The surgical anatomy of the small saphenous vein and adjacent nerves in relation to endovenous thermal ablation

BackgroundThermal damage to peripheral nerves is a known complication of endovenous thermal ablation (EVA) of the small saphenous vein (SSV). Therefore, the main objective of this anatomic study was to define a safe zone in the lower leg where EVA of the SSV can be performed safely.MethodsThe anatomy of the SSV and adjacent nerves was studied in 20 embalmed human specimens. The absolute distances between the SSV and the sural nerve (SN) (closest/nearest branch) were measured over the complete length of the leg (>120 data points per leg), and the presence of the interlaying deep fascia was mapped. The distance between the SSV and the tibial nerve (TN) and the common peroneal nerve was assessed. A new analysis method, computer-assisted surgical anatomy mapping, was used to visualize the gathered data.ResultsThe distance between the SSV and the SN was highly variable. In the proximal one-third of the lower leg, the distance between the vein and the nerve was <5 mm in 70% of the legs. In 95%, the deep fascia was present between the SSV and the SN. In the distal two-thirds of the lower leg, the distance between the vein and the nerve was <5 mm in 90% of the legs. The deep fascia was present between both structures in 15%. In 19 legs, the SN partially ran beneath the deep fascia. In the saphenopopliteal region, the average shortest distance between the SSV and the TN was 4.4 mm. In 20%, the distance was <1 mm. The average, shortest distance between the SSV and the common peroneal nerve was 14.2 mm. The distance was <1 mm in one leg.ConclusionsAt the saphenopopliteal region, the TN is at risk during EVA. In the distal two-thirds of the lower leg, the SN is at risk for (thermal) damage due to the small distance to the SSV and the absence of the deep fascia between both structures. The proximal one-third of the lower leg is the optimal region for EVA of the SSV to avoid nerve damage; the fascia between the SSV and the SN is a natural barrier in this region that could preclude (thermal) damage to the nerve.

Clinical RelevanceIatrogenic damage to peripheral nerves is a known, incapacitating complication of endovenous thermal ablation (EVA) of the small saphenous vein (SSV). Although EVA is quickly replacing conventional surgery as the treatment of choice for saphenous ablation, no consensus has been reached regarding the surgical landmarks for a safe EVA of the SSV. This study describes and visualizes the anatomic limits in relation to the sural nerve and deep crural fascia, the tibial nerve, and the common peroneal nerve using a new anatomy mapping tool, computer-assisted surgical anatomy mapping. The results offer the surgeon a better understanding of the complex anatomy of the SSV and thereby provide surgical guidelines to reduce complications of EVA of the SSV.