Updated: Apr 07, 2023
  • Author: Wesley M White, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Practice Essentials

A varicocele is a dilatation of the pampiniform venous plexus and the internal spermatic vein. Varicocele is a well-recognized cause of decreased testicular function and occurs in approximately 15-20% of all males and in 40% of infertile males. Understanding the significance of this anatomic abnormality in the infertile patient requires a brief review of the history, background, and current concepts of functional anatomy, as well as the methods and results of surgical repair, when repair is indicated. [1]


History of the Procedure

In De Medicina, written during the first century AD, the Roman nobleman Cornelius Celsus credits the Greeks with the first description of a varicocele, and describes several forms of surgical intervention. [2]

In the 16th century. Ambroïse Paré (1500-1590), the most celebrated surgeon of the Renaissance, described this vascular abnormality and attributed it to melancholic blood. Barfield, a British surgeon, first proposed the relationship between infertility and varicocele in the late 19th century. Shortly thereafter, other surgeons reported the association of varicocele with an arrest of sperm secretion and the restoration of fertility following repair. Through the early 1900s, reports by other surgeons continued to describe the association of varicocele with infertility.

In the 1950s, after a report of fertility following varicocele repair in an individual known to be azoospermic (ie, without sperm), the idea of surgically correcting varicoceles as a clinical approach to certain kinds of male infertility gained support among American surgeons. Research continued, leading to many published studies that associated varicoceles with impaired semen quality. [3]

In these studies, researchers documented a recurrent pattern of low sperm count, poor motility, and predominance of abnormal sperm forms; this became known as the stress pattern of semen. Although not synonymous or specific to varicocele, the term suggests early evidence of testicular damage. Urologists then began to assess male infertility through the study of sperm, which are evaluated for count, percentage of motile forms, forward movement or motility, and morphology (shape or form); the semen is also evaluated.



A varicocele is a dilatation of the pampiniform venous plexus within the scrotum. Approximately 15-20% of the healthy fertile male population is estimated to have varicoceles; however, 40% of infertile men may have them. How a varicocele impairs sperm structure, function, and production is unknown, but researchers believe it interferes with testicular thermoregulation.




Although varicoceles appear in approximately 20% of the general male population, they are much more common in the subfertile population (40%). In fact, scrotal varicoceles are the most common cause of poor sperm production and decreased semen quality. Varicoceles are easy to identify and to surgically correct.



Varicoceles are much more common (approximately 80-90%) in the left testicle than in the right because of several anatomic factors, including the following:

  • The angle at which the left testicular vein enters the left renal vein
  • The lack of effective antireflux valves at the juncture of the testicular vein and renal vein
  • The increased renal vein pressure due to its compression between the superior mesenteric artery and the aorta (ie, nutcracker effect)

Also of importance is that a clinical left varicocele is often accompanied by a subclinical right varicocele. Up to 35-40% of men with a palpable left varicocele may actually have bilateral varicoceles that are discovered upon examination. A 2004 study by Gat et al suggested that up to 80% of men with a left clinical varicocele had bilateral varicoceles revealed by noninvasive radiologic testing. [4]

Varicoceles vary in size and can be classified into the following three groups:

  • Large - Easily identified by inspection alone
  • Moderate - Identified by palpation without bearing down (Valsalva maneuver)
  • Small - Identified only by bearing down, which increases intra-abdominal pressure, thus impeding drainage and increasing varicocele size


Varicoceles can have detrimental effects on sperm concentration, motility, and morphology, and can reduce sperm DNA integrity and other aspects of sperm function. [5]  Several theories have been proposed to explain the harmful effect of varicoceles on sperm quality, including the possible effects of pressure, oxygen deprivation, heat injury, and toxins.

Despite considerable research, none of the theories has been proved unquestionably, although an elevated heat effect caused by impaired circulation appears to be the most reproducible defect. Supporting this hypothesis is the fact that a varicocele created in an experimental animal led to poor sperm function with elevated intratesticular temperature. Regardless of the mechanism of action, a varicocele is indisputably a significant factor in decreasing testicular function and in reducing semen quality in a large percentage of men who seek infertility treatment.

An unproven hypothesis holds that a varicocele may represent a progressive lesion that can have detrimental effects on testicular function. [6] An untreated varicocele, especially when large, may cause long-term deterioration in sperm production and even testosterone production. If an infertile male has bilateral varicoceles, both are repaired to improve sperm quality.



A patient with a varicocele is usually asymptomatic and often seeks an evaluation for infertility after failed attempts at conception. From 2% to 10% of patients with varicocele complain of pain, which is typically described as a dull, aching, or throbbing pain in the testicle, scrotum, or groin; rarely, it can be acute, sharp, or stabbing. [7]

Careful physical examination remains the primary method of varicocele detection. An obvious varicocele is often described as feeling like a bag of worms. Scrotal examination for varicocele should be a facet of the standard urologic physical examination because of the potential for varicoceles to cause significant testicular damage. The presence of a varicocele does not mean that surgical correction is a necessity.

Bogaert and colleagues analyzed the paternity rates of 361 men older than 30 years who had received early screening and diagnosis of varicocele (at age 12 to 17 years; mean age 15.3 years). Of the 158 men who had an active desire to have a child, 85% of those who had been managed with observation only had achieved paternity, compared with 78% of those treated with antegrade sclerotherapy for varicocele. The investigators concluded that early screening and treatment for varicocele had no impact on paternity in adulthood. [8]

In men with a varicocele, the presence of an initially abnormal semen quality may be a risk factor for future deterioration of semen quality. In a prospective study of men with a mean follow-up of 5 years, among men with an abnormal semen analysis at presentation, the quality of semen degenerated in 28 subjects (87.5%); however, but among men with initially normal semen quality, only 6 patients (20%) had degenerated quality during follow-up. [9]



Reasons for surgical correction of a diagnosed variocele include relieving significant testicular discomfort or pain not responsive to routine symptomatic treatment, reducing testicular atrophy (volume < 20 mL, length < 4 cm), and addressing the possible contribution to unexplained male infertility. A varicocele may cause progressive damage to the testes, resulting in further atrophy and impairment of seminal parameters.

A 2014 committee opinion of the American Society for Reproductive Medicine and the Society for Male Reproduction and Urology recommended considering treatment of varicocele in the male partner of a couple attempting to conceive when most or all of the following conditions are met [10] :

  • The varicocele is palpable on physical examination of the scrotum
  • The couple has known infertility
  • The female partner has normal fertility or ­a potentially treatable cause of infertility, and time to conception is not a concern
  • The male partner has abnormal semen parameters

A man with a palpable varicocele who is not currently attempting to achieve conception is a candidate for varicocele repair if he has one or more of the following [10] :

  • Abnormal semen analysis results
  • A desire for future fertility
  • Pain related to the varicocele

Similarly, 2019 European Association of Urology guidelines in male infertility recommend considering varicocele repair in patients with the following [11] :

  • Clinical varicocele
  • Oligospermia
  • Infertility duration of ≥2 years
  • Otherwise unexplained infertility in the couple.
  • Varicocele treatment is recommended for adolescents with progressive failure of testicular development documented by serial clinical examination.

The guidelines recommend against varicocele treatment in infertile men who have normal semen analysis or in men with subclinical varicocele. [11]

A scrotal varicocele is the most correctable factor in a male with poor semen quality; therefore, varicocele repair should be considered a viable choice for appropriately selected individuals and couples with otherwise unexplained infertility because varicocele repair has been shown to improve semen parameters in most men and possibly improve fertility; in addition, the risks of varicocele repair are small.

A systematic review and meta-analysis found that in oligospermic and azoospermic patients with clinical varicocele, repair of the varicocele leads to improved live birth rates and pregnancy rates with in vitro fertilization (IVF) or IVF/intracytoplasmic sperm injection (ICSI). In men with persistent azoospermia after varicocele repair who require testicular sperm extraction for IVF/ICSI, varicocele repair improves sperm retrieval rates.

Prognostic features

In a prospective study in 123 patients by Shabana et al, the following three preoperative findings were major predictors for a successful outcome of varicocelectomy [12] :

  • Grade II or III varicocele
  • Sperm density >8 million/mL
  • Sperm progressive motility >18%

Condorelli et al found that in patients with varicocele accompanied by dilation of the periprostatic venous plexus (DPVP), sperm progressive motility remained low after varicocele repair, whereas it improved significantly in patients without DPVP.  In addition, patients with DPVP were significantly more likely to have seminal fluid hyperviscosity, and their viscosity quantitative measurement remained significantly higher after varicocele repair, compared with patients without DPVP. [12]

Varicoceles in adolescents

The results of treating varicoceles in adolescents are not as clear as the results of treating varicoceles in adults. Although varicoceles first become apparent in adolescence, their natural history and its timeline for the onset of detrimental effects on testicular function remain unclear. Varicoceles occur in approximately 10-15% of the fertile male population, but not all varicoceles impair sperm function, overall semen quality, or fertility. [13, 11, 14]

Important determinations to be made regarding varicoceles in adolescents are whether (1) the varicocele is a progressive lesion and (2) early repair of the varicocele would prevent infertility.

In 1977, Lipshultz and Corriere suggested that varicoceles were associated with testicular atrophy that was progressive with age. [15] They also observed that testicular biopsy specimens taken from prepubertal boys with varicoceles already revealed histologic abnormalities. However, Diamond et al from Harvard have challenged this concept. [16]

In 1987, Kass and Belman were the first to demonstrate a significant increase in testicular volume after varicocele repair in adolescents. [17] Although Kass and Belman noted catch-up growth, they did not study semen parameters. Collecting a semen sample from an adolescent is not always easy; consequently, studying the effects of a varicocele and the benefits of treatment is difficult.

The indications for repairing varicoceles in adolescents include the following:

  • Significant testicular asymmetry (>20%) demonstrated on serial examinations
  • Testicular pain
  • Abnormal semen analysis results

Very large varicoceles may also be repaired; however, in the absence of atrophy, this indication is relative and controversial. Young men with varicoceles but normal ipsilateral testicular volume should be offered follow-up monitoring with annual objective measurements of testicular volume, semen analyses, or both.

For complete discussion, see Varicocele in Adolescents.


Relevant Anatomy

The testes are the paired male genital organs that contain sperm, cells that produce and nourish sperm (spermatogonia and Sertoli cells, respectively), and cells that produce testosterone (Leydig cells). The testes are located in a sac called the scrotum. The epididymis is a small tubular structure attached to the testes that serves as a storage reservoir wherein sperm mature.

Sperm travel through the vas deferens, which connects the epididymis to the prostate gland. The vas deferens is in the scrotum and is part of a larger tissue bundle called the spermatic cord. The spermatic cord contains the vas deferens, blood vessels, nerves, and lymphatic channels.

The pampiniform plexus is composed of the veins of the spermatic cord. These veins drain blood from the testes, epididymis, and vas deferens and eventually become the spermatic veins that drain into the main circulation of the kidneys. The pampiniform venous plexus may become tortuous and dilated, much like a varicose vein in the leg. In fact, a scrotal varicocele is simply a varicose enlargement of the pampiniform plexus above and around the testicle. Two other veins, the cremasteric and the deferential, also drain blood from the testicles; however, they are rarely involved in the varicocele process.

The image below illustrates the basic anatomy.

A large varicocele is seen through the scrotal ski A large varicocele is seen through the scrotal skin. In a patient with a varicocele, the dilated vessels of the pampiniform plexus are easily appreciated within the scrotum.


Opinions vary regarding the value of repairing subclinical varicoceles in infertile men, but most experts do not recommend it. A 2014 committee opinion of the American Society for Reproductive Medicine and the Society for Male Reproduction and Urology advises that varicocele treatment is not indicated in patients with subclinical varicocele or in those with either normal semen quality or isolated teratozoospermia. [10] :

In addition, discovery of a varicocele at the time of vasectomy or vasectomy reversal is a relative contraindication to immediate repair. A 6-month delayed repair is recommended to allow the development of collateral vessels in order to decrease the chance of vascular compromise to the testicle.