Exodontia.Info
Eagle Syndrome
(Stylohyoid Syndrome /
Styloid Syndrome /
Styloid-Stylohyoid Syndrome &
Styloid–Carotid Artery Syndrome)
Useful Websites:

Wikipedia

Radiopaedia.org

Radiopaedia.org


Useful Articles:

AJR 1983.  The Eagle Syndrome

Austral Dent J 1997.  Eagle’s Syndrome Masquerading as Pain of Dental Origin.
Case Report

BDJ 1999.  Eagle’s Syndrome - An Unusual Cause of a Clicking Jaw

JCCA 2003.  Eagle’s Syndrome - A Case of Symptomatic Calcification of the
Stylohyoid Ligaments

Stomatologija Baltic Dent & Maxillofac J 2004.  Clinic, Diagnostics & Treatment
Peculiarities of Eagle’s Syndrome

Diagn Interv Radiol 2005.  Three-Dimensional CT of Eagle’s Syndrome

JOMS 2007.  Styloid-Stylohyoid Syndrome (Eagle's Syndrome).  Literature Review
& Case Report

Eur Rev Med & Pharmacol Sci 2008.  Atypical Chronic Head & Neck Pain - Don’t
Forget Eagle’s Syndrome

JOMS 2010.  Eagle’s Syndrome - A Novel Surgical Approach to the Styloid
Process Using a Preauricular Incision

OHDMBSC 2010.  Case Report of a 27-Year-Old Patient Suffering From Eagle’s
Syndrome

Saudi Dent J 2011.  Case Report.  Eagle’s Syndrome – A Case Report & Review
of the Literature

Int Arch Otorhinolaryngol 2013.  Case Report.  Eagle’s Syndrome
Last Updated 7th October 2015
What is Eagle Syndrome?

Eagle syndrome (ES) represents symptoms brought on by
compression of regional structures by elongation of the
styloid process or ossification (calcification) of the
stylo-
hyoid / stylo-mandibular ligaments.

Patients with
ES may present with a sore throat, ear pain,
or even with
foreign body symptoms in the pharynx
secondary to
pharyngeal & cervical nerve interactions.

Since the symptoms are variable and non-specific, patients
seek treatment in several different clinics such as
Ear, Nose
& Throat
, GP's, Neurology, Neurosurgery, Psychiatry, and
the last but not the least
Dentistry / Oral & Maxillofacial
Surgery
.

It was described in 1937 by Watt Eagle.
Anatomical Structures in the Neck involved in Eagle Syndrome
What are the Signs & Symptoms of Eagle Syndrome?

Depending on the underlying pathogenetic mechanism and the anatomical
structures compressed or irritated by the
styloid process, symptoms vary greatly,
ranging from
cervico-facial pain to cerebral ischæmia.

Clinical presentation is varied and establishing a causative relationship between the
styloid process / stylohyoid ligament and symptoms can be challenging.

The syndrome can be divided into 2 main subtypes:

  1. due to compression of cranial nerves (Trigeminal, Facial, Glossopharyngeal,
    & Vagus nerves) &
  2. due to compression of carotid artery


Cranial Nerve Impingement

Patients can have symptoms related to compression and irritation of cranial nerves
in the region (
cranial nerves V, VII, IX and X) such as:

  • facial pain while turning the head
  • facial paræsthesia (numbness)
  • dysphagia (problems swallowing)
  • foreign body sensation (globus hystericus)
  • pain on extending tongue
  • change in voice (lasting for only a few minutes)
  • sensation of hypersalivation
  • tinnitus or otalgia

On palpation of the styloid process tip, symptoms should ideally be exacerbated.

(Carotid) Arterial Impingement

Compression of the Carotid Artery may also produce vascular / ischæmic
symptoms as well as pain along the artery to the supplied territory (thought to be
mediated by the
[ortho-]sympathetic plexus) including:

  • mechanical compression such as visual symptoms, syncope (fainting) &
    carotid dissection
  • (ortho-) sympathetic plexus irritation (carotidynia) such as eye pain & parietal
    pain


What are the Causes of Eagle Syndrome?

In most cases, the cause is not known however the condition is sometimes
associated with disorders causing
heterotopic calcification / ossification such as
abnormal
Calcium-Phosphorus metabolism and chronic renal failure.

The cause of onset of pain in patients previously free of symptoms is unknown, but
several mechanisms have been proposed that include:

  • rheumatic styloiditis caused by pharyngeal infections
  • trauma
  • tonsillectomy, and
  • involutional changes associated with ageing (e.g., degenerative cervical
    discopathy, which may shorten the cervical spine and alter the direction of the
    styloid process).

The
patho-physiological mechanisms for the pain of ES include:

  • 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 & results in
    pain
  • Impingement on the carotid vessels by the styloid process, producing irritation
    of the sympathetic nerves in the carotid arterial sheath
  • Degenerative & inflammatory changes in the tendonous portion of the
    stylohyoid insertion (insertion tendinosis)
  • Irritation of the pharyngeal mucosa by direct compression by the styloid
    process
  • Stretching & fibrosis involving the V, VII, IX & X cranial nerves


The mere presence of an elongated styloid process or mineralisation of the
stylohyoid complex radiographically in the presence of cervico-pharyngeal pain
does not automatically confirm a diagnosis of
ES.

There are reasons from 3 aspects.

1.        Many patients with an
ossified stylohyoid complex are asymptomatic.
2.        There does not appear to be any correlation between the severity of pain &
the extent of
ossification of the stylohyoid complex.
3.        The majority of symptomatic patients have had no recent history of surgery
(such as a tonsillectomy) or any other
cervico-pharyngeal trauma.


Who does it affect?

ES is a rare disease.  0.04 - 0.08% of population suffers from ES, whereas 1.5 –
3.0 % of adults have some of the complaints due to the pathology of the
styloid
apparatus
.

ES occurs mainly in 30 - 50-year-old patients as regional ligaments & the soft
tissues of the
styloid process become less elastic with age & offer more
resistance to surrounding hard tissue structures. However, it has also been
reported in children.


Do I need any special tests?

The diagnosis of ES must be based on a good medical history & physical
examination.

It should be possible to feel an elongated
styloid process by careful intra-oral
palpation, placing the index finger in the tonsillar fossa and applying gentle
pressure.

If pain is reproduced by palpation & either referred to the ear, face or head, the
diagnosis of an elongated
styloid process is very likely.  A styloid process of
normal length is usually not palpable.  Injection of local anaesthetic into tonsillar
fossa relives pain and can be used as a diagnostic tool.

The diagnosis of
ES can be ascertained with imaging which includes lateral head
and
neck radiographs, Towne radiograph, OPG, lateral-oblique mandible plain
film
etc.

Radiographic Features

The normal length of the adult styloid in an adult thought to be approximately 2.5
cm while an elongated
styloid is considered > 3 cm. If this definition is used, ~4%
of the population have an elongated process, however only a small proportion of
them (4 - 10%) are symptomatic.  Elongation can be
unilateral or bilateral.

When mechanical vascular compression is potentially the cause of
ischæmic
symptoms that
angiographic examination (CT angiography / catheter
angiography
) obtained with the patient's head positioned to reproduce symptoms
may demonstrate mechanical
stenosis of the carotid artery.

Imaging only demonstrates elongation of the
styloid process and proximity to
surrounding key structures.  The diagnosis of
ES is based on multiple clinical and
radiographic factors.
How is it treated?

In many cases, once the cause of pain has been attributed to the styloid process
rather than a more sinister entity, no further treatment is required, perhaps
supplemented with analgesics.

  • Trans-pharyngeal injection of steroids / local anæsthetics.  Use of LA can be
    used as a confirmatory procedure.
  • Anti-epileptic preparations. Carbamazepine (600mg - 800mg / day) for 2 - 3
    weeks
  • Anti-histamines
  • Application of heat
  • Traditional Chinese medicines
  • Trans-pharyngeal manipulation with manual fracturing of the styloid process
  • The supporting component consists of the medicaments widening the blood
    vessels, neuroleptics, antidepressants & tranquilizers.

The most satisfactory & effective treatment is surgical shortening of the
styloid
process
through either an intra-oral or extra-oral approach.

The most significant advantage of an external approach is enhanced exposure of
the styloid process & the adjacent structures & this outweighs all other
considerations. It also facilitates the resection of a partially
ossified stylohyoid
ligament
. Trans-oral resection causes no outside scars, but involves the risk of
deep cervical infection & possible neuro-vascular injury.  Persistent pain even
after surgical excision may be as high as 20%.

Prognosis of
ES is guarded by surgical failures (up to 20% of patients). This may
be due to intra-operative injury, subsequent
fibrous entrapment syndrome or
inadequate shortening of the
styloid process, assuming that the diagnosis was
correct in the first place.


Differential Diagnosis

A differential diagnosis of ES should include:

•        
laryngo-pharyngeal dysæsthesia
•        trigeminal / glossopharyngeal neuralgia, neuralgia of sphenopalatine
ganglia
•        TMJ disorders, temporomandibular arthritis, cervical vertebral arthritis,
temporal arteritis
•        temporal rachitis
•        chronic tonsillo-pharyngitis
•        hyoid bursitis, Sluder’s syndrome, histamine cephalgia
•        esophageal diverticula
•        benign or malign neoplasms
•        cluster type headache, migraine type headache
•        dental malocclusion, unerupted or impacted molar teeth & faulty dental
prostheses
OPG showing bilateral calcified styloid processes
styloid processes (below)
CT showing bilateral calcified styloid processes & ligaments (below)