Ischemic stroke due to internal carotid artery dissection associated with an elongated styloid process (Eagle syndrome)

Introduction Pathophysiology of cervical artery dissection is complex and poorly understood. In addition to well-known causative and predisposing factors, including major trauma and monogenic connective tissue disorders, morphological characteristics of the styloid process have been recently recognized as a possible risk factor for cervical internal carotid artery dissection. Aims To study the association of the anatomical characteristics of styloid process with internal carotid artery dissection. Methods Retrospective, multicenter, case–control study of patients with internal carotid artery dissection and age- and sex-matched controls. Consecutive patients with internal carotid artery dissection and controls with ischemic stroke or transient ischemic attack of any etiology excluding internal carotid artery dissection, who had performed computed tomography angiography, diagnosed between January 2010 and September 2016. Two independent observers measured styloid process length and styloid process distance to internal carotid artery. Results Sixty-two patients with internal carotid artery dissection and 70 controls were included. Interobserver agreement was good for styloid process length and styloid process–internal carotid artery distance (interclass correlation coefficient = 0.89 and 0.76, respectively). Styloid process ipsilateral to dissection was longer than left and right styloid process in controls (35.8 ± 14.4 mm versus 30.4 ± 8.9 mm and 30.3 ± 8.2 mm, p = 0.011 and p = 0.008, respectively). Styloid process–internal carotid artery distance ipsilateral to dissection was shorter than left and right distance in controls (6.3 ± 1.9 mm versus 7.2 ± 2.1 mm and 7.0 ± 2.3 mm, p = 0.003 and p = 0.026, respectively). Internal carotid artery dissection was associated with styloid process length (odds ratio = 1.04 mm−1, 95% confidence interval = 1.01–1.08, p = 0.015) and styloid process–internal carotid artery distance (OR = 0.77 mm−1, 95% confidence interval = 0.64–0.92, p = 0.004). Conclusion Longer styloid process and shorter distance between styloid process and cervical internal carotid artery are associated with cervical internal carotid artery dissection.

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Recurrence of internal carotid artery dissection associated with elongated styloid process: A case report

Surgical Neurology International ◽

10.25259/sni_536_2021 ◽

2021 ◽

Vol 12 ◽

pp. 473

Author(s):

Shigeomi Yokoya ◽

Hidesato Takezawa ◽

Hideki Oka ◽

Akihiko Hino

Keyword(s):

Carotid Artery ◽

Internal Carotid Artery ◽

Internal Carotid ◽

Styloid Process ◽

Carotid Artery Dissection ◽

Artery Dissection ◽

Elongated Styloid Process ◽

Initial Onset ◽

Long Term Follow Up ◽

Ischemic Attack

Background: An elongated styloid process is known to cause ischemic stroke. Previous reports claim that internal carotid artery (ICA) dissection due to the elongated styloid process has good outcomes when treated conservatively; however, long-term follow-up has not been attempted and recurrence in the later period has not been reported so far. We report a case of recurrence of symptoms over a decade after the initial onset. Case Description: A 59-year-old man experienced a transient ischemic attack (TIA) 10 years ago. Six years ago, he experienced hemispheric TIA, and magnetic resonance angiography revealed a diminished signal of the left ICA; however, no further examination was performed. Four years ago, he experienced another transient amaurosis attack and was treated with antiplatelet therapy because no embolic source was detected using ultrasonography examination, and he was diagnosed with idiopathic ICA dissection. Recently, he experienced a third amaurosis fugax attack. Digital subtraction angiography and cone-beam computed tomography demonstrated left cervical ICA dissection due to elongated styloid process. He underwent surgical resection of the left styloid process and cervical stent placement. He had no ischemic attacks postoperatively. Conclusion: The elongated styloid process may cause recurrent ischemic attacks over a decade due to ICA dissection.

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