Dispensability of fimbriae: ovum pickup by tubal fistulas in the rabbit.

This study was carried out to test the general belief that fimbriae should be considered almost indispensable to ovum capture. Surgical procedures, including resection of the mesotubarium superius and infundibulum tubae together with the creation of a fistula, are described. An attempt to enhance tubal patency by temporarily using estrogens is discussed. Ovum pickup was determined by flushing both tubes and the uterus 2 days following ovulation induction. The prior use of estrogens did not appear to have increased subsequent ovum pickup in control animals; on the contrary, it even seems possible that estrogens had negatively influenced pickup by the fistulas. With five fistulas, however, three recovered ova represented a pickup rate of 7% to 14% of all ova available following one human chorionic gonadotropin-induced ovulation. These figures suggest that ovum pickup by terminal ampullary fistulas is not negligible; they might indicate that absence of fimbriae offers neither good protection against pregnancy following sterilization nor a hopeless prognosis for fimbriectomy reversal when a distal patent tube is present.