Etiopathogenesis/Causative Factors

The following are the presently accepted indications for TMJ TJR :

• 1

  Inflammatory arthritis involving the TMJ that is not responsive to other modalities of treatment

• 2

  Recurrent fibrosis or ankylosis (or both) not responsive to other modalities of treatment

• 3

  Failed tissue grafts (bone and soft tissue)

• 4

  Failed alloplastic joint reconstruction

• 5

  Loss of vertical mandibular height or occlusal relationships (or both) because of bone resorption, trauma, developmental abnormalities, or pathologic lesions

Pathologic Anatomy

Severe pathology associated with mandibular dysfunction and anatomic distortion of the TMJ complex dictates the need for TJR. Because of the multifaceted composition of the TMJ complex and its reliance on coordinated masticatory muscle function, it is an unreasonable expectation that a reconstructed TMJ can be returned to its “normal” premorbid function. Thus, there will always be some functional disability involved in any reconstructed joint, either autogenous or alloplastic.

In a multiply operated patient with an anatomically distorted joint reconstruction, chronic neuropathic pain will be a major component of that patient’s disability. Therefore, it is important for both the surgeon and the patient to understand that the primary goal of any type of TMJ reconstruction is restoration of objective mandibular function and form. Any subjective pain relief gained must be considered only of merely secondary benefit.

Pathologic Anatomy

Severe pathology associated with mandibular dysfunction and anatomic distortion of the TMJ complex dictates the need for TJR. Because of the multifaceted composition of the TMJ complex and its reliance on coordinated masticatory muscle function, it is an unreasonable expectation that a reconstructed TMJ can be returned to its “normal” premorbid function. Thus, there will always be some functional disability involved in any reconstructed joint, either autogenous or alloplastic.

In a multiply operated patient with an anatomically distorted joint reconstruction, chronic neuropathic pain will be a major component of that patient’s disability. Therefore, it is important for both the surgeon and the patient to understand that the primary goal of any type of TMJ reconstruction is restoration of objective mandibular function and form. Any subjective pain relief gained must be considered only of merely secondary benefit.

Diagnostic Studies

A detailed history and head, neck, and oral examination, including evaluation of the occlusion and any oral orthotic devices that the patient has been using, are important. This should be followed by a careful review of any previous imaging (plane films, magnetic resonance imaging, computed tomography) available to determine the need for further imaging to correlate any findings with the chief complaint, history, and clinical examination.

Appropriate laboratory studies may be required, such as in patients suspected of having high inflammatory arthritic disease.

Unmounted and mounted study models are helpful in determining compensatory changes in the occlusion that may necessitate orthodontic management before reconstruction. Severely compromised occlusal or skeletal relationships (or both) must be considered and planned for correction because they will affect mandibular stability after reconstruction and the longevity of alloplastic devices as a result of abnormal wear forces.

Past and recent clinical photographs are helpful in determining the onset of conditions such as unilateral condylar hyperplasia/hypoplasia and apertognathia associated with pathology or previous TMJ surgery.

Present and previous medical and dental records can provide useful information in preparing for future reconstructive surgery and anesthesia, especially in patients with a long history of narcotic use for controlling pain or management in a pain clinic.

If there is any concern regarding the patient’s preoperative psychological state, thorough evaluation by a psychologist or psychiatrist familiar with patients with TMJ disorders is essential before any reconstruction is undertaken. Unrealistic expectations of pain control and functional or esthetic results must also be considered and dealt with accordingly.

Presurgical Considerations

Presurgical diagnostic local anesthetic (without vasoconstrictor) blocks of the joint or masticatory muscles (or both) may be performed to try to determine the cause of the pain, as well as to demonstrate the concept of centrally mediated pain to the patient.

Presurgical use of botulinum toxin or muscle relaxants and physical therapy such as ultrasound can be considered, but to date no studies have provided any data that these treatments are helpful in decreasing postoperative masticatory muscle pain in such cases.

Treatment/Reconstructive Goals

Regardless of whether the TMJ is reconstructed with alloplastic, allogeneic, or autogenous material, the following should be the management goals :

• 1

  Improve mandibular function and form

• 2

  Reduce suffering and disability

• 3

  Contain excessive treatment and cost

• 4

  Prevent morbidity

Specific Treatment and Techniques