Anatomical characteristics of the styloid process in internal carotid artery dissection: Case–control study

Abstract

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, 95% confidence interval = 1.01-1.08, p = 0.015) and styloid process-internal carotid artery distance (OR = 0.77 mm, 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.

The anatomic basis for ultrasound in the diagnosis and treatment of styloid process–related diseases

“…Located between the ICA and the external carotid artery, the distal end of the SP extends inwards, forwards, and downwards (10,11). As shown in our current study, ultrasound could clearly reveal the positional relationship between the SP and blood vessels in the neck.…”

Diabetes, hypertension, smoking, and hyperlipidemia as risk factors for spontaneous cervical artery dissection: Meta-analysis of case-control studies

“…3 Sixty-one percent of CeAD is spontaneous (sCeAD), occurring without trauma. 4 Many studies investigated the etiology and risk factors of sCeAD, and identified numerous genetic and environmental factors including α1-antitrypsin deficiency, 5 hyperhomocystinemia, [6][7][8] recent infection, 9,10 styloid process length [11][12][13] or its proximity to the hyoid bone, 14 arterial tortuosity, [15][16][17] and connective tissue disorders. 18,19 However, cardiovascular risk factors such as smoking, hypertension, and diabetes were less investigated.…”

Prevalence of Stylohyoid Complex Elongation among Patients Attending RAK College of Dental Sciences Clinic

“…Three muscles are attached to SP, namely the stylopharnygeous, stylohyoid and styloglossal muscles, in addition to the stylohyoid and stylomandibular ligaments. Anatomically, it has an intimate close contact with the upper portion of carotid space and its contents, including the cranial nerves V, IX (1). Its normal length ranges between 20-30 mm; however, it shows variation among different people (2).…”