Breaking paradigms in choroidal fissure arteriovenous malformations: Anatomical aspects, surgical subtypes, and microsurgical resection case series.

Background: Despite being a rare location, choroidal fissure (CF) arteriovenous malformations (AVMs) are associated with considerable morbidity and mortality, due in part to the fact that their bleeding usually occurs intraventricularly. In addition, they present deep venous drainage and, depending on their size, may involve eloquent structures such as the thalamus. They represent a challenge for microsurgical treatment, due to its deep location and to the presence of important neurovascular structures closely related. In this article, our objective is to present the application of the anatomy to the microsurgical treatment of this type of AVM, making it a suitable choice, by describing the anatomical aspects to be considered, the surgical subtypes with their respective surgical approaches and to demonstrate what has been stated with a series of cases of microsurgical resection of this type of AVM. Methods: Cadaver dissection was performed to describe the microsurgical anatomy of the CF, lateral ventricles, and periventricular structures. Application of this anatomy is illustrated through description of three surgical cases, each one related to one of the described subtypes of AVMs of the CF. Results: The division into three subtypes according to the AVM's angioarchitecture and to their topography in this region was carried out. After microsurgical resection, the patients evolved without visual field impairments, memory complaints, or permanent neurological complications. Conclusion: Application of anatomy to microsurgery and knowledge of AVM's angioarchitecture constitutes a definitive and safe way to achieve the resection of these deep and complex AVMs, making it an adequate therapeutic option.