Posterior circulation stroke following embolization of glomus tympanicum?relevance of anatomy and anastomoses of ascending pharyngeal artery. A case report.

SUMMARY: Embolization in the territory of the ascending pharyngeal artery (APA) can be unsafe even after detailed pretherapeutic angiographic evaluation due to changes in haemodynamics and opening of anastomotic channels. A 60-year-old woman underwent angiogram and embolization for glomus tympanicum tumour. The glomus tympanicum tumour was embolized using contour PVA particles of 150-250 um. At the end of the particulate injection the patient had posterior circulation stroke. The check angiogram showed near total devascularisation of the tumour and in addition filling of the left vertebral artery through an anastomotic channel. MRI confirmed the infarct in the posterior circulation. The ascending pharyngeal artery has potential anastomoses to all neighbouring major arteries, and the anastomoses to the vertebral artery in our case were through the musculospinal artery. This case highlights the importance of potential vascular anastomotic channels as a cause of ischaemic complication during the embolization procedure. It also highlights the fact that dangerous anastomoses may only be visualised in the later phase of embolization probably due to changes in the haemodynamic pressure. The angiographic anatomy of APA is reviewed with potential communications with the internal and external carotid and vertebrobasilar systems.