In 1880 Lungren first carried out tubal ligation following cesarean section for the purpose of female sterilization (Knight and Summit, 1946), which Blundell had suggested in 1834 (Young, 1944). Thereafter numerous methods have been devised by many investigators to assure tubal sterilization but with varying, failure pregnancy rates (Madlener, 1919; Irving, 1924; Pemeroy, 1930; Kroener, 1935; Uchida, 1961; et al.).
Among those the Pomeroy method of tubal ligation is the most widely used because of its effectiveness and ease with which it can be performed. Its failuree rate has been reported between 0. 19 and 0. 5% (Garb, 1957; Overstreet, 1964; White, 1966).
In recent years laparoscopic tubal sterilization has become popularized in conformity with increased demand of world-wide family planning programs, because it can be performed as an outpatient procedure with either general or local anesthetics. In laparoscopic sterilization, the electrocoagulation of the tube has been the standard technique of tubal occlusion (Anderson, 1937; Power and Barnes, 1941; Palmer, 1962; Step toe, 1967), however, it has the danger of causing seilous burns during the procedure.
To avoid such a burn injury during electrocagulation, non-electrical methods such as the clip application technique by Evans (1953) and Hulka (1973) and the silastic band application technique by Yoon et al (1974) were developed and they are under further study.
Despite the various methods of tubal sterilization, only a few investigators have. studied the pathologic process of tubal occlusion by gross and microscopic examination. Anatomical findings by Marquez-Monter et al (1972) were presented of fallopian tubes occluded from 4-28 months via culdoscopy and using tantalum clips for the purpose of fertility control in 47 women. They described that different patterns of lumen narrowing leading to permanent occlusion may be obtained in consequence of either different individual tubal response to the clipping procedure or to a different force of compression of the clip.
Yoon et al (1974) had within 1 year laparoscopic reexamination in 4 patients who had tubal ligation by the silastic band; 3 patients demonstrated separation and closure of the proximal and distal ends of the fallopian tubes at the site of the applied silastic bands. Therefore, these were similar in appearance to fallopian tubes following the Pomeroy procedure. In the last one, the silastic bands were in position and contained fibrosed segments of tube. So far, there is no systematic explanation about the foreign-body reaction and the location of silastic band as well as the condition of the tube after long application of a silastic band, and also there is a lack of information concerning the pathologic process to the tubal occlusion.
This experiment was undertaken to study the fallopian tubes ligated by silasic band and by chromic catgut for the pathologic process of tubal occlusion. It was done to investigate the mechanism of tubal occlusion in rabbits using both silastic and chromic catgut as well as to study the foreign body reaction and the ultimate location of the silastic band.
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