2. Temporomandibular Joint Dysfunction

Question 1

Vascular supply of TMJ

Answer 1

Branches of the superficial temporal, maxillary, and masseteric arteries

Question 2

Nerve supply of TMJ

Answer 2

Branches of the auriculotemporal with contributions from the masseteric and posterior deep temporal nerve

Question 3

Define myofascial pain dysfunction (MPD)

Answer 3

Non-articular TMJ disorder that manifests itself as dull regional masticatory myalgia that worsens with function and can lead to a decreased range of motion. It can involve the muscles of mastication and any combination of the supramandibular and inframandibular muscle groups (most common TMJ disorder).

Question 4

Etiology of myofascial pain dysfunction

Answer 4

Parafunctional habits
Life stressors
Apertognathia and/or overjet greater than 6mm
Lack of posterior dentition leading to muscle hyperactivity

Question 5

Types of degenerative joint disease (2)

Answer 5

Non-inflammatory degenerative joint disease (osteoarthritis)
Inflammatory arthritis (RA, JRA, psoriatic arthritis, gout, pseudogout, ankylosing spondylitis, reactive arthritis)

Question 6

What is internal derangement of the TMJ?

Answer 6

Disorder of the TMJ in which the articular disk is in an abnormal position as it relates to the condyle and fossa when the teeth are in occlusion. Malposition of the disk may lead to pain, instability, decreased ROM, and abnormal mobility of the mandible

Question 7

Etiology of TMJ internal derangement

Answer 7

Trauma, joint laxity, parafunctional habits, altered joint lubrication system, anchored disk phenomenon (disk adhesion to articular fossa), MPD

Question 8

How is internal derangement diagnosed?

Answer 8

Decreased MIO, deviation, deflection, palpable clicks (reciprocal), and crepitus. Patients often have pain in preauricular region as opposed to side of face.

MRI (T1, T2). Disk displaced often in anteromedial vector. Osseous changes and abnormal contours of the disk.

Question 9

What is the Wilkes classification?

Answer 9

Classifies degree of internal derangement

Stage I: painless clicking, no pain or locking. ADD. Normal disk displaced AM.

Stage II: occasional painful clicking, intermittent locking. ADDwR. Mild disk deformity. No osseous changes.

Stage III: frequent painful clicking with severe limitation in ROM. Joint tenderness. ADDw/oR. Moderate disk deformity, no osseous changes. Possible adhesions.

Stage IV: restricted ROM, chronic pain, creptius. ADDw/oR. Marked disk deformity, osseous changes. Disk perforated.

Stage V: joint pain, crepitus. Disk displaced. Marked disk deformity, severe osseous changes. Perforated disk. Severe osseous changes of condyle and fossa.

Question 10

What is ankylosis of the TMJ?

Answer 10

True ankylosis is intra-articular fusion within the joint space resulting in hypomobility. Can be bony, fibrous, or fibro-osseous. Can be complete vs. incomplete. Can be caused by trauma, infection, otitis media, RA, psoriatic arthritis, prolonged immobilization, and previous TMJ or orthognathic surgery.

Question 11

What are two common accepted classifications of TMJ ankylosis?

Answer 11

Topazian (1984): 1. only condyle; 2. extends to sigmoid notch; 3. entire condyle, sigmoid notch and coronoid.

Sawhney (1986): 1. flattened condylar head with close approximation to joint space; 2. flattened condyle, bony fusion on outer aspect of articular surface; 3. bony block bridging ramus and zygomatic arch; 4. wider bony block completely replaces architecture of the joint.

Question 12

What is the KABAN protocol?

Answer 12

Seven step protocol for treatment of TMJ ankylosis in pediatric patients:
1. aggressive resection of fibrous or bony ankylotic mass
2. coronoidectomy on affected side and measure MIO intraoperatively
3. coronoidectomy on contralateral side if you cannot achieve MIO >35mm
4. lining TMJ with temporalis myofascial flap or native disk
5. reconstruction of ramus-condyle unit with DO or CCG
6. early mobilization of the jaw
7. aggressive physiotherapy

Question 13

How is fibrous ankylosis treated surgically?

Answer 13

More conservatively than bony ankylosis. Lysis of adhesions and fibrosis, diskectomy.

Question 14

What can be adjunctive treatment to surgical treatment of ankylosis?

Answer 14

Aggressive PT. Frequent follow-up. Consider radiation therapy (20Gy in 10 fractions) to prevent recurrence and consider when using autogenous grafting as recurrence is higher.

Question 15

When is a costochondral graft used?

Answer 15

CCG used in growing child. Ease of adaptation and remodeling, low morbidity, low rate of infection, low cost.

Harvest ribs 4-7 (direct cartilagenous connection to sternum. 6 most commonly harvested (inframammary crease, avascular plane). Right rib so not confused with cardiogenic pain. Some advocate rib from contralateral side for appropriate curvature.

Question 16

Describe rib harvest technique.

Answer 16

-Incision inframammary crease (5cm)
- Dissection through subq tissue, fascia, plane b/t pectoralis major and rectus abdominis.
- Two fingers to straddle fifth and sixth intercostal space. Incision through periosteum. Dissect around rib subperiosteally.
- Sharp blade to make cartilaginous incision. No more than 3cm in children to avoid overgrowth of ridge and to prevent separation of cartilaginous cap.
- Pull rib laterally and section. Check for pleural tears with saline/valsalva.
- Close periosteal sleeve. Close fascia. Postop CXR.

Question 17

T1 MRI

Answer 17

Fat bright (white)
Better for anatomy eval
Marrow fat in condyle will have high signal intensity
Gyri of brain do not show white banding. Orbits gray.
Disk and cortical bone black due to low proton density (same with T2).

Question 18

T2 MRI

Answer 18

Water is bright and fat is dark
Brain gray.
Better to look for effusions and pathology.
Bone marrow less bright (condyle looks gray)
Disk and cortical bone black due to low proton density (same with T1)
Bright signal from gyri of brain.

Question 19

OLD CARTS acronym

Answer 19

O: onset
L: location
D: duration
C: character
A: aggravating/associated symptoms
R: relieving
T: timing
S: severity

Question 20

Arthrocentesis indications

Answer 20

For acute closed lock, previous surgery with continued discomfort, TMJ arthralgia, Wilkes classification 1, 2, 3.

Question 21

Arthrocentesis contraindications

Answer 21

Ankylosis, overlying skin infection, inability to appreciate regional anatomy.

Question 22

Describe technique for arthrocentesis

Answer 22

-Draw canthal tragal line (Holmlund-Hellsing line)
-First point 10mm ahead of line and 2mm below (deepest point of glenoid fossa)
-Second point 20mm ahead and 10mm below (height of articular eminence)
-Prep skin
-Local w/out epi
-Insufflate joint space with 27-gauge needle with LR
- 18-gauge at 45 degree angle anteriorly to reach zygomatic arch and walk into superior joint space
- Posterior port in similar manner with 18-gauge
- Irrigate with at least 100cc
- Remove anterior port. Inject 40mg/mL Kenalog
- Manipulate joint under anesthesia, check opening
- Aggressive ROM exercises, NSAIDs, splints

Question 23

When is disk repositioning procedure indicated?

Answer 23

Surgical procedure to manually reposition disk into premorbid position. Indications are failure of conservative therapy, Wilkes 2-5.

Question 24

Describe disk reposition technique

Answer 24

Incision preauricular crease, skin, subq
- Attention to superior portion. Dissect through temporoparietal fascia to temporalis fascia (glistening white).
- Temporal branch of facial nerve runs within TP fascia 8-35mm (avg 20mm) from bony anterior extent of EAM.
- Palpate zygomatic arch, incise through periostium and dissect subperiosteally until you appreciate joint capsule
- Insufflate joint with local. Make incision into joint capsule to enter superior joint space.
- Mobilize disk, assess for perforations (repair if small, remove disk if large).
- Disk can be plicated in posterolateral vector to disk capsule or temporalis fascia with non-resorbable suture or Mitek anchor.
- Close in layers

Question 25

TMJ TJR indications

Answer 25

Failed previous TMD surgeries
Severe arthritic joint
Loss of vertical mandibular height and occlusal relationship
Pathology
Ankylosis- either bony or fibrotic
Condylar agenesis

Question 26

Surgical technique for TMJ TJR

Answer 26

Preauricular approach to joint capsule.
- incision preauricular crease through skin, subq
-superior portion of incision- through TP fascia to temporalis fascia (glistening white). Temporal branch of facial nerve runs within TP fascia 8-35mm from bony anterior extent of EAM (avg 20mm).
-Palpate zygomatic arch, incise through periosteium. Dissect subperiosteally to joint capsule. Insufflate with LA.
- Incision in periosteum of lateral aspect of condylar head in T-shape fashion to expose lateral aspect of condyle. Expose anterior and posterior regions of condylar neck. Pack site

Submandibular approach
- 2cm below inferior aspect of mandible. Inject vasoconstrictor.
-6cm incision through skin, subq to platysma
-Undermine
-Sharp dissection through platysma to superficial layer of deep cervical fascia. Disect through with nerve stimulator to test for marginal mandibular nerve.
- Dissect out facial artery and vein. Isolate and clamp/tie vessels.
- Divide pterygomasseteric sling.

Condylar resection
- Condyle retractors, resect exposed condyle (15mm clearance for condyle and fossa.)

Fossa preparation (for TMJ concepts reproduce any contouring noted on model.
- Secure fossa component (only 2 screws to start)

Condyle component
- Place in MMF
- Place condyle prosthesis, 2 screws

Final screw securement
Ensure ROM 32-35mm
Irrigate and close in layers

Question 27

Myofascial pain dysfunction potential treatment

Answer 27

• Treatment to address etiology (stress, anxiety, bruxism, clenching, malocclusion, parafunctional oral habits, internal derangement of TMJ, rheumatologic diseases, fibromyalgia, and vasculitis)

Conservative therapy: stress management, occlusal splint therapy, PT, heat, NSAIDs, muscle relaxants, anxiolytics.

Orthodontic therapy

Trigger point injections (local w/ or w/o steroid directly into tender areas of muscles).

Botulinum toxin to reduce muscle activity.

Question 28

Mahan’s test

Answer 28

Biting on a tongue depressor on one side that elicits pain in contralateral TMJ is positive test that suggests intracapsular pathology.

If ipsilateral pain, muscular etiology