The use of virtual planning and navigation in the treatment of temporomandibular joint ankylosis.

Temporomandibular joint ankylosis is not common in our community but can occur as a result of severe facial trauma or significant connective tissue disorders such as rheumatoid arthritis, osteoarthritis and psoriatic arthritis, and unfortunately as a result of iatrogenic causes. Ankylosis surgery is aimed at gap arthroplasty and mobilization of the joints. However, the removal of the bony ankylosis and the production of a gap between the ramus of the mandible and the base of the skull is often difficult because of the size of the ankylosis and the anatomy on the inner aspect of the mandible. As a result of this, the author has found that surgical navigation has been useful with the removal of the ankylosis, both on the medial side of the mandible and the cranial base. Once the ankylosis has been freed and the mandible mobilized, the gap arthroplasty needs to be maintained or the release of the ankylosis will fail and the joints will re-ankylose. It is important to maintain the space produced by the arthroplasty but this is difficult when autogenous materials such as temporalis muscle, dermis fat and other like materials are used. The gap ultimately closes under the influence of the masseter and medial pterygoid muscles and the ankylosis may return. This case report presents three representative patients in whom ankylosis has been released and the gap reconstructed with a total alloplastic joint replacement. All patients have had their ankylosis removed with the aid of a navigation system and all patients have been reconstructed with bilateral Biomet prosthesis. One patient has had their implant selected using virtual planning and the production of templates to help with placement of the stock implant.