Technical improvements over the past twenty years have made endos copy the procedure of choice for examination of the hollow organs of the genitourinary and gastrointestinal tracts. The development of electro surgical techniques, laser technology, injection therapy, and a wide variety of other modalities now allow the endoscopist to treat many problems that in the past required open surgery. The simultaneous development of transcutaneous abdominal sonography has had an equally dramatic impact on the practice of gastrointestinal and geni tourinary surgery. The marriage of these proven...