Percutaneous endovascular embolization of the spermatic vein for the treatment of male varicocele is one of the most performed interventional procedure around the world.  It is considered an easy procedure with an optimal learning curve, but, in order to achieve good results, the knowledge of the different techniques and embolic agents is crucial.

From an educational point of view, the procedure can be divided in three different steps: vascular access, venography, embolization.

1. Vascular access: right common femoral vein, right internal jugular vein, or antecubital vein access can be used. Ultrasound should be always used to guide venous puncture.  There is non-statistical significance in differences in dose and screening time and practitioner preference could be the main factor in choosing the access site. But, in certain cases, the antecubital option should be preferred, for example in case of bilateral varicocele or in case of patient predilection. Moreover, some authors suggest the antecubital vein and right internal jugular vein accesses could be associated with easier access to the left renal vein and a higher pushability (9). In case of arm approach, the target veins are the basilic, cephalic and the brachial vein. It is important to assess the diameter, the distance from the skin, and the path of travel (straight veins are easier to cannulate). Patient compliance could be higher in case of arm approach than the groin one (FIG 2). The transbrachial approach has been proved to be safe, effective, inexpensive, and minimally invasive even in the pediatric population (10).
2. Venography: after the introducer sheath is positioned, in order to negotiate the left renal vein several catheters could be used. Main preference is for 5F to 7F catheters (renal catheters or Cobra C1-C2 Type for femoral approach or Simmons/JB2 for antecubital approach).At L2 level the left renal vein is negotiated with the help of a hydrophilic guidewire. A non-aggressive injection of contrast may be needed, while the patient performs a Valsalva maneuver, to ensure seating of the catheter tip in the Internal spermatic vein and for identifying reflux through incompetent valves. If the varicocele is present the contrast agent should fill the internal spermatic vein in a retrograde fashion, towards the testis, especially during a Valsalva maneuver. The visualization of the internal spermatic vein anatomy and the presence of collateral that originates from the renal hilum or paralumbar space is crucial to plan the treatment. Different anatomical variants have been reported in the literature and their correct visualization is essential(11-12)(FIG 3). Particular care should be taken to avoid vessel spasm, which hinders the ability to proceed with the procedure and obscures collaterals. Sometimes microcatheters can be used to negotiate internal spermatic vein.
3. Embolization: A variety of agents can be used to occlude the internal spermatic vein, including coils, plugs, glue, sclerosant agent.

• Coils and plugs:  the 0.035-in. or 0.038-in. metallic coils are deployed at the level of the inguinal canal to occlude the vein. They should be approximately 20% larger than the estimated diameter of the internal spermatic vein. If distal access is difficult, then 0.025-in. or 0.018-in. coils are delivered via any of the standard appropriately sized coaxial microcatheters currently available. Near total occlusion of the lumen can usually be achieved with two or three coils but some authors suggest different approaches, for example coiling of the whole course of the internal spermatic vein or “sandwich” approach with curls of coils in different portions of the vein (FIG 4) The placement of the last coil should be done with cure without protruding into the left renal vein. Poorly deployed coils may migrate into the central venous circulation.  In literature are reported rare cases of right atrium/pulmonary migration, Tungsten coil erosion, nickel allergy associated with the use of Coils as embolic agents. (13- 14). Plugs are used in rare situations, due to high cost.
• Sclerosant agent: sclerosant agents can be used in liquid form (with 1 ml of contrast to be better visualized during injection) or foam form. Approximately 2-6 mL of 3% sodium tetradecyl sulfate is injected into the spermatic vein at the level of the ischiopubic bones while the patient performs a Valsalva maneuver and with compression over the pampiniform plexus below the injection site to prevent reflux into the scrotum. The foam is a mix of 2 ml of sclerosant agent, 1 ml of saline solution and 3ml of air, agitated vigorously. One milliliter of saline flush is used to clear the catheter.  The catheter should be retracted from the mid to upper ISV, and a repeat venogram is performed, paying particular attention to the presence of any previously unidentified collateral channels. Just like any other liquid embolic agents, there could be some complications. For example in literature are reported rare case of reflux of sclerosant agent exiting in myocardial infarction or stroke. (15-16). In order to avoid the migration of the sclerotic agents an interesting method consists in utilizing sclerosant agent injection through an occluding balloon catheter in liquid form, with the contemporaneous compression of the pampiniform plexus with a tourniquet applied at the basis of the scrotal sac. This technique avoids any reflux or migration of liquid sclerosant agent. (17)(FIG 5)
• Combo coils and sclerosant agent: the combination of coils and sclerosants is the most popular treatment followed by the use of coils or sclerosants as single agents. The initial coil is placed at the level of the internal ring of the inguinal canal, where the vein transition from vertical to oblique. The first coil is placed to avoid that the following injection of sclerosant agent could reflux into the scrotum.
• Glue: cyanoacrylate and similar are increasingly used in varicocele occlusion thanks to low cost.  The bolus of glue is introduced into the catheter after it has been flushed with 5% dextrose solution and is pushed out of the catheter by another bolus of dextrose solution. As the glue comes in contact with blood the polymerization process starts and permanent occlusion of the vessel occurs. The preferred injection modality is with the catheter in distal internal spermatic vein dribbling a trail of glue while is withdrawn with the patient performing Valsalva maneuver and contemporaneous compression of the pampiniform plexus. Glue appeared to have the lowest varicocele recurrence rate (<5%). Over-injection of glue will result in the extension into the renal vein or embolization into the pulmonary artery, there is the risk of a glued catheter. The use of glue allows fast procedures, leading to less radiation than treatment with mechanical or sclerosing agents (18). (FIG 6)
• Laser: EVLA has been first introduced in the treatment of venous insufficiency.  In the treatment of male varicocele, it has been proved to be safe and effective, even if in small research. It uses a radial 1470 nm laser fiber (Biolitec AG, Germany), inserted coaxially into a 5F 70 or 90 cm long sheath till the distal portion of the vein (FIG 7). The occlusion is performed by the application of an energy/cm of 50J at 5 W (power), in continuous wave fashion in three different locations of the left spermatic vein below L3 in order to avoid non-target damage of the crossing ureter(19). This procedure utilizes only thermic energy without the release of any embolic agent and it could avoid any complication related to migration, allergies, not target embolization associated with the use of the well-known embolic agents.