A narrative review on cervical artery dissection-related cranial nerve palsies.

Introduction: This study aimed to emphasize the importance of cranial nerve (CN) palsies in spontaneous cervical artery dissection (sCeAD). Methods: A search term-based literature review was conducted on "cervical artery dissection" and "cranial nerve palsy." English and German articles published until October 2023 were considered. Results: Cranial nerve (CN) palsy in sCeAD is evident in approximately 10% of cases. In the literature, isolated palsies of CN II, III, VII, IX, X, and XII have been reported, while CN XI palsy only occurs in combination with other lower cranial nerve palsies. Dissection type and mural hematoma localization are specific to affected CN as CN palsies of II or III are solely evident in those with steno-occlusive vessel pathologies located at more proximal segments of ICA, while those with CN palsies of IX, X, XI, and XII occur in expansive sCeAD at more distal segments. This dichotomization emphasizes the hypothesis of a different pathomechanism in CN palsy associated with sCeAD, one being hypoperfusion or microembolism (CN II, III, and VII) and the other being a local mass effect on surrounding tissue (CN IX, X, XI, and XII). Clinically, the distinction between peripheral palsies and those caused by brainstem infarction is difficult. This differentiation is key, as, according to the reviewed cases, peripheral cranial nerve palsies in sCeAD patients mostly resolve completely over time, while those due to brainstem stroke do not, making cerebrovascular imaging appraisal essential. Discussion: It is important to consider dissections as a potential cause of peripheral CN palsies and to be aware of the appropriate diagnostic pathways. This awareness can help clinicians make an early diagnosis, offering the opportunity for primary stroke prevention.