Pulsatile tinnitus caused by an aberrant artery running over the surface of mastoid bone

Objective Pulsatile tinnitus (PT) caused by an aberrant artery is rare. We report an unprecedented cause of PT resulting from an aberrant artery coursing the mastoid surface, and qualitatively discuss the pathophysiology of PT. Methods This case study reports a 41-year-old woman who presented with persistent PT at her right retromastoid region. Contrast-enhanced computed tomography revealed an aberrant branch of the artery that coursed over the cortex of the mastoid bone. Surgical ligation of this aberrant artery was performed under local anesthesia. Results Intraoperative findings suggested that PT transmitted via bone-conduction route due to the direct contact of the vascular and mastoid surface. PT was completely resolved upon surgical removal of this causative segment. Ultrasonographic and hemodynamic analysis showed that the turbulent kinetic energy and high regional wall pressure were the major contributory factors causing PT. Spectro-temporal analysis showed that PT fluctuates at frequency 500~2000 Hz, which differs from those of venous PT. Conclusion Judicious preoperative and intraoperative assessments of PT ensure the surgical efficacy of PT. Objective ultrasonographic and computational studies can provide detailed hydroacoustic characteristics of PT.