Abstract: The invention concerns an endoscopic instrument for the high frequency surgical treatment of tissue in body cavities by using a liquid produced as a result of a wash penetrating the cavity. The instrument has a shaft which can be introduced into the cavity and by means of which an active electrode can be placed in the liquid volume. The instrument further has a neutral electrode and a high-frequency generator to which both electrodes are connected by insulated leads. The invention is characterized in that the neutral electrode is arranged at a distance from the active electrode in the liquid volume.

Abstract: A device for flushing the urinary bladder (1) has an instrument inserted from the outside into the inside of the bladder and a feed line (17a, 17b, 10) from a supply receptacle (16) feeding pressurized flushing liquid and a drain line (11, 15) to a drain. The interior bladder fluid pressure is regulated by a pressure regulator connected through the feed line to the bladder. The regulator is held at constant height. The pressure regulator has a valve (31, 32) controlling the flow cross-section which is in turn controlled by the pressure sensor (27) located on the side of the valve facing the bladder and ascertaining the pressure in the feed line (17b, 10). The feed conduit between the regulator and the bladder has a constant flow resistance smaller than the minimum possible flow resistance of the drain conduit multiplied by a maximum pressure variation P.sub.Fmax and divided by a maximum allowable bladder pressure P.sub.Bmax.

Abstract: A cutting electrode for medical resectoscope has an insulated loop support displaceable in the axial direction of the resectoscope shaft, the distal end of the support carrrying an un-insulated cutting loop extending from the end of the loop support transversely to the axial direction a predetermined distance depending on the extent of cutting desired. A spacer carried by the loop support extends distally in front of the cutting loop and laterally of the cutting loop a smaller distance than that of the cutting loop and is shaped to provide smooth, low-friction engagement with tissues with which it comes in contact.

Abstract: A device for preparing the insertion canal for inserting an endoscope for percutaneous nephroscopy includes a tubular member which can be guided on a guide wire inserted through the patient's skin and tissue into the renal calyx. The tubular member carries one or more scalpel blades at its distal end for creating incisions along the path of the wire which can then be expanded to provide a canal for the endoscope. Gripping, orientation and insertion depth indicating means are also disclosed.