Eagle syndrome - An overview

SA Journal of Radiology ISSN: (Online) 2078-6778, (Print) 1027-202X Page 1 of 5 Review Article Eagle syndrome – An overview Author: Kavitaa Nedunchezhian1 Affiliation: 1 Private practice, Chennai, India Corresponding author: Kavitaa Nedunchezhian, Dates: Received: 28 June 2017 Accepted: 04 Aug. 2017 Published: 21 Sept. 2017 How to cite this article: Nedunchezhian K. Eagle syndrome – An overview. S Afr J Rad. 2017;21(1), a1247. https://doi.org/10.4102/sajr. v21i1.1247 Copyright: © 2017. The Authors. Licensee: AOSIS. This work is licensed under the Creative Commons Attribution License. Eagle syndrome represents symptoms brought about by compression of vital neurovascular and muscular elements adjoining the styloid process because of the elongation of styloid process or ossification of the stylohyoid or stylomandibular ligament. It is crucial for dentists, otolaryngologists and neurologists to be aware of the elongation of the styloid process and associated signs and symptoms. This article reviews the aetiopathogenesis, classification, investigative procedures and treatment modalities associated with Eagle syndrome. Introduction Eagle syndrome (ES) or stylohyoid syndrome is a rare condition that occurs because of the elongation of the styloid process or calcification of the stylohyoid ligament, characterised by painful sensation in the head and neck region.1 This condition was first elucidated by the American Otorhinolaryngologist Watt Weems Eagle in 1937.2 Most of the patients with styloid elongation or calcified stylohyoid ligament may be asymptomatic. Only 4% of affected individuals are known to experience symptoms.3 Symptoms may arise only when these ossified structures exert pressure on the various vital structures in the cervico-facial region. Symptomatic patients may experience a wide spectrum of symptoms, including pain in cervico-facial region, pharyngeal discomfort, painful neck movements, change in voice, painful tongue movements, increased secretion of saliva, otalgia and headache. The normal styloid process measures approximately 2.5 cm – 3.0 cm in length.2 Aetiopathogenesis The aetiology of ES is not clearly known. Although few suggest that dystrophic and degenerative changes in the hyoid complex of the styloid process might be the cause for ES, others suggest that cervico-facial inflammations, tumours, tonsillectomies and trauma could play a major role in causing ES.4 The suggested pathophysiological mechanisms for the pain in Eagle syndrome5 The following are the different aspects that could lead to pain because of the Eagle syndrome: • Compression of the neural elements, the glossopharyngeal nerve, lower branch of the trigeminal nerve and/or the chorda tympani by the elongated styloid process; • Fracture of the ossified stylohyoid ligament, followed by proliferation of granulation tissue that causes pressure on surrounding structures, resulting in pain; • Impingement on the carotid vessels by the styloid process, producing irritation of the sympathetic nerves in the arterial sheath (Figure 1); • Degenerative and inflammatory changes in the tendinous portion of the stylohyoid insertion, a condition called insertion tendinosis; • Irritation of the pharyngeal mucosa through direct compression by the styloid process; and • Stretching and fibrosis involving the fifth, seventh, ninth and tenth cranial nerves in the posttonsillectomy period. Classification systems Read online: Scan this QR code with your smart phone or mobile device to read online. Eagle hypothesised that the syndrome has two types: the classic type and the carotid artery type. These types were also elucidated in the studies of Breault6 and Lorman and Biggs.7 The classic type is often noticed in patients with a history of tonsillectomy and arises secondary to the stimulation of the trigeminal (fifth), facial (seventh), glossopharyngeal (ninth) and vagus http://www.sajr.org.za Open Access Page 2 of 5 Review Article a b Styloid Process Elongation Internal Caro d External Caro d Vagus Nerve Internal Jugular FIGURE 1: Schematic representation of (a) elongated styloid process causing impingement on vital structures versus (b) normal styloid process. a c b R R R Sources: Adapted from Langlais RP, Miles DA, Van Dis ML. Elongated and mineralized stylohyoid ligament complex: A proposed classification and report of a case of Eagle’s syndrome. Oral Surg Oral Med Oral Pathol. 1986;61:527–532. https://doi.org/10.1016/0030-4220(86)90400-7 FIGURE 2: Radiographic classification system of styloid elongation (a) Type I (b) Type II (c) Type III, according to Langlais et al.8 (tenth) cranial nerves or their associated branches. Eagle speculated that after tonsillectomy, these individuals develop scarring near the styloid apex which subsequently compresses or stretches nerve structures in the space surrounding the styloid process, causing pain. In the carotid artery type, the styloid process gets associated with the carotid nerve plexus and causes a foreign body sensation in the pharynx and cervical pain on rotation of the head. The radiographic classification system according to Langlais et al.8 includes the following three types of appearances (Figure 2): http://www.sajr.org.za • Type I – Represents an uninterrupted, elongated styloid process. • Type II – The styloid process apparently being joined to the stylohyoid ligament by a single pseudo-articulation, which gives the appearance of an articulated elongated styloid process. • Type III – Consists of interrupted segments of the mineralised ligament, creating the appearance of multiple pseudo-articulations within the ligament. Classification of elongation of styloid process based on type of calcification: Open Access Page 3 of 5 • Type I – Elongated • Type II – Pseudo articulated • Type III – Segmented Classification of elongation of styloid process based on pattern of calcification: • • • • A – Calcified outline B – Partially calcified C – Nodular D – Completely calcified Review Article added advantage of 3-D over 2-D radiographic imaging (conventional radiography) is the elimination of superimposition of anatomic structures and appreciation of soft-tissue changes, which is seldom visible in 2-D radiographic imaging. Barium swallow studies can show the impression of the elongated styloid process as a filling defect.3 Treatment Classification based on angulation: • Narrow • Normal • Wide Diagnosis The preliminary diagnosis of ES is based on a proper medical history and extraoral cum intraoral examination. The elongated styloid process can be felt intraorally by digital palpation. A gentle pressure is exerted using the index finger over the tonsillar fossa; if pain is reproduced or referred to face, head, neck or ear, the presumptive diagnosis of an elongated styloid process is very likely to be present. A styloid process of normal length is usually not palpable. Injection of local anaesthetic into the tonsillar fossa reli (...truncated)