TMJ Ankylosis

Temporomandibular Joint (TMJ) ankylosis is a condition characterized by the abnormal fusion of the mandibular condyle to the temporal bone, leading to restricted jaw movement. This condition can significantly impact a patient's ability to open their mouth and perform normal functions such as eating and speaking.

Causes and Mechanisms of TMJ Ankylosis

1. Condylar Injuries:

   • Most cases of TMJ ankylosis result from condylar injuries sustained before the age of 10. The unique anatomy and physiology of the condyle in children contribute to the development of ankylosis.

2. Unique Pattern of Condylar Fractures in Children:

   • In children, the condylar cortical bone is thinner, and the condylar neck is broader. This anatomical configuration, combined with a rich subarticular vascular plexus, predisposes children to specific types of fractures.
   • Intracapsular Fractures: These fractures can lead to comminution (fragmentation) and hemarthrosis (bleeding into the joint) of the condylar head. A specific type of intracapsular fracture known as a "mushroom fracture" occurs, characterized by the comminution of the condylar head.

3. Formation of Fibrous Mass:

   • The presence of a highly osteogenic environment (one that promotes bone formation) following a fracture can lead to the organization of a fibrous mass. This mass can undergo ossification (the process of bone formation) and consolidation, ultimately resulting in ankylosis.

4. Trauma from Forceps Delivery:

   • TMJ ankylosis can also occur due to trauma sustained during forceps delivery, which may cause injury to the condylar region.

Etiology and Risk Factors

Laskin (1978) outlined several factors that may contribute to the etiology of TMJ ankylosis following trauma:

1. Age of Patient:

   • Younger patients have a significantly higher osteogenic potential and a more rapid healing response. The articular capsule in younger individuals is not as well developed, allowing for easier displacement of the condyle out of the fossa, which can damage the articular disk. Additionally, children may exhibit a greater tendency for prolonged self-imposed immobilization of the mandible after trauma.

2. Type of Fracture:

   • The condyle in children has a thinner cortex and a thicker neck, which predisposes them to a higher proportion of intracapsular comminuted fractures. In contrast, adults typically have a thinner condylar neck, which usually fractures at the neck, sparing the head of the condyle within the capsule.

3. Damage to the Articular Disk:

   • Direct contact between a comminuted condyle and the glenoid fossa, either due to a displaced or torn meniscus (articular disk), is a key factor in the development of ankylosis. This contact can lead to inflammation and subsequent bony fusion.

4. Period of Immobilization:

   • Prolonged mechanical immobilization or muscle splinting can promote orthogenesis (the formation of bone) and consolidation in an injured condyle. Total immobility between articular surfaces after a condylar injury can lead to a bony type of fusion, while some movement may result in a fibrous type of union.

An ulcer is a break in the continuity of the skin or the mucous membrane.

Mode of onset:  Traumatic ulcers heal when the traumatic agent is removed., If it persists it becomes chronic as in the case of dental ulcer of the tongue. Ulcers may develop spontaneously as in the case of gumma (syphilitic ulcer). It may develop with varicose veins called varicose ulcer, which develops in the lower third of the leg.

Sometimes a malignant ulcer develops in a scar called Marjolin’s ulcer. Special features are:

 No pain - as there are no nerves. It does not spread - as there is scar tissue. No metastases - as there are no lymphatics Treatment:- Wide excision.

Classification of Ulcer

A) Pathologically

I. Non-specific ulcers:

a. Due to infected wound after trauma, that is physical or chemical agents.

b. Due to local infection example dental ulcer, pressure sore

 Specific ulcers: Caused by specific infection

a. Syphilitic ulcers (Hunterian chancre)

b. Tubercular  ulcers, actinomycosis

Trophic ulcer:- Caused by two factors:

Diminished nutrition due to inadequate blood supply to the tissues

Eg. Ulcers in Buerger’s Disease, Artherosclerosis

b. Diminished or absence of sensation of the skin leading to perforating ulcer of the foot

iv. Malignant ulcer: Due to squamous cell carcinoma, rodent ulcers and melanoma.

B) Clinical classification of ulcers

1. Acute Ulcer:  The edge is inflamed oedematous and painful with slough in the floor and n o granulation tissue. Profuse purulent Discgarge seen

2. Healing ulcers: edge sloping with bluish margin The floor is covered with a red, healthy granulation tissue.

3. Chronic or callous ulcer (non- healing) There is no tendency to heal by itself, the base is jndurated  unhealthy granulation tissue is present in the floor The edge is rounded and thickened.

Chronic ulcer occur due to:

Chronic infection , Defective circulation , Foreign body, Persistent local oedema , Malignancy , Diabetes , Malnutrition (loss of proteins), Gout

Specific Ulcers

Tubeculous Ulcer

Edge Undermined, floor contains granulation tissue a watery discharge is present. Caseous material is found in the floor of the ulcer. It usually occurs in tubercular lymphadenitis in the neck, axilla or groin.

Syphilitic Ulcer

a) Huntarian Chancre or  primary sore or hard chancre: usuaIly occurs over the genitalia especially on penis. Occurs in the primary stage of syphilis Ulcer is round or oval, it is hard,indurated, elevated and painless It feels like a button, discharges serum containing spirochetes (cork screw) which is highly infective.

b) In the Secondary stage mucous patches and condylomata occurs The ulcers are shallow white patches, of sodden thickness which occur in the mouth and tongue. Condyloma are hypertrophied epithelium with serous discharge occurring in mucocutaneous junction around the anus. The regional lymphnod (inguinal transverse chain) are enlarged.

c) In tertiary stage of syphilis gummatous ulcers occur They have a punched  out edge and wash Ieather floor. They occur on the subcutaneous bones like sternum and tibia. They are painless and refuse to heal.

Soft Sore (chanchroid)

They are painful muitiple ulcers, with copious discharge. They are caused by Bacillus Ducrey  lncubation time is 3 to 4 days. located on glans penis and prepuce is due to venereal infection. They are associated with enlarged called bilateral inguinal lymphnodes

Tropical ulcer:

a) Oriental Sore - due to L. Tropica (lieshmaniasis)

b) Ulcers and sinuses are due to guinea worm abscess

c) Histoplasmosis with multiple ulcers on the tibia.

d) Chronic ulcers due to yaws

e) Amoebic ulcers occur in colon_and rectum , flask shaped ulcers , undermined edge , caused by  Entamoeba Histolytica

Varicose Ulcer:

Associated with varicose veins. Occurs on the inner aspect of the lower third of leg , chronic ulcer The surrounding area is pigmented and eczema is present. The sore is longitudinally oval It does not penetrate the deep fascia and is painless The base is adherent to the periosteum of the tibia

Rodent ulcer

Usually Occurs on the face above a line joining the lobule of the ear to the angle of the mouth. Usually occurs at the inner canthous of the eye . Edge is raised and rolled, Erodes the deeper structures and the bone, the lyrnph nodes are not involved.

Treatment: If small wide excision is done with skin grafting, If large, radiotherapy is given.

Malignant Ulcer

Occurs due to chronic irritation as in the case of malignant ulcer of the tongue. The edge is everted. The floor is covered with slough and tumor tissue The regional lymph nodes are hard.

Initially mobile later becomes hard

Treatment: Wide excision is done.

Marjolin ulcer: Malignant Ulcer occurring on scar of Burns