Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins.

Lower-extremity venous insufficiency is a common condition, associated with considerable health care costs. Endovenous laser ablation is increasingly used as therapy, but its mechanism of action is insufficiently understood. Here, direct absorption of the laser light, collapsing steam bubbles and direct fiber-wall contact have all been mentioned as contributing mechanisms. Because fiber tips have reported temperatures of 800-1,300 degrees C during endovenous laser ablation, we sought to assess whether heat conduction from the hot tip could cause irreversible thermal injury to the venous wall. We approximated the hot fiber tip as a sphere with diameter equal to the fiber diameter, having a steady state temperature of 800 degrees C or 1,000 degrees C. We computed venous wall temperatures due to heat conduction from this hot sphere, varying the pullback velocity of the fiber and the diameter of the vein. Venous wall temperatures corresponding to irreversible injury resulted for a 3 mm diameter vein and pullback velocities <3 mm/s but not for 5 mm and > or =1 mm/s. The highest wall temperature corresponded to the position on the wall closest to the fiber tip, hence it moves longitudinally in parallel with the moving fiber tip. We concluded that heat conduction from the hot fiber tip is a contributing mechanism in endovenous laser ablation.

Minimally invasive techniques in the treatment of saphenous varicose veins.

Lower extremity venous insufficiency is common and increases with age. In addition to classical symptoms, it may result in skin changes and venous ulcers. Chronic venous insufficiency has a great impact on patients' health-related quality of life and is associated with considerable health care costs. Surgical ligation of the junction with or without stripping has been the standard of care in the treatment of insufficient great and small saphenous veins. However, the recurrence rates are relatively high and surgery may be associated with serious adverse events and considerable down time; it is also cosmetically suboptimal. To improve efficacy, patients' health-related quality of life and treatment satisfaction and to reduce serious side effects, costs, and postoperative pain, several minimally invasive techniques have been introduced in the last decade. Dermatologists have played an important role in the development of these new therapies of truncal varicose veins. Of the new therapies, ultrasound-guided foam sclerotherapy, endovenous laser therapy, and radiofrequency ablation are the most common and challenge surgery as the "gold standard" of care for patients with varicose veins. The objective of this review is to inform clinicians about these 3 therapeutic options for truncal varicose veins and to describe and compare the procedures, indications, efficacy, and safety profile.