Anastomosis device with collapsible distal head element

A surgical instrument for bonding body tissue in a hollow organ, the surgical instrument comprising:

• an instrument shank or shaft having a distal end and a first tool element fixedly arranged on the distal end of the instrument shank or shaft;
• a second tool element positioned distally from the first tool element and supported by the instrument shank or shaft to be axially movable relative to the first tool element;
• and
• an annular sleeve-like cutting element being held in an axially moveable manner for cutting body tissue,
• the second tool element comprising a plurality of tool element members in the form of arms that are radially deflectable, the tool element members protruding at least in part in a radial direction and spaced apart from each other in a circumferential direction,
• the first tool element being equipped with at least one electrode having an annular shape,
• the second tool element being equipped with a plurality of electrode elements provided at proximal ends of each of the arms that respectively face the first tool element, the electrode elements being radially moveable by deflecting the arms, wherein the electrode elements are circumferentially distanced apart with clearances in between and thereby forming together an annular shape,
• the second tool element comprising a biasing member that exerts a biasing force to bias the tool element members in a radially inward direction and an axially moveable retaining disk arranged at a radial inner side of the tool element members,
• the cutting element comprising a cutting edge pointing in a proximal direction, the cutting element forming part of the retaining disk to jointly form a stop member which defines a stop for the tool element members,
• the stop member being operable in a first axial position to hold the tool element members against the biasing force of the biasing member in which the tool element members assume a maximum outer diameter,
• the stop member further operable in a second axial position to release the tool element members, allowing the tool element members to deflect radially inwardly by the biasing force of the biasing member and simultaneously the stop member cuts body tissue in the proximal direction.