Computer-guided gap arthroplasty: a new approach to the execution of preplanned osteotomies for the treatment of bony ankylosis of the temporomandibular joint.

The purpose of this study was to assess the efficacy of 3-dimensional, printed, patient-specific guides to direct virtual gap arthroplasties that were designed for five patients with advanced unilateral ankylosis of the temporomandibular joint. The guides were used to mimic the intraoperative creation of five preplanned osteotomies, as well as simulating the width and depth of the bone cleavage. The accuracy of the devices in guiding the surgical simulation was assessed by superimposing the preoperative and postoperative computed tomographic scans. The devices were easily put in place with smooth uniform surgical bone cleavage, and favourable postoperative outcomes. The statistical analysis between the planned and surgical gaps, showed that the difference in dimensions was not significant (p=0.1018). The patient-specific gap arthroplasty was neither too near the skull base nor did it jeopardise the height of the mandibular ramus.