Does varicocele cause urinary retention?

Varicocele is swollen testicle veins. Just the veins. These veins carry de-oxygenated blood back to the heart. They really are not associated with your bladder. However, there is a fact that blood pooling from varicocele causes a 70–120 fold increase in testosterone pooling and exposure in surrounding tissue. It is actually a major cause of benign prostatic hyperplasia (BPH). BPH is associated with urinary retention.

Therefore, yes, indirectly, varicocele can effect urinary retention by causing hypertrophy of the prostate and surrounding tissue through testosterone pooling.

I’m doubtful that it effects varicocele effects urinary retention in any other way. Just think about it. Varicocele is simply varicose veins of the testicles. This pools toxicities and testosterone, and causes over heating of the testicles. Not much else to it in all honesty. I don’t see how any of those factors other than testosterone would effect urination.
In fact
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Reference: Reversal of benign prostate hyperplasia by selective occlusion of impaired venous drainage in the male reproductive system: novel mechanism, new treatment - Gat - 2008 - Andrologia - Wiley Online Library