Introduction

Vestibular schwannomas, also known as acoustic neuromas, are intracranial, extra-axial nerve sheath tumors that grow slowly and originate from the Schwann cells, investing the vestibular part of the vestibulocochlear nerve (1). When these tumors enlarge, they eventually take up a significant portion of the cerebellopontine angle, which frequently results in symptoms like tinnitus, vertigo, and hearing loss. Schwannomas are solitary in 90% of the instances and are categorized as grade 1 benign tumors by the World Health Organization. Acoustic neuromas reportedly occur in 0.6-1.9 individuals per 100,000 population (2). The patient’s age, their neurological state, the size, and other features of the tumor influence the treatment plan. Radiation therapy, stereotactic radiosurgery, and microsurgery are available as treatment alternatives. Microsurgical resection is the gold standard for treating large vestibular schwannomas (3). It is frequently carried out utilizing the trans-labyrinthine, middle cranial fossa, or retro-sigmoid approaches (4). Any size of vestibular schwannomas can be removed with the retro-sigmoid approach; however, with this surgical intervention, there is a risk of mortality and postoperative complications in 0.2% and 22% of patients, respectively (5). These complications include facial nerve damage, trigeminal nerve dysfunction, aggravated gait associated with damage to the cerebellum, CSF leaks, and meningitis (6). A very unusual side effect of retro-sigmoid craniotomy is postoperative AV fistulas, which take time to appear clinically (7) (8). Similarly, the vertebral artery may inadvertently be harmed, even though it is beyond the surgical field, because of its abnormal course and loss of anatomical landmarks (9) (10). It is very rare in the literature to find vertebral artery pseudoaneurysm and AV fistula formation between the vertebral artery and sigmoid sinus (11). Such lesions typically follow either penetrating trauma or iatrogenic trauma (12) (13). Surgical correction has historically been the preferred course of treatment for such lesions. Alternative endovascular techniques have also been introduced that allow selective occlusion of the vascular injury (14). Both methods do, however, require sacrificing the vertebral artery. Another alternative endovascular approach is the use of a covered stent or flow diverting stent, which maintains vessel patency (15) (16). Herein, we report a unique case of iatrogenic pseudoaneurysm and arteriovenous fistula in Pakistan that was successfully treated with a covered stent.