Stylohyoid Syndrome – Case Series

INTRODUCTION

           The styloid process is a slender, osseous projection derived from the second branchial arch, or Reichart's cartilage.¹ The elongated styloid process can be a source of craniofacial and cervical pain and remains a diagnostic challenge to many.²The symptoms and clinical signs associated with an elongated styloid process (ESP) were first described by Eagle in 1937 and were later called Eagle's syndrome or stylalgia.¹

           The painful symptoms may be related to previous trauma with fracture of styloid process or to previous tonsillectomy.¹ Eagle's syndrome more frequently affects women than men, with a prevalence of 0.04-0.08% whereas 1.5-3.0% of adults have some of complaints due to the pathology of this apparatus.³ The studies in India have estimated that in 19.4-52.1 % of general population there was radiographic evidence of elongated styloid The styloid process is a slender, osseous projection derived from the second branchial arch, or Reichart's cartilage. The normal length of the styloid process ranges from 2 to 4.77 cm; most are less than 3cm process.⁴The aim of this report is to describe 8 cases with the diagnosis of Eagle's syndrome without previous history of tonsillectomy who visited our institute and were treated.

CASE REPORT

           The patient demographics included eight patients with Eagles syndrome treated in the Department of Oral and Maxillofacial Surgery, of 21-50 years of age (Table 1). Six patients were males and all had complaint of pain in throat and difficulty in swallowing. The mean onset of symptoms varied from 8-84 months prior to diagnosis. The physical examination of tonsillar fossa revealed tender swelling. (Figure 1)

The radiological investigations incuded Orthopantamogram, Lateral radiograph, Skull –AP view, Towne & Reverse Towne projections wherein the stylohyoid ligament was visualized on the posterior aspect of right mandibular ramus and angle of mandible running superiorly from the styloid process to the lesser cornu of hyoid bone. The elongated styloidprocess was classified as type I, II or III on basis of Langlai's et al classification. (Figure 2 & Figure 3)

           Surgical resection of the styloid process was performed through an intraoral approach using a Gigli saw in seven patients and extraoral approach in one case. All the patient were discharged the next day. On follow-up, the patients reported complete resolution of their symptoms. (Figure 6)

RESULTS

           None of the patients had previous history of tonsillectomy. All the patients presentedwith pain in throat and difficulty in swallowing. One patient did not have any palpable neck mass nor referred otalgia. The average lengths of the styloid process were 3cm. (Figure 4)

           In the present case series except one, all patients had unilateral elongation of styloid process. Two patients had Langlai's type 3 pattern while remaining six patients had Langlai's type 1 pattern. Histopathological examination of specimen of all cases revealed compact bone with areas of endochondral ossification (Figure 5A & B) except one case where bundles of collagen fibres with flecks of calcification were noted. (Table 2)

DISCUSSION

           The origin of the styloid process is from three of the four separate centres of development of Reicharts cartilage of second branchial arch ie the tympanohyal which gives rise to base of styloid process, the stylohyal which gives rise to styloid shaft and ceratohyal which gives rise to two ligaments stylohyoid and stylomandibular.^{5, 6}Embryologically, ESP may be caused by increased calcification of the stylohyal, which results in the long body of the styloid process. Furthermore, the ceratohyal and/or the stylohyoid ligament may become ossified due to their embryologic potential to differentiate into the epihyal bone or in response to trauma.⁵

Other theories for stylohyoid elongation that have been proposed include

1) Congenital elongation,

2) Elongation at the cartilaginous junction of the tympanohyale and stylohyoid, which may occur due to a delay in ossification,

3) Status post-trauma as a result of reactive hyperplasia,

4) Association with early onset of menopause.^1,2,7

     Originally Watt W. Eagle (1937) an otorhinolary ngologist presented two possible outcomes of the Elongated Styloid Process

     a) Classical (stylohyoid) syndrome: almost always following tonsillectomy, dull & persistent pharyngodynia, dysphagia and odynophagia, facial/cervical pain.^6,8

     b) Stylohyoid syndrome/Carotid artery syndrome is a form of carotidynia, which arises due to compression of internal/external carotid arteries by the styloid apparatus. It is characterized by cervical pain arising when internal carotid artery is compressed, provoked and aggravated by rotation and compression of neck, radiating to the supraorbital and parietal region.⁹If external carotid artery is irritated / impinged, pain radiates to the infraorbital region, temporal and mastoid regions.^5,6,10

           However the mere presence of an elongated process or mineralization of the stylohyoid complex radiographically in the presence of cervicopharyngeal pain does not confirm the diagnosis of Eagle's syndrome. The reasons are three fold. 

• Many patients with an ossified stylohyoid complex are asymptomatic
• No correlation between the severity of pain and the extent of ossification of the stylohyoid complex. ^5,11
• The majority of the symptomatic patients have had no recent history of tonsillectomy or any other cervicopharyngeal trauma.^{5, 11}

           None of the patients in the present study had previous history of tonsillectomy. Only a small minority of ESP cases were symptomatic. The elongation of styloid process is frequently bilateral. However, unilateral ESP when seen is more common in women in middle age than men. Several studies have concluded that there is a variation in length of stylohyoid ligament complex and this varies from individual to individual.⁷In the present study only one patient presented with had bilateral ESP.

           In Eagle's syndrome, an abnormally long styloid process or ossified stylohyoid ligament produces pharyngeal pain, otalgia, odynophagia, and dysphagia exacerbated by swallowing.²Some patients may complain of dysphagia or globus hystericus.⁹

           Proper diagnosis of Eagle's syndrome is therefore critical to the treatment. Reproduction of the patient's pain on palpation of the tonsil or tonsillar fossa and relief of this discomfort by injection of local anesthetic are diagnostic.²

           Mineralization of the stylohyoid ligament may occur in various sites along its course and may be visualized on panoramic radiographs. Pseudoarticu lations may form which are related to the embryological development of this ligament. The radiographic classification system of Langlai'sincludes three types of radiographic appearances.^4,11

• The Type I pattern represents an uninterrupted, elongated styloid process
• Type II is characterized by the styloid process apparently being joined to the stylohyoid ligament by a single pseudoarticulation. This gives the appearance of an articulated elongated styloid process and is the type present in our patient
• Type III consists of interrupted segments of the mineralized ligament, creating the appearance of multiple pseudoarticulations within the ligament

           The differential diagnosis of Eagle's syndrome includes Cranial nerve neuralgia, such as that involving the Trigeminal, Glossopharyngeal, Superior laryngeal, and Primary geniculate ganglion, Tempromandibular joint diseases and Chronicpharyngotonsilitis.

           Unerupted or Impacted molar teeth, Improper fitting dentures, and pharyngeal & tongue base tumors may cause referred pain similar to that produced by an elongated styloid process.^5,6 In pediatric patient, neck pain must warrant an appropriate evaluation for any evidence of neck masses, including Congenital cysts, and Neoplastic process of benign or malignant origin, such as Lipoma, Fibroma, Liposarcoma, and Fibrosarcoma.⁹

           Non surgical treatment by infiltration of steroidal drugs and local anaesthetics⁵ as suggested by Evans and Clainnont do not have satisfactory long term results. Styloidectomy is the treatment of choice. It can be performed transorally which was introduced by Eagle or by an extraoral approach described by Loeser and Caldwell.

           Transoralstyloidectomyhas been preferred; the advantage of this method is brevity and the absence of cervical scar. The disadvantages are poor visibility leading to iatrogenic injury to neurovascular structures. ^5,6,10

CONCLUSION

           By evaluating the eight cases of ESP that have reported to our out-patient department, we have observed that investigations of styloid process are rarely included, in clinical examinations of patients with Orofacial pain and mandibular dysfunction.

           Medical and Dental physicians should be educated to include ESP, as a differential diagnosis and to consider its possibility in these cases of Orofacial pain.

ACKNOWLEDGMENT

The authors wish to acknowledge the support extended by Mrs. Dorothy Anita, Senior Technician, Vydehi Institute of Dental Sciences and Ms. Priyadarshini, Junior Technician, Vydehi Institute of Dental Sciences.