The fallopian tubes are 7-14cm long and the intramural segment ranges from 1,5 to 2.5cm with an average diameter of 100 micron. The intramural portion of the tube is divided in to two segments: a proximal segment, approximate 1 cm in length which follows a straight path, and a 1.5cm distal segment, which is sinuous. The course of the intramural tube is tortuous in 69% of the hysterectomy specimen in one study4.The thick muscular wall and convoluted intramural course make the uterotubal junction a likely site for blockage by uterine debris.

Tubal obstruction can be due to chronic salpingitis, salpingitis isthmica nodosa (SIN),intratubal endometriosis,amorphous material (e.g,mucus plugs),or spasm. Most of the proximal tubal obstructions are thought to be caused by inflammatory process or endometriosis which leads to local fibrosis. But only in 7 out of 18 cases, the surgically resected segment of the occluded tube showed an organic pathology5. In the rest of the cases the tubes appeared normal or with moderate fibrosis or inflammation. So a surgical correction is not warranted in majority of proximal tubal blocks since there is no true block. This principle is the basis for tubal cannulation.

Proximal tubal blockage, suggested by failure of contrast medium to enter the intramural or isthmic portion of either tube, is diagnosed in 10%-20% of HSG’s performed for infertility6.There are no pathognomonic radiographic findings to confirm the presence of tubal obstruction or occlusion. Characteristic findings are seen only in SIN, where a stippled or honeycombed appearance on HSG indicates retained contrast medium in small diverticular projections. Some investigators suggest that selective salpingography may serve as a diagnostic test: if tubal patency is established , then obstruction likely was due to spasm or mucous debris. In support of this, Letterie and Sakas evaluated histologic findings in 15 pateints (27 tubal segments) at laparotomy after failed tubal cannulation7. They found that 93% of these patients had severe disease, suggesting that tubal cannulation might distinguish functional obstructions from true occlusion.

So confirmation of proximal tubal blockage requires a second HSG, selective salpingography or chromopertubation by laparoscopy.

Now it is proposed that the functional proximal tubal obstructions are due to some sort of “tubal plugs” and is the basis for the newer technique of tubal cannulation by hysteroscopy ,sonography or fluoroscopy.

Selective salpingography consists of passing a catheter through the cervix into the proximal tubal ostium, then injecting contrast medium directed to ostia8. Increased pressure generated by direct injection may overcome obstructions associated with plugging. Selective salpingography usually is performed under fluoroscopic guidance.

There are several reports of tubal cannulation using abdominal and transvaginal ultrasound guidance9. The image is inferior to that obtained with fluoroscopy, but air bubbles flowing into the cul-de-sac are an unequivocal sign of tubal patency.

Tubal recanalisation by hysteroscopic control offers a number of advantages over other techniques. First the guidance of the tubal catheter in to the tubal ostia is simple because it is done under direct vision. Second, since it is done along with a laparoscopy the presence of distal tubal disease can be diagnosed and treated simultaneously. So it offers a one-step evaluation and treatment in infertile patient with proximal obstruction.

Hysteroscopic cannulation is a relatively simple technique. Different custom made catheter systems are available. Essentially it consists of a flexible guide wire to negotiate the intramural portion of the tube and a cannula to direct it towards the tubal ostia. A flexible or rigid hysteroscope is done under GA if a simultaneous laparoscopy is performed.

We use a 21 Fr.rigid hysteroscope with 7 Fr.operating channel. Guide wire is Terumo
Guide wire (Radifocus guide wire M diameter O.89mm) and cannula is a 7F outflow catheter.Hysteroscopy is performed and the ostia identified. The7 Fr. Outflow catheter is now introduced through the operating channel and aligned towards the ostia. Terumo guide wire is then introduced through the outflow catheter.

The hysteroscope and outflow catheter are positioned in such a way that, if the guide
Wire is pushed it should enter the ostia.The flexibility of the guid wire is altered by varying the length of the guide wire protruding from the outer catheter.

The guide wire is now pushed into the ostai for 2-3 cm,always keeping the outflow catheters almost in a straight line for easy sliding. If difficulty is encountered, laparoscopy control may be used. It is not necessary to cannulate the ampullary portion
Of tube because it can damage the delicate mucosa. The procedure is repeated on the other side. The hysteroscope is withdrawn and chromopertubation done and observed through the laparoscope to confirm the result of cannulation.

Another catheter system available is Novy set which includes an external catheter with a memory, a 3 Fr.cannulate the orifice and a guide wire to catheterize the fallopian tube. Angioplasty catheter can also be used for cannulation.The balloon can be distended to give a long lasting mechanical dilatation.

Perforation is reported in up to 10% of attempted procedures. Use of appropriate flexible catheter may decrease the risk of perforation. When perforation occurs,it is left to heal spontaneously. Infection is rare.

Transcervical tubal cannulation shouldn’t be performed in presence of known pelvic infection. A marked by distorted uterine cavity may make the procedure technically difficult. The procedure shouldn’t be attempted in patients with known distal tubal disease as it can increase the chance of developing an ectopic pregnancy.

We had reported our initial experience of hysteroscopic cannulation in 31 cases (58 tubes) of proximal tubal obstruction10.At least one tube could be cannulated in 26 cases (83.9%). Associated distal tubal disease was present in 3 cases. 9 patients conceived after hysteroscopic cannulation. Five of these patients had associated pathologists. There

were no ectopic pregnancies. We performed hysteroscopic cannulation in 124 cases subsequently with similar results.

Proximal tubal block is a common infertility problem and needs confirmation by repeat
HSG or laparoscopy .Considering the simplicity of the procedure ,hysteroscopic cannulation should be tried as the first procedure for proximal tubal block. If the procedure is not successful or a pregnancy is not achieved, IVF is recommended. Laparotomy and microsurgical anastamosisis indicated in few situations where other simpler methods fail and technical expertise is available.

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