The oblique occipital sinus: anatomical study using bone subtraction 3D CT venography

Area of Science:

• Neuroanatomy
• Vascular Anatomy
• Radiology

Background:

• The oblique occipital sinus (OOS) is an anatomical variant where an occipital sinus drains into the sigmoid sinus.
• Understanding the OOS is crucial for interpreting venous drainage patterns in the posterior cranial fossa.

Purpose of the Study:

• To determine the frequency and anatomical characteristics of the oblique occipital sinus (OOS).
• To analyze the relationship between the OOS and the transverse sinus (TS).
• To assess the clinical significance of the OOS in neurosurgical and radiological evaluations.

Main Methods:

• Retrospective analysis of 1805 brain CT angiographies performed between 2013 and 2015.
• Utilized a 64-slice multi-detector CT (MDCT) system for image acquisition.
• Detailed evaluation of OOS presence, morphology, and association with transverse sinus hypoplasia or aplasia.

Main Results:

• The oblique occipital sinus (OOS) was identified in 41 patients (2.3% prevalence).
• Significant anatomical variations in OOS morphology were observed.
• A hypoplastic or aplastic transverse sinus (TS) was present in 75.6% of patients with an OOS.

Conclusions:

• The oblique occipital sinus (OOS) exhibits considerable anatomical variability.
• In some cases, the OOS may serve as the primary intracranial venous drainage pathway, compensating for an underdeveloped transverse sinus (TS).
• Preoperative assessment of posterior fossa lesions necessitates careful evaluation of the OOS due to its potential role in venous drainage and association with TS abnormalities.