Background and importance: Elongated styloid processes sometimes compress the cervical carotid artery, causing transient ischemic attacks. Most patients with Eagle syndrome who experience transient ischemic attacks have bilateral elongated styloid processes; therefore, it is necessary to determine which side is causing the Eagle syndrome to treat it. This is the first report of the usefulness of 3-dimensional angiography and near-infrared spectroscopy (NIRS) for the diagnosis of Eagle syndrome.
Clinical presentation: A 40-year-old man experienced transient loss of consciousness when flexing his neck. On 3-dimensional computed tomography, bilateral elongated styloid processes were revealed. We were able to determine the side of concern using 3-dimensional angiography and NIRS. Three-dimensional angiography with his neck flexed showed a compressive dent in the cervical portion of the left internal carotid artery. On NIRS, during neck flexion, the concentrations of oxygenated hemoglobin and total hemoglobin decreased in his left motor area, which was resolved immediately when he returned his neck to its natural position. This led to decreased cerebral blood flow in the left hemisphere of his brain. After partial removal of left styloid process, he was symptom free, even when keeping his neck flexed. NIRS showed that the concentrations of oxygenated hemoglobin increased in the left motor area during neck flexion.
Conclusion: We report the usefulness of 3-dimensional angiography and NIRS for diagnosing Eagle syndrome. Three-dimensional angiography and NIRS can visualize anatomic structures and provide hemodynamic information for an appropriate surgical strategy.