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.
