Page 121 - Demo

Stock or patient-specific TMJ replacement1194Two scales often used to evaluate TMD severity and joint degeneration are the Wilkes’ staging classification for internal derangement of the TMJ and the Helkimo index.(30,31) Whereas the Helkimo index has three subindexes (anamnestic, clinical, and occlusal dysfunction), the Wilkes classification is based on both clinical and radiological properties. Both indexes have wide ranges, with the final stage coming into consideration for TMJ TJR surgery.(30,31) As such, while two patients might have a similar score on the Helkimo index(31), the amount of bony destruction can be significantly different. However, surgeons are currently unable to report this distinction in severity due to the lack of diagnostic tools for end-stage TMD. Nevertheless, anatomical abnormality affects both the choice of implant system and one- versus two-stage surgery, as well as the post-operative results. When comparing MMO, pain and diet, the relative numbers of patients with ankylosis and severe inflammatory/degenerative joint disease in the study group can affect the post-operative improvements.(5,27,32)Table 9. Grading of ankyloses of the TMJ by Turlington and Durr.(29)Grade 0 No bone islands visibleGrade 1 Islands of bone visible within the soft tissue around the jointGrade 2 Periarticular bone formationGrade 3 Apparent bony ankylosisAbbreviation: TMJ: temporomandibular joint.Many surgeons prefer the use of a patient-fitted system in case of more severe anatomical abnormalities.(5,8,33,34) This was illustrated by Gonzalez-Perez et al.(17) who opted for a PSI system in patients with large and complex defects. The amounts of subjective and objective improvement diminish as the severity of anatomical abnormalities and number of previous treatments increases, due to compromised (neuro)muscular anatomy and function.(13,35,36) When a patient-fitted system is preferred in case of severe TMJ degeneration or in revision surgery, it is obvious that its potential for post-operative improvement is more limited compared to a stock implant system that is usually indicated in less severe or primary cases. This is a major contributor to bias in the meta-analysis. Nikolas de Meurechy NW.indd 119 05-06-2024 10:14