Introduction
Background
Varicoceles develop as a result of dilatation and tortuosity of veins of the pampiniform plexus secondary to retrograde flow into the internal spermatic vein (ISV). A varicocele is a common abnormality, occurring in approximately 15% of men. Some patients may have scrotal pain and swelling, but more importantly, a varicocele is considered to be a potential cause of male infertility.1,2,3 This relationship is controversial, but improved fertility and sperm quality have been reported after treatment, including occlusive treatment for varicoceles. On physical examination, large varicoceles are easily identified as the classic "bag of worms" surrounding the testis. Ultrasonography, particularly Doppler ultrasonography, allows accurate diagnosis of varicoceles, even subclinical varicoceles.1,4,5,6,7
For excellent patient education resources, visit eMedicine's Men's Health Center and Imaging Center. Also, see eMedicine's patient education articles Testicular Pain and Understanding the Male Anatomy.
Longitudinal sonogram through the left testicle. This image shows several large anechoic tubes (2.4-6 mm in diameter) lying behind the upper and middle poles of the testicle. The diameter of these tubes increased by 1.5-2 mm with a Valsalva maneuver (not shown). T = testicle; v = varicocele.
Left testicular venogram. This image shows a left testicular varicocele before embolization. Note: radiographs of varicoceles should be avoided to restrict radiation exposure.
Upper image: Longitudinal sonogram through the pampiniform plexus of the left testis. The image shows several anechoic tubes. Lower image: The application of color Doppler imaging in the same patient shows bidirectional flow within the anechoic tubes.
Pathophysiology
A varicocele (ie, dilatation of the veins of the pampiniform plexus) may be caused by incompetent or absent valves of the spermatic veins. The right spermatic vein enters obliquely into the inferior vena cava and is somewhat protected anatomically. Idiopathic varicoceles are more common on the left, where the right-angled entry of the left spermatic vein into the relatively horizontal left renal vein leads to a greater incidence of varicoceles.
Far less usual causes of a varicocele may be due to the compression of a renal vein by tumor, an aberrant renal artery, and an obstructed renal vein. Other rare causes implicated in the causation of varicoceles include azygos-hemiazygos continuation with an anomalous intrahepatic connection (bilateral varicocele), aortic aneurysm associated with an aorta–left renal vein fistula,8 false aneurysm from an aortic graft, and inferior vena caval obstruction.
The diagnosis of a varicocele is clinically important for several reasons. Varicoceles cause pain, which is usually experienced as a dragging discomfort. Solitary right varicoceles may be associated with renal and retroperitoneal masses, including renal cell carcinomas. The presence of a varicocele may be associated with infertility.
Factors implicated in the causation of infertility include impaired spermatogenesis and sperm motility secondary to elevated scrotal temperature, slow blood flow or stasis within the dilatated vein, and reflux of toxic material from the adrenal vein. Testicular biopsy in patients with infertility and varicoceles show some changes that are indistinguishable from those of primary testicular failure. These include a variety of changes in the Leydig and Sertoli cells.
Venous hypertension in the spermatic cord veins may be responsible for the aforementioned effects on the testis. The size of the varicoceles may not be a key predictor of infertility in that size seems to have no relationship to improvement in spermatogenesis after corrective surgery.9 In all probability, subclinical varicoceles may be responsible for the vast majority of cases of male infertility.
With Doppler ultrasonography, 2 types of retrograde flow in varicoceles have been described. These include the shunt-type varicocele and the stop-type varicocele (see Image below and Image 6 in Multimedia).10 The shunt-type varicocele occurs in 86% of patients and is associated with diminished sperm quality as well as with a medium to large varicocele. The stop-type varicocele involves reflux, which is only brief, and the sperm quality is normal and associated with a subclinical varicocele. Shunt-type Doppler flow occurs because insufficient distal valves allow spontaneous and continuous reflux from the internal spermatic vein into the cremasteric vein and the vein of the vas deferens via collateral vessels. The stop type of flow, also known as the pressure type, occurs in patients with intact intrascrotal valves. This type allows only a brief period of reflux from the spermatic vein into the pampiniform plexus when a Valsalva maneuver is performed.
Line diagram of a typical bidirectional Doppler recording of a stop-type varicocele (red) in which flow is stopped by a competent valve in the pampiniform plexus above the level of communicating veins. The shunt-type of varicocele is depicted in blue. Because the valves in the pampiniform plexus contiguous to the testicular veins are incompetent or absent, venous flow is shunted via communicating veins into orthograde draining veins; these are shown to represent deferential and cremasteric veins at contrast venography.
On bidirectional Doppler sonograms, steady flow is recorded in both retrograde and orthograde fashions. Note: Several factors affect the flow, including the position of the patient, Valsalva maneuvers, and the position of the probe.
Recurrence of varicoceles can be as high 20% in patients after embolotherapy and/or surgical ligation of varicoceles. Hamm et al found that thermography is superior to ultrasonography in the follow-up imaging of patients who had undergone sclerotherapy and who were evaluated for persistent venous disease.11
Intratesticular varicoceles are seen in fewer than 2% of the symptomatic population. These may mimic other intratesticular lesions on sonography. Earlier studies have shown that intratesticular varicoceles are an extension of extratesticular varicoceles; however, a study by Das et al showed fewer cases were associated with extratesticular varicoceles. Intratesticular varicoceles are frequently bilateral; however, when they are solitary, the intratesticular varicoceles are more common on the right side.6
Frequency
United States
Clinical varicoceles occur in 10-15% of men; they are found in 21-39% of men in whom infertility is investigated. The varicoceles are mostly left sided. Subclinical varicoceles have been reported in 40-75% of infertile men. The incidence of bilateral varicoceles varies from 10-70%, with the higher percentage reported by McClure and Hricak in infertile men with palpable and nonpalpable varicoceles.7
International
The frequencies of varicoceles in Europe are similar to those in the United States, but the incidence in the rest of the world is unknown.
Mortality/Morbidity
Patients with varicoceles may present with vague discomfort or infertility. The most consistent semen abnormality in men with varicoceles is poor sperm motility, followed by abnormal sperm morphology and a reduced sperm count. After varicocele embolotherapy, as many as 50% of subfertile men are able to achieve pregnancy in their female partners.
The cost and morbidity related to embolotherapy for varicoceles are less than the cost and morbidity after surgical treatment. With surgery, complications such as a hematocele/hydrocele and epididymitis may develop. An acute varicocele may be a presenting feature of a more serious underlying pathology, such as a retroperitoneal tumor.
Age
Men of any age can be affected, although most patients present in early adult life.
Anatomy
The components of pampiniform plexus include the location of the ISV in a ventral location, which drains the testis. The vein of the vas deferens is mediodorsal and drains the epididymis. The cremasteric vein on the laterodorsal aspect drains the scrotal wall. All of these veins merge to form the pampiniform plexus. Distal to the superficial inguinal ring, the pampiniform plexus is drained by 3-4 veins traversing the inguinal canal to the abdomen through the deep inguinal ring. These veins coalesce into 2 veins, which ascend in the retroperitoneum; the veins join to form the ISV, before opening into the middle of the renal vein on the left and the inferior vena cava on the right.
The left ISV enters the left renal vein directly opposite the adrenal vein. In 20% of patients, the left ISV may immediately split into 2 or 3 branches before entering the left renal vein. An important collateral vein joins the ISV overlying the upper third of the sacroiliac joint. This collateral may communicate with the inferior mesenteric vein and is usually accompanied by a parallel collateral vessel from the inguinal canal. In addition, collateral vessels from the proximal and distal renal veins as well as the capsular vein join the ISV just above or below the upper third of the sacroiliac joint.
The testicular veins contain valves. Anatomically, most of the valves are located in the upper 1-6 cm of the ISV. As mentioned earlier, varicoceles are more common on the left, and several anatomic factors have been implicated in the increased incidence of left-sided occurrence of a varicocele, including the 90º junction of the left ISV and the left renal vein. In addition, it has been postulated that the overlying descending colon may impede venous return, particularly when an individual is constipated. The association of proximal compression of the left renal vein by the overlying aorta and the superior mesenteric artery has also been implicated in producing increased venous pressure in the left renal vein and, thus, pressure transmission into the ISV.
After sclerotherapy or occlusion of the varicocele, venous return is via the ductus deferens, cremasteric, and scrotal small veins.
In an erect posture, the normal diameter of the largest spermatic vein at the level of the inguinal canal is seldom greater than 2.2 mm, as measured with ultrasonography. This measurement increases to 2.7 mm with a Valsalva maneuver.
Presentation
- A minority of patients are symptomatic, with testicular discomfort and swelling.
- Large varicoceles are easily identified on physical examination; they have the classic "bag of worms" appearance surrounding the testis.
- In patients referred for infertility, the search for varicoceles begins with a physical examination and palpation, with the patient in the supine and upright positions and with and without a Valsalva maneuver.
- Dubin and Amelar devised a grading system to classify varicoceles, as follows12 :
- Grade 1 refers to a varicocele that is palpable only during a Valsalva maneuver.
- Grade 2 refers to a varicocele in which the lesion is palpable without a Valsalva maneuver.
- Grade 3 refers to a varicocele that is visually detectable.
Most experts believe that varicoceles can potentially cause infertility. Evidence supporting this assumption includes the fact that varicoceles are more common in infertile man than in the general population. Men with varicoceles have abnormalities of the semen and testicular histology; semen quality and pregnancy rates increase after varicocele repair.
Acute varicoceles on either side are suggestive of tumors that are either compressing or causing thrombosis of the ISVs. Acute symptomatic varicoceles may be suggested when varicoceles are present solely on the right side or when they remain engorged when the patient is in the supine position. In both adults and children, varicoceles may cause progressive testicular atrophy.
Preferred Examination
Ultrasonography is the examination of choice for investigating varicoceles, and it remains the most practical and most accurate noninvasive technique.1,5,6,7
The role of radionuclide studies and magnetic resonance imaging (MRI) in the investigation of varicoceles is limited; these offer no advantage over ultrasonography.
Venography is the most reliable modality for the detection of subclinical varicoceles because the findings demonstrate abnormal retrograde flow into the spermatic veins or pampiniform plexus. However, the procedure remains invasive and is usually reserved for patients undergoing sclerotherapy.
The ionizing radiation of computed tomography (CT) scanning limits its use.
Limitations of Techniques
- Ultrasonography does not always show reflux into the spermatic veins or pampiniform plexus.
- An ultrasonographic diagnosis of varicocele does not always indicate that such a lesion is the cause of the patient's symptoms and/or infertility.
- Venography is highly accurate, but the procedure is invasive and exposes the patient to ionizing radiation.
Differential Diagnoses
Other Problems to Be Considered
Aberrant renal artery compressing the left renal vein
Aortic aneurysm associated with aorta–left renal vein fistula
Azygos-hemiazygos continuation with anomalous intrahepatic connection (bilateral varicocele)
Compression of the left renal vein by tumor
False aneurysm from aortic graft
Inferior vena cava obstruction
Obstructed left renal vein symptomatic varicoceles
More on Varicocele |
 Overview: Varicocele |
| Imaging: Varicocele |
| Follow-up: Varicocele |
| Multimedia: Varicocele |
| References |
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References
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Further Reading
Keywords
varicocele, spermatic cord venous dilatation, spermatic cord vein dilatation, spermatic cord vein dilation, spermatic cord venous dilation, pampinocele, dilatation of veins of pampiniform plexus, varicosity of pampiniform plexus veins, incompetent valves of spermatic veins, bag of worms, absent valves of spermatic veins, male infertility, internal spermatic vein, pampiniform plexus, male infertility, scrotal swelling, scrotal pain
