An apparatus for separating a first layer of tissue, such as the peritoneum, from a second layer of tissue, such as the properitoneal fascia. The apparatus includes a main envelope that defines a main inflatable chamber. The apparatus also includes an introducing device that introduces...http://www.google.co.uk/patents/US5704372?utm_source=gb-gplus-sharePatent US5704372 - Endoscopic inflatable retraction devices for separating layers of tissue, and methods of using 
