In medical tubular-shaft instruments for gripping and cutting tissue, a safe mode of operation is absolutely essential. It is particularly important that the operating physician be provided at all timIn medical tubular-shaft instruments for gripping and cutting tissue, a safe mode of operation is absolutely essential. It is particularly important that the operating physician be provided at all times with sufficient information allowing him to determine whether the tissue that was to be severed has been successfully severed. According to the invention, electrodes are provided on the instrument,es with sufficient information allowing him to determine whether the tissue that was to be severed has been successfully severed. According to the invention, electrodes are provided on the instrument,as a result of which a mechanical contact between a cutting blade (51) and an associated cutting surface (12) can be determined electrically. as a result of which a mechanical contact between a cutting blade (51) and an associated cutting surface (12) can be determined electrically.