["Bidirectional tunneler": an improved tunneler and shunt instrument for vascular surgery]

When autologous veins or vascular prostheses are implanted for bypass operations or hemodialysis shunts, the use of an appropriate tunneling device is recommended. In order to avoid perigraft hemorrhage and allow undelayed graft incorporation, the tunneler should match the diameter of the implant. Interchangeable shafts with various lengths and blunt tips of various diameters are prerequisites for versatile applicability. The tunneling instrument designed by Kelly and Wick was until now the most versatile on the market. Its main drawback is a handle that is welded to one end of the shaft thus preventing "bi-directional" use. We therefore developed a modified "Bi-directional Tunneler". Its handle can be attached to both ends of the shaft and allow at the same time torsional rigidity for directional guiding. Thus, e.g. in a femoro-popliteal bypass, the distal anastomosis can be accomplished first, followed by the introduction of the "Bi-directional Tunneler" from the knee to the groin. In a further step the tip and handle are interchanged and the graft is also passed from the knee to the groin. Thus, the "Bi-directional Tunneler" offers hitherto unknown versatility in bypass as well as in hemodialysis shunt surgery.