7. In 23.6% of cases, an irregular pathway of the VA or irregular anatomy of a cervical pedicle was seen, with the highest incidence of irregularities found at C-2. Conclusions Computed tomography angiography is a valuable tool that can help determine the relationships between cervical pedicles and the VA as well as irregular VA pathways. Pedicle diameter, safe zone, and occupational ratio of the VA in the foramen determine the risk associated with instrumentation and should be assessed individually. Based on the authors' measurements, C-4 and C-7 can be considered critical levels for CPS placement. Because of this and the high incidence of irregular VA pathways and different entry points, it may be helpful to review neck CT angiography studies before considering posterior instrumentation procedures in the cervical spine.

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Response to letter to the editor (NRAD-13-78) Re: Variations in the origin of the vertebral artery and its level of entry into the transverse foramen diagnosed by CT angiography Dan Meila; Marcin Tysiac; Friedhelm Brassel

Neuroradiology ◽

10.1007/s00234-013-1168-3 ◽

2013 ◽

Vol 55 (5) ◽

pp. 651-651

Author(s):

Akira Uchino

Keyword(s):

Vertebral Artery ◽

Ct Angiography ◽

Transverse Foramen ◽

Letter To The Editor

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Variations in the origin of the vertebral artery and its level of entry into the transverse foramen diagnosed by CT angiography

Neuroradiology ◽

10.1007/s00234-013-1142-0 ◽

2013 ◽

Vol 55 (5) ◽

pp. 585-594 ◽

Cited By ~ 26

Author(s):

Akira Uchino ◽

Naoko Saito ◽

Masahiro Takahashi ◽

Yoshitaka Okada ◽

Eito Kozawa ◽

...

Keyword(s):

Vertebral Artery ◽

Ct Angiography ◽

Transverse Foramen

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Re: Variations in the origin of the vertebral artery and its level of entry into the transverse foramen diagnosed by CT angiography

Neuroradiology ◽

10.1007/s00234-013-1161-x ◽

2013 ◽

Vol 55 (5) ◽

pp. 649-649

Author(s):

Dan Meila ◽

Marcin Tysiac ◽

Friedhelm Brassel

Keyword(s):

Vertebral Artery ◽

Ct Angiography ◽

Transverse Foramen

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Anomalous vertebral artery at the craniovertebral junction in a patient with Down syndrome

Journal of Neurosurgery Spine ◽

10.3171/spi.2004.1.3.0338 ◽

2004 ◽

Vol 1 (3) ◽

pp. 338-341 ◽

Cited By ~ 22

Author(s):

Masashi Yamazaki ◽

Masao Koda ◽

Minori Yoneda ◽

Atsuomi Aiba ◽

Hideshige Moriya

Keyword(s):

Down Syndrome ◽

Vertebral Artery ◽

Ct Angiography ◽

Three Dimensional ◽

Odontoid Process ◽

Craniovertebral Junction ◽

Transverse Foramen ◽

Content Type ◽

Ossiculum Terminale ◽

The Right

✓ The authors report a case of a patient with Down syndrome in whom the abnormal course of the right vertebral artery (VA) at the craniovertebral junction (CVJ) was accurately demonstrated on three-dimensional (3D) computerized tomography (CT) angiography. The patient was a 5-year-old boy, who developed severe myelopathy. Bone abnormalities were also present at the CVJ, including atlantoaxial and occipitoatlantal instabilities, a hypoplastic odontoid process, and ossiculum terminale. Three-dimensional CT angiography revealed that the right VA was duplicated after emerging from the C-2 transverse foramen. One half of the duplication, an artery that was as large as the left VA, turned posteromedially and entered the spinal canal between C-1 and C-2. The other half, a very small artery, ran as usual and passed through the C-1 transverse foramen. The authors performed an occipitocervical posterior fusion and a C-1 laminectomy. Intraoperatively the course of the anomalous VA was identified on Doppler ultrasonography, and the surgical approach and bone excision were undertaken carefully to avoid VA injury. Postoperatively, resolution of myelopathy was marked. In the surgical treatment of patients with Down syndrome, surgeons should consider the possibility that a VA anomaly is present at the CVJ. With preoperative 3D CT angiography, the anomalous VA can be identified precisely and the possible risk of intraoperative VA injury predetermined.

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Mild trauma causing cervical fracture through transverse foramen leading to a vertebral arteriovenous fistula

BMJ Case Reports ◽

10.1136/bcr-2021-241735 ◽

2021 ◽

Vol 14 (6) ◽

pp. e241735

Author(s):

Mikkel Schou Andersen ◽

Willy Krone ◽

Sune Munthe

Keyword(s):

Vertebral Artery ◽

Arteriovenous Fistula ◽

Vertebral Artery Dissection ◽

Artery Dissection ◽

Digital Subtraction ◽

Trauma Mechanism ◽

Transverse Foramen ◽

Cervical Fractures ◽

Vertebral Arteriovenous Fistula ◽

Ct Angiogram

Vertebral arteriovenous fistula (vAVF) is an uncommon vascular disease defined as abnormal connections between the vertebral artery or its branches extracranially with nearby venous structures. This case report outlines the case of a man in his late 70s presenting with C1–C3 fractures after a mild trauma falling down a small staircase. CT angiogram (CTA) gave suspicion of vertebral artery dissection and pseudoaneurysm; however, digital subtraction angiography revealed a fracture-induced vAVF successfully treated endovascularly with coils. In conclusion, cervical fractures involving the transverse foramen regardless of trauma mechanism should result in a CTA. Endovascular treatment with ipsilateral vertebral artery closure is preferred due to its feasibility and safety.

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Cervical Vertebral Artery to Facial Branch External Carotid Artery Bypass: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opaa028 ◽

2020 ◽

Author(s):

Benjamin K Hendricks ◽

Robert F Spetzler

Keyword(s):

Carotid Artery ◽

Vertebral Artery ◽

Artery Bypass ◽

Video Recording ◽

Distal Segment ◽

External Carotid Artery ◽

External Carotid ◽

Transverse Foramen ◽

Institutional Review ◽

V1 Segment

Abstract Posterior circulation ischemia often presents with dizziness, ataxia, visual disturbances, or motor-sensory deficits. The vertebral artery stenosis most frequently involves the V1 segment proximal to the foraminal segment. This patient demonstrated critical stenosis of the left V1 segment of the vertebral artery related to atherosclerotic disease. A left cervical dissection was performed, and the cervical transverse foramen was opened to permit exposure of the vertebral artery in the V2 segment. The vertebral artery was proximally occluded and transected. An endarterectomy was performed, and an end-to-end anastomosis of the facial branch of the external carotid artery to the distal segment of the transected vertebral artery was completed. Indocyanine green angiography was used to confirm patency of the anastomosis. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

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