No abstract

Although vestibular schwannoma is a benign entity and the most commonly encountered cerebellopontine angle mass lesion, it is a diverse disease. 1,2 Microsurgical management of vestibular schwannoma requires technical mastery and a nuanced ability to respond to dynamic neuroanatomic conditions. [3][4][5][6] One such anatomic variation of note is the presence of an anterior inferior cerebellar artery (AICA) vascular loop near cranial nerves VII and VIII. 7,8 Here, we report an unusual case in which we encountered 2 loops of AICA adherent to the dura during resection of a vestibular schwannoma. The patient is a 31-year-old female with a history of right-sided hearing loss, who was diagnosed with a presumed vestibular schwannoma on MRI. The decision was made to perform a hearing preservation surgery using a right retrosigmoid craniotomy. The patient consented to this procedure. Unexpectedly, we encountered 2 AICA loops that were found to be tethered to the petrous temporal dura. Both AICA loops were displaced and protected from the surgical plane by creation and subsequent reflection of dural flaps. The remainder of the procedure proceeded in a routine fashion, and a gross total resection was achieved. Postoperatively, the patient had intact House-Brackmann grade 1 facial nerve function, as well as subjectively preserved hearing. The patient has been diseasefree for more than 4 years, and there has been no evidence of tumor recurrence or additional hearing loss. Overall, this video demonstrates strategies for management of this uncommon but potentially dangerous anatomic variant, alongside a hearing-preserving resection of the patient's moderately large vestibular schwannoma. Images at 3:03 reused with permission.