What is an Effective and Safe Surgical Treatment for Internal Derangement of the TMJ?
First, what is internal derangement of this particular joint? If we look at the normal temporomandibular joint, sometimes referred to as the “jaw” joint we will see several things. It, first, is not a single joint, but has bilateral joints which make up how the jaw is to function against the base of the temporal bone of the normal skull. In a very brief way, we can describe the single joint as a “ball” and “socket” type of joint which allows the two surfaces to be separated by a fibrous disc, and surrounded by a capsule which confines the two bone surfaces and allows for motion and lubrication and nutrition. The socket portion, which is the underside of the temporal bone of the skull, is not quite like the hemispherical hip joint socket, but perhaps a bit more like the shape of a knee joint. In actuality, if you were to look at the TMJ “socket” from a lateral view on an x-ray, it would appear more like a socket connected to an upside down ski-slope running forward.
Perhaps to give the reader a more graphic picture would be to show an x-ray of a patient’s two separate TMJs on a single Panorex type x-ray. If we look at the right side of the film, we see an x-ray of a patient’s joint which is aging, but still functioning. Perhaps the left side more clearly shows the “S” curve of the patient’s joint which is covered by a metal implant. The patient’s own, natural”condyle” or ball portion is shown resting against the bottom surface of the Christensen TMJ implant. Normally, as the jaw opens or moves to the opposite side, it allows the normal condyle to move forward on the “ski slope” which medically we term, the “articular eminence”. It is never meant to rest, bone against bone” but to be separated by a relatively thin fibrous disc, which acts as a “separating” medium between the two bone surfaces. This, when healthy, allows for pain-free motion of the jaw and of that particular joint.
Unfortunately, this ‘separating media” or disc can wear out or become displaced or even perforated. When that happens, then the two bone surfaces begin to “rub” on each other, thus causing harm to the bone surfaces and causing pain, “grinding” and lack of motion for the patient.
In 1960, Dr. Bob Christensen innovated the first successful surgical treatment for this condition known as internal derangement of the temporomandibular joint. As we can see on this next picture, the upper part of the TMJ on this human skull, I covered by a metal, Co-Cr implant, known either as the Christensen Partial TMJ implant or as the Fossa-Eminence Prosthesis. Since that innovation some 50 years ago, tens of thousands of these implants have been implanted in selective patients, with fantastic success, thus allowing for normal, pain-free function. Some of these implants are still functioning 40 plus years later, never requiring another surgery.
In some cases where the correct surgical treatment was not instituted early enough, the patient was then required to have a “Total” TMJ reconstructive surgery accomplished, which can be very successful when required, but which is a much more complicated and more risk prone surgery. The actual Partial and Total TMJ Christensen implants are seen on the plastic anatomical model shown below.
Hopefully, these rather graphic pictures will give you, the reader, a more understandable idea of what constitutes a very safe and very effective treatment for internal deragnement of the temporomandibular joint.
The graph shown below are taken from a TMJ Implant, Inc’s. Prospective and Retrospective Study, showing how effective this treatment option has and can be for the suffering patient. Although this graph will be harder for the unprofessional viewer to perhaps comprehend, what it is showing is how pain has been reduced from an average level of approximately 7.5 on a 10 cm VAS graph toless than 2.0. In brief, lay terms it means that the pain went fron a very high level to a very low and tolerable level for the total seen in literally thousands of patients over a 36 month period of time..
If we were to look at the degree of disease advancement we had seen pre-operatively in these internal derangement patients we would see they range from patients where the disc was misplaced but not perforated, then to those where a perforation was present to some patients with more advanced arthritis to some where a fibrous fusion has occurred between the “ball” and the “socket”. These last ones are the more severe and certainly may totally or partially restrict the mobility of the joint. I every instance, the pain was reduced from 7.4 or 8.0 to well below 2.0 on the VAS scale of pain.
Perhaps this next testimony will give the clearest picture of what some of these patients have had to endure, when faced with internal derangement of their own temporomandibular joints, and how some of the earlier treatment options were not helpful. In this case, this patient had her Christensen Partial TMJ implants implanted well over 20 years ago, and her progress has been most encouraging and remarkable.