No abstract

The current studies results demonstrate that hydrojet spinal surgery might be a safe new method for surgery of disc protrusion and contained prolapse.

Schlüsselwörter: Knochen, Knpchenzement, Endoprothese, Revision, Wassersträhl Konventionelle Werkzeuge haben bei Prothesenrevisionen nur eine limitierte Reichweite im schmalen Zementmantel. Das Druckwasserstrahlschneiden erlaubt eine schmale und präzise Schnittführung und kommt daher als alternative Methode für die Knochenzemententfernung in Frage. Diese Studie vergleicht die Schneidleistung eines gepulsten Wasserstrahls mit jener eines kontinuierlichen Wasserstrahls in Knochenzement (PMMA) und Knochen. 55 Knochen-Proben (Rinderfemora.) und 32 Proben aus PMMA wurden mit einem kontinuierlichen und einem gepulsten Wasserstrahl bei unterschiedlichen Druckniveaus (40 MPa, 60 MPa) und Pulsfrequenzen (0 Hz, 50 Hz, 250 Hz) gekerbt. Um einen Vergleich zu ermöglichen, wurden die Kerbtiefen auf die hydraulische Leistung des auf das Material auftreffenden Strahlanteils bezogen. Während die leistungsbezogenen Kerbtiefen

Water jet techniques have been used in industrial cutting, drilling and cleaning applications for more than 30 years. Plain water is typically used for the cutting of non-metallic materials. The addition of abrasive substances to the stream allows almost any material to be cut. The first medical applications were reported in the early 1980s, when the water jet was used to cut organs. The present study investigates the use of water jet cutting technology for endoprosthesis revision surgery. Bone and PMMA (polymethylmethacrylate) samples were cut at different pressures using an industrial water jet cutting device. Using plain water at 400 bar, PMMA was cut selectively without damaging the bone; above 400 bar, bone was also cut, but the cutting depths in PMMA were significantly greater (p < 0.05). Adding a water-soluble abrasive disaccharide to the water results in a significantly higher removal rate for both materials (p < 0.05), but selectivity is lost, although the differences in cutting depth between the two materials was significant (p < 0.05). With an abrasive, the quality of the cut was better for both materials. The water jet technology--in particular the abrasive technique--can be used to cut biomaterials such as bone and bone cement. The diameter of the jet is a great advantage when working in the confined area at the prosthesis interface. The cutting process is essentially cold, thus eliminating a thermal effect, and the jet reaction forces are relatively low. Accurate manipulation of the hydro jet nozzle is possible both manually and by robot. The results obtained show that it is possible to remove prostheses with this cutting technique, rapidly and with little damage to the surrounding tissue. Problem areas are the development of sterile pumps and the "depth control" of the jet.

No abstract

The different mechanical properties of the joint capsule and the stratum subsynoviale lead to the selective cutting of the water jet. Since the joint capsule was not damaged, the feasibility of WJ synovectomy has been proven. The device can be used for synovectomy in parts of the joint that are not visible as well as in very small joints.