|Year : 2012 | Volume
| Issue : 4 | Page : 275-278
Calcified stylohyoid ligaments: A diagnostic dilemma
Atul Kaushik1, Renu Tanwar1, Payal Garg1, Monika Kaushik2, Rajneesh Panwar3, Shobhit Garg3
1 Department of Oral Medicine, Diagnosis and Radiology, SGT Dental College and Hospital, Farukh Nagar Road, Gurgaon, India
2 Meenakshi's Innovative Dentistree, 1217, Sector21, Gurgaon, India
3 Department of Radiodiagnosis, Medicity Hospital, Gurgaon, Haryana; Mata Channan Devi Hospital, Janakpuri, New Delhi, India
|Date of Web Publication||12-Jul-2013|
Meenakshi's Innovative Dentistree, 1217, Near Shopping Complex, Sector 21, Gurgaon, Haryana
Calcification or ossification of elongated stylohyoid ligaments is often an incidental finding on radiographs. Abnormal elongation of the styloid process may cause compression of a number of vital nerves and vessels related to it and these symptoms may be confused with other causes of head and neck pain. The diagnosis is often difficult as a result of the vague symptomatology. This paper discusses the pain patterns, clinical presentation, radiologic findings and treatment of elongated calcified stylohyoid ligaments.
Keywords: Calcified stylohyoid complex, stylohyoid ligament syndrome, eagles syndrome, referred pain eagles syndrome, referred pain, stylohyoid ligament syndrome
|How to cite this article:|
Kaushik A, Tanwar R, Garg P, Kaushik M, Panwar R, Garg S. Calcified stylohyoid ligaments: A diagnostic dilemma. SRM J Res Dent Sci 2012;3:275-8
|How to cite this URL:|
Kaushik A, Tanwar R, Garg P, Kaushik M, Panwar R, Garg S. Calcified stylohyoid ligaments: A diagnostic dilemma. SRM J Res Dent Sci [serial online] 2012 [cited 2019 Sep 20];3:275-8. Available from: http://www.srmjrds.in/text.asp?2012/3/4/275/114976
| Introduction|| |
The stylohyoid ligament is a fibrous cord stretched between the tip of the styloid process of the temporal bone and the lesser horn of the hyoid bone. The styloid process together with the stylohyoid ligament is referred as the stylohyoid complex.  Ossification of the stylohyoid complex usually extends downward from the base of the skull bilaterally and may compress a number of vital structures adjacent to it, producing inflammatory changes that include continuous chronic pain in the pharyngeal region, radiating otalgia, phantom foreign body sensation and dysphagia.  Various conditions associated with symptomatic ossification of the stylohyoid ligament include Eagle's syndrome, stylohyoid syndrome and stylohyoid chain ossification. However the diagnosis is often difficult as a result of the overlapping features and vague symptomatology.  Awareness of these conditions is important to all health practitioners involved in the diagnosis and treatment of neck and head pain. The aim of this paper is to describe the morphological appearance, clinical presentation, pain patterns, radiologic findings and management of elongated calcified stylohyoid ligaments.
| Case Reports|| |
A 32 year old female patient reported the dental clinic/OPD with complaint of pain in the right side of the neck on swallowing food since last three months. Pain was Pain was noticed for the first time three months back, moderate in intensity, paroxysmal in nature, lasted for few minutes after swallowing food and radiated towards the right temporal region and right side of the neck below the angle of mandible. Patient experienced similar episodes of pain on turning the head to the left side. There was no history of any trauma or surgery in the head and neck region. Patient's medical history was not significant. Extra oral examination revealed bilateral symmetry of the face. Palpation of the upper part of the tonsillar fossae was performed intra-orally using gloved fingers. A blunt bony elevation was felt in both the sides on palpation. The right tonsillar fossa was injected with 1 ml of 2% lidocaine and the symptoms subsided on local anaesthesia. A provisional diagnosis of Stylohyoid syndrome was arrived at. Radiographic examination for the patient included panoramic radiograph and advanced imaging like computed tomography of skull base and 3 dimensional (3D) reconstruction. Panoramic radiograph revealed elongated calcified styloid processes bilaterally, with the right styloid process measuring 37 mm and the left styloid process measuring 38 mm. The right styloid process showed uninterrupted elongation with completely calcified outline and the left styloid process showed uninterrupted elongation with nodular pattern of calcification [Figure 1]. Computed tomographic volume scans were performed from skull base down to the level of C6 employing 0.625 mm sections. Multiplanar reconstructions were also performed for 3D reconstruction which revealed elongated calcified styloid processes bilaterally [Figure 2]. Based on patient's history, clinical and radiological findings, a final diagnosis of Stylohyoid syndrome was arrived at. Patient was advised non steroidal analgesics three times a day for five days and was referred to the team comprising oral surgeons and otorhinolaryngologists for styloidectomy. The patient was kept under regular follow up for a period of 2 years post styloidectomy and the patient was free of any symptom.
|Figure 1: Panoramic radiograph showing elongated calcified styloid process bilaterally (white arrows)|
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|Figure 2: Computed tomographic three dimensional reconstruction images demonstrating enlargement of styoid process bilaterally (white arrows)|
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A 58 year old male patient reported the dental clinic with complaint of pain in the right side of the jaws on chewing and swallowing food for last one year. Pain was mild, dull, intermittent, lasted for few minutes after swallowing and radiated towards the right side of the neck below and behind the angle of mandible. Patient's medical history was non-contributory. Past dental history revealed that the patient had undergone extraction of grossly decayed 48 from a local dentist one year back. The post extraction period was eventful and the patient developed pain on chewing and swallowing food for last one year. Extra oral examination revealed bilateral symmetry of the face. Intra-orally fixed partial dentures were present in relation to upper left back and lower right back teeth. Multiple decayed teeth and generalized periodontal pockets were present. Extraction socket of 48 was healed. A provisional diagnosis of chronic generalized periodontitis was arrived at.
Panoramic radiograph was advised for the patient which who revealed generalized horizontal bone loss and root stumps of 48. An incidental finding was elongated ossified styloid processes bilaterally, with the right styloid process measuring 48 mm and the left styloid process measuring 42 mm. Both the right and left styloid processes showed uninterrupted elongation with calcified outline [Figure 3]. Palpation of the upper part of the tonsillar fossae was performed bilaterally using gloved fingers. A blunt bony elevation was felt in the right side and a sharp prick in the left side on palpation. The right tonsillar fossa was injected with 1 ml of 2% lidocaine and the symptoms subsided on local anaesthesia.
|Figure 3: Panoramic radiograph showing elongated ossified styloid process bilaterally (white arrows)|
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Based on patient's history of traumatic extraction in relation to 48, clinical and radiological findings, a final diagnosis of Eagles syndrome was arrived at. Patient was advised non steroidal analgesics three times a day for five days. Extraction of 48 root stump was done under local anesthesia and the patient was referred to the team comprising oral surgeons and otorhinolaryngologists for styloidectomy.
The patient was kept under regular follow up for a period of 2 years post styloidectomy and the post surgical period was uneventful.
A 45 year old female reported to the dental department with the complaint of swelling in upper half of right side of face since last 1 year, which is gradually increasing in size. Her past medical history and general physical examination was non-contributory. Extra-oral examination revealed a diffuse swelling on right side of face extending antero-posteriorly from a line through pupil of eye to a line passing 1 cm beyond the lateral canthus of eye and superoinferiorly from infraorbital rim to ala-tragus line. Swelling was firm in consistency with mild tenderness towards the inferior portion of swelling. An intra-oral examination revealed presence of swelling on the hard palate and causing obliteration of the right maxillary vestibule. Maxillary right premolars were grossly decayed.
Panoramic radiograph of the patient revealed a well defined radiolucent lesion with corticated borders extending from periapex of 13 to mesial aspect of 18. The lesion had caused displacement of floor of right maxillary sinus. An incidental finding was elongated and ossified styloid processes bilaterally. The right side styloid process was measuring 36 mm and left side styloid process was measuring 20 mm. Both the right and left styloid processes showed uninterrupted elongation with complete calcification [Figure 4]. The patient was asymptomatic without any history of nagging to intense pain in the pharynx on swallowing, turning the head or opening the mouth. No tenderness was noted on palpation of the tonsillar fossae. Based on patient's clinical and radiographic findings, the final diagnosis of radicular cyst in relation to carious maxillary right premolars.
|Figure 4: Panoramic radiograph showing elongated ossified styloid process bilaterally (white arrows)|
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| Discussion|| |
The stylohyoid chain components are derived embryologically from the first and second branchial arches in four distinct segments. These segments are derived from Reichert's cartilages that ossify in two parts - the styloid process and the lesser horn of the hyoid bone. Connecting these two structures is the stylohyoid ligament. The styloid process together with the stylohyoid ligament is referred as the stylohyoid complex. 
In 1937, Eagle proposed that the average length of the styloid process ranges from 2.5- to 3.0 centimeters.  The length of the styloid process has been defined in various studies from radiographs or 3-Dthree-dimension computed tomography. If the length of the process or the mineralized part of ligaments appears 30 mm or more in radiographs, this can be considered an elongated styloid process. Length in combination with increased acuity in deviation from the norm both anteriorly and medially is a risk factor. Langlais et al. proposed a radiographic classification of elongated and mineralized stylohyoid ligament complex. This classification was based on types of elongation and patterns of calcification of stylohyoid ligament.  Actual causes of styloid process elongation is poorly understood although several theories have been proposed like congenital elongation due to persistence of a cartilaginous analog of stylohyal, calcification of the stylohyoid ligament by an unknown process and growth of osseous tissue at the insertion of the stylohyoid ligament. 
Many important anatomical structures are in close proximity to the styloid process and the stylohyoid ligament. It is therefore worth studying the variability of these structures and analyzsing the possible effects of an ossified stylohyoid complex. The styloid process has attachments to two ligaments - stylohyoid ligament and stylomandibular ligament and three muscles - stylopharyngeous, stylohyoid, and styloglossus. The nerve supply comes from the glossopharyngeal, facial, and hypoglossal nerves, respectively. The internal carotid artery, the internal jugular vein and the accessory and vagus nerves lie medially. The external carotid artery runs laterally to the stylohyoid ligament. The elongated styloid process and the ossified stylohyoid ligament can compress some of these structures, leading to mild or severe clinical symptoms.  The pathophysiological mechanism of these symptoms is not very clear. The following theories have been proposed including traumatic fracture of styloid causing proliferation of granulation tissue, which compresses the adjacent structures, compression of adjacent nerves, stylohyoid insertion tendonitis, irritation of pharyngeal mucosa by direct compression or post tonsillectomy scarring, impingement of carotid vessels, producing irritation of sympathetic nerves in the arterial sheath. 
Even when extensive ossification of one or both stylohyoid ligaments is seen, more than 50% of patients are clinically asymptomatic as seen in the 3 rd case report. Very little correlation exists between the extent of ossification and the intensity of the accompanying symptoms. One symptom is vague, nagging to intense pain in the pharynx on swallowing, turning the head, or opening the mouth, especially on yawning. When this entity is associated with discomfort and the patient has a recent history of neck trauma, the condition is called Eagle's syndrome as diagnosed in the 2 nd case report. The elongated styloid process and local scar tissue probably causes symptoms by impinging on the glossopharyngeal nerve. Similar clinical findings without a history of neck trauma constitute stylohyoid (carotid artery) syndrome as diagnosed in the 1 st case report. The patient may describe attacks of otalgia, tinnitus, temporal headache, and vertigo or transient syncope. In these patients, pain is produced by mechanical irritation of sympathetic nerve tissue in the arterial wall, producing regional carotidynia. These individuals usually are over 40 years of age. This condition is more prevalent than Eagle›s syndrome.  In differential diagnosis, laryngopharyngeal dysesthesia has to be considered as well as dental malocclusion, neuralgia of sphenopalatine ganglia, temporomandibular arthritis, glossopharyngeal and trigeminal neuralgia, chronic tonsillo-pharyngitis, hyoid bursitis, Sluder's syndrome, histamine cephalgia, cluster type headache, esophageal diverticula, temporal arteritis, cervical vertebral arthritis, benign or malign neoplasms and migraine type headache. 
Several imaging modalities have been used for the diagnosis of Eagle's syndrome. The conventional radiographs include lateral head and neck radiograph, Towne radiograph, panoramic radiograph, lateral-oblique mandible plain film and anteroposterior head radiograph. Superimposition of several osseous structures, and distortion and magnifications secondary to angulations are the potential disadvantages of conventional radiographs. Currently, 3D spiral CT is the most advanced diagnostic imaging technique to evaluate the stylohyoid chain in spatial geometry, with accurate length measurements. The detailed information about the course and relations of the stylohyoid chain and the relation of important adjacent anatomic structures also allows pre-operative planning, thereby reducing the potential for iatrogenic intra-operative injury. 
Injection of local anaesthetic into the tonsillar fossa relieves pain. Treatment is mainly surgical, where the elongated styloid process is shortened by trans-tonsillar or by external approach. Injection of steroid into the lower tonsillar fossa is advised for patients unfit for surgery. Eagle initially described tonsillo-styloidectomy by the intraoral route, where a trans-pharyngeal approach was used to extract the styloid process after tonsillectomy. 
| Conclusion|| |
In patients presenting with symptoms in the throat with associated headaches or facial pain, a thorough detailed case history and physical examination of the head and neck are mandatory. An awareness of pain syndromes related to the styloid process is important to all health practitioners involved in the diagnosis and treatment of neck and head pain.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]