Objective: Endovenous laser therapy (EVLT) is a new minimally invasive treatment for varicose veins employing laser ablation of the long saphenous vein (LSV) under tumescent local anaesthesia. Concerns about thermal injury to perivenous nerves (tibial, peroneal, sural) have prevented its use for saphenopopliteal/short saphenous incompetence. This study assesses heat dissipation around the LSV during EVLT.
Methods: In 12 consenting patients undergoing EVLT (Local research ethics committee approved), thermocouples (inserted percutaneously) were positioned (ultrasound control) 3, 5 and 10 mm from the LSV following perivenous injection of tumescent anaesthesia (0.1% lignocaine at room temperature). The 810-nm diode laser delivery system delivered 1-s pulses (12 W power) with 1-s intervals during laser fibre withdrawal at 3 mm/s.
Results: The maximum recorded temperatures at 3, 5 and 10 mm were 43.3°C, 42.0°C and 36.0°C, with median temperatures (±interquartile range) of 34.5°C (30.8–40.0), 33.7°C (30.5–39.9) and 31.1°C (30.3–33.3), respectively.
Conclusions: Although intravascular laser-tip temperatures of up to 1334°C have been recorded in experimental models of EVLT, these results indicate that heat dissipation into adjacent tissues is minimal. Thus, careful ultrasound-guided injection of adequate volumes of perivenous local anaesthetic and the associated heat-sink effect should allow safe use of EVLT in treating saphenopopliteal/short saphenous incompetence.
