In Pomroy's method a section of the fallopian tube in excised and the ends ligated. It can be reversed. In Aldridge's method the fimbrial end is buried in the broad ligament. This also can be reversed. In Madlener operation the tube is crushed and ligated. This has a failure rate of 7% and is not done now. This can also be reversed. Fimbriectomy involves excision of the fimbriae and leads to permanent irreversible sterility. Ref: Shaw's Textbook of Gynaecology, 12th Edition, Page 187