Mechanical Dilation With a Nylon Monofilament for 0.1-mm Anastomoses

Despite advances in supermicrosurgical techniques, the ability to anastomose vessels with a diameter of less than 0.2 mm remains limited. One of the reasons for this limitation is that the dilation methods currently available, such as inserting the tip of a microforceps into the lumen or topical application of a vasodilator such as papaverine hydrochloride or xylocaine spray, are not effective in very small vessels. To overcome this problem, we have developed a method whereby nylon monofilaments are placed inside the vessel lumen to act as a dilator. Using this method, a smaller nylon monofilament is inserted into the vessel as a guide before inserting a larger nylon monofilament as a dilator. After the smaller guide monofilament has been inserted, it is then much easier to insert another monofilament for dilation, even if it is a larger one. Using this method, even a vessel with a diameter of less than 0.1 mm could be dilated to greater than 0.2 mm. The dilator monofilament can also be used as an intravascular stent in the anastomosis. We have found that anastomosis of vessels with a diameter of less than 0.1 mm is possible using this method. In our experience, the immediate patency rate has been 100%. We believe mechanical dilation with a nylon monofilament is helpful for supermicrosurgery and even ultramicrosurgery.