How RISUG Works

Plastic With a Punch: How RISUG Works

A vasectomy is minor surgery, but it's surgery all the same. Even silicone plugs require skilled microsurgery techniques to get them into the vas deferens and then to take them out. The advantages of RISUG become apparent when you consider the procedure. Here's how it goes.

First, the doctor numbs the skin of the scrotal sac. Then, above one testis, he creates a small hole -- one just big enough to locate the vas deferens. After he exposes a short length of the white tube, he uses a syringe to inject about 70 milligrams of styrene maleic anhydride (SMA). The doctor inserts the needle down the length of the vas, making sure the polymer fills the center opening of the tube. As soon as the needle is removed, the vas withdraws into the scrotum, and the doctor repeats the procedure on the other testis. The whole treatment takes about 15 minutes and requires no stitches -- just a small bandage over the puncture.

This ends the "surgical" aspect of RISUG, but the contraceptive compound still needs a little time before it becomes fully functional. In the minutes following the procedure, the polymer solidifies and clings to the microscopic folds making up the inner lining of the vas deferens. The gel doesn't completely block the tube, which means sperm can still make it to the urethra and exit through the penis. But the sperm aren't granted safe passage. As they swim through the plastic-coated vas deferens, the cells become neutralized by the compound's net positive charge. Their tails coil up, their bodies get bent and their cell membranes burst. What comes out in the semen is a collection of broken-down, good-for-nothing sperm totally incapable of fertilizing an egg.

Oh, yeah, and get this: The gel lasts for eight to 10 years or until a man decides he wants to become fertile again. Then it's another quick trip to the doctor, who injects a small dose of sodium bicarbonate into the vas deferens. The baking soda increases the pH inside the vas, which dissolves the polymer. Within a few days of the reversal treatment, normal, healthy sperm once again appear in the man's semen.

So why isn't RISUG more widely available? Are clinical trials uncovering hidden dangers or side effects? Up next, we'll cover the clinical reality of RISUG.