Overcoming a localised obstruction of the isthmus or the interstitial segment of the fallopian tube by pushing a wire or a catheter through it, enabling (in some cases) the tube to be 're-canalised' and so to remain open after being blocked before; it's an attractive alternative to tubal anastomosis and can be performed either during the investigation of tubal infertility with hysteroscopy, laparoscopy and falloposcopy or at the time of carrying out a hysterosalpingogram. Because not all tubes that seem to be blocked are in fact blocked (sometimes a normal tube will not allow fluid to pass through it for hormonal reasons or because of a spasm), care needs to be taken to investigate the tube properly before canalisation is undertaken.

A nodular ('nodosa') thickening of the fallopian tube's isthmus ('isthmica'), probably due to previous salpingitis. Can cause localised obstruction of the tube and, if the obstruction is partial, an ectopic pregnancy can be caused. Overcomeable with microsurgery or tubal canalisation.