Flow Analysis of Central Venous Outflow Tract: A New Approach to Understanding Pulse-Synchronous Tinnitus

Area of Science:

• Neurosurgery
• Cardiovascular Physiology
• Biomedical Engineering

Background:

• Pulse-synchronous tinnitus (PST) is associated with anatomical variations in the central venous outflow tract (CVOT).
• Sigmoid sinus (SS) dehiscence and diverticulum are implicated in PST.
• Understanding the hemodynamics of the CVOT is crucial for explaining PST mechanisms.

Purpose of the Study:

• To investigate blood flow turbulence, pressure, and wall shear stress in the CVOT.
• To propose a mechanism linking CVOT anatomy to SS dehiscence and PST.
• To analyze fluid dynamics in symptomatic and asymptomatic sides of PST patients.

Main Methods:

• Utilized computational fluid dynamics (CFD) with a turbulent model.
• Reconstructed 3D venous models from CT scans of 3 PST patients (symptomatic and asymptomatic sides).
• Simulated pulsatile blood flow and analyzed velocity, pressure, turbulent kinetic energy (TKE), and shear stress.

Main Results:

• Symptomatic sides with SS diverticulum exhibited increased vorticity and higher TKE, with cardiac cycle periodicity.
• Elevated TKE was noted on the symptomatic side, especially with SS diverticulum.
• Lower pressure and highest shear stress near narrow segments were observed on the symptomatic side.

Conclusions:

• CFD modeling suggests low CVOT pressure may cause SS dehiscence.
• Periodic TKE increases in the CVOT might be the underlying cause of PST.
• This study provides a hemodynamic mechanism for PST related to CVOT anatomy.