TMJ Ankylosis

Ankylosis is a Greek word which literally means ‘stiff joint’. It denotes no mobility of the joint.Inability to open the mouth beyond 5mm opening due to fusion of the bone to the base of the skull. Ankylosis is of different types depending upon the location,tissue involved and extent of fusion.

Ankylosis mainly of two types true and false

• In true ankylosis there is bony fusion of the bone of the TMJ with the base of the skull in the front of ear.This is very severe case of ankylosis
• False ankylosis is due to factors other then bony fusion such as muscle spasm, and other pathologies 

Causes

• Trauma: This is the main cause of the TMJ ankylosis. Trauma may be due to several factors such as accidents, surgical trauma, bone fracture.
• Infections such as arthritis,otitis media
• Surgical complications of TMJ joint surgery, orthognathic surgery
• Inflammation due still’s disease,ankylosing spondylitis

Signs

• Patient is unable to eat due to Inadequate masticatory (chewing) function 
• Restricted mouth opening 
• Inhibited facial and physical growth 
• Impaired speech due involved muscles 
• Facial asymmetry if only one side is affected 
• Patient has difficulty in breathing and the chances of sleep apnea is very high in these patients.
• Chances of carious teeth, misaligned teeth are common due to inability to access oral cavity properly

Sequelae

• Facial growth distortion: Due to fusion and tissue deficiency face structure is distorted.
• Nutritional impairment due to problem in eating.
• Malocclusion

Diagnosis

• Conventional radiography is the best way to diagnose TMJ ankylosis
• OPG(orthopantomograph) is the complete x-ray of upper and lower jaw in the single X-ray film.
• 3D CT scan show true ankylosis very clearly and diagnosis made easy.
• MRI

Treatment

Aims and objectives 

• To release ankylosed mass and create gap for the movement of the bone. improvement of the patient’s oral hygiene and nutritional needs
• To reconstruct normal height of the jaw bone and restore normal facial profile. 

Exercises

TMJ exercises are those exercise which stimulate the jaw opening. There are various types of exercise for TMJ problems. These exercises should be performed gently and correctly otherwise these can cause severe problems. Here all the TMJ Exercises that proven useful in treating ankylosis

Surgical: Surgical approaches to TMJ ankylosis

CONDYLECTOMY

Incision is given at the level of the condylar neck.Head of the jaw bone is separated carefully wound is then sutured in layers. Deviation of the jaw to the effected side and anterior open bite are common complication after this surgery

GAP ARTHROPLASTY

This procedure is for severe bony ankylosis. Excess bone is removed for creation of the gap between the head of the jaw bone and base of the skull. This formed gap permits mobility of the jaw. 

INTERPOSITIONAL ARTHROPLASTY

This approach is similar to the gap arthroplasty and commonly used surgical protocol of choice now a days. Like gap arthroplasty gap is created but the gap is then filled with some kind of materials so as to avoid reoccurrence and to maintain the normal height of the jaw bone.

Complications of surgery

• Hemorrhage to the facial artery is common
• Damage to the ear  
• Damage to the parotid gland
• Damage to the teeth