A varicocele is a cluster of large, dilated veins that drain blood away from one or both of the testicles. All men have veins in this area. A varicocele develops during puberty if the veins lack the small leaflets or valves that keep blood from flowing backward. Varicose veins in the legs usually occur when the valves lose their strength, but with a varicocele, the valves were missing from the outset. The blood still flows toward the heart as it would normally, but when a man stands, the vein fills and blood flow may be a bit sluggish, allowing the vein to stretch.
Most men do not even know they have a varicocele (or sometimes one on each side of the scrotum). Sometimes a physician will point it out during a physical examination. Other times, it is only discovered after an abnormal semen analysis alerts the physician to look for a varicocele. To find the varicocele, the doctor must examine the man’s testicles while he is standing upright. When a man lies down flat on his back, the veins tend to collapse. Although you might expect a varicocele to look like the swollen blue canals you would see in a varicose vein on someone’s leg, the skin of the scrotum is often thick enough to hide the varicocele. A man would be unlikely to see it, even if he looked carefully in the mirror.
You might guess that a varicocele would form if a man did heavy manual labor or perhaps lifted weights. You would be wrong, however. About 15 percent of American men develop varicoceles by adulthood. No one understands why they occur in some men and not others. Historically, the first recorded description of a varicocele was by Celsius, a Greek physician in the first century B.C. He not only described the varicocele accurately, but was skilled enough to notice that in some men the affected testicle (usually the left) was smaller than its opposite partner.
Despite the fact that varicoceles have been recognized for 2,000 years, we still do not completely understand why they interfere with sperm quality. Indeed, some men with varicoceles have excellent semen quality and establish pregnancies without a problem. Others can have anything from mild to severe problems with their fertility. There are several current theories regarding why a varicocele impacts on fertility.
It is no accident that the testicles hang in the scrotal pouch below a man’s abdomen. They function best in a cooler environment. If the testicles are exposed to the normal body temperature of 98.6 F, sperm formation stops. In the scrotum, the temperature is about 4 or 5 degrees cooler. Research suggests that a varicocele increases the temperature of the testicle, not necessarily to the point of stopping sperm production, but enough at times to change the process. As a result, fewer sperm cells are manufactured, and those that do mature may be less motile (i.e., less powerful swimmers) or misshapen. Another theory is that a varicocele may cause a harmful backflow of chemicals from the adrenal gland on the same side. The adrenal glands sit on top of each kidney and produce hormones that help the body cope with physical and emotional stress. The veins draining blood concentrated with stress hormones from the adrenal glands lie just above the veins draining the testicle. A varicocele may allow the te sticles to get a hefty dose of these chemicals. Other researchers have focused on the idea that blood pooling in the enlarged veins no longer delivers a healthy amount of oxygen to the sperm-producing areas of the testicle. More recent experiments, however, show that a varicocele actually results in an increase in the blood flow to a testicle. The result, though, is an increase in temperature, probably accounting for the decrease in sperm quality.
Obviously, our knowledge about varicoceles is far from complete. Some experts still believe that varicoceles are not a major cause of infertility. Despite the ongoing controversy, we think the evidence does point to varicoceles as a cause of infertility in some men. In 1992, the World Health Organization sponsored a study to determine the impact of varicoceles on semen quality. Members of an international study group examined over 9,000 men in couples with infertility. Twenty-five percent of men with abnormal semen analyses had a varicocele, compared to only 11 percent of those who had normal sperm quality.
Another theory is that a varicocele may cause a harmful backflow of chemicals from the adrenal gland on the same side. The adrenal glands sit on top of each kidney and produce hormones that help the body cope with physical and emotional stress. The veins draining blood concentrated with stress hormones from the adrenal glands lie just above the veins draining the testicle. A varicocele may allow the testicles to get a hefty dose of these chemicals. Other researchers have focused on the idea that blood pooling in the enlarged veins no longer delivers a healthy amount of oxygen to the sperm-producing areas of the testicle. More recent experiments, however, show that a varicocele actually results in an increase in the blood flow to a testicle. The result, though, is an increase in temperature, probably accounting for the decrease in sperm quality.
About 15 percent of men have a varicocele. Many of these men have no known problems with fertility. In recent years, specialists have disagreed, sometimes passionately, about when and whether a varicocele should be treated. While not every varicocele needs to be corrected, there are situations where getting rid of a varicocele can significantly improve fertility.
Again, a number of studies indicate that destroying varicoceles can improve sperm quality for some men, but others have not found treatment to be effective. Still, there are more studies that weigh in on the positive side. One that we find very compelling was done in Israel. A group of infertile couples in which the husbands had varicoceles was followed for three years. Half of the men had their varicoceles corrected and half were just observed for the first year. Of the men who had varicocele surgery, 44 percent established a pregnancy during the next year, compared to only 10 percent of the men who remained under observation. At the end of the year, the remaining men who had not had surgery were offered the operation. Ultimately, slightly more than two-thirds of men who had surgery got their wives pregnant.
The relationship between having a varicocele and having reduced semen quality is strong, but it is not 100 percent. Each couple must be evaluated for their unique infertility factors. Just because a man has a varicocele does not mean he will have trouble fathering a child. Even if a man has a varicocele and also abnormal semen quality, the varicocele may not always account for the fertility problem. Suspicion should be high that the varicocele is part of the problem, however. Overall, research suggests that about two-thirds of men who have procedures to fix a varicocele improve at least one aspect of their semen quality. About 40 percent ultimately establish a pregnancy.
The most common way of correcting a varicocele is to use surgery to tie off the dilated veins. The veins are easiest to spot in the scrotum, but the incision is made in the groin area or upper scrotum where many veins join to become few. Those remaining veins are tied off with delicate sutures. In recent years, urologists who are experienced microsurgeons have used the operating microscope to magnify even the smallest veins. This may allow them to effectively tie off all the dilated veins through a smaller incision. Other surgeons still prefer the more standard approach, using a somewhat larger incision in the groin area, similar to one that would be made to repair a hernia.
Women who have gone through infertility testing are often familiar with laparoscopy, a thin telescope is inserted into the body through a small opening just below the navel. This type of approach can also be used on men, to tie off the varicocele at the point where the veins enter the muscular opening in the wall of the abdomen. After the patient is given general anesthesia, a thin telescope attached to a camera is inserted through the small incision, followed by two smaller probes that are passed through tiny openings made on each side between the navel and the pubic bone. These probes form a passageway through which surgical instruments can be passed. The surgeon uses these instruments to separate the veins of the varicocele from the artery and lymph vessels. Then the surgeon passes a special stapling tool through one of the small openings and blocks off the veins using stainless steel clips.
There is even a way of correcting a varicocele without making a surgical incision at all. This method is called transvenous (i.e., through the vein) embolization (i.e., creation of a clot in a vein). Embolization is done by an interventional radiologist who has had special training. The radiologist uses an X-ray viewing screen (fluoroscope) to see the blood vessels in the crucial area. A very thin tube, called a catheter, is threaded into a neck vein (jugular vein) or thigh vein (femoral vein). Under X-ray guidance, it is passed through the larger blood vessels until it reaches the veins that drain the testicle. This catheter is about the size of a thin spaghetti noodle. The vein and its branches are identified by injecting them with a special X-ray contrast material (dye). Now that the target can be seen, the radiologist plugs the varicocele by passing small stainless steel coils through the catheter and releasing them into each branch of the varicocele. The coils stay in place, creating a blood clot that effectively blocks the vein. In addition to the small coils, an irritating liquid (such as a dense sugar solution) can be injected through the catheter. When the liquid hits the vein, it causes a scarring process to begin, which ultimately shuts off blood flow through the vein. Embolization can be done with very little recovery time. Men are often back to full activities within two days-shorter even than the healing time after microscopic or laparoscopic surgery.