The first step to the endoluminal treatment is the introduction of the needle into the vein. With duplex the optimal point is to be found. One possibility is to use the most distal point of reflux as the point of entry into the vein to be treated. In the case of the great saphenous vein, this is usually found in the proximal lower leg or the distal thigh. In general, all the entry locations can be chosen on the inner side of the leg, so long as this is consistent with the pathological findings. In very obese patients, where the vein lies too deep, an alternative is to choose an entry point via a more superficial venous tributary provided it is below the distal end point of reflux. Alternatively, if the vein calibre permits, this can be accessed further distally. There are very few entry problems with the small saphenous vein on account of its relatively superficial position. Puncture of the vein at the ankle may be hampered by bony prominences like the lateral malleolus.

Endovenous obliteration procedures are usually performed via a percutaneous puncture. Entry into the vein through a cutdown or using a phlebectomy hook is a possibility; however, it detracts from the minimally invasive nature of the operation and experience with the procedure will generally render these techniques obsolete. Insertion of a peripheral venous catheter or needle followed by a guidewire is performed under ultrasound control. During puncture, the transducer head can be oriented transversally or longitudinally to the axis of the vein, according to the operating doctor’s personal preference (Fig. 12.2).

The following measures facilitate ultrasound-guided percutaneous venous access:

Whether the treatment method is radiofrequency, endoluminal laser ablation or one of the newer procedures, a suitable diameter tube or angiography catheter is then slid over the introduced guidewire. Once the guidewire is removed, this will allow the introduction of the laser fibre, radiofrequency catheter or other endovenous ablative device. With bare laser fibres, the use of a sheath of the same length as the vein to be treated is recommended. This reduces the risk of perforation since an unprotected bare laser fibre, when advanced, can lodge into the vein wall. The process of introducing the tube or catheter need not necessarily be controlled by ultrasound, so long as the wire and catheter advance easily and without resistance.

However, the final resting positioning of the end point of the endoluminal ablation device close to the deep vein system requires precise ultrasound control. This location must be documented in relation to the distance from the saphenofemoral or saphenopopliteal junction; knee flexion must be avoided as this can cause a change in the final position. If the tip of the endovenous ablation device is positioned too close to the deep vein system, this can lead to thrombus extension into deep veins. This is true for all endovenous procedures. For this reason the point of the catheter or laser fibre must not be positioned less than 1–2 cm from the saphenofemoral junction (Fig. 12.3a). If a cyanoacrylate glue deployment catheter is used, this distance should be 5 cm in order to avoid unintentional introduction of the cement applicator into the deep vein system (Fig. 12.3b). In treatment of the small saphenous vein, the catheter or fibre should be positioned up to the point where the vein lies directly under the crural fascia which is just as it turns down towards the popliteal vein.

However, the use of ultrasound support may be advisable, and in some cases indispensible, during positioning of the guidewire, particularly if the wire cannot be advanced without resistance. Possible reasons for this might be a previously undiscovered segment of hypoplasia which can occur in up to 25 % of patients; Sect. 2.​4.​4). Other impediments include marked tortuosity which occurs in 1–2 % of patients or calibre variations in around 7 % of patients (Ricci and Caggiati 1999). With complete vein occlusion, a second puncture proximal to the occlusion is required in order to ablate the remaining segment. With very tortuous veins, some passages may be impossible to navigate. When it proves difficult to push the wire forward, the course of the vein is first analysed in three dimensions using ultrasound. The passage where the hindrance occurs is very often S-shaped. In such cases, it is sometimes possible to advance the wire by stretching the course of the vein using digital pressure on the skin at the affected region (Fig. 12.4 ) or by simply straightening the leg.

The principal advantage of carrying out the operation under tumescent anaesthesia, as compared to general or regional anaesthesia, is that peri-venous structures can be protected from the effects of the heat generated by radiofrequency or laser. In particular, with tumescent anaesthesia, the patient can inform the operating doctor if there is any heat damage to the principal nerves. For example, if radiating pain occurs in the heel area due to irritation of the sural nerve, the energy source can quickly be turned off and the catheter repositioned a few millimetres along. Tumescent anaesthesia seems not to be required in mechanochemical ablation or acrylic cement deployment.

Tumescent anaesthetic is injected into the peri-venous space, preferably in a slight Trendelenburg position (Fig. 12.5). In this way the analgesic effect is obtained immediately, and the operation can be started directly after the injection. The use of an automated roller pump is easier than using direct injections by hand. Both injection of the tumescent solution and the Trendelenburg position lead to a significant reduction of the vein diameter. This means that a smaller volume of blood is present in the vein around the catheter. In endovenous laser ablation, a small amount of remaining blood results in better energy transfer to the vein wall because it facilitates the formation of steam bubbles and convection currents. This is in contrast to radiofrequency closure where the operator applies additional manual pressure over the catheter point to try to expel the remaining blood from the vein lumen. This is because radiofrequency works by conductive heat transfer making the presence of blood unnecessary or counterproductive. In contrast to peri-venous injection fluid constrained within the saphenous compartment, tumescent solution around a superficial vein disperses more easily. Therefore, care must be taken to ensure an adequate volume of tumescence remains between the skin and vein. This will avoid thermal damage to the dermis and consequent hyperpigmentation.

During radiofrequency ablation, ultrasound monitoring is superfluous, since the principal focus of the operator is on maintaining the target temperature at the catheter point. This temperature is easier to maintain if the operator applies pressure over the catheter point. This is considerably easier using manual compression applied directly with the hand than with the ultrasound probe.

In contrast to radiofrequency ablation, manual pressure over the laser fiber tip should be avoided. This is especially true when a bare fibre is used, because this action may facilitate vein wall perforation. Furthermore, residual blood is needed to obtain a better, more regular transfer of laser energy to the vein wall. This takes place through convection currents or, more accurately, via a turbulent flow of steam bubbles and blood (Fig. 12.6). Continuous ultrasound monitoring of the endovenous laser process in case of bare fibres allows the formation and spreading of steam bubbles to be observed and in particular allows significant perforations of the vein wall to be recognised in time. This is identified when steam and gas bubbles spread into the surrounding tissues during an extraluminal release of laser energy. In this event lasering is stopped and the fibre is withdrawn a few millimetres, after which normal endovenous ablation can be resumed.