A Previously Unreported Arterial Variant of the Suboccipital Region Based on Cadaveric Dissection

Abstract

Introduction Several arterial variants have been reported to occur around the posterior arch of the atlas. Understanding the various anomalies and diagnosing them preoperatively can dramatically reduce the risk of surgical insult during neurosurgical procedures. Herein we report a case of an arterial variant found just below the posterior arch of C1.

Case Report During the routine dissection of the suboccipital region via a posterior approach, an unusual bulge was identified just inferior to the inferior capitis oblique muscle. With further dissection, the structure was identified as a tortuous internal carotid artery.

Conclusion Arterial variants around the posterior arch of C1 are surgically significant and can result in catastrophic injuries if unappreciated. Most of these variants will be related to the vertebral artery. To our knowledge, an arterial variant of the internal carotid artery in this location, as reported herein, has not been previously reported.

Keywords

anatomy - anomaly - carotid artery - C1 - suboccipital triangle

Informed Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent form is available for review by the Editor-in-Chief of this journal on request.

• References

• 1 Fine AD, Cardoso A, Rhoton Jr AL. Microsurgical anatomy of the extracranial-extradural origin of the posterior inferior cerebellar artery. J Neurosurg 1999; 91 (04) 645-652
• 2 O'Donnell CM, Child ZA, Nguyen Q, Anderson PA, Lee MJ. Vertebral artery anomalies at the craniovertebral junction in the US population. Spine 2014; 39 (18) E1053-E1057
• 3 Montechiari M, Iadanza A, Falini A, Politi LS. Monolateral type I proatlantal artery with bilateral absence of vertebral arteries: description of a case and review of the literature. Surg Radiol Anat 2013; 35 (09) 863-865
• 4 Yamazaki M, Okawa A, Hashimoto M, Aiba A, Someya Y, Koda M. Abnormal course of the vertebral artery at the craniovertebral junction in patients with Down syndrome visualized by three-dimensional CT angiography. Neuroradiology 2008; 50 (06) 485-490
• 5 Kirkland JD, Dahlin BC, O'Brien WT. The transclival artery: a variant persistent carotid-basilar arterial anastomosis not previously reported. J Neurointerv Surg 2016 neurintsurg-2016-012464.rep
• 6 Wakao N, Takeuchi M, Nishimura M. , et al. Vertebral artery variations and osseous anomaly at the C1-2 level diagnosed by 3D CT angiography in normal subjects. Neuroradiology 2014; 56 (10) 843-849
• 7 Cohen JE, Grigoriadis S, Itshayek E. Type II proatlantal artery (occipital subtype) with bilateral absence of the vertebral arteries. Clin Anat 2011; 24 (08) 950-952
• 8 Lasjaunias P, Vallee B, Person H, Ter Brugge K, Chiu M. The lateral spinal artery of the upper cervical spinal cord. Anatomy, normal variations, and angiographic aspects. J Neurosurg 1985; 63 (02) 235-241
• 9 Peeling L, Fiorella D. Balloon-assisted guide catheter positioning to overcome extreme cervical carotid tortuosity: technique and case experience. J Neurointerv Surg 2014; 6 (02) 129-133