Thursday, June 2, 2011

Styloid-carotid artery syndrome

A 42-year-old commercial pilot was placed on medical leave because of frequent episodes of syncope that occurred when he turned his head to the extreme right lateral position. The patient's partner said that these syncopal episodes were accompanied by jerky movements that resembled seizure activity. The patient would regain consciousness as soon as his head became realigned in the midline. As his symptoms increased in severity and frequency, he began to experience transient episodes of blindness in his right eye.
The patient was seen by a neurologist, who ordered computed tomography (CT) and magnetic resonance imaging (MRI) of the nead and neck with contrast; the MRI demonstrated no abnormalities. Magnetic resonance arteriography and magnetic resonance venography showed that the circle of Willis was patent, as were the internal and external jugular veins bilaterally. However, computed tomographic (CT) angiography demonstrated that the styloid processes were elongated and the stylohyoid ligaments were calcified bilaterally. In addition, the lumen of the right carotid artery appeared to be narrowed by 50% as a result of its tortuous course around the calcified ligament.
The patient was taken to the operating room for surgical resection. Intraoperative neurophysiologic monitoring detected no signs of abnormal brain activity. He successfully underwent a transcervical resection of approximately 5 cm of the elongated right styloid process and calcified ligament without complication. His postoperative course was uneventful, and his syncope resolved.
In 1937, Eagle and Durham described 2 cases of post-tonsillectomy pharyngeal pain that had been caused by an elongated styloid process; this condition is now known as Eagle's syndrome. (1) In 2002, Prasad et al described their experience with 58 cases of Eagle's syndrome over a 10-year period. (2) All of their patients had presented with a chief complaint of pain, and their diagnosis was based on palpation of the tonsillar fossa, a panoramic x-ray, and a positive lidocaine infiltration test. All of these patients underwent resection via a transoral approach. The longest styloid process excised measured 3 cm.
In 2000, Bafaqeeh subclassified Eagle's syndrome into two types: its classic form and an entity he called styloid-carotid artery syndrome. (3) Our patient's presentation, diagnosis, and treatment more closely resembled styloid-carotid artery syndrome than classic Eagle's syndrome. On presentation, his primary symptoms were syncope and associated neurologic manifestations, including blindness, that had been caused by not only an elongated styloid process but by a calcified stylohyoid ligament, as well. On axial CT, the extent of calcification of the stylohyoid ligament was not well appreciated, nor was its close association with the carotid artery. However, the association was clearly demonstrated on the sagittal reconstruction of the CT angiography. In view of the extent of the calcification and its proximity to the carotid artery, a transcervical approach was favored over the transoral approach.
Special recommendations for the diagnosis and management of patients with styloid-carotid artery syndrome include sagittal CT angiography with reconstruction when clinical suspicion is high, intraoperative neurophysiologic monitoring, and a transcervical approach to resection.

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