Intraoperative Investigation of Vibration and Acoustic Characteristics of Venous Pulsatile Tinnitus Using Confocal Laser Displacement Sensor, Doppler Ultrasonography, and Piezoelectric Film Sensor: A Pilot Study

The vibrations of a thinned sigmoid plate and exposed sinus vessel wall in patients with sigmoid sinus wall anomalies (SSWAs) have long been speculated to be a pivotal cause of venous pulsatile tinnitus (PT). This is the first in vivo study to investigate whether vibrations resulting from SSWAs induce PT using multiple sensor systems. A confocal laser displacement sensor system was intraoperatively deployed to gauge displacements of the focal anatomical structure in 12 subjects with venous PT with or without SSWAs. Doppler ultrasonography was performed to detect the blood flow and psychoacoustic characteristics of PT. Computational fluid dynamics (CFD) and piezoelectric sensors were deployed to assess the relationship between the vessel wall pressure and hemodynamics. The ultrasonographic examination showed that the PT pitch matched the blood flow sampled at the center of the sinus lumen in all subjects and that there was no statistical difference between the displacements of the sigmoid plate and vessel wall before separation, indicating that PT is strongly associated with flow-induced noise rather than vibration-induced noise. In addition, the quantitative water occlusion test can be potentially indicative for the surgical and mechanistic study of PT.