Angioscopic study of the major dural venous sinuses in human cadavers.

OBJECTIVE: Neurointerventional surgery is witnessing a growth in transvenous procedures by using endovascular devices and techniques developed, optimized, and used in the arterial system. However, major dural venous sinuses differ from arteries in their non-circular (often triangular) cross sectional geometry and in the multiple structures that protrude or cross their lumens, such as septations, false channels, ostia of draining veins (cortical and dural venous channels), intraluminal bands, and arachnoid granulations. To address this gap in the literature, we used the 'live' cadaver model previously developed and validated to study the anatomical phenotypes of intraluminal structures with angiography and high resolution angioscopy.

METHODS: The internal jugular veins (IJVs) of six head and neck human cadaveric specimens were catheterized, and a peristaltic pump was used to infuse 0.9% saline. Cerebral venograms, including two-dimensional and three-dimensional cone beam CT venograms, were performed by injecting iodinated contrast at the confluence of the major dural sinuses. Then, an angioscope was used to study the anatomical structures in the lumen of transverse/sigmoid sinuses (n=12) and superior sagittal sinuses (SSSs) (n=6). Angioscopic evaluation was done retrogradely through the IJVs and anterogradely by direct transcranial access through burr holes (at the anterior sagittal sinus and one on the torcular Herophili). Descriptive statistics were performed to evaluate anatomical structures.

RESULTS: In six cadaveric specimens, arachnoid granulations were identified in 10 of 12 transverse sinuses (83.3%), most commonly in the proximal (or medial) and middle segments, and less frequently in the distal (or lateral) segment. Arachnoid granulations were more often identified on the left side (6/6, 100%) than on the right (4/6, 66.7%). The SSS demonstrated septations in five of six specimens (83.3%), each containing two or more septa. Arachnoid granulations within the SSS were observed in five specimens (83.3%), typically clustered along the middle to posterior third. The transverse sinus contained an average of 3.0±0.9 of intraluminal bands per side, distributed nearly symmetrically (right 3.0±0.8; left 2.8±0.8). Ostial openings were identified along all segments of the SSS, with the highest concentration at the junction of the middle and posterior segments.

CONCLUSIONS: The intraluminal anatomy of the major dural venous sinuses differed markedly from that of the cerebral arteries, underscoring its relevance for endovascular venous approaches. Crossing septations and bands, protruding arachnoid granulations, and ostia of venous branches were consistently identified. These structures may interact with devices and directly affect procedural safety and efficacy in endovascular venous interventions.