Endovenous Laser Ablation (EVLA or EVLT) is usually performed in patients with varicose veins or the consequences of truncal venous incompetence (“hidden varicose veins“) causing swelling of the ankles, tired legs, venous eczema, skin discolouration at the ankles or venous leg ulcers. The patient is diagnosed using duplex ultrasound scanning by an expert who scans the patients standing up with their weight on the other leg. Once the diagnosis has been made, Endovenous Laser Ablation (EVLA or EVLT) may be discussed as part of the treatment with the patient.
Endovenous Laser Ablation (EVLA or EVLT) is almost always performed under a local anaesthetic with the patient awake. Sometimes if the surgeon or doctor is unconfident, or if the patient demands, it can be performed under sedation, spinal or epidural anaesthesia or general anaesthesia. However all of these are suboptimal, as the surgeon or doctor performing Endovenous Laser Ablation (EVLA or EVLT) relies on the patient to tell them if there is any pain during the procedure (to protect nerves, muscle or skin being accidentally burnt) and the risk of deep vein thrombosis is reduced by the patient walking normally immediately after the procedure.
Once the patient is ready for treatment, positioned on the operating table, with skin prepared and a sterile area formed, the vein to be treated is identified using ultrasound. The ultrasound is usually performed by a second expert with a sterile cover over the ultrasound probe, enabling the surgeon or doctor performing the procedure to have two free hands to manipulate the equipment. The patient is tipped head up at this point to allow the vein to dilate and be a bigger target to cannulate.
Under this ultrasound control, local anaesthetic is first injected to numb the skin. Through the numb patch a hollow needle or “cannula” is inserted into the vein to be treated. For the Great Saphenous Vein (GSV), the patient is lying on their back and the entry point is usually around or below the knee (although some still prefer to enter into this vein around the ankle). In difficult Great Saphenous Veins, there may be the need to enter this vein in two or three different places and close it in sections. For the Small Saphenous Vein (SSV) the patient is lying on their front and the entry point is at the bottom of the calf muscle. For the Anterior Accessory Saphenous Vein (AASV) the entry point is usually on the front of the thigh.
Usually the entry point is merely a small pinhole. Very occasionally, the vein can be difficult to cannulate and a small “cut down” is used. This is when a small incision is made in the skin and the vein hooked up to have the laser device inserted into it under direct vision. However, with experience, this is rarely needed.
Once the cannula is inside the vein, different companies have different procedures. Usually a “Seldinger” technique is used where a thin wire is passed up the cannula, the cannula is removed and then a dilator with a larger cannula lying over it is passed up over the wire and therefore into the same vein. Using this technique, the wire and dilator can then be removed leaving the larger cannula within the vein. This then gives a big enough channel for the laser sheath or endovenous laser device to be passed into the vein. Other techniques allow a thin endovenous laser device to be passed straight up the vein without a guide wire being needed.
- In some EVLA systems a guidewire is positioned precisely using ultrasound guidance – in others the EVLA device itself is positioned under ultrasound control
- Duplex ultrasound probe to guide the whole operation very accurately
- Cannula positioned into vein under ultrasound
Once the endovenous laser sheath or endovenous laser device has been passed up the vein to the top under ultrasound guidance, local anaesthetic solution can be then injected around the vein. This causes the vein to contract around the endovenous laser device as well as causing numbing of the area. In addition, adding fluid helps get rid of the laser heat before it damages tissue around the vein. This sort of local anaesthesia is called “tumescence” or “tumescent anaesthesia” in view of the large volume of fluid injected around the vein. The patient is also tipped head downwards for treatment to help the contraction of the vein.
- Laser energy closes the vein immediately
- Local anaesthetic (tumescence) is injected around the vein that is being treated
- EVLA sheath and fibre (or EVLA device) has been passed up the vein into the correct position under ultrasound control
- EVLA fibre is used in some systems – with other systems, the sheath and fibre are one device
Once the ultrasound has shown that enough local anaesthetic solution (or tumescence) has been injected around the vein, the tip of the laser is checked to make sure it is in exactly the right position. If it is an end firing laser, the heating effect can be profound up to 2 cm in front of the tip. Therefore the endovenous laser fibre or endovenous laser device is pulled back 2 cm from the junction with the deep-vein. If the new radial firing endovenous laser device is being used, the device can be put right up to the junction with the deep-vein, as the area vein wall ablated by the laser can be precisely predicted.
The laser is then fired at a set power and the surgeon or doctor performing the procedure withdraws the laser at a steady and predetermined rate to make sure the whole length of vein is treated correctly.
- The vein closed by EVLA is destroyed by heat – this heals by ‘fibrosis’ – which means the body digests the dead vein, preventing regrowth by neovascularisation
- EVLA fibre being withdrawn at a set rate through a cannula to ensure closure of the vein
Provided the endovenous laser fibre or device is in the correct vein, that adequate tumescence has been placed around the vein, and the patient has been placed head down during treatment and the correct power and pullback have been performed, the vein should be completely ablated immediately and should never open again in the future.
In some patients this might be the end of the procedure. In others, other veins might be treated by Endovenous Laser Ablation (EVLA or EVLT), or there may be other procedures performed at the same time. This would have be decided at the time of planning the treatment.
Next page: The advantages and disadvantages of EVLAThis website was last updated on 03/10/17.