Categorizing the distribution of the saphenous nerve in relation to the great saphenous vein.

Saphenous donor site neuralgia is a cause of morbidity post-coronary artery bypass surgery. Saphenous nerve damage during harvesting of the great saphenous vein is thought to be responsible. We dissected 37 cadaveric lower limbs from the knee fold to the dorsal venous arches, to study the spatial relations of the saphenous nerve and great saphenous vein to identify its distribution within the leg. Distribution of the saphenous nerve was categorized into Type A, where the nerve traveled inferiorly and split into an anterior and posterior branch during its course between the knee fold and medial malleolus, Type B, where the nerve traveled anterior to the vein with a small caliber branch traveling posteriorly at the proximal end, Type C where two main branches originated at the knee fold, one anterior to and one posterior to the vein. Overall the vein and nerve crossed in 27 out of the 37 cases (73%), occurring between 5 and 29 cm from the malleolus (60% occurred between 16 and 26 cm). In 32 (86%) of cases, the distal part of the nerve and vein were tightly adhered to each other within a common sheath. The length of adherence ranged from 3 to 26 cm with an average of 14 cm. The saphenous nerve is highly vulnerable during harvesting of the great saphenous vein due to its close relationship and crossing branches. Knowledge of the distribution categories of the nerve can help guide the surgeon to avoid damaging nerve branches during harvesting.