Geometric considerations of disk repositioning procedures

One approach to treatment of internal derangements of the temporomandibular joint (TMJ) is surgical remodeling and repositioning of the disk and its attachments. Nine joints exhibiting disk displacements (four histological series and five magnetic resonance imagining (MRI) series) were studied to analyze the geometrical and mechanical implications of surgical repositioning. In the central tomographic plane, for example, these cases would have required repositioning the disk 6.9 mm posteriorly (+/- 3.3 mm), removing 5.2 mm (+/- 1.6 mm) of remodeled retrodiskal tissue, and trimming 2.1 mm (+/- 2.0 mm) of disk. This suggests that from gross geometric considerations alone, there is not sufficient viable joint tissue to recommend disk repositioning as a routine procedure.