Abstract

PIP: The radiographic appearance of ring-like densities in the true pelvis, when associated with pain, may suggest the presence of ureteral calculi or phleboliths, leading to either misdiagnosis or oversight by the physician who is unfamiliar with the appearance of fallopian tube occlusion rings. Tubal ligation of any type may be associated with intermittent lower abdominal pain. The recognition of fallopian tube occlusion rings may result in an accurate diagnosis of the cause of pelvic pain. 2 figures illustrate the appearance of the rings. Silicone rubber rings may be placed over a knuckle of the midfallopian tube as a highly reliable sterilization technique. The rings themselves are composed of barium sulfate-impregnated dimethypolysiloxane, an inert siliconized synthetic rubber. They have an outside diameter of 3.6 mm, an inner diameter of 1.0 mm, and are 2.2 mm thick. Foreshortening, obliquity, and film magnification may result in minor variations in dimensions. A review of more than 4000 procedures during the early experience with occlusion ring sterilization, the number of pregnancies was less than 1 in 600. The pregnancies usually occurred because conception occurred before the procedure or because of misplacement of the rings. Lower abdominal pain and bleeding continue as the most serious postoperative complications. Within the true pelvis the fallopian tube occlusion rings may lie close to the course of the pelvic ureters, simulating ureteral calculi. Ureteral calculi rarely have central lucencies. When seen at an angle or on end no central lucency may be visible. The rings may be overlooked amidst pelvic phleboliths. Arterial calcifications are curvilinear yet usually form an incomplete circle, and they rarely appear as sharply marginated as fallopian tube occlusion rings.