Surgical cutter operated with direct current

A surgical implant-cutting instrument of bipolar type, operating on direct current, the implant-cutting instrument comprising:

• an instrument head on which at least two mutually opposing instrument branches are arranged which between them define a cutting gap extending in a longitudinal direction of the implant-cutting instrument, for receiving therebetween an electrically conductive implant or implant section;
• a current control device;
• and an electric/electronic contact quality detection device, wherein mutually facing longitudinal sides of the at least two mutually opposing instrument branches each form an electrode or are each equipped with at least one electrode, wherein at least one electrode is spherical cap-shaped so that the electrodes achieve at their mutually facing sides a punctiform contact, wherein the current control device is configured to apply to the electrodes a DC cutting current comprising a direct current of predetermined or adjustable current strength in a pulsed or timed way such that a quantity of current in at least one current pulse or cutting impulse is sufficient to melt, from the outside, a wire portion of the implant in contact between the electrodes at locations where the electrodes and the wire portion of the implant contact each other, and wherein the electric/electronic contact quality detection device is configured to perform a contact-quality detection test sequence prior to a cutting operation of the instrument and chronologically before application of the DC cutting current to the electrodes, or separately and independently from the cutting operation, the contact-quality detection test sequence providing an application to the electrodes of a test current below the DC cutting current, or an application to the electrodes of the DC cutting current but with a test impulse duration below a duration of the at least one current pulse or cutting impulse, in each case in order to determine a contact resistance between the electrodes and the implant or implant section, according to a principle of four-conductor-measurement.