Styloid Process Abnormalities and Carotid Artery Dissection in Ischemic Stroke: A Combined Narrative Review and Retrospective Cohort Study

Background: Styloid process abnormalities, classically associated with Eagle syndrome, have increasingly been implicated in cerebrovascular events through mechanical interaction with cervical vessels. Methods: This study combined a structured narrative review of the relationship between styloid process anatomy and internal carotid artery dissection with a single-center retrospective observational cohort. Consecutive patients with acute ischemic stroke were evaluated to identify cases of extracranial internal carotid artery dissection, in whom styloid process anatomy, carotid morphology, and potential mechanical triggers were subsequently assessed. The narrative review was supported by a structured PubMed/MEDLINE search and a PRISMA-style study-selection process. No formal meta-analysis was performed, and the institutional cohort did not include an age- and sex-matched control group. Results: The literature search identified 34 eligible reports for the narrative synthesis. Among 1621 consecutive ischemic stroke admissions, 17 patients (1.04%) had extracranial internal carotid artery dissection. Elongated styloid processes (≥30 mm) were identified in 11/17 patients (64.7%), and carotid tortuosity was present in 10/17 patients (58.8%). Several patients had identifiable mechanical or traumatic precipitating factors. Conclusions: Styloid process elongation and carotid tortuosity were frequently observed in patients with extracranial internal carotid artery dissection. These findings support careful assessment of styloid–carotid anatomy in selected patients with carotid dissection. However, the small sample size, retrospective design, and absence of a control group preclude causal inference and require validation in larger controlled studies.