Many patients suffer from acute or chronic painful limited function of the temporomandibular joint, of the masticatory and partially of the cervical spine muscles. Within this large group of so-called cranio-mandibulary dysfunctions there are three main sections, which can however also appear in combination due to reciprocal enhancement:
While most of these dysfunctionalities can be reversed by combined conservative forms of treatment (avoiding hard food, reduction of stress factors combined with various relaxation techniques, occlusal splints, physiotherapy and painkillers and relaxing medication), the proportion of joint diseases requiring surgery is 5 % at most. Surgery to the temporomandibular joint is usually only advisable after unsuccessful conservative therapy. Adequate, individual occlusal splint treatment for example in order to reduce tooth grinding or pressing, or to normalize a faulty bite (which overburdens the temporomandibular joint and the masticatory muscles) can be carried out over a period of some months.
If ensuingly after corresponding clinical and computer tomographical diagnosis it is clear that the pain and limited movement emanate primirly from the temporomandibular joint, minimally invasive surgical techniques are first used as therapy for these temporomandibular joint diseases: arthrocentesis is carried out under local anaesthetic, also known as arthrocentesis and lavage, where the upper region of the jaw joint is punctured with two thin needles and rinsed with liquid under pressure. As a result of this minimally invasive measure, fine scars are dissolved and inflamed areas and protein material, which can be responsible for causing pain, are rinsed out. This can also cure an inflamed jaw surface or synovial fluid. This can sometimes result in the repositioning of a badly positioned disc, and/or a locked jaw can become unlocked, if this is accordingly treated within the first 48 hours at the latest after initial symptoms.
If arthrocentesis does not prove successful in the long run, arthroscopic surgery under general anaesthetic is required, which from the start is basically very similar to arthrocentesis. Here a camera as well as diverse surgical instruments are introduced through selective entry points into the upper part of the temporomandibular joint. These miniature tools (for example scalpels, scissors or even laser probes) enable the exact removal of adhesions, fully visibly. It is also possible to smooth damaged joint areas to facilitate regeneration. A displaced disc, which has blocked the joint’s movement for a long time, can be returned to its original position. The informative value of this arthroscopy with regard to the evaluation of perforated joint cartillage due to adhesions is however limited, so that an arthroscopic examination without pathological findings does not necessarily mean that the joint cartillage or its suspending apparatus are not damaged.
When all the above mentioned conservative and minimally invasive treatment procedures have been exhausted, and if the temporomandibular joint itself, due to an accident, deterioration, inflammation, dysfunctional growth or dysplasia is severely damaged, or there are such severe changes due to malignant neoplasm, then open surgery is called for. The target of open entry points, where a differentiation is made between an approach behind the ear (retro-auricular) and one in front of the ear (pre-auricular), is to replace certain badly damaged parts of the joint with tissue,either produced naturally in the body or in some case produced artificially. The cosmetic result using both points of entry is considered excellent.
Target of the open surgical therapy is to encourage tissue regeration as well as compensation through surrounding structures (e.g. muscles). Surgical measures to reconstruct and/or remove the Discus articularis (gliding cartilage) are differentiated from disc replacement operations, so called inter-positioning surgery, using tissue produced in the body or artificial tissue. The repeated unintentional emergence of the joint head from its socket is usually treated by ablation of the front joint protuberance (eminectomy). This alleviates the autonomous return of the joint head to the socket, on the other hand the mobility range of the joint in its upper region is restricted due to scarring.
A modern therapy alternative nowadays is the direct administration of botulinum toxin under EMG control to the masticatory muscle M. Pterygoideus lateralis that is responsible for wide opening of the mouth. This form of therapy however requires good patient collaboration. With chronic inflammation, severe arthritic changes or one-sided increased growth of the joint head itself, ablation to smooth and thus to functionally adapt the surface of the joint (condylar shaving) is used. As one danger here is the ensuing stiffening of the joint, this procedure is usually combined with the removal of the often damaged disc, which then has to be replaced by fascia of the temporal muscle, or a cartilage transplant either produced in the body or artifically, in order to separate both joint surfaces which are now in contact.
The actual excision of the joint head, the so-called condylectomy, is carried out in the case of various joint diseases such as tumours, or severe destruction due to inflammation or after a series of previous operations. In the case of ankylosis, the osseous stiffening of a joint, a condylectomy to restore the joint fissure is usually required, in to which cartillage or muscle is transfered for permanent separation. In the unlikely case of all above mentioned surgical measures not leading to the required stable result, or severely deformed jaw joints continue to exist, it may be necessary to implant an individually made, artificial complete temporomandibular joint prosthesis. Nowadays these are usually individually fitted to the patient using computer tomographical data.
One special feature is the surgical care of temporomandibular joint fractures. While in the past lengthy splint treatment was the main form of treatment, which sometimes led to functional and anatomical results which were in need of improvement, nowadays it is possible to reconstruct such fractures exactly using a retro-auricular entry point, and to fix this with small screws. One disadvantage of this method is the danger to the facial nerve, which lies close to the operation field. The distinct advantage of this surgical procedure, which has been significantly optimized in our clinic in the last few years, is that it is possible for the patient to move and put pressure on the joint at once. An open temporomandibular joint operation basically requires good patient collaboration, where ensuing intensive post-care with physiotherapy is indispensable, and this is crucial for the complete success of the treatment.
Picture 1 and 2: CT in coronary layers of a two-sided temporomandibular joint fracture (1) and (2) after osteosynthetic treatment.
Picture 3: Arthroscopic view of a temporomandibular joint: swollen synovia in arthritis
Picture 4: Puncture of the right temporomandibular joint for rinsing (arthrocenthesis)