Vertebral artery arteriovenous fistula: Complication following cervical spinal fusion

We report a rare case of extradural arteriovenous (AV) fistula of the right vertebral artery and vein following cervical spinal fusion. A 68-year-old female patient presented with complaints of a persistent buzzing sound in her right ear for 4 months that began following cervical spinal fusion surgery via an anterior approach. A right-sided bruit was noted and the patient was referred for a carotid duplex study. A carotid duplex was performed on a Philips IU22 using a 9-3 linear array transducer. The exam revealed a high-velocity vertebral artery waveform with spectral broadening and venous component suggestive of an AV fistula. Magnetic resonance angiography (MRA) of the neck confirmed a right extradural AV fistula at the level of C4 between the right vertebral artery and vein. The patient subsequently underwent angiography and coil embolization of the right vertebral artery. Postembolization angiography revealed resolution of the AV fistula and occlusion/near occlusion of the vertebral artery distal to the embolization. While vascular injuries are a known complication of spinal surgery using the anterior approach, it is rare for them to present as a late finding. Duplex evaluations of the carotid arteries for patients’ subjective noise complaints often do not reveal significant pathology; though in cases involving a history of prior surgical intervention, ultrasound may be useful in identifying iatrogenic vascular injury