Silicone devices for tubal occlusion: radiographic description and evaluation

Abstract

Hysteroscopically placed silicone devices for occlusion of fallopian tubes have been evaluated in over 1,300 patients as a means of contraception during the past five years. Radiologic evaluation of the device is vital to the gynecologist both at initial implantation and for follow-up. Normal appearance of plugs and typical examples of complications including separation, extravasation, and abnormal configurations, are presented.

PIP: The silicone fallopian tube implant is being evaluated as a means of contraception. With implants in over 1300 patients, it is important that radiologists be familiar with their typical appearance and proper radiographic evaluation. The occlusion device is placed hysteroscopically after localization of the tubal ostea in the cornual portion of the uterus. The ostea is occluded by a catheter fitted with a detachable tip. Silicone solution is pumped through the tip into the fallopian tube. Curing occurs in situ with the silicone crosslinking to itself and to the detachable tip. Both tubes are occluded during the same procedure. After implantation, pelvic radiographs are obtained for evaluation. Frontal radiographs of the pelvis are obtained after implantation for evaluation. Points to be considered are configuration of the tubal plug, which should be larger in the ampullary portion than at the isthmus or in the cornual portion of the tube; the length of the plug, which should be approximately 6 cm; and the continuity of the plug and the tip. Because of considerable tortuosity of the fallopian tubes, it is often necessary to obtain oblique radiographs to evaluate the entire length of the occlusion device properly. Follow-up radiographs are obtained 3 months later to check the location and to insure continuity of the devices before regular contraceptive measures are stopped. Further follow-up radiographs are obtained 2 years after placement to evaluate late separation. Complications encountered can be grouped into those dealing with device placement, those related to silicone separation, and those dealing with tubal abnormality. Abnormal configuration and placement can be due to injection of silicone solution into the uterine wall with typical extravasated appearance. This configuration is believed to be due to injection into the myometrium or venous sinusoids. Discontinuity of the occlusive device occurs as a result of either incomplete filling of the tube or failure of crosslinkage of the plug to the tip. Abnormal configurations tend not to be retained. Delayed separation is demonstrated on follow-up radiographs with the remainder of the plug being extruded into the peritoneal cavity. Radiographic evaluation of the silicone tubal occlusion device is vital to the gynecologist to insure proprer placement and configuration of the implant. Initial evaluation should insure the integrity of the device. The gynecologist should be alerted when either separation or abnormal configuraton of the silicone is observed.