mise à jour du
15 février 2009
Int J Oral Maxillofac Surg
  TMJ Disorders
A Report of Post-Traumatic Eagle's Syndrome
A. Klecha, H. Hafian, B. Devauchelle, B. Lefevre
Bâillements et stomatologie - Yawning and stomatology


eagle syndrome
The occurrence of pharyngeal and facial symptoms caused by a styloid process (SP) of abnormal length and/or orienta- tion was observed in 1937 by W Watt Eagle.
Pain in the throat referred to the ear and a sensation of a foreign body especially on swallowing are the main symptoms. He reported that pain could be stimulated by talking, and that a distortion of taste and gagging could be present. Since Eagle's seminal work, new pain locations (neck, tongue, submandibular region, shoulder, teeth), new triggering circumstances (neck move- ment, mouth opening, yawning, drinking hot or cold liquids or sodas), and new symptoms (dysphonia, facial and pharyngeal paresthesia, hypersalivation, syncopal events and eye scintillation) have been reported.
The frequency of ossification of the styloid chain (SP, stylohyoid ligament and greater horn of the hyoid bone) (SC) has been found to vary from 4% to 30% and to be mostly asymptomatic. Eagle estimated the frequency of symptoms in patients presenting an elongated SP3 to 4%. The etiology of the anatomical anomaly is unknown. The main hypotheses to explain the ossification of the SC rely on heredity, embryology and metaplasia.
In some cases of Eagle's Syndrome symptoms occur without identifiable etiol- ogy. Theories on the symptoms' pathogenesis involve degenerative transformations due to repetitive mechanical stress and the ageing process. Tonsillectomy and neck trauma with fracture of the SP or of an ossified stylohyoid ligament (SHL) are recorded as starting events. A case of Eagle's Syndrome caused by neck trauma without observable injury to the SC is reported here. The clinical features involved an unusual symptom mimicking osteoarthrosis of the temporomandibular joint (TMJ).
Case Report A 39-year-old woman was referred to the authors' dental department for pain in the right TMJ that had started after a car accident 3 months before the visit. The whiplash had caused a sprain of the neck at the level of C5 and pain in the TMJ area. The patient had been treated for 7 weeks by wearing a collar, given analgesics and muscle relaxants and physical therapy. The neck pain subsided, but the pain in the TMJ area persisted. The patient then consulted the maxillofacial surgery department of the hospital and received a prescription for non steroid anti-inflammatory drugs and opiate analgesic drugs; these were unsuccessful. An orthopantomogram (OPT) was performed.
At the first visit to the dental depart- ment, the history of her symptoms was recorded and a clinical examination performed. The onset of the TMJ area pain had happened immediately after the accident. The patient located the pain in the throat, behind the ear and above the TMJ. Although the patient indicated the site of the pain with her fingers on her skin, the pain was not felt superficially. The pain sometimes radiated to the right shoulder with a sensation of electricity and to the submandibular region, and was dull, permanent, causing insomnia, and exacerbated by swallowing, masticating and opening the mouth beyond a certain range (singing and yawning).
Swallowing was accompanied by the sensation of being skinned by some sort of spike. Three weeks after the accident, the patient had experienced an acute exacerbation of the pain as she was turn- ing to switch a button. At the same time, she experienced a sensation of 'cracking' behind the right ear. A few days later, the pain returned to its previous intensity and remained unchanged. After this event, the patient felt in the same location as the source of pain, a sensation she described as 'gravel' during mouth opening and chewing.
Clinical examination of mandibular motion, both TMJ and masticatory musculature were unremarkable except a slight tenderness to palpation of the right deep masseter, which was different from the patient's chief complaint. The pain could be triggered by clenching the teeth and extension of the neck. Occlusal exam- ination revealed significant wear of the anterior teeth due to bruxism. Examination of the OPT revealed bilateral ossification of SHLs. A computerised tomography (CT) scan was performed, which showed that both SHLs were composed of multiple non- jointed mineralized segments from the tip of the SP to the extremity of the lesser cornu of the hyoid bone.
No difference could be noted between the right and left ligaments. Owing to the tenderness of the right masseter, and the evidence of past or current bruxism, it was decided to test this etiological hypothesis. Muscle relaxant treatment, nocturnal occlusal splint therapy and physical therapy of mandibular movements were successively performed, unsuccessfully. Diagnosis of Eagle's Syn- drome was then assumed and the patient underwent an operation. The right SP and a portion of the right SHL were removed through an extra-oral approach. The total length of the resection was 2.5 inches. The patient experienced complete relief of her initial symptoms a few days following surgery, and was still free of symptoms at a three and a half year follow-up. Discussion Misdiagnosing Eagle's Syndrome as a TMD is not uncommon in the literature.
The role of trauma was misidentified in the present study; whiplash may cause symptoms consistent with TMD. The sensation of 'gravel' that occurred during functional activities had never been reported before. This symptom can be interpreted as crepitation and lead to a misdiagnosis of osteoarthrosis of the TMJ. Eagle reported a sensation of foreign body like 'metallic substances'. GODDEN et al. related a case of very loud clicking related to a pseu- doarticulated SHL that occurred when swallowing and mouth opening.
The apparent location of pain in pre- auricular and temporal areas and func- tional activities that exacerbate pain are common characteristics of TMD. The correct diagnosis relied on the examiner understanding the exact loca- tion of the gravel sensation and pain through clinical interview. Pain on swallowing, which is unusual in TMD, and the foreign body sensation are important clinical findings for differen- tial diagnosis with TMD. This is note- worthy in cases where Eagle's Syndrome and TMD co-occur. Palpation of the tonsillar fossa has been strongly suggested as a diagnostic test to confirm Eagle's Syndrome by triggering the pain and leading to the perception of the anatomic anomaly as a firm mass.
Intraoral palpation can fail to induce pain or to perceive the anatomic anom- aly, which is obvious on OPT. The chief complaint of the patient and the characteristics of pain should be the determining information for diagnosis of Eagle's Syndrome. The present study demonstrates that neck trauma can lead to Eagle's Syndrome in the absence of an observable lesion of the ossified SC. The certainty of the causal relationship was established through the patient's history, with symptoms arising immediately after the accident. Injury to the SHL and the adjacent structures are thought to be routine consequences of whiplash, and might lead to referred pain to the subauricular and mastoid area. In the case of an ossified ligament, which is a hard structure, painful symptoms might be exacerbated or maintained through mechanical irritation of nervous, muscular and vascular nearby elements.
Fibrous or cartilaginous unions have been identified between the segments of ossified SHL in an anatomical study; such unions, if injured may lead to painful symptoms. Thorough interviewing of the patient is crucial in the diagnosis of Eagle's syndrome. Rheumatologists and orthopaedic specialists and physiatrists should be aware that Eagle's Syndrome is a possible consequence of whiplash, even if no lesion of the SC is observed radiologically. Dental practitioners should consider the po sibility of Eagle's Syndrome and examine SC on OPT and search for pain on swallowing whenever patients report post-traumatic orofacial pain or articular sound- like sensations.