A lithotrite which forms part of an instrument used by urologists for crushing concretions in the urinary tract is provided by the invention as a modified form of the cutting loop of a resectoscope, which is an instrument normally used in transurethral resection procedures.

Method and device for catheterizaton within human ducts so as remove concretions, plaques or sclerotic clots, including generating exteriorally of the human body a series of high voltage pulses of sufficiently low amperage to avoid harm to human tissues, directing said pulses within an insulating medium into the human ducts to the situs of said concretions and selectively discharging sid pulses radially outwardly in order to impact across the surface of said concretions. A liquid may be flowed peripherally of discharging and against the concretion so as to achieve a hydroelectric cavitation. A suggested apparatus includes a pair of flexible electrodes insulated one from the other and co-terminating at the situs of the concretion. The positive electrode is positioned coaxially of the encircling negative electrode, such that the electrical discharging is radially outwardly from the positive electrode to the encircling surface of the negative electrode.

An instrument for attacking calculi of a patient by hydraulic impacts formed by electrical discharges in a liquid medium surrounding the calculi by detecting if the discharge end of the lithotrite of the instrument is adjacent to tissue of the patient and detecting by measuring the conductivity of the liquid medium and determining whether the measured conductivity falls within predetermined levels.

Method and device for disintegrating concretions, or sclerotic clots within human ducts. The method and system are particularly adapted to disintegrating stones in the ureter and kidney, as well as the bladder. The method includes axially abutting the concretion within the human duct while outwardly distending the walls of the duct adjacent the concretion, directing a series of high voltage, low amperage pulses into the ducts and discharging the pulses radially outwardly across the surface of the concretions, while flowing a liquid peripherally of the discharging pulses, so as to direct an hydroelectric impact against the concretion. The outward distending of the walls and the flowing liquid, particularly in narrow human ducts such as the ureter, prevent tissue damage by shock and burning.

A method and device is described for removing concretions such as calculus stones within human ducts such as the ureter or kidney. The device includes a flexible probe insertable through the human duct so that a tip thereof is juxtaposed against the concretion. The probe includes a positive electrode extending coaxially within the conduit and embedded in a solid electrically insulative material. A negative electrode is coextensive with and outwardly encircles the positive electrode. The solid electrically insulative material stops short by a distance R from the end of the probe, thereby leaving a recess without solid insulation between negative and positive electrodes at the tip end of the probe. The recess achieves a more efficient fragmentation of target calculi at lower energy, with less human tissue damage and increase in useful probe life.