RESUMO
BACKGROUND: Parietal atretic cephalocele (PAC) is a small, subscalp lesion with underlying extracranial meningeal, neural, and glial tissues. In this paper, we analyze the related literature on the continuum of PAC-associated venous anomalies and report an exemplary case. METHODS: The PubMed Medline database was searched using the following search algorithm: (Atretic encephalocele) OR (Rudimentary meningocele,) OR (Atypical meningocele) OR (Meningocele manqué) OR (Meningeal heterotopia). Only papers detailing the venous anomalies associated with PACs have been included. RESULTS: A total of 30 papers in our search documented PAC-associated venous abnormalities. The overall number of cases reported was 68 (including our exemplary case). The most frequently identified associated venous anomaly was the presence of a "fenestrated superior sagittal sinus" recorded in 48.5% of cases (n = 33), followed closely by "persistent falcine sinus" in 47% (n = 32) and vertical embryonic positioning of the straight sinus (SS) in 44% (n = 30). The complete absence of a SS was reported in 39.7% (n = 27) and various anomalies of the Galenic system were reported in 26.8% of cases (n = 12). CONCLUSION: Although benign in nature, PACs are often a marker for the presence of complex and variable cerebral venous malformations, requiring extensive preoperative imaging workup for both the superficial and deep venous systems to obtain an accurate understanding of the anatomy of the venous system and guide surgical planning.
RESUMO
BACKGROUND: Absence or hypoplasia of the internal carotid artery (ICA) is a rare congenital anomaly that is mostly unilateral and highly associated with other intracranial vascular anomalies, of which saccular aneurysm is the most common. Blood flow to the circulation of the affected side is maintained by collateral pathways, some of which include the anterior communicating artery (Acom) as part of their anatomy. Therefore, temporary clipping during microsurgery on Acom aneurysms in patients with unilateral ICA anomalies could jeopardize these collaterals and place the patient at risk of ischemic damage. In this paper, we review the literature on cases with a unilaterally absent ICA associated with Acom aneurysms and provide an illustrative case. METHODS: We combined our experience of one case of a unilaterally absent ICA associated with an Acom aneurysm with the 33 existing publications on the same subject in the literature, for a total of 40 cases. We provide a detailed systematic literature review of this association of vascular anomalies, exploring different aspects regarding the collateral pathways and how they impact management strategies and propose a management algorithm to deal with such association. RESULTS: The mean age was 48.2 ± 16.5 years. The aneurysmal rupture was the most common presentation (75%). Agenesis was observed in 70% of patients, followed by hypoplasia (20%) and, finally, aplasia (10%). Lie Type A was the most common pattern of collaterals (50%), with Types B and D being of almost equal proportions. Most aneurysms were located at the A1-Acom junction contralateral to the anomalous side (Fisher's Exact test; P = 0.03). One case of temporary clipping was reported in the literature. CONCLUSION: Acom aneurysms in patients with unilateral ICA anomalies, given they are more commonly present contralaterally, could be of acquired etiology, warranting periodic screening in asymptomatic patients. Temporary clipping might be safe in patients with Type D collateral pattern, while those with Types A or B may require intraoperative rupture risk assessment and a tailored management plan to avoid disrupting collateral flow and causing ischemia.
