either you aren't stating the problem correctly or the correct name of the procedure.
If you are talking about Varicocele embolization, then yes, it is safe and CAN be effective. Depending upon the MD who is doing it and your particular extent of problem. Typically it is an Interventional Radiology procedure in which the draining veins of the testicles are embolized with coils, (little thin metal wires shaped like tornados or balls or some other 3D shape. These are advanced through a catheter and placed into the vein, basically 'blocking' bloodflow. Depending upon the actual problem, this might require several coils or possibly just one, in the left gonadal vein. (Typically drains to the left Renal Vein and valves can become incompetant, thereby allowing for backflow through a long column of blood.
It is a safe and appropriate procedure in the appropriate person and in skillful hands.