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BackgroundExternal ventricular drain (EVD) placement is one of the most common procedures in neurosurgery. Neurosurgeons generally prefer to access the ventricles via Kocher's point since it is the most common point of entry to this area; however, this point is used to describe different anatomic landmarks and is not welldefined. ObjectiveThe present study aims to describe and provide an anatomical assessment of a novel ventriculostomy access point developed by the authors using computerized tomography (CT) scans performed on 100 patients. Materials and methodsData were collected from 100 randomly selected patients with normal ventricular anatomy found on their 1.0 mm-slice CT scans performed at the Burdenko Neurosurgical Center from March 2019 to June 2021. The CT inclusion criteria were: CT slices < or = to 1 mm and absence of brain herniation. Patients with brain mass lesions, severe brain edema, and pneumocephalus were excluded. Age, gender, and ventricular size were not exclusion criteria. ResultsThe mean patient age was 43.58 years (range 4-73), with 50 men and 50 women. The mean Evan's index was 25.7 % (SD=4.38 %, range 10.2-41.0 %). No differences were found between the angles of EVD placement on either side (89.50±1.22 degrees on the right and 89.60±1.14 degrees on the left). Hence, nearly all EVD cases had been placed perpendicularly to the skull surface at a pinpoint location. ConclusionThe proposed point of successful ventriculostomy placement in this study was 3 cm from the bregma along the coronal suture. The angle of EVD placement was approximately 90 degrees in almost all patients and was independent of the patient's age and the side of the head that was entered. Little correlation was found between the value of the entry angle and Evan's index. The point is simply identifiable, and its entry is easily accessible in practice.

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CSF-venous fistula is a relatively new and unexplored cause of spontaneous intracranial hypotension syndrome (SIH). The syndrome was first described in 1974 in a patient with chronic lumbar puncture-associated headache after digital subtraction myelography. After 40 years, CSF-venous fistula was considered as the cause of the SIH syndrome in patients with orthostatic headache. CSF-venous fistula is a pathological connection of the subarachnoid space and the adjacent epidural vein or veins. It is one of the top three causes of SIH along with dural defects and meningeal diverticulum. Despite the insufficient assessment of the prevalence of CSF-venous fistulas, some authors consider the syndrome to be the cause of 25 % of the cases. Positional headaches, as well as headaches associated with cough and Valsalva maneuver, are the most common symptoms in patients with CSF-venous fistulas. These patients are characterized by typical MRI signs of intracranial hypotension, such as a clear visualization of pachymeninx, venous congestion, an increase in the size of the pituitary gland, brain sagging syndrome, tonsillar herniation, etc. However, due to the rarity of this disease, algorithms for its diagnosis and treatment have not been established. Management of patients is usually limited to conservative treatment as the first-line method. This includes EBP alone or in combination with fibrin glue. Open surgery for ligation or coagulation of the fistula is used in cases of failed conservative treatment. Endovascular occlusion of the draining vein is a relatively new and less common treatment. The article presents a systematic review of the literature and analysis of the clinical results of various types of treatment for CSF-venous fistulas (EBP, surgical excision and endovascular embolization).