Selective Hysterosalpingogram
As helpful as a hysterosalpingogram (HSG) can be to diagnose a blockage in the fallopian tubes, there are times when an HSG will suggest that the fallopian tubes are blocked when in actuality they are not. This false appearance of a blockage occurs when there is scarring in the tube or you experience pain during the HSG, both of which can cause the tube to spasm and therefore appear blocked.

In order to double check that your tube is actually blocked, as well as to correct it if it is, a selective hysterosalpingogram will be performed. During this procedure, a tiny, 2mm thick catheter is inserted into your vagina and directed to the tube that appears to be blocked. The specialist will then try to inject radiographic contrast dye into the tube. If this is successful, and the dye spills into your abdominal cavity, then there is no blockage. However, if the dye is unable to go anywhere, then this indicates a blockage, which can be corrected with a wire-guided cannulization.

Fixing the Block
A wire-guided cannulization can pick up where the selective HSG left off. For this procedure, a 1mm thick catheter will be inserted into your tube. Next, a 0.18mm wire is inserted that your specialist will be able to guide through the fallopian tube in order to remove the debris that may be causing the blockage. The catheter is then passed over the wire and another selective HSG is done to see whether or not the blockage has been corrected.

If both your tubes are blocked, your chances of conceiving after being able to successfully unblock at least one tube are generally pretty good. However, a wire guided cannulization for one blocked tube has not been found to significantly improve your chances of a pregnancy. Therefore, your specialist may advise you against having this procedure done if you already have one open tube.

You may experience some minor discomfort during the procedure but it should be less than with an HSG. As with a hysterosalpingogram, a wire guided cannulization carries the risk of infection as well as the possibility of an allergic reaction to the dye. Additionally, there is the possibility of puncturing the tube. However, because the wire is so tiny, the chance of this happening is extremely small.