The invention relates to a method of severing or removing a biological structure, in particular bone, having a water-jet cutting system from which a severing medium under high pressure is discharged, and to a cutting-nozzle element and a water-jet cutting system.
Such methods are known on the market and are in use in many different forms and designs. In particular in medicine, it is known to sever, for example from outside, a bone by water-jet cutting. A disadvantage with this is that, in conventional water-jet cutting methods, the soft tissue, and not only the bone, is destroyed. The vascular system in the soft tissue at the bone is important in particular for the knitting of the bone or for the regeneration of the callus. It is therefore necessary during the water-jet removal or severing of biological substances, in particular of bones, to carry out the removal or severing of the bone as carefully as possible. In conventional water-jet cutting methods, the water is applied directly to the exposed bone via a cutting nozzle, in the course of which the vascular system in the bone is also damaged.
An arrangement for cutting by means of a liquid jet has been disclosed by EP 0 636 345 A1, in which arrangement an additional medium is added to a liquid jet by means of vacuum. In this case, pulsing of a liquid jet is produced in a handle, the liquid jet being discharged under pressure losses via an elongated cannula adjoining the handle.