Definition and Description of Varicoceles
A varicocele is an abnormal dilation and tortuosity of the veins within the pampiniform plexus of the spermatic cord in the scrotum. 1, 2
Anatomical Description
Varicoceles represent enlargement of the internal testicular vein and pampiniform venous plexus within the spermatic cord, creating a network of dilated, tortuous veins surrounding the testis. 1
The dilated veins can originate from multiple locations: enlarged veins exit the testis and traverse the gubernaculum in 48% of cases, while enlarged external spermatic veins are present in 74% of affected cords. 3
Small internal spermatic veins typically drain into larger veins more proximally in the spermatic cord, with an average of 3.6 lymphatics identifiable per spermatic cord during surgical dissection. 3
Clinical Grading System
Varicoceles are graded based on physical examination findings and vein diameter measurements: 4
- Grade I: Mean maximal vein diameter of 5.0 mm (palpable only with Valsalva maneuver)
- Grade II: Mean maximal vein diameter of 5.8 mm (palpable without Valsalva)
- Grade III: Mean maximal vein diameter of 6.6 mm (visible through scrotal skin)
- Normal testicular units: Mean vein diameter of 2.5 mm for comparison 4
The diagnostic hallmark on physical examination is an increase in diameter of the spermatic cord during the Valsalva maneuver. 4
Epidemiology and Clinical Significance
Varicoceles affect approximately 15% of the general male population but are found in 35-40% of men presenting with infertility, making them the most common correctable cause of male factor infertility. 5, 4, 6, 2
Higher varicocele grades (particularly grade 3) are associated with worse semen parameters and greater testicular dysfunction, though only 20% of men with documented varicoceles will ultimately experience fertility problems. 4, 1
Pathophysiologic Mechanisms
Varicoceles cause testicular damage through multiple mechanisms: 5
- Elevated scrotal temperature from venous pooling
- Testicular hypoxia from impaired venous drainage
- Reflux of toxic metabolites from renal and adrenal veins
- Increased oxidative stress and DNA damage to sperm
Imaging Characteristics
Scrotal Doppler ultrasound confirms varicocele diagnosis by demonstrating: 4
- Dilated pampiniform plexus veins (>2.5-3.0 mm diameter)
- Reversal or augmentation of venous flow with Valsalva maneuver
- Evaluation of testicular volume asymmetry (>2 mL or 20% difference suggests clinically significant varicocele) 4
Important caveat: Routine ultrasonography to identify non-palpable (subclinical) varicoceles is discouraged, as treatment of these does not improve semen parameters or fertility rates. 5, 4