Sudies in simpler tubocclusion methods

Abstract

This report reviews animal and human studies undertaken to develop simpler, safer, and more acceptable methods of female sterilization. Animal studies revealed inadequate prevention of pregnancy by tubocclusive methods from within the uterus, and the laparoscopic route was chosen. A series of clips were evaluated, and a clip was designed which would have a spring load, be wide enough to cause true tissue necrosis, have a firm grip on the tube to prevent dislodgement, and have a smooth external surface. Extensive human trials of the clip and applicator have resulted in over 1,000 patients with clips applied by 27 physicians in 10 centers throughout the world. Six pregnancies appear to have been due so far to application onto structures other than the isthmic portion of the tube. Complications due to the clip itself appear to be minimal, and the feasibility of performing this operation under local anesthesia in a hospital facility other than the operating room is currently under evaluation.

PIP: Studies leading toward current developments of simpler female tubocculsion are reviewed. Transvaginal occlusion of the uterotubal junction has had relatively high failure and complication rates. To overcome the hazards of blind application, hysteroscopy was used. A continuing tubal patency rate of 10-15% after electrocoagulation leaves this method in the experimental stage. Other experimental methods of occluding the tubes from below have included cryosurgery, biologic glues, silver nitrate paste, quinacrine, and prosthetic devices such as silicon injection and plugs. For a peritoneal approach the methods of Pomeroy and vaginal colpotomy have been used. Culdoscopy, using plastic or metal clips for the tubes, was not satisfactory but culdoscopy and tubal resection are currently performed. Laparoscopy, with advances in equipment and optics, has led to greater use of this method. Bowel perforations from electrocoagulation have stimulated use of nonelectrical methods of tubal occlusion. The pig was chosen for animal studies. A clip was designed to be used through the laparoscope. It would occlude the tube, not be easily displaced, and could be removed for reanastomsis. This clip was approved for trial in humans. The clips have been applied under local anesthesia. Full operating room facilities have not been needed. Nitrous oxide was found to be better than carbon dioxide for induction of pneumoperitoneum. In 1973, a total of 10 residents, 8 U.S. physicians, and 9 overseas physicians were trained to use the especially designed clip applicator. They are all currently using this method. Auxiliary equipment for gas regulation was designed as a portable unit. As of March 1974 there have been 400-500 sterilizations, using this clip, done in the U.S. and an additional 500-600 done overseas for a total of over 1000 cases. In the Chapel Hill series, 8% of patients have experienced vagal reflex during the recovery period. This has responded promptly to atropine given iv. Skin infections have followed in 2 cases and 2 patients were hospitalized postoperatively to treat an unsuspected PID. In all, 2 laparotomies have been needed. No deaths have been reported. Malfunctioning clip applicators have caused a few difficulties. To date 6 pregnancies have been reported, all from the Chapel Hill series. In all known failures, clips were found to have been incorrectly placed. The clips have been effective in occluding the isthmic portion of the tubes. Later reanastomosis would therefore be more easily done than after the Pomeroy operation The potential of this method for population control is significant.