Eagle Syndrome Secondary to Osteoradionecrosis of the Styloid Process

CASE REPORT

Ochsner Journal 17:195–198, 2017 Ó Academic Division of Ochsner Clinic Foundation

Anna K. Bareiss, BA,1 David Z. Cai, MD,2 Amit S. Patel, MD,2 BrianA.Moore,MD3,4

1Tulane University School of Medicine, New Orleans, LA 2Department of Otolaryngology – Head and Neck Surgery, Tulane University School of Medicine, New Orleans, LA 3Department of Otolaryngology, Ochsner Clinic Foundation, New Orleans, LA 4The University of Queensland School of Medicine, Ochsner Clinical School, New Orleans, LA

Background: Eagle syndrome is a rare condition caused by elongation of the styloid process or ossification of the stylohyoid ligament. The symptomatology can be vague but may include dysphagia, odynophagia, otalgia, foreign body sensation, facial pain, trismus, headache, tinnitus, increased salivation, and/or voice changes. Case Report: We present the case of a 58-year-old male believed to have acquired Eagle syndrome secondary to osteoradionecrosis of the styloid process following radiation therapy used as adjuvant treatment for a surgically resected pT2N1M0 squamous cell carcinoma of the right tonsil. Conclusion: Radiation is a common component of treatment for head and neck cancers. The diagnosis of Eagle syndrome secondary to osteoradionecrosis of the styloid process is an elusive, but important, diagnosis to consider because the condition can be treated successfully.

Keywords: Eagle syndrome, osteoradionecrosis, radiotherapy

Address correspondence to Brian A. Moore, MD, Department of Otolaryngology, Ochsner Clinic Foundation, 1514 Jefferson Hwy., New Orleans, LA 70121. Tel: (504) 842-4080. Email: [email protected]

INTRODUCTION 100% of the desired radiation dose. On the left side, the Eagle syndrome, also called stylohyoid syndrome or area of the submandibular gland to the clavicle was stylocarotid artery syndrome, is believed to result from the radiated with care to spare the parotid gland to minimize elongation of the styloid process or ossification of the the risk of subsequent xerostomia. stylohyoid ligament, resulting in irritation of cranial nerves V, Five months after completing radiation therapy, the VII, IX, and X.1 Symptomatology varies widely and may patient presented with right-sided jaw pain, trismus, include dysphagia, odynophagia, otalgia, foreign body intermittent right-sided otalgia, dysphagia, and feelings of sensation, facial pain, trismus, headache, tinnitus, increased warmth and redness over his right parotid region. His salivation, and/or voice changes.1,2 We present a novel clinical examination revealed a desiccated area of the case in which Eagle syndrome apparently resulted from lateral pharyngeal wall with what appeared to be exposed radiation-associated osteonecrosis of the styloid process bone. Soft tissue neck computed tomography (CT) with and also review the literature on Eagle syndrome including contrast revealed a right styloid process that was fragment- the history of the disease entity, symptomatology, epidemi- ed distally and abutting against the posterior right orophar- ology, etiology, diagnosis, and treatment. ynx (Figure). The patient agreed to an intraoral resection of the styloid process. Intraoperatively, a necrotic right styloid CASE REPORT process was visualized extruding into the right oropharynx, A 58-year-old male with a medical history significant for and a 2-cm segment was resected. Final pathologic pT2N1M0 squamous cell carcinoma of the right tonsil diagnosis revealed acute osteomyelitis with no evidence underwent transoral robotic surgery consisting of a right of metastatic disease. During the follow-up 1 month later, lateral oropharyngectomy with palatal flap and posterior the patient denied any further pain, dysphagia, otalgia, or pharyngeal wall–flap reconstruction and a right modified odynophagia. radical neck dissection of level I to level IV lymph nodes in November 2013. He subsequently received intensity- DISCUSSION modulated radiation therapy (66 Gy) that was completed Eagle syndrome was first described by Watt Eagle in 1937 in March 2014 after surgical ablation and reconstruction. when he reported 2 cases involving elongation of the styloid Fields of radiation covered the tonsillar fossa to the clavicle process resulting in a constellation of symptoms that were on the right side, with the styloid process receiving at least distinct from primary glossopharyngeal neuralgia.3 The

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ically.5,7 While the incidence of an elongated styloid process in the general population is controversial, only 4%-10% of patients with this anatomic variation report symptoms.5,6,8 Additionally, Eagle syndrome has been diagnosed in patients with a normal-length styloid process. In this situation, the pathology is attributed to inflammatory and degenerative changes in the area, specifically insertion tendonitis.9 A normal styloid process is 2.5-3.0 cm and never palpable.1,5,10 When the styloid process becomes longer than 3 cm, it is considered elongated and is at increased risk for causing symptoms.1,6 Typically, the styloid processes are elongated bilaterally, but patients tend to experience unilateral symptoms.11 Eagle syndrome is more common in patients >30 years and has a female preponderance.2,5,12 While length of the styloid process is paramount in the discussion of Eagle syndrome, discussing the orientation of this structure in space is also important.1 The styloid process is in an important region of the neck, as it is surrounded by the external carotid artery, the internal carotid artery containing the sympathetic chain, the occipital artery, the internal jugular vein, the accessory nerve, the hypoglossal nerve, the vagus nerve, and the glossopharyngeal nerve.2 Any deviation of the styloid process can interfere with this important anatomy and cause symptoms Figure. Axial computed tomography of the neck with of Eagle syndrome. In a retrospective controlled study in contrast demonstrates the fragmented right styloid process which all subjects had an elongated styloid process (>30 projecting into the oropharynx (arrow). mm), Okur et al found a significant difference in medial angulation measurement on 3-dimensional (3D) CT of the styloid process—a columnar-shaped, bony projection from styloid process in symptomatic vs asymptomatic patients.6 the petrous portion of the temporal bone—is situated Furthermore, Yavuz et al reported a significant difference in anterior to the stylomastoid foramen, lateral to the pharyn- anterior angulation measurement on plain radiographs in a geal wall, and between the internal and external carotid retrospective controlled study.4 arteries.4 It derives from the Reichert cartilage, part of the The proposed etiologies of Eagle syndrome are diverse. second brachial arch. The stylohyoid ligament connects the One explanation is regressive ontogenic development in styloid process to the lesser cornu of the hyoid bone. Eagle which mesenchymal elements in Reichert cartilage provoke syndrome is anatomically characterized by elongation of the ossification of the stylohyoid complex. A related theory styloid process or calcification of the stylohyoid ligament, involves reactive metaplasia causing ossification, presum- resulting in a wide range of clinical symptoms. ably after trauma. Additionally, variations of the stylohyoid In a subsequent publication in 1949, Eagle defined 2 complex are suggested to result from developmental syndromes related to the styloid process: the classic anomalies of aging, congenital dysmorphism, reactive syndrome and the styloid process-carotid artery syndrome.5 hyperplasia following surgery or chronic irritation, rheuma- The classic syndrome is more common and often associ- tologic-related processes, and genetic makeup of an ated with a tonsillectomy. The predominant symptoms are autosomal recessive trait with low penetrance and expres- pain/soreness in the throat, a foreign-body sensation, and sivity.10 Last, the dysendocrine theory proposes that otalgia that can be attributed to the postoperative healing ossification results from hormone disruption in postmeno- process that indirectly encompasses cranial nerves V, VII, pausal women.1,10 This theory is interesting because Eagle IX, and X.5 The styloid process-carotid artery syndrome syndrome has a female preponderance. results from an elongated, angulated, or displaced styloid Based on our review of the English language literature, process impinging on the internal or external carotid we believe that our case is the first reported case of Eagle artery.5,6 This impingement can decrease blood flow and/or syndrome apparently resulting from osteoradionecrosis of cause carotidynia, resulting in symptoms of headache and the styloid process. Osteoradionecrosis, one of the severe facial pain, depending on where the impingement occurs. If complications of radiotherapy, results from hypovascular- the impingement occurs on the internal carotid artery, hypoxic-hypocellular conditions that cause breakdown of parietal headaches throughout the distribution of the tissue that leads to bone exposure. Additionally, any ophthalmic artery are likely. Alternatively, if the impingement inflammation or trauma to the area further increases the is on the external carotid artery, facial pain below the level of energy/oxygen needs of the local tissues, compounding the the eye is common.5 risk of osteoradionecrosis.13 The possibility of osteoradio- Eagle syndrome is thought to be an uncommon occur- necrosis development is dose-dependent and highest at a rence; however, the reported incidence of an elongated dose of >60 Gy.14 While intensity-modulated radiation styloid process varies. Eagle reported a clinical incidence of therapy has many benefits compared to traditional radiation 4%, while Kaufman found an incidence of 28% radiograph- therapy, how this treatment affects the chance of developing

196 Ochsner Journal Bareiss, AK osteoradionecrosis is not clear.14 Therefore, it seems A lidocaine infiltration test can establish the diagnosis of reasonably important to consider the development of Eagle syndrome. This test involves injection of 1 mL of 2% osteoradionecrosis of the styloid process causing Eagle lidocaine into the tonsillar fossa in an awake patient. If the syndrome following radiation treatments of the head and patient’s symptoms diminish or disappear within 5 minutes neck. of injection, the test is considered positive and supports the Huang et al propose 3 important components for diagnosis of Eagle syndrome.12 diagnosing skull base osteoradionecrosis.13 First, consid- Most cases of Eagle syndrome can be successfully ering symptoms in relation to the location of the necrotic treated with surgical resection of the styloid process. bone is important. This point is especially relevant to the However, conservative management should be attempted presented case, as the osteoradionecrosis of the styloid first, as surgery puts the valuable structures surrounding the process appears to have caused Eagle syndrome. Second, styloid process at risk. Pharmacologic treatment options radiologic evaluation with CT or magnetic resonance include antiinflammatories, anticonvulsants, and antidepres- imaging is valuable. Third, endoscopic visualization (if sants. Additionally, repeated corticosteroid/anesthetic injec- possible) is helpful in determining the diagnosis. Huang et tions can be performed in the office setting.18,19 al concluded that surgical resection is the best treatment for When conservative options fail, surgery is the treatment of osteoradionecrosis at the skull base, and thus, the choice. Two approaches are typically considered for diagnosis can be definitively confirmed by pathologic resection of the styloid process: the intraoral approach evaluation.13 and the extraoral approach. The intraoral approach is Eagle syndrome is typically diagnosed in a standard simpler, has a shorter operative time, and does not leave fashion including symptom evaluation, palpation of the a visible scar; however, the surgical exposure is wider, styloid process in the tonsillar fossa, radiologic interpreta- putting critical nerves and blood vessels at risk. The tion, and possibly, a lidocaine infiltration test.12 Palpation of intraoral method also has the potential to lead to a deep 1,19 the styloid process in the tonsillar fossa may reproduce or neck space infection. To prevent infection, prophylactic intensify symptoms for the patient.1 Ability to palpate the antibiotics are recommended whenever the pharynx is 2 styloid process depends on the height of the patient, the incised. Alternatively, the extraoral approach involving a length and thickness of the patient’s neck, the position of cervical incision provides good visualization and a reduced the styloid process in terms of angulation, and the risk of infection; however, more surgical time is required, provider’s experience in palpating the tonsillar fossa.2 The recovery is longer, and scarring may be a cosmetic 1,19 protrusion of the styloid process into the tonsillar fossa can concern. In 2015, Kiralj et al proposed that the length be classified into 3 grades: grade I in the upper pole, grade of the styloid process or the calcified ligament should 19 II in the middle pole, and grade III in the lower pole of the determine the surgical approach. In the presence of tonsillar fossa. Grades II and III are the most common ossification of the stylohyoid complex or a styloid process classifications for location of the styloid process within the extending to the hyoid bone, the extraoral approach is safer. tonsillar fossa.12 However, if the styloid process is shorter or not ossified, the In addition to a thorough history and physical examina- intraoral approach should suffice. tion, radiologic evaluation is valuable in the diagnosis of Eagle syndrome. Traditionally, plain radiographs have been CONCLUSION used to view the styloid process, particularly using an Eagle syndrome is a rare entity with vague symptomatol- orthopantomogram. However, these films are limited by the ogy and ambiguous incidence and etiology, yet the appearance of superimposed structures and magnification.1 approach to diagnosis and treatment is well defined. To In fact, Monsour et al reported a magnification of 1.373 our knowledge, our case is the first reported case of Eagle inherent in orthopantomography.15 Thus, 3D-CT is the gold syndrome apparently resulting from osteoradionecrosis of standard for diagnosis of Eagle syndrome because it is the styloid process; however, we believe it is probably not more accurate in determining the length and angulation of the only case following head and neck radiation therapy. the styloid process.16 In a 2014 article, Kamal et al further Although the incidence of Eagle syndrome is low, this support 3D-CT as the best imaging modality to diagnose disorder is an important consideration for patients present- Eagle syndrome.17 They state that the images allow ing with vague complaints following radiation to the head visualization of the detailed anatomy of the area that can and neck, and if the condition is diagnosed, it can be treated help the clinician deduce the exact etiology and plan a successfully. surgical approach. While quantifying the length and angulation of the styloid ACKNOWLEDGMENTS process is important, Kent et al suggest that the proximity of The authors have no financial or proprietary interest in the the styloid process to the tonsillar fossa is a more subject matter of this article. appropriate diagnostic component.8 In their 2015 study, they used 3D-CT imaging to measure the distance from the REFERENCES tip of the styloid process to the mucosal-air interface of the 1. Piagkou M, Anagnostopoulou S, Kouladouros K, Piagkos G. Eagle’s syndrome: a review of the literature. Clin Anat. 2009 Jul; ipsilateral palatine tonsil and showed that the styloid 22(5):545-558. doi: 10.1002/ca.20804. process was significantly closer to the tonsillar fossa in 2. Bafaqeeh SA. Eagle syndrome: classic and carotid artery types. J the symptomatic group compared to the control group. This Otolaryngol. 2000 Apr;29(2):88-94. finding supports a hypothesis of glossopharyngeal nerve 3. Eagle WW. 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