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Author for correspondence: Dr Fatemeh Hassannia, Otology/Neurotology, University Health Network, Toronto, ON, M5G 2C4, Canada E-mail: [email protected]
Dr F Hassannia takes responsibility for the integrity of the content of the paper
Introduction
Vascular pulsatile tinnitus is a perceived and not infrequently heard sound synchronous with the heartbeat, without any external stimulus. It can be attributed to both arterial and venous causes. It is generated by turbulent blood flow through stenotic or irregular vascular structures in and around the petrous bone.1 A sigmoid sinus diverticulum is increasingly identified as a treatable cause of pulsatile tinnitus.
A sigmoid sinus diverticulum is usually defined as a well-circumscribed sac, in which the sigmoid sinus focally protrudes into the adjacent mastoid area.2,3 The exact mechanism of how a sinus diverticulum develops remains unclear, but it is likely that pulsatile tinnitus occurs as a result of turbulent blood flow in the diverticulum transmitted through bone to the cochlea. Studies have suggested that pulsatile tinnitus can resolve after remodelling of venous blood flow, such that the diverticulum is excluded from the circulation.
Materials and methods
In those felt to have a symptomatic and technically accessible sigmoid sinus diverticulum, an extensive cortical mastoidectomy is performed via a post-auricular incision. Using a selection of cutting and diamond burrs, the bone is removed from and around the sigmoid sinus in its entirety, superiorly and inferior to the diverticulum. This involves retro-labyrinthine and occipital dural plate exposure, to allow for compression of the sigmoid sinus, enabling proximal control in the event of a breach of the sinus or its diverticulum. The diverticulum can additionally be identified with the aid of intra-operative Doppler ultrasonography. Bone is removed circumferentially in a 360-degree fashion around the diverticulum and its neck.
A large Weck Horizon clip (Teleflex Medical, Durham, North Carolina, USA) (Figure 1) is placed around the neck of the diverticulum, isolating...