I would like to comment on the interesting article entitled “Intraoral approach for arthroplasty for correction of TMJ ankylosis” by K o et al. In the article, K o et al. claim the intraoral arthroplasty technique can avoid the complications that are seen when using the extraoral approach to TMJ arthroplasty.

The external TMJ arthroplasty approach can be considered as a genuinely safe and reliable approach when using techniques that have been described in the literature. For example, P oliti et al. proposed the deep subfascial approach to the TMJ as a safe method that avoids the risk of facial nerve injury. There are no visible facial scars because the incision can be made in the retrotragal position with a temporal extension. Hemorrhage might represent a hazard only as concerns the internal maxillary artery. This same artery may be at risk via the intraoral approach, however, control of bleeding with be much more difficult than with the extraoral approach.

K o et al. list several intraoral approaches in their Table 3, failed to mention an innovative intraoral endoscopic approach first described by S embronio et al. In this technique, the ankylotic bone excision was performed through the pre-auricular access and the resection was completed intraorally, with endoscopic assistance, using a piezoelectric osteotome. The endoscope made it easy to check the medial aspect of the resection and to suture the flap. In addition, the intraoral endoscopic guidance may be useful to in safely removing the ankylotic mass and anchoring the temporalis muscle and fascia flap more accurately, thus reducing the risk of re-ankylosis.

K o et al. add that the disadvantages of their approach include the limited surgical field and the requirement for the surgeon to have a good sense of orientation. However, with the endoscopic approach, this can be overcome by placing small, remotely placed incisions with acceptable scars through which the endoscope is placed thus permitting, direct visualization of a magnified and illuminated surgical field, and unobstructed views for the assistant.

K o et al. also discusses the use of gap arthroplasty with this intraoral approach. There are concerns with limiting treatment of the ankylosis with gap arthroplasty. The operation’s primary goal has always been a meticulous and radical removal of the ankylotic area in order to restore the physiologic function of the lower jaw . To ensure such a total resection, it is important to pay attention to the medial and upper aspects of the joint. In my experience, as is that of K aban et al. re-ankylosis is commonly caused by incomplete removal of the ankylotic mass, especially in the medial and upper aspect of the joint. Furthermore, the intraoral approach is unable to reach the upper part of the joint, thus possibly limiting total removal of the ankylotic mass. Finally when completing total resection of the ankylotic mass, the shortened ramus may need to be reconstructed with either with autogenous materials such as the costochondral graft or alloplastic joint prosthesis . None of these techniques are possible with the intraoral approach.

Other disadvantages and complications of gap arthroplasty for the treatment of TMJ ankylosis, includes the onset of pseudoarthrosis, and a greater risk of re-ankylosis. To reduce the risk, many promote the placement of an interpositional material to prevent re-ankylosis . However, partial ankylotic bone resection can lead not only to the reorganization of the whole mass, but also to the complete encapsulation of the interposition materials . Thus the intraoral approach has its limitations should gap arthroplasty be used with or without an interpositional material.

Therefore, the intraoral approach cannot be considered as an alternative; it should be seen as an adjunctive technique to improve the treatment of temporomandibular joint (TMJ) ankylosis.