Apparatus and method for expanding a perivascular cavity at a surgical site includes an elongated retractor having a tip at the distal end for convenient insertion into a perivascular cavity, and having a slidable coupler near the proximal end for convenient coupling to an elevator element supported...http://www.google.es/patents/US5921919?utm_source=gb-gplus-sharePatente US5921919 - Perivascular self-retaining retractor and method
