OMS TMJ

Question 1

Name the two descriptive categories of TMJ disorders. Which is most common?

Answer 1

Extra-articular disorders and intra-articular disorders. Extra-articular disorders are far more common.

Question 2

Contrast the findings in TMJ osteoarthritis and TMJ synovitis.

Answer 2

Osteoarthritis is a degenerative disease in the TMJ, as it is in
other joints in the body. It is caused by a loss of articulating tissues and can be described as a mechanical,
noninflammatory disease with bone-on-bone contact. By
contrast, TMJ synovitis is definable by its inflammatory nature. Inflammatory mediators may accumulate secondary to trauma, disk malfunction, or parafunctional habits.

Question 3

What is the best imaging modality for the TMJ?

Answer 3

Disk displacement and internal derangement of the TMJ are
best imaged using MRI. Bony diseases such as ankylosis or degenerative joint disease are best evaluated using CT.
Panorex may be used as to screen for fracture, condylar
resorption, or large pathology.

Question 4

How is TMJ internal derangement classified?

Answer 4

The Wilkes classification
● Stage 1: Asymptomatic, painless clicking; mild disk displacement with reduction
● Stage 2: Occasional painful clicking or locking; mild disk
displacement and deformity
● Stage 3: Joint pain with functional changes (limited
opening); nonreducing disk with deformity
● Stage 4: Chronic pain and functional deficit, degenerative
osseous changes, and disk deformity
● Stage 5: End stage with crepitus, degenerative joint
disease (DJD), and disk perforation or loss

Question 5

Name the two categories of TMJ disk displacement.

Answer 5

● Disk displacement with reduction (often heard as popping or clicking)
● Disk displacement without reduction (usually no associated noise)
Note: Often, displacement with reduction leads to dis-
placement without reduction, which limits range of motion.
This may be reversed with conservative therapy or with
arthrocentesis or arthroscopy.

Question 6

In the case of anterior disk displacement with or without reduction, what are the indications for
intervention?

Answer 6

Pain, impaired mobility (especially acute closed lock), joint
locking, failure to respond to conservative therapy
Asymptomatic joint noise is common (in up to 35% of
Americans).

Question 7

How does osteoarthritis of the TMJ manifest?

Answer 7

Degenerative joint disease or arthritis of the TMJ most
commonly affects the elderly population, but it can affect
all ages. Painful motion and joint loading are the hallmarks,
along with CT findings of DJD. Myofascial pain symptoms
must be ruled out. Unless related to ankylosis, it will not
vastly reduce range of motion.

Question 8

What are the risk factors for septic TMJ arthritis?

Answer 8

History of trauma, burn, surgery or dental work, and systemic factors such as autoimmune disease, diabetes,
immunosuppression, sexually transmitted infection, or prolonged steroid use

Question 9

What is the most common systemic inflammatory

condition to affect the TMJ?

Answer 9

Rheumatoid arthritis. Traditional rheumatologic laboratory
studies in addition to MRI are useful for establishing a
diagnosis.

Question 10

What radiographic findings are expected in acute posttraumatic TMJ arthralgia?

Answer 10

Widening of the joint space might be seen, but radiographs

may also be entirely normal.

Question 11

How should trismus be clinically evaluated in a
patient with head and neck cancer who has
undergone radiation?

Answer 11

Objectively measure the mouth opening (opening < 35 mm
is generally considered restricted) and compare with
subjective assessment of restriction as well as its effect on
daily functions. Assess for pain on opening or other
symptoms besides simple restriction of opening from
fibrosis.

Question 12

What is the best initial therapy for postradiation

trismus?

Answer 12

Stretching exercises, including insertion of stacked tongue

blades or use of a commercial device such as Therabite. This requires multiple daily treatments over a period of months.

Question 13

How should ankylosis of the TMJ be managed?

Answer 13

Many algorithms have been described, but most include a description of resection of the ankylotic mass with ipsilateral coronoidectomy. Reconstruction is often with costochondral grafting, with or without an interpositional
temporalis myofascial flap. Early and rigorous physiotherapy
is imperative.

Question 14

Auriculocondylar syndrome is thought to develop from abnormalities in which branchial arches and
which craniofacial bones are most commonly affected?

Answer 14

Known also as Goldenhar syndrome, hemifacial microsomia, and branchial arch syndrome, it affects the first and second branchial arches. There is high variability of
expression and may affect the mandible, condyle, maxilla,
zygoma, orbit, and temporal bones.

Question 15

Describe the clinical features of auriculocondylar

syndrome.

Answer 15

● Auricular abnormalities (question-mark ear with constricted middle to lower thirds of the pinna, auricular cleft)
● TMJ/condylar abnormality (mandibular hypoplasia, condylar hypoplasia, or dysmorphism)
● Facial asymmetry with chin deviation toward the affected
side
● Micrognathia
● Microstomia

Question 16

Describe the clinical features of mandibular condylar hypoplasia.

Answer 16

Usually unilateral with mandibular deviation toward the affected side and severe malocclusion.

Question 17

Define the condition of mandibular condylar

hyperplasia.

Answer 17

● Excessive, progressive unilateral growth of mandibular
condyle resulting in aesthetic and functional problems
such as facial asymmetry, occlusal disturbance, and joint
dysfunction
● Imaging must distinguish condylar hyperplasia from
osteochondroma.
● Condylar hyperplasia may also be described in terms of
hemimandibular hypertrophy and hemimandibular elongation

Question 18

How does bone single-photon emission CT scan aid in the diagnosis of mandibular condylar
hyperplasia?

Answer 18

Technetium-99 radioisotope uptake is increased in the
hyperplastic condyle, which is indicative of unilateral
condylar activity. This is sensitive but nonspecific. Uptake is
also increased with inflammation, infection, and neoplasia.
Results should be interpreted along with clinical presentation.

Question 19

Define myogenous temporomandibular disorders.

Answer 19

Pain and dysfunction of the TMJ area that results from
abnormal function or disease processes of the muscles of
mastication. It is also known as masticatory myalgia and includes the following subtypes: myofascial pain, myositis, muscle spasm, and muscle contracture.

Question 20

What features characterize myofascial pain dysfunction syndrome (MPD)?

Answer 20

MPD is a dull, aching pain in the mandible, temple, or face
that is associated with specific trigger points and can
usually be reproduced by palpation of trigger points. Pain is
typically located over the muscles of mastication or neck
musculature rather than over the joint proper. MPD may be
with or without concurrent intra-articular disease.

Question 21

What features characterize myositis of the masticatory musculature?

Answer 21

Diffuse, continuous pain over the entire muscle that may
limit range of motion and cause swelling. Inflammation of
the muscle is secondary to injury or infection, and pain
worsens with muscle use.

Question 22

Describe the initial steps to treat masticatory

myalgia.

Answer 22

Rest the jaws and muscles by adhering to the following: soft
diet, avoiding caffeine, using heat or ice, take NSAIDs, avoid
parafunctional habits, avoid sleeping on the stomach, and
avoid excessive or prolonged jaw opening.

Question 23

How is a patient with complex myogenous masticatory pain treated after conservative measures have failed?

Answer 23

A pain clinic or pain team is most useful. Physical therapy,
along with pharmacologic and lifestyle interventions, are helpful, as comprehensive treatment offers the best chances of success.

Question 24

What differentiates masticator muscle contracture
from muscle contracture associated with masticator
muscle spasm?

Answer 24

Chronicity. Masticator muscle contracture is a chronic
condition with continued muscle shortening, whereas
masticator muscle spasm is an acute condition that is often
accompanied by pain.

Question 25

Describe lateral pterygoid spasm.

Answer 25

Acute, involuntary contracture of the lateral pterygoid muscle
● The muscle is shortened and produces decreased jaw
mobility (often acute open lock) and accompanying
localized pain.

Question 26

What differentiates myofascial pain dysfunction

syndrome from fibromyalgia?

Answer 26

These may share underlying disease processes and are
along the same spectrum. In general, fibromyalgia is
notable for more diffuse muscle pain, greater association
with sleep disorders, and depression. Myofascial pain is
influenced more by regional factors (posture, parafunc-
tional habits, trauma, etc.).

Question 27

What reconstructive options are available for TMJ

arthroplasty?

Answer 27

The mainstay for modern arthroplasty is total and hemijoint
prostheses. Autogenous grafts, such as costochondral
grafts, may also be used. Gap arthroplasty may be
augmented with a temporalis myofascial flap. Conchal
cartilage has also been used as a disk replacement.

Question 28

How often is surgery indicated for disorders of the TMJ, and what are the absolute indications?

Answer 28

Only 5% of cases require surgical intervention. Absolute
indications include treatment of neoplasia, joint ankylosis, or congenital/growth abnormalities that could alter maxillofacial growth.

Question 29

Name the different surgical interventions for TMJ disease.

Answer 29

Arthrocentesis, arthroscopy, modified condylotomy, and
open joint surgery (including disk repair, repositioning,
diskectomy, eminectomy, and joint replacement).

Question 30

A significant complication of open TMJ surgery is

damage to the facial nerve. Which branch of the facial nerve is most commonly injured?

Answer 30

The temporal division of the facial nerve; temporary weakness is present in 5% of cases, and permanent
weakness is reported in up to 1% of cases. Other complications include hemorrhage, occlusal changes, persistent change, heterotopic bone formation, and fibrous
adhesion formation.