Comment to: Ultrasonography study on the segmental aplasia of the great saphenous vein, by Oguzkurt L. Phlebology 2013 [Epub ahead of print].

This is a prospective study to assess the frequency and anatomic distribution of the segmental absence or aplasia of the GSV using ultrasonography. 670 limbs of 335 consecutive patients who had signs and symptoms related to venous insufficiency of the leg were evaluated. Venous clinical severity scores ranged from 0 to 20The GSV was examined for its diameter, its relation with the fascial compartments and venous reflux on both legs. Diagnosis of segmental absence of the GSV was established when ultrasonography showed that the saphenous vein left the compartment and there was not any other saphenous vein in it. If a normal diameter or smaller than normal diameter vein remained in the compartment all along its course, this was not considered segmental aplasia and excluded from the study. Segmental aplasia was classified into three subgroups.
Type 1: The GSV leaves the saphenous compartment in the leg and joins it at any point in the thigh.
Type 2: The GSV leaves the saphenous compartment in the leg and joins it in the leg just below the knee.
Type 3: The GSV leaves the saphenous compartment in the thigh and joins it more cranially in the thigh.
The current study showed that the segmental aplasia of the GSV was seen in one-third of limbs on each side and was mostly unilateral; it was always present in its mid portion below or above the knee . It was found in 223 of 670 limbs (33%) in the whole patient population. It was type 1 in 59%, type 2 in 29%, and type 3 in 12% of the patients. It was was seen in 65 of 189 limbs (34.4%) with GSV insufficiency and 45 of 146 limbs (30.8%) with normal GSV on the right side, and 65 of 194 limbs (33.5%) with GSV insufficiency and 44 of 141 limbs (31.2%) with normal GSV on the left side.
There was no relation between the presence of segmental aplasia of the GSV and the presence of GSV or SSV insufficiency in the same limb among patients with CEAP scores 1 and above.
Aplasic segment of the GSV may prevent progression of any kind of endovenous device such as surgical stripper, laser fiber, or radiofrequency ablation probe. Care must be taken not to cause thermal damage during endovenous thermal ablation of the insufficient connecting or bridging vein as this vein comes closer to the skin after leaving the saphenous compartment. This vein was named as accessory saphenous vein or tributary vein. An alternative term such as the saphenous connecting vein or bridging vein regarding its function or the saphenous bow regarding its shape might be more appropriate.
The etiology of segmental aplasia or hypoplasia of the GSV is unknown. It was assumed to be due to a developmental prevalence of vessels with the most favorable hemodynamic condition over the greater vessels that underwent atrophy.