Tunnelling instruments for vascular grafts: problems and solutions.

Abstract

When autologous veins or vascular prostheses are implanted for bypass operations or haemodialysis, the use of an appropriate tunnelling device is extremely helpful. In order to avoid perigraft haemorrhage and allow undelayed graft incorporation, the tunneller should match the diameter of the implant. Interchangeable shafts of various lengths and blunt tips of various diameters are prerequisites for a versatile instrument. Most instruments on the market have an important drawback: the handle is welded to one end of the shaft thus preventing "bi-directional" use. We have therefore developed a modified tunneller that can be used equally well in either direction. The connection between shaft and handle affords torsional rigidity and thus allows precise guidance during insertion. The handle can be attached to both ends of the shaft. Thus, for example, in a femoro-popliteal bypass, the distal anastomosis can be constructed first, followed by the introduction of the tunneller from the knee to the groin. As a next step the tip and handle are interchanged and the graft is passed from the knee to the groin. When a haemodialysis shunt with a PTFE-loop is inserted, the bidirectional use of the tunneller makes it possible to insert the graft with a smooth curve into the smallest possible cavity. Thus, the new instrument set called the "Bi-directional Tunneller" is more versatile and easier to use than other tunnellers presently available.