Nerve injuries during laser treatment for varicose veins are a potential risk. The nerves at particular risk are the saphenous nerve (1*) and the sural nerve (2*). It has been estimated that nerve injury may occur in over a third of laser treatments of the great saphenous vein and nearly one in twenty small saphenous vein treatments.
A recent study from Germany (3*) has even suggested that saphenous nerve injury is more likely after endovenous laser than after surgical stripping. The study authors have proposed that in some cases the nerve may have been injured by the needle during administration of the tumescent local anaesthetic.
Mechanisms by which the nerve might possibly be injured.
- Firstly, the nerve might injured by the needle during the cannulation of the vein itself. This is probably very rare but it is possible that the nerve could be transected by the needle.
- Similarly, a needle stick injury might occur during the administration of local anaesthetic causing a neurotemesis.
- Finally, the thermal ablation could cause the direct transfer of heat energy to the nerve causing a thermal neuropraxia — a burn injury.
These are the possible strategies to avoid nerve injury.
- Firstly, the nerve and vein can be imaged in transverse section to identify a site of cannulation where the nerve and vein are sufficiently far apart to minimise the risk of thermal energy transfer.
- Secondly, the vein and nerve can be imaged in transverse section during the cannulation to ensure that the vein is cannulated directly and that the needle tip does not impinge on the nerve.
- Thirdly, the nerve, vein and needle tip can be kept in view during tumescent anaesthetic administration by scanning in transverse section at all times.
- Lastly, the needle should be withdrawn immediately and the thermal ablation terminated immediately if pain is felt in the sensory distribution of the nerve at risk. In fact, performing these treatments under local anaesthetic is much safer than under general anaesthetic for this very reason. When pain occurs, the treatment should be terminated or the needle withdrawn, making the possible risk of nerve injury less likely.
My team and I take particular care to avoid nerve injuries during varicose vein treatment and in this video I describe how we have developed our own methods. In the last 5 years, we have had no serious nerve injuries during varicose vein treatments.
- Mundy L, Merlin TL, Fitridge RA, Hiller JE Systematic review of endovenous laser treatment for varicose veins. Br J Surg 2005; 92: 1189-1194
- Gibson KD, Ferris BL, Polissar N, Neradilek B, Pepper D Endovenous laser treatment of the short saphenous vein: efficacy and complications. J Vasc Surg 2007; 45(4): 795-803
- Flessenkamper I, Stenger D, Hartmann M, Roll S Endovenous laser therapy vs high ligation/stripping for varicosity of the great saphenous vein Phlebologie 2013; 43:7-11