Bilateral eagle syndrome: A rare entity

Abstract

Elongated styloid process or Eagle syndrome is a rare condition presenting with a wide range of symptoms including throat pain, foreign body sensation, neck pain, and ear pain. Establishing a diagnosis requires a high index of suspicion and understanding of this entity by the physician. Computed tomography (CT) is the gold standard to diagnose Eagle syndrome. Conservative medical treatment with analgesics, oral steroids, and anticonvulsants are offered in patients who refused surgery. The mainstay of treatment is surgical resection through transoral or transcervical approaches. We describe a rare case of bilateral Eagle syndrome which presented with chronic foreign body sensation in the throat but aggravated by fish bone ingestion. Flexible nasopharyngolaryngoscopy (FNPLS) and cervical x-ray did not reveal any foreign body but showed an incidental finding of elongated styloid process bilaterally. Contrast-enhanced CT scan of the neck confirmed the finding of the elongated styloid process bilaterally. The patient underwent transoral endoscopic assisted bilateral styloidectomy following tonsillectomy. There was complete resolution of the symptoms during postoperative follow-up. This approach is recommended to avoid external scarring, minimize postoperative pain, and shorter hospital stay.

Introduction

Eagle syndrome is a rare clinical condition characterized by neuropathic and vascular occlusive symptoms caused by calcification of the stylohyoid ligament or temporal styloid process elongation. The length and direction of the styloid process compressing onto the adjacent neurovascular elements of the neck cause symptoms ranging from mild discomfort to acute neurological presentation. Additionally, it is known as stylohyoid syndrome, styloid syndrome, or styloid–carotid artery syndrome and is classified as classic or stylocarotid type. The classic type frequently present with a triad of dysphagia, odynophagia, otalgia, and radiating orofacial or cervical pain. In the stylocarotid type, impingement of the internal or external carotid artery, exacerbated by contralateral head rotation, results in vertigo, syncope, stroke, or even sudden death. ¹ The styloid process normally has a mean length of 21–29.5 mm. As a result, a styloid process greater than 30 mm in length increased the likelihood of developing Eagle syndrome. ² Conservative treatment with analgesics and anticonvulsants may help patients who have refused surgery alleviate symptoms, but surgical resection via the transoral or transcervical approach remains the treatment of choice.

Case report

A 46-year-old female presented with chronic persistent left-sided globus sensation associated with neck pain. The symptom was aggravated after she allegedly ingested a fish bone and described the pain as pricking in nature. Clinical examination revealed bilateral grade II tonsils with no obvious foreign body by inspection and palpation. However, pain was elicited on deep palpation of the bilateral tonsillar fossa. Flexible nasopharyngolaryngoscopy (FNPLS) and other ears, nose, throat, and neck examinations were unremarkable. The cervical X-ray did not reveal any foreign body, however, there was an incidental finding of bilateral elongated styloid process (Figure 1). Computed tomography (CT) of the neck confirmed the findings of the bilateral elongated styloid process (Figure 2). Her symptoms persisted despite conservative treatment with an oral antibiotic. Subsequently, she underwent transoral endoscopic assisted of bilateral styloidectomy following tonsillectomy. Styloid processes were removed in piecemeal with a Kerrison punch to avoid injury to neighboring vital structures. This was assisted with a zero-degree rigid endoscope for better visualization (Figure 3). The total length of the styloid processes removed from the left and right sides was 2 cm and 1.5 cm, respectively (Figure 4). She was well postoperatively and allowed discharged the next day. On follow-up 1 month after surgery, the patient remained asymptomatic and pain-free.

Figure 1.

Lateral neck x-ray showing obliquely oriented linear calcification (about 3.5 cm long) in the expected position of the styloid process / stylohyoid ligament (blue arrow).

Figure 2.

Coronal (Left) and sagittal (Right) CT scan images of the neck showing bilateral processes with prominent stylohyoid calcification.

Figure 3.

Intraoperative view of left styloid process exposed via transoral approach with endoscopic assistance.

Figure 4.

The length of the left styloid processes removed was 2 cm (blue arrow) and 1.5 cm from the right styloid (green arrow).

Discussion

The Reichert’s cartilage, which is formed by the second pharyngeal arch, is the origin of the styloid process. The stylohyoid, stylopharyngeus, styloglossus, stylohyoid, and stylomandibular ligaments attach to it as it projects inferiorly from the petrous temporal bone. The internal jugular vein, internal carotid artery, facial nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, and hypoglossal nerve are all located medial to the styloid process. ³ Eagle Syndrome is described as symptomatic abnormal lengthening of the styloid process or ossified styloid ligaments that impede the function of adjacent neurovascular and muscular structures. ⁴

Epidemiologically, the prevalence of elongated styloid processes in adults is estimated to be 4%, whereby only 4% are symptomatic because of the elongation. A retrospective study by Asutay et al. among the Eastern Eagean Turkish population revealed a prevalence of elongated styloid processes of 7% and symptomatic elongated styloid processes of 3.5%. This demonstrates how uncommon this entity could be. The styloid process has a usual length of 2.5–3.0 cm. Any length greater than this is referred to as an elongated styloid process, which may result in Eagle syndrome.^5,6 Interestingly, our patient had an elongated styloid process on both sides. Although it was previously believed that this condition had a 3:1 female-to-male predominance, recent research indicates that there is no significant gender predisposition. ⁷ Intriguingly, women are more likely than men to experience bilateral elongation (64.58% vs 35.41%). Bilateral styloid process elongation is more frequent than unilateral elongation. Based on age predisposition, it is more likely to be present at 40th to 60th decade of life. ⁷

Watt W. Eagle, who described this condition for the first time in 1937, explains it in two distinct ways. Firstly, it caused cervical pain, dysphagia, odynophagia, and referred pain to the ear. The second explanation, which is uncommon, is referred to as ‘stylocarotid artery syndrome’, in which the elongated styloid process compresses the carotid artery and their associated periarterial nerve plexus, resulting in ocular and facial pain, transient ischemic symptoms, syncope, or even carotid artery dissection in rare cases. ⁸ Due to the abnormal length and direction of the styloid process, it has been hypothesized that the pain is caused by impingement of the glossopharyngeal nerve as it crosses over the superior constrictor muscle. Eagle syndrome is most frequently noticed in patients who have undergone tonsillectomy or pharyngeal trauma. Our patient’s symptoms may have been precipitated by pharyngeal trauma caused by a fish bone foreign body. Foreign body sensation occurs in up to 55% of patients with Eagle’s syndrome, similar to our patient. Surprisingly, she experienced symptoms in both tonsillar regions which is a rare occurrence. Generally, most patients experienced symptoms unilaterally. The diagnosis was confirmed by imaging with cervical X-ray and CT, revealing the culprit for the foreign body sensation.

Eagle syndrome is difficult to diagnose due to its variable and non-specific symptoms. Saccomanno et al. proposed four distinct diagnostic criteria for this confusing entity. ⁹ The first parameter is clinical manifestation as determined by a thorough history and examination to rule out other potentially serious causes, such as malignancy. The second parameter is determined by digital palpation of the tonsillar fossa to inflict pain. Radiological examinations such as a skull X-ray, an orthopantomogram, and a CT scan will confirm the diagnosis of the styloid process elongation. CT scan is the gold standard for visualizing the styloid complex’s anatomy and relationship to its surroundings. Finally, immediate symptom relief following lidocaine infiltration (1 mL 2%) into the tonsillar fossa is also diagnostic for Eagle syndrome.

Even though some literature suggested that Eagle Syndrome can be successfully treated by non-surgical treatment, the cure rate is only 64.3%, compared to styloidectomy which has a cure rate of 91.8%. ¹⁰ The transoral approach consists of six simple steps: palpation of the styloid process through transoral exposure, tonsillectomy, dissection of the pharyngeal constrictors against the styloid process, separating the inserted ligaments and muscles against the styloid process, resection of the styloid process in fragments, and closure across the planes. ¹¹ Since this patient had no contraindications for surgery, surgical treatment via transoral approach was chosen given medical treatment failure. We performed bilateral tonsillectomy with a cold instrument under direct visualization to expose the tonsillar bed and excised the styloid process assisted by a rigid zero-degree endoscope. Endoscopic visualization aided significantly in performing a precise styloid excision and avoiding unnecessary trauma to vital neighboring structures. Attributed to the reason that this patient experienced symptoms on both sides, bilateral endoscopic-assisted styloidectomy was performed. We chose and recommended this approach because it avoids external scarring, is more cosmetically acceptable, and takes less time. Even though it may not permit total exposure of the styloid process, it does enable sufficient resection to relieve symptoms in many cases. ¹² This treatment was considered successful, as the patient’s symptoms resolved completely after 3 weeks of postoperative follow-up. Most patients will show improvement in their pain severity following surgery, whether transoral or transcervical. ¹³

Conclusion

Eagle syndrome is an essential clinical entity for otolaryngologists to diagnose because of the wide range of presentations, the potential for serious complications, as well as the fact that it is often treatable. This is a clear example of a condition for which the etiology has eluded the treating physician for an extended time. Conservative drug therapy is beneficial but has a transient effect. Both transoral and transcervical styloidectomy have been shown to provide significant pain relief with few adverse effects.