Varicocele is a condition where the veins in the scrotum swell and enlarge. This is typically caused by faulty valves in the veins that allow blood to flow backwards. Left untreated, a varicocele can lead to infertility or other complications by increasing scrotal temperature. Common complications of varicocele surgery include infection, bleeding, and hydrocele formation. The surgery aims to correct the valve problem in the veins to improve blood flow and potential fertility issues.