[Arthroscopic dorsal ligament plasty using a hydrojet knife in the TMJ]

The aim of the study was the development and proof testing of an arthroscopic dorsal ligament plasty using a hydrojet knife in the pig TMJ before using in man.

The dorsal TMJ ligament of ten pigs (country breed) was irradiated with a hydrojet (diameter 120 microm, working pressure 90 bar) under arthroscopic visualization. Postoperatively the pigs were controlled for 10 weeks before sacrifice. The isolated TMJs were examined by light microscope and the results compared with untreated pig TMJs. The flows over our arthroscopic instruments were measured to exclude the possibility of damaging surrounding structures by pressure.

Clinically we found no complications after arthroscopic surgery. Food intake was normal and development of body weight according to the food offered. Histology revealed tissue reorganization connected with increased collagen fibre production. Our calculations showed no pressure higher than 1000 mm water column in the TMJ under our working conditions.

The idea of arthroscopic dorsal ligament plasty using a hydrojet works in pig TMJs. Experience in TMJ arthroscopy is necessary. We found no danger of barotrauma under arthroscopy with the hydrojet. The results indicate dorsal ligament shortening by development of scar formations. In our opinion the method can be used for the therapy of dorsal ligament elongation and disk displacements in the TMJ of man.