The horizontal part of the third segment (V3) of the vertebral artery (VA) is a critical anastomotic site for bypass procedures involving either donor or recipient vessels. It is rare for the V3 segment to deviate from its typical course of passing through the atlanto-transverse foramen. V3 anomaly encountered in occipital artery (OA)-V3 bypass surgery has not been previously reported. Here, we present a case involving a patient undergoing bypass surgery due to recurrent post-stent occlusion at the first segment (V1) of the left VA. During the operation, it was noted that the V3 horizontal segment could not be identified within the left VA groove, leading to initial suspicion of left V3 disuse atrophy attributed to prolonged chronic ischaemia. Consequently, there was a need to modify the operative method and to transition from an OA-V3 bypass to an OA-posterior inferior cerebellar artery bypass. Post-operative computed tomography angiography confirmed that indeed, the left V3 did not traverse through the transverse foramen of the atlas and instead entered the dural membrane between the first cervical vertebra (C1) and the second cervical vertebra (C2).

BACKGROUND: Bow Hunter\'s syndrome (BHS), also known as rotational vertebral artery occlusion (RVAO), is a rare condition characterized by dynamic vertebrobasilar insufficiency due to position-dependent occlusion of the vertebral artery (VA). In the existing literature, most cases of BHS are attributed to osteophytic compression originating from the occipital condyle or within the transverse foramen, often accompanied by anatomical abnormalities of the VA. However, cases presenting solely with VA anomalies in the absence of any cervical vertebral structural abnormality are rare. This case report presents a unique instance of BHS in a 56-year-old male, attributed to the anomalous origin of the right VA and the absence of the left VA, without cervical structural abnormalities.
METHODS: The patient exhibited symptoms like episodic dizziness and vertigo, which were exacerbated by rightward head rotation and alleviated upon returning to a neutral position. Diagnostic evaluation, including digital subtraction angiography, revealed that the right VA originated from the right common carotid artery and compression-induced stenosis of the right VA during head rotation. Conservative management, including avoidance of certain head movements and anti-arteriosclerosis medication, led to symptom resolution over a two-year follow-up period.
CONCLUSIONS: This report contributes to the understanding of BHS by highlighting a rare vascular anomaly presentation and incorporates a review of 14 similar case reports in the literature describing that an anatomical abnormality of the VA is mainly responsible for the pathology of BHS in the absence of cervical vertebral anomalies, thus emphasizing the need for careful diagnostic and management strategies.

Cervicocerebral artery dissection stands out as a significant contributor to ischemic stroke in young adults. Several studies have shown that arterial tortuosity is associated with dissection. We searched Pubmed and Embase to identify studies on the association between arterial tortuosity and cervicocerebral artery dissection, and to perform a review on the epidemiology of cervicocerebral artery tortuosity and dissection, pathophysiology, measurement of vessels tortuosity, strength of association between tortuosity and dissection, clinical manifestation and management strategies. The prevalence of tortuosity in dissected cervical arteries was reported to be around 22%-65% while it is only around 8%-22% in non-dissected arteries. In tortuous cervical arteries elastin and tunica media degradation, increased wall stiffness, changes in hemodynamics as well as arterial wall inflammation might be associated with dissection. Arterial tortuosity index and vertebrobasilar artery deviation is used to measure the level of vessel tortuosity. Studies have shown an independent association between these two measurements and cervicocerebral artery dissection. Different anatomical variants of tortuosity such as loops, coils and kinks may have a different level of association with cervicocerebral artery dissection. Symptomatic patients with extracranial cervical artery dissection are often treated with anticoagulant or antiplatelet agents, while patients with intracranial arterial dissection were often treated with antiplatelets only due to concerns of developing subarachnoid hemorrhage. Patients with recurrent ischemia, compromised cerebral blood flow or contraindications for antithrombotic agents are usually treated with open surgery or endovascular technique. Those with subarachnoid hemorrhage and intracranial artery dissection are often managed with surgical intervention due to high risk of re-hemorrhage.

BACKGROUND: Stump syndrome is defined as a clinical syndrome resulting from a distal intracranial vessel embolic stroke due to an extracranial vessel occlusion. Similar to the anterior circulation, the recurrence of ischemic strokes in territories supplied by the posterior circulation in the presence of vertebral artery occlusion is termed Vertebral Artery Stump Syndrome (VASS).
METHODS: We conducted a literature review, identifying 72 patients with transient ischemic attacks (TIAs) or ischemic strokes attributed to VASS, according to Kawano criteria. We categorized all patients in two groups focusing on the therapeutic management those who underwent primary medical treatment and those who received endovascular or surgical treatment either in acute or chronic phase.
RESULTS: In the anticoagulant therapy group, only 1 patient had a stroke recurrence. Among the 4 on antiplatelets, all had recurrences, but 3 benefited from switching to anticoagulants or endovascular therapy. In the endovascular therapy group, worse outcomes were linked to acute large vessel occlusion. Endovascular treatment of the vertebral artery, in a chronic phase, was explored in literature for recurrent TIAs or minor strokes suggesting that this could be a viable therapeutic alternative when medical treatment failed in preventing recurrence of ischemic stroke.
CONCLUSIONS: Some studies suggest that anticoagulant medical therapy may be beneficial for VASS and endovascular therapy has also been reported for selected patients. However, data on treatment outcomes and prognosis are still underreported, making treatment decisions challenging. Randomized Controlled Trials are needed to establish the optimal treatment approach.

OBJECTIVE: The vertebral artery (VA) is a vital branch of the subclavian artery, coursing through the transverse foramina of the cervical vertebrae, and playing a crucial role in irrigating the posterior region of the arterial cerebral circle, also known as the Polygon of Willis. Among the various possible alterations that can affect the VA, vertebral artery hypoplasia (HAV) emerges as a significant variant. This study aims to discern the anatomical features of HAV and its correlation with the clinical conditions of the posterior cerebral circulation.
METHODS: The databases Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS were searched until January 2024. Two authors independently performed the search, study selection, and data extraction. Methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). Pooled prevalence was estimated using a random effects model.
RESULTS: A total of 24 studies met the established selection criteria, with a total of 8847 subjects. In this study, 6 articles were included for the meta-analysis with a total of subjects. The average prevalence of VAH reported in each study was 11% (95% CI 10-12%); the studies had a heterogeneity of 41% based on the funnel plot and a low risk of bias.
CONCLUSIONS: The prevalence of VAH is low, but in the presence of this condition, the changes are mainly in diameter rather than morphological. If it is present, some clinical safeguards must be taken to avoid complications such as stroke.

UNASSIGNED: Direct vertebrovertebral fistulas (VVFs) involving the V3 segment of the vertebral artery (VA) are rare. Endovascular treatment (EVT) can be used to obliterate these VVFs.
METHODS: Case 1 was a 30-year-old male with limb weakness. He had grade V muscle strength in his limbs. Angiography confirmed a low-flow direct VVF of the V3 segment. The right VA was well developed. Coiling of the VVF and its parent VA obliterated the VVF. The vertebrobasilar arteries had sufficient blood from the right VA. Postoperatively, the patient recovered well. Case 2 was a 51-year-old male with headache and weakness of the limbs. He had grade IV muscle strength in his limbs. Angiography revealed a high-flow direct VVF in the V3 segment. The left VA was well developed. Coiling of the VVF and its parent VA obliterated the VVF. The vertebrobasilar arteries had sufficient blood from the left VA. Postoperatively, the patient recovered well.
UNASSIGNED: Direct VVF of the V3 segment is difficult to treat, and EVT, including reconstructive and deconstructive approaches, can be an effective treatment option. According to this case report and literature review, reconstructive EVT is ideal; however, it is difficult to perform. Currently, deconstructive EVT may be the mainstream option for treating direct VVF of the V3 segment.
CONCLUSIONS: In certain cases where the contralateral VA is well developed, coiling the fistula and the parent VA is still an effective treatment.

BACKGROUND: The aberrant origin of the right subclavian artery (ARSA), also known as the lusoria artery, is a congenital malformation with an incidence of 0.5-4.4%. Most cases are incidental due to minimal clinical manifestations. Computer tomography (CT) is important in diagnosing and evaluating these patients.
METHODS: We conduct a computerized search in two databases, PubMed and EMBASE, for articles published between 1 January 2022 and 31 December 2023, PROSPERO code: CRD42024511791. Eligible for inclusion were case reports and case series that presented the aberrant origin of the right subclavian artery. The main outcome was the highlighting of the morphological types of ARSA. In this context, we proposed a new classification system of this anomaly. The secondary outcome was the evaluation of the demographic distribution of the lusoria artery.
RESULTS: Our search identified 47 articles describing 51 patients with ARSA. The typical course for ARSA is retroesophageal, being registered in 49 out of 51 patients. This malformation is frequently associated with Kommerell diverticulum (15 out of 51), troncus bicaroticus (7 out of 51), and aberrant origins of the right vertebral artery (7 out of 51). We observed a higher incidence of the condition among women (32 out of 51) compared to men (19 out of 51). From a demographic point of view, ARSA is more frequent in the \"44 to 57 years\" and \"58 to 71 years\" age ranges.
CONCLUSIONS: ARSA is a congenital malformation resulting from a defect in the development of the aortic arches. The imaging studies such as computer tomography play a defined diagnostic role.

OBJECTIVE: This article presents a comprehensive exploration of neurovascular anatomy of the encephalon, focusing specifically on the intricate network within the posterior circulation and the posterior fossa anatomy; enhancing understanding of its dynamics, essential for practitioners in neurosurgery and neurology areas.
METHODS: A profound literature review was conducted by searching the PubMed and Google Scholar databases using main keywords related to neurovascular anatomy. The selected literature was meticulously scrutinized. Throughout the screening of pertinent papers, further articles or book chapters were obtained through additional assessment of the reference lists. Furthermore, four formalin-fixed, color latex-injected cadaveric specimens preserved in 70% ethanol solution were dissected under surgical microscope (Leica Microsystems Inc, 1700 Leider Ln, Buffalo Grove, IL 60089, USA), using microneurosurgical as well as standard instruments, and a high-speed surgical drill (Stryker Instruments 1941 Stryker Way Portage, MI 49002, USA). Ulterior anatomical dissection was performed.
RESULTS: Detailed examination of the basilar artery (BA), a common trunk formed by the union of the left and right vertebral arteries, denoted a tortuous course across the basilar sulcus. Emphasis is then placed on the Posterior Inferior Cerebellar Artery (PICA), Anterior Inferior Cerebellar Artery (AICA) and Superior Cerebellar Artery (SCA). Each artery\'s complex course through the posterior fossa, its divisions, and potential stroke-related syndromes are explored in detail. The Posterior Cerebral Artery (PCA) is subsequently unveiled. The posterior fossa venous system is explained, categorizing its channels. A retrograde exploration traces the venous drainage back to the internal jugular vein, unraveling its pathways.
CONCLUSIONS: This work serves as a succinct yet comprehensive guide, offering fundamental insights into neurovascular anatomy within the encephalon\'s posterior circulation. Intended for both novice physicians and seasoned neuroanatomists, the article aims to facilitate a more efficient clinical decision-making in neurosurgical and neurological practices.

BACKGROUND: Vertebral artery injury (VAI) following blunt trauma can lead to acute or delayed life-threatening posterior fossa ischemic stroke. Its management raises controversial issues and is still open to debate.
METHODS: We report the case of a 48-year-old male who presented a life-threatening posterior circulation ischemic stroke, secondary to a vertebral artery dissection caused by a cervical spine fracture. This case was successfully managed through intravenous thrombolysis and endovascular thrombectomy followed by antiplatelet therapy and an anterior cervical discectomy and fusion. At the one-year follow-up, the patient had no persisting deficit and was back working as a policeman.
CONCLUSIONS: Rapid management of patients with dramatic clinical presentation can lead to full recovery. Implications include a systematic screening of blunt trauma VAI through computed tomography angiography when dealing with high-risk cervical spine fractures; patients harboring both a cervical spine fracture and a VAI must be transferred to a tertiary referral hospital able to deal both with strokes and cervical spine surgery to ensure responsiveness in case of stroke.

BACKGROUND: The vertebral artery (VA) is in close proximity to bony structures, nerves and nerve sheaths of the cervical spine and craniovertebral junction (CVJ). These structures can be sources of tumors that are responsible for displacement, encasement and sometimes invasion of the VA. Removing these tumors while minimizing the risk of vascular injury requires thorough knowledge of the vascular anatomy, risk factors of vascular injury, the relationships of each tumor type with the VA, and the different surgical approaches and techniques that result in the best outcomes in terms of vascular control, tumoral exposure and resection.
OBJECTIVE: To present an overview of preoperative and anatomical considerations, differential diagnoses and various approaches to consider in cases of tumors in close relationship with the VA.
METHODS: A review of recent literature was conducted to examine the anatomy of the VA, the tumors most frequently affecting it, surgical approaches, and the necessary pre-operative preparations for ensuring safe and maximal tumor resection. This review aims to underscore the principles of treatment.
CONCLUSIONS: Tumors located at the CVJ and the cervical spine intimately involved with the VA, pose a surgical challenge and increase the risk of incomplete removal of the lesion. Detailed knowledge of the patient-specific anatomy and a targeted pre-operative work-up enable optimal planning of surgical approach and management of the VA, thereby reducing surgical risks and improving extent of resection.