A disposable catheter (fine tube) is introduced into the main leaky varicose vein (at the level of the inner side of the knee) through a small opening in the skin. The catheter is then passed up the vein in the thigh to the level of the junction with the deep vein (sapheno-femoral junction). Local anaesthetic is injected around the vein along its length in the thigh. This has the effect of dissipating the heat produced by the VNUS catheter and reduces pain.
The surgeon will position the closure catheter into the diseased vein under ultrasound guidance. The tiny radiofrequency powered catheter will deliver a computer controlled high frequency electrical current (heat) to the diseased vein wall leading to shrinkage and complete closure of the varicose veins. After the diseased vein segment is closed the catheter is pulled back and the cycle repeated all the way down the thigh to the point of entry of the catheter into the skin. Once the long truncal vein (long saphenous vein) is closed blood flow is re-routed to other healthy veins in the limb.
Following the procedure, full length compression hosiery (stockings) is applied and worn for 2 weeks, removed only for showering. Immediate ambulation is encouraged and the patients return to normal activities within 24 hours.
The occluded varicose veins will, with time, be obliterated and slowly removed by the body in the following months.
How good are the results of the VNUS technique?
The success of any VNUS procedure is measured by:
- The occlusion rates (how many of the treated veins remain closed) after VNUS Results indicate that immediate closure of the truncal vein using VNUS technique is very encouraging with the majority of reports in the literature indicate that 90% of the veins remain occluded at 2 years and one recent study observed persistent closure rate of 88% at 3 years.
- Reported complications following VNUS technique occlusion of varicose veins include deep vein thrombosis (DVT), paraesthesia (usually numbness), pain, bruising, localized heat injury to skin, haematoma (collection of blood under skin) and superficial thrombophlebitis (pain, inflammation along the course of treated vein). The most serious of these, DVT, is generally less than 1% (although we have not seen a case in our practice). Paraesthesia occurs in 2-16% of patients but is temporary in majority of cases.
Criticisms of minimally invasive procedures
One of the criticisms of endovenous ablation is that if phlebectomies (avulsion of the varicosed tributaries of side branches) are also required, a more extensive procedure needs to be planned possibly in an operating suite using general anaesthetic.
Arguably however, in many cases extensive multiple phlebectomies may not be required as many disappear once the pressure within the venous system is reduced by removing the source of reflux i.e.; the truncal vein (long or short saphenous vein). It is a point to bear in mind that the more extensive the varicosities are (specially if tortuous) the less likely that they will be suitable to endovenous methods.