The problem

The disc of cartilage which lies in your jaw joint has moved out of its normal position between the bones.

What is a jaw joint arthrocentesis?

An arthrocentesis is a procedure during which the jaw joint is washed out with sterile fluid. It aims to return the disc of cartilage to its normal position within the joint.

What does the treatment involve?

An arthrocentesis usually takes place under a general anaesthetic, ie you will be put to sleep completely. While you are asleep two small needles will be inserted into the jaw joint. One of these needles allows sterile fluid to be pumped into the joint under pressure. The second needle allows fluid to be drained out of the joint.

Will anything else be done at the same time?

While you are asleep your lower jaw will often be manipulated in an attempt to encourage the disc of cartilage back into its normal position.

How will I feel after the operation?

The area in and around the jaw joint is often uncomfortable for a day or two after the procedure. You may find it necessary to take simple painkillers (eg Ibuprofen) during this time. There will also be some swelling in front of your ear. You may also find it difficult to open your jaw for a few weeks.

Will I need another appointment?

You will need to return a few weeks after surgery to have your jaw joint checked by your surgeon. Arthrocentesis is not always successful and even in those people who have an improvement following the procedure it can take several months for this to occur.

What is arthroscopy?

Arthroscopy is a form of keyhole surgery in which a small telescope is inserted into a joint. This allows the inside of the joint to be examined in great detail. It can diagnose as well as treat problems within the jaw joint.

What does the operation involve?

Arthroscopy is usually carried out under general anaesthesia (ie you are put to sleep completely). The arthroscope (telescope) is very slender and is introduced into the jaw joint through a small cut in front of the ear. If your surgeon also plans to treat problems within the joint other fine instruments will be inserted through a second small cut.

What can I expect after surgery?

The area around your jaw joint may be swollen for a couple of days following surgery. The procedure is not a particularly painful one but you may find that you need to take simple painkillers (eg Ibuprofen) for a couple of days. Most people stay in hospital overnight.

Do I need any time off work?

This varies enormously from person to person and also depends on what type of job you do. Most people require a couple of days off work. It is important to remember that you cannot drive or operate machinery for 48 hours after a general anaesthetic.

What can I expect when I get home?

You will find that your jaw joint may be a little bit uncomfortable and stiff for a few days following surgery. It is usual to rest the jaw joint and eat a soft diet for this amount of time. Occasionally you can find that your bite may change for a couple of weeks.

What are the possible problems?

Even though your surgeon looks into your jaw joint with an arthroscope it may not be possible to treat your problem with this technique. "Open" jaw joint surgery which involves making a cut in front of the ear is therefore occasionally still necessary. Such open surgery would be carried out on another occasion.

What is arthroscopy?

Arthroscopy is a form of keyhole surgery in which a small telescope is inserted into a joint. This allows the inside of the joint to be examined in great detail. It can diagnose as well as treat problems within the jaw joint.

What does the operation involve?

Arthroscopy is usually carried out under general anaesthesia (ie you are put to sleep completely). The arthroscope (telescope) is very slender and is introduced into the jaw joint through a small cut in front of the ear. If your surgeon also plans to treat problems within the joint other fine instruments will be inserted through a second small cut.

What can I expect after surgery?

The area around your jaw joint may be swollen for a couple of days following surgery. The procedure is not a particularly painful one but you may find that you need to take simple painkillers (eg Ibuprofen) for a couple of days. Most people stay in hospital overnight.

Do I need any time off work?

This varies enormously from person to person and also depends on what type of job you do. Most people require a couple of days off work. It is important to remember that you cannot drive or operate machinery for 48 hours after a general anaesthetic.

What can I expect when I get home?

You will find that your jaw joint may be a little bit uncomfortable and stiff for a few days following surgery. It is usual to rest the jaw joint and eat a soft diet for this amount of time. Occasionally you can find that your bite may change for a couple of weeks.

What are the possible problems?

Even though your surgeon looks into your jaw joint with an arthroscope it may not be possible to treat your problem with this technique. "Open" jaw joint surgery which involves making a cut in front of the ear is therefore occasionally still necessary. Such open surgery would be carried out on another occasion.

Arthroscopy is a form of keyhole surgery in which a small telescope is inserted into a (TMJ) joint. This allows the inside of the joint to be examined in great detail. It can diagnose as well as treat problems within the jaw joint.

Synovium of the Posterior Pouch (Medial Synovial Drape), the Oblique Protuberance (Retro-Diskal Synovium), the Retrodiskal Synovial Tissue Attached to the Posterior Glenoid Process, and the Lateral Recess of the Retrodiskal Synovial Tissue showing - Synovium Adhesions, Synovium Redundancy & Creeping, Moderate degeneration of the Articular Surface and a Ragged Perforated meniscus with Fibrillations as well as Fibro-cartilage Scuffing.

Myrhaug introduced eminectomy as a new method of operation for chronic disloca­tion of the temporomandibula joint. He thought that if the eminence was eliminated the habitually dislocat­ing condyle could easily return to the glenoid fossa. Later eminectomy was also suggested as one of the forms of treatment of severe closed lock of the TMJ, and also for the treatment of internal derangement of the TMJ.

Stages of the progression of inter­nal derangement were described by Wilkes and his classification was modified by Bronstein. In devel­oping a rationale for surgical treatment for internal derangement, consideration must be given to all structures involved, namely the dental occlusion, the condyle, the articular fossa and the disc. If the articu­lar disc is not diseased and the dental occlusion is sta­ble, the disc can be repositioned within the fossa if sufficient space is created. If conservative methods of treatment have failed, the necessary space is most eas­ily created by reduction of the articular eminence. In addition, eminectomy removes the physical barrier to articular disc activity. Eminectomy therefore rapidly and effectively decompresses the intracapsular com­partment by creating a larger anterior recess in the superior joint space. This allows free unrestricted movement of the meniscus without entrapment of the neurovascular zone of the posterior attachment. Indirectly, the principle of intracapsular decompres­sion has formed the basis of most operations that have been used to treat internal derangement of the TMJ.

There can be considerable variation in the anatomical dimensions of the TMJ, and this has been fully discussed in an article by Kerstens et al. on the rationale for eminectomy. The slope of the posterior surface of the eminence, defined by the angle formed between the Frankfort horizontal and a line running from the most cephalic point of the fossa to the most convex point of the anterior of the eminence, may vary from 89° to l6^°. This variation may also occur in the same joint in a mediolateral direction. Where there is a low angle (shallow fossa) the intermediate zone of the disc is situated between the condyle and the eminence in the open-mouth position. The action of the temporalis and masseter muscles in closing the mouth results in a posterosuperior direction of force on the anterior part of the posterior band of the disc, allowing the condyle to slide back into the fossa. This is also assisted by the elasticity of the ligament and relax­ation of the lateral pterygoid muscle. Where there is a steep angle (deep fossa), forces to close the mouth will be similar, but the effect of the forces of closure are directed more posteriorly to the posterior band of the disc or even to the bilaminar zone. As a result of this unfavorable force and change in the elastic­ity of the posterior ligament, internal derangement with anterior displacement of the disc is much more likely with a steep angle than with a low angle. Therefore, reduction of this steep eminence angle, i.e. eminectomy, should effectively decompress the intracapsular compartment by creating a larger ante­rior recess in the superior joint space. This will allow freer, unrestricted movement of the disc without entrapment of the neurovascular zone of the poste­rior attachment.

Atkinson and Bates reported that the biomechanics of the TMJ are altered when the angle of the emi­nence is steep. Although the force vectors applied to the joint by the temporalis and masseter muscles remain unchanged, the difference between the shallow and steep eminence is the position of the disc. For the disc to maintain a proper contact between the condyle and the eminence, it must rotate further forward on the condylar head. This rotation places the posterior band of the disc anterior to the vector of force of the temporalis muscle. The addition of the posterior thrust of the masseter muscle dislodges the condylar head posteriorly and this leaves the disc anteriorly dis­placed. Eminectomy will create the necessary intracapsular space to allow the disc to take its optimum position within the fossa.

The following criteria adapted from the American Association of Oral and Maxillofacial Surgeons should be taken into account before embarking on TMJ surgery:

• Proved TMJ internal derangement or other structural joint disorder with appropriate imag­ing;
• Evidence that suggests that the symptoms and objective findings are the result of a structural dis­order;
• Pain or dysfunction or both of such magnitude to disable the patient;
• Previous unsuccessful non-­surgical treatment; previous management, to the extent possible, if bruxism, oral parafunctional habits, other medical and dental conditions, and other contributing factors that may affect the outcome of surgery;
• Patient's consent after a discussion of potential complications, goals to achieve, success rate, timing, postoperative management, and other approaches including no treatment. These conditions maximize the potential for a successful outcome but cannot guarantee it.