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CASE REPORT
Stylohyoid Ligament Syndrome –Solving the riddle with 3D
Computed Tomography
Renu Tanwar1, Chandrashekhar L.2, Asha R. Iyengar2 K.S.Nagesh2, Subhash BV2
1 Department of Oral Medicine
and Radiology
SGT Dental College
Budhera, Gurgaon 123505
U.P., India
ABSTRACT
2 Department of Oral Medicine
and Radiology,
D A P M R V Dental College
Bangalore 560078
Karnataka, India
Journal of Dental Sciences and Research
Vol. 2, Issue 2, Pages 1-5
Orofacial pain can be associated with stylohyiod ligament calcification or enlargement of styloid
process. Calcification or ossification of the stylohyoid ligament is infrequent, often incidental
finding on radiographs, however when the source of pain is from the styloid process or calcified
stylohyoid ligaments it is referred to as Eagle's syndrome. This case report discusses the pain
pattern, clinical presentation, radiologic findings of stylohyoid ligament syndrome.
Keywords: Stylohyoid Ligament Syndrome, 3D-CT, Eagle's Syndrome
INTRODUCTION
Pain in the orofacial region can result due to presence of
elongated styloid process unilaterally or bilaterally due
to pressure exerted on various vital structures in the neck
region. In conditions of hemifacial pain of obscure
causation, the oral diagnostician should consider
Stylohyoid syndrome as a possible diagnosis.
Stylohyoid syndrome occurs due to elongation of
stylohyoid process or calcification of stylohyoid
ligament. In such cases, imaging helps in identifying
abnormally elongated styloid process or calcified
stylohyoid ligament. Recent imaging modalities
including three dimensional computed tomography aid
in assessing the length and anatomical relationship of
elongated styloid process with vital structures and for
outlining the plane of incision for surgical treatment.
CASE REPORT
A 32 year old female patient came to the Department of
Oral Medicine and Radiology, with chief complaint of
pain on right side of inside of the mouth since last three
months. She was apparently well three months ago when
she first experienced severe pain in right side of the
mouth on swallowing the food while having dinner. Pain
was of primary incidence, severe in intensity
paraoxysmal in nature and it lasted for two to three
minutes after swallowing ,and radiated towards the right
Address for correspondence:
Dr Renu Tanwar
E-mail: [email protected], [email protected]
Access this article online
Website: http://www.ssdctumkur.org/jdsr.php.
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temporal region and side of the neck below the lower jaw
on the right side. Patient experienced similar episodes of
pain on swallowing and turning the head to the left side at
that time. The patient did not report any change in the
nature of the pain since its first occurence and symptoms
of pain were initiated on turning the head towards left
side. Patient did not gave history of decreased salivation,
dryness of the mouth, trauma in head and neck region or
surgery with respect to the neck or tonsillar region. On
extraoral and intraoral examination no significant
findings were observed. On intraoral palpation, mild
tenderness was observed on bidigital palpation of floor
of the mouth on the posterior side. A provisional
diagnosis of Stylohyoid syndrome was arrived at.
Radiographic examinations included conventional
radiographs such as Mandibular true occlusal view,
Panoramic radiograph, Lateral oblique view of the ramus
of the mandible and advanced imaging as Computed
Tomography of the head and neck including 3D
Computed Tomography.
Panoramic radiograph showed the elongated 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 calcified outline and the left styloid
process showed uninterrupted elongation with nodular
complex pattern of calcification (Figure 1).
The lateral oblique view of of ramus of right side of the
mandible showed elongated styloid process with the tip
of styloid process extending nearly upto the angle of the
mandible on the right side (Figure 2).
Vol. 2, Issue 2, September 2011
Fig. 1: Panoramic radiograph showing enlargement of
styloid process on either sides
Fig. 3: coronal and sagittal sections demonstrating
prominent styloid process
Fig. 2: Lateral oblique view of the ramus of mandible –
right side
three times a day for five days and was referred to oral
surgeon for surgical management.
Computed Tomography was done and volume scans were
performed from skull base down to the level of C6
employing 0.625mm sections. Multiplanar
reconstructions were also performed for 3D
reconstruction (Figure 3 & 4).
The following observations were made :
1) Presence of elongated styloid process were seen
bilaterally.
2) Right styloid process measured 3.9mm.
3) Left styloid process measuerd 4.2mm.
4) No obvious evidence of calcification of stylohyoid
ligament was found on CT images.
Based on Patient's history,clinical and radiological
findings,a final diagnosis of Stylohyoid Syndrome was
arrived at. Patient was advised non steroidal analgesics
DISCUSSION
The stylohyoid chain consists of the styloid process, the
lesser cornu of the hyoid bone and its connecting
ligament. The stylohyoid chain is derived from Second
branchial arch or Hyoid arch known as Reichert's
cartilage. The styloid process is a small, tapering
projection of the temporal bone located anterior to the
stylomastoid foramen..The styloid process lies between
the internal and external carotid arteries, posterior to the
tonsillar fossa and lateral to the pharyngeal wall. The
styloid process has attachments to three muscles and two
ligaments. The stylohyoid ligament itself, extends from
the tip of the styloid process to the lesser cornu of the
hyoid bone. The stylomandibular ligament extends from
the styloid process to the angle of the mandible. The three
muscles include the stylopharyngeous, stylohyoid, and
styloglossus. The nerve supply comes from the
glossopharyngeal, facial, and hypoglossal nerves,
respectively. The internal jugular vein and the accessory,
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hypoglossal, vagus, and glossopharyngeal nerves are
located medial to the styloid process. The
glossopharyngeal nerve emerges from the anterior part
of the jugular foramen, medial to the styloid process,
where it then curves around the posterior border at the
level of the origin of the stylohyoid muscle. This
anatomic relationship is important as a cause of
glossopharyngeal neuralgia in reported cases with an
elongated and ,or fractured styloid process as the
etiologic cause[1] .
In 1937,Eagle proposed that the average length of the
styloid process ranges from 2.5 to 3.0 centimeters[2].
In 1964, Developmental theory was proposed by Lengele
and Dhem3 for the elongation of styloid process based on
morphogenesis of of Reichert's cartilage. According to
them, elongation of styloid process should be
congenital. However it was also agreed by them that
further growth was possible through the cartilaginous
cap of the tip of the styloid process.
Langlais et al4 proposed a radigraphic classification of
elongated and mineralized stylohyoid ligament
complex.This classification was based on types of
elongation and patterns of calcification of stylohyoid
ligament. (Table 1 & 2) (Figure 4).
Because of an elongated styloid process or a calcified
stylohyoid ligament, a patient with Eagle's syndrome
may develop non-specific pain, which may change with
head movements at the ear or neck. Additionally, a
patient with an elongated styloid process may have
referred pain to the jaw joint or upper extremities, or
dysphagia or foreign body-like irritation throughout the
pharynx[5].
There are several different theories, which try to explain
the etiopathology of Eagle's syndrome such as
congenital elongation of the styloid process and
calcification and ossification of the stylohyoid
ligament6. Fini et al. reported that past tonsillectomy is
related to Eagle's syndrome[7].
In differential diagnosis, laryngopharyngeal dysesthesia
has to be considered as well as dental malocclusion,
TABLE 1: MORPHOLOGIC CHARACTERISTICS OF STYLOID PROCESS
TYPES
NOMENCLATURE
RADIOGRAPHIC APPEARANCES
I
ELONGATED
Uninterrupted integrity of styloid image(>25-28mm).
II
PSEUDOARTICULATED
Styloid process is joined to the mineralized stylomandibular
or stylohyoid ligament by a single pseudoarticulation,
usually located superior to inferior border of the mandible.
III
SEGMENTED
Short or long continuous portions of the styloid process or
uninterrupeted segments of mineralized ligament.
TABLE 2 : PATTERNS OF CALCIFICATIONS
PATTERNS
CALCIFIED OUTLINE
Thin radiopaque cortex and a central lucency that constitutes most
of the process.
PARTIALLY CALCIFIED
Thicker radiopaque outline with almost complete opacification as
well as small and occasionally discontinuous radiolucent core.
NODULAR COMPLEX
Knobby or scalloped outline which may be partially calcified with
varying degree of central radiolucency.
COMPLETELY CALCIFIED
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RADIOGRAPHIC APPEARANCES
Totally radiopaque with no evidence of a radiolucent interior.
REFERENCES
1)
Fig. 4: Three dimensional reconstruction demonstrating
enlargement of styoid process on either sides
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[8, 9].
Several imaging modalities have been used for the
diagnosis of Eagle's syndrome thus far, including lateral
head and neck radiograph, Towne radiograph, panoramic
radiograph, lateral-oblique mandible plain film,
anteroposterior head radiograph, and CT. Also, barium
swallow studies can show the indentation of the
elongated styloid process as a filling defect[10] .
Frommer J. Anatomic variations in the stylohyoid chain and
their possible clinical significance. Oral Surg 1974;
38:659–667.
2) Eagle WW.Elongated styloid process :Report of two
cases.Arch Otolaryngol 1937;25:584-587.
3) Lengele B,Dhem A.Microradiographic and histological study
of styloid process of temporal bone.Acta Anat1989;135;193199.
4) L a n g l a i s R P, L a n g l a n d O E , N o r t j e C J . S o f t t i s s u e
radiopacities.Chapter 19. Diagnostic imaging of the
jaws.Philadelphia : A Lea and Febiger.1995. p.617-621 '
5) K.C.Prasad et al, “Elongated styloid process (Eagle's
syndrome): a clinical study,” Journal of Oral and
Maxillofacial Surgery, vol. 60, no. 2, pp. 171–175, 2002..
6) Balbuena L, Hayes D, Ramirez SG, Johnson R. Eagle's
syndrome (elongated styloid process). South Med J 1997;
90:331-334.
7) Fini et al. The long styloid proc- ess syndrome or Eagle's
syndrome J Craniomaxillofac Surg 2000; 28:123-127.
8) Harma R. Stylalgia: clinical experiences of 52 cases. Acta
Otolaryngol 1966; 224:149.
9) Politi M, Toro C, and Tenani G.A Rare Cause for Cervical
Pain: Eagle's Syndrome. International Journal of Dentistry
Volume 2009, Article ID 781297, 1-3.
10) A Savranlar, L Uzun, M Birol Uður, T Özer.Threedimensional CT of Eagle's syndrome. Diagn Interv Radiol
2005; 11:206-209.
11) Chiang C, Liao Y,
Yang W. Three-Dimensional
Reconstruction CT in Diagnosis of Eagle's Syndrome: a
Retrospective Study. Chin J Radiol 2006; 31: 221-225.
12) LEE S K. Eagle's syndrome with 3-D Reconstructed CT:two
cases report .Chin J Radiol 2004; 29: 353-357.
Superimposition of several osseous structures, and
distortion and magnifications secondary to angulations
are the potential disadvantages of conventional
radiographs and, in particular, panoramic films. 3D-CT
images reformatted from the raw data obtained with a
spiral scanner provide all the information about the
styloid process, including its length, direction, and
anatomical relations. 3D-CT is an objective diagnostic
tool to outline the anatomy, tailor the surgical plan, and
offer a detailed explanation to the patients as well.
Another advantage of the 3D-CT images is three
dimensional length measurements, which are impossible
in 2D images[11,12].
In conclusion, 3D-CT is a valuable diagnostic imaging
tool in patients with Eagle's syndrome that allows
clinicians to evaluate the styloid process in spatial
geometry, make accurate length measurements, and
explain the problem in detail to patients, all of which
make this technique superior to conventional imaging
modalities.
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