Recurrence after varicocele surgery is the most commonly encountered problem after varicocele surgery. The chances of recurrence vary with different surgical approaches. The highest recurrence rate after open surgery via retroperitoneal route is reported up to 7-35% with an average of 14.97%, followed by embolization surgery with 2-24% with a flat 12.7%, laparoscopic surgery with a recurrence rate of 2.17-7.14% with an average of 4.3%, traditional surgery via inguinal route with a lower recurrence rate of 2.63% and microsurgery with the lowest recurrence rate of 1.05%. So, why does recurrence occur after varicocele surgery? First of all, the most common cause of recurrence is a leaky internal spermatic vein. With careful surgery, it is very unlikely that a larger vessel will be missed during surgery. What is missed are often small branches of the vein, which are difficult to identify with the naked eye and easy to miss without the use of microscopic magnification equipment. These small vessels will gradually expand later, leading to recurrence. The second major cause of recurrence is the failure to ligate the external spermatic veins. There are three venous reflux systems in the spermatic cord: the internal spermatic vein, the external spermatic vein and the vas deferens vein, all of which are associated with the development of varicocele. The external spermatic veins have a large variation, and some people have no external spermatic veins, or they travel abnormally, making them difficult to find intraoperatively. The external spermatic veins usually leave the spermatic cord at the external ring opening and can be found via the inguinal or external ring opening route, whereas retroperitoneal or laparoscopic surgery cannot ligate the external spermatic veins due to the high incision location, which accounts for the high recurrence rate after retroperitoneal or laparoscopic surgery. Other less common causes include retroperitoneal space-occupying lesions such as renal tumors that can also lead to recurrence. In addition, varicose veins of the vas deferens are also a cause of recurrence. The vas deferens has two venous return systems, one of which can be preserved to meet the return of the testes. If the vas deferens is found to be dilated intraoperatively, exceeding 3 mm, it should be ligated.