What is a varicocele?

A varicocele is a collection of abnormally swollen veins in the scrotum. These swollen veins are similar to varicose veins, which can develop in the legs and other places in the body.

Varicoceles involve dilation of the pampiniform plexus, which is a group of small veins located in the spermatic cord. The spermatic cord is a bundle of nerves, ducts, and blood vessels connecting the testicles to the abdominal cavity. Normally, blood drains from the testicles through the pampiniform plexus to the internal spermatic vein towards the heart; however, in a varicocele, the blood flows backwards towards the testicles.

Varicoceles grades

Doctors classify varicoceles into three grades:ⁱ

• ‍Grade 1: The varicocele is only palpable with the Valsalva maneuver (closing the mouth and pinching the nose while attempting to forcefully blow out, which increases pressure in the abdomen and therefore on the testicular veins).
• ‍Grade 2: The varicocele is easily palpable while standing without the Valsalva maneuver.
• ‍Grade 3: The varicocele is visible upon inspection of the scrotum. Large grade 3 varicoceles may look like a “bag of worms” within the scrotum.ⁱⁱ

Varicoceles prevalence

Varicoceles are more likely to occur in older individuals and can get larger as a person gets older. Levinger et al (2007) completed a study of 504 males over the age of 30 and found that the prevalence of varicocele increased by about 10 percent with each decade of life, reaching 75 percent in individuals above 80 years old.ⁱⁱⁱ

Overall, varicoceles occur in 15 percent of males. They appear to be more prevalent among males with subfertility, affecting 35 to 50 percent of males with primary infertility (people who have never conceived) and 45 to 81 percent of males with secondary infertility (people who have had at least one previous conception).^iv,v

How does a varicocele impact fertility?

An important function of the pampiniform plexus is to cool the testicles by giving off heat as blood is drained out of the scrotum. Spermatogenesis (creation of sperm) requires a cooler temperature than the rest of the body. When there is a varicocele, blood pools in the scrotum, which can increase scrotal temperature and lead to impairment or disruption in sperm production.^vi

In children, a varicocele can also prevent the testicle from developing normally, which can lead to testicular atrophy (shrinkage). Sperm production may also be impaired in that testicle.

Studies also suggest that varicoceles can have detrimental effects on sperm production, maturation, and transport.^vii While the degree of the impact on fertility is uncertain, research indicates that varicocele surgery can significantly improve natural pregnancy outcomes and reduce the need for assisted reproductive technologies (ART).

A meta-analysis by Kim et al (2013) looked at 610 couples diagnosed with varicoceles and subfertility. Of the males, 311 patients underwent a surgical procedure of their varicocele and 299 received no varicocele treatment. The researchers found that the rate of natural pregnancy was 21.8 percent in the group that underwent varicocele surgery compared to 11.0 percent in the group that did not.^viii The researchers concluded that surgical repair of varicocele increased the odds of natural conception for patients with palpable varicocele and impaired semen quality.^ix

Surgical varicocele repair has also been shown to improve intrauterine insemination (IUI) outcomes. In a study with 58 couples undergoing IUI, 34 males underwent varicocele treatment and 24 did not. The IUI pregnancy rate was 11.8 percent among the group who underwent surgical varicocele treatment, compared to 6.3 percent in the group that did not.^x

What are the symptoms of a varicocele?

Varicoceles may cause pain in the testicles, typically described as dull, aching, or throbbing; testicular pain associated with varicoceles is rarely acute or stabbing. Some individuals may also notice a “heaviness” in the scrotum, which worsens with prolonged standing, exercise, or activity.^xi

That said, varicoceles usually have no symptoms and are often diagnosed incidentally upon physical examination or during a fertility evaluation.^xii

Varicoceles are found in the left testicle 80 to 90 percent of the time. If a left-sided varicocele is present, there is a 30 to 40 percent chance that a varicocele will be present on the right side as well.^xiii

What causes a varicocele?

There are multiple potential causes of varicoceles. Here are three of the most common causes:^xiv,xv

• ‍Valve weakness or absence: All veins contain valves that prevent the backflow of blood. It is thought that the most common cause of a varicocele is weakness or absence of these valves. If there are weak or absent valves, blood will drain towards the testicle with gravity instead of back towards the heart.
• ‍Angle of internal spermatic vein to renal vein: On the left side, the internal spermatic vein drains into the left renal vein. Sometimes, these veins come together at a sharp angle, which disrupts the blood flow in the veins. It can lead to an enlargement of the internal spermatic vein and pooling of blood in the scrotum.
• ‍Compression of internal spermatic vein between blood vessels: Also on the left side, the internal spermatic vein can get caught between two other blood vessels: the aorta and the superior mesenteric artery. The internal spermatic vein becomes compressed, resulting in reduced blood flow out of the scrotum and causing abnormal enlargement of the scrotal veins. This issue is called the “nutcracker” effect.

Rarer causes of varicoceles include a blood clot in the veins or a mass in or near the kidney leading to compression of veins.

Genetics may also play a role in the development of large varicoceles. A study by Griffiths et al (2018) found that compared to people with a grade 1 varicocele, people with a grade 2 or 3 varicocele were more likely to have a father with a varicocele.^xvi

In addition, males with a lower body mass index (BMI) may be at higher risk for more severe varicoceles. A 2021 meta-analysis of 11 studies found that BMI was higher in people with grade 1 varicoceles, compared to those with grade 2 and 3 varicoceles.^xvii

How are varicoceles diagnosed?

Varicoceles are common and usually found on physical examination in adolescents or during fertility evaluations. The standard diagnostic test for varicoceles is a physical exam. The patient is instructed to stand and take a deep breath or perform the Valsalva maneuver while a doctor palpates the scrotum and testicles.^xviii

In some circumstances (i.e., if the diagnosis of a varicocele is uncertain), a scrotal ultrasound is performed.^xix Ultrasound is the most-used imaging modality for a varicocele.  Ultrasound may also identify “subclinical” varicoceles, which are varicoceles that cannot be detected on a physical exam. However, the current consensus is that subclinical varicoceles should not be treated, as they have not been shown to impact fertility.^xx

Ultrasound imaging can also be used to determine the degree of backward blood flow, known clinically as reflux. The degree of reflux ranges from I to V, with Grade V being the most severe.^xxi

What treatments exist for varicoceles and how successful are they?

Treatment of varicoceles depends on the age of the patient, semen analysis parameters, desire for fertility, and symptoms.^xxii,xxiii

Among adolescents and children, varicocele treatment is somewhat controversial. In general, it is recommended that treatment be considered if there is a difference in testicular size (i.e., a smaller testicle on the side of the varicocele) or if the patient has an abnormal semen analysis. If the varicocele is asymptomatic and the testicles are of equal size, the varicocele can be monitored yearly or every two years with an exam and semen analysis once the patient reaches adolescence.^xxiv,xxv

In the case of an adult with a varicocele, treatment is considered only when the varicocele is palpable; treatment of subclinical varicoceles (varicoceles seen only on ultrasound) has not been shown to improve fertility. Additionally, the following criteria should be met:^{xxvi, xxvii}

• The patient or couple has known infertility
• The female partner has normal fertility or correctable infertility
• The male partner’s semen analysis is abnormal

Varicocele treatment can also be considered in patients with normal semen analyses if the patient has varicocele pain. In this case, treatment is unlikely to improve fertility but may help with symptoms.

Various techniques exist for the surgical repair of varicoceles, including open, microscopic, or laparoscopic surgery, as well as radiologic varicocele embolization:^xxviii,xxix

• ‍Open or microscopic surgery: An incision is made in the lower abdomen, groin, or upper scrotum and the swollen vessels are clipped or tied off.
• ‍Laparoscopic surgery: A surgeon makes a few small incisions in the abdomen to tie off the spermatic veins where they enter the abdomen.
• ‍Interventional radiologic embolization: This procedure involves accessing the veins with a needle and injecting coils or glue to block off the vessels and direct flow away.  

Are varicoceles curable without surgery?

Varicoceles are not cured without surgical or radiological intervention. However, as noted above, treatment is only indicated if the varicocele is associated with infertility or pain.

Pharmacological agents such as oral or topical medications can be used to treat the pain associated with varicoceles. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil®, Motrin ®), as well as scrotal elevation, and limiting physical activities, can help alleviate testicular pain associated with a varicocele.^xxx,xxxi

What happens if a varicocele is left untreated?

In adults, an untreated varicocele is unlikely to cause permanent damage to the testicle. Among children and adolescents, an untreated varicocele can sometimes lead to impaired testicular development. A meta-analysis conducted by Nork et al (2014) found that varicoceles negatively affect sperm production and motility in young males aged 15 to 24, which can lead to male infertility. The authors suggest that treating varicoceles in this younger population may be beneficial in preserving testicular and sperm function, as well as future fertility.^xxxii

What are the other risks or complications associated with varicoceles?

In addition to male infertility, there are other risks or complications associated with varicoceles:

• Scrotal and testicular pain
• Swollen scrotum
• Slow testicular growth in children
• Low testosterone production

Conclusion

Many males have varicoceles and never experience any symptoms or problems with their reproductive health. However, research does suggest that varicoceles are more prevalent in individuals with fertility issues.

Patients experiencing varicocele symptoms should talk to a healthcare provider. Treatment for problematic varicoceles is available and may also improve fertility and pregnancy outcomes.