Tubal reproductive function and the development of reversible sterilization techniques.

Research has begun to search for a reliable method of reversing female sterilization. Tuboplastic microsurgical techniques performed in rabbits have revealed pertinent information concerning the oviduct and its mechanisms essential to reproduction. The oviduct is described in 4 anatomic sections: 1) interstitial portion in the wall of the uterus; 2) isthmic portion distal to uterotubal junction; 3) ampullary region; and 4) the infundibulum. The average length of the human tube is 4-12 cm. Well developed collateral blood supply to the oviduct assures adequate perfusion of the tube. Tuboplastic surgery does not comprise tubal vascular perfusion. The neuroanatomy of the oviduct is described. The distal portion of the tube is supplied by vagal fibers from the ovarian plexus. Four cell types are found in the epithelium: 1) ciliated; 2) secretory; 3) intercalary; and 4) deciliated. Cilia transport ovum to abdominal ostrium of the oviduct. Reversal of segments of a rabbits isthmus or ampulla did not prevent pregnancy. Nor did the uterojunction prove critical to reproduction. More research is needed to determine whether tuplastic surgery can restore functional continuity between rejoined tubal segments particularly with regard to normal epithelial function and contractile activity. It must be ascertained how much residual tube isthmus and ampulla are needed to restore optimal pregnancy rates by studying ovum transport. Exact condition of the Fallopian tubes should be documented at laparoscopy and at surgery. Correlation of observations with subsequent fertility will help determine the relative value of various tubal regions. Until more research is completed fimbriectomy should not be performed.