Instrument for the surgical removal of a defective heart valve

An instrument for the surgical removal of a defective heart valve, comprising:

• two body members arranged coaxially and at a distance to one another at or on an elongated member, these body members being able to move axially relative to one another by means of the elongated member in such a way that their instrument cutting elements aligned opposite one another cut out a defective heart valve positioned between the body members,
• the cutting elements of the body members can be radially collapsed, i.e., their radial distance from the instrument axis becomes smaller, for the surgical introduction of the instrument into the surgical field, and there is a contact protective sheath fitted to the elongated member, which is narrow in diameter, and which can be moved axially onto the body members having the radially collapsed cutting elements, so that the advancing (distal) end of the instrument comprising the contact protective sheath fitted to the elongated member, the sheath being narrow in diameter, is moved through the defective heart valve by the width of the piece until it is in a position in which one body member is found on one side of the defective heart valve and the other body member is found on the other side of the defective heart valve,
• the contact protective sheath is pulled off axially from the body members in this position and the cutting elements of the body members can be radially expanded, i.e., their radial distance from the instrument axis is increased up to a diameter that corresponds to the diameter of the defective heart valve to be cut out and to the diameter of the new heart valve that is subsequently to be inserted surgically,
• wherein the cutting elements of each of the body members are formed of two semicircular cutting ring halves, which are joined to one another on the end to form a circular cutting ring by means of a single-axis hinge joint, wherein each half of the cutting ring is made of an elastically deformable flat material strip and each is pre-shaped true to size in edge-wise format to the semicircle diameter required in the radially expanded state,
• wherein the hinge axes of the cutting ring halves are aligned perpendicular to the axis of the elongated member and each is attached by means of the head end of an elastically deformable fish joint that is resistant to extension and compression, the fish joints extending in the longitudinal direction of the elongated member and each is mounted at the elongated member by its foot end,
• and wherein each cutting ring half is held by means of another elastically deformable fish joint that is resistant to extension and compression, extending in the longitudinal direction of the elongated member and mounted on the elongated member by its foot end, the head end of which is coupled to the center of the semicircle on the semicircular-shaped cutting ring halves in the extended state, whereby this coupling and/or the elastically deformable fish joint of the cutting ring halves permits conducting a swivel movement of almost 90° around an axis running crosswise to the fish joint.