Bifurcated Great Saphenous Vein: A Report on Its Therapeutic and Diagnostic Perspectives.

The great saphenous vein (GSV) is the longest superficial vein in the body extending from the medial malleolus to groin skin crease level. The clinical usage of GSV has made its anatomical variations noteworthy. Since many tributaries accompany it, GSV is often mistaken with the variant vein. Duplication and persistence of accessory GSV are the two major clinically significant anatomical variations of the GSV which is frequently misinterpreted as a synonym. In the present case, we report a unique variation of GSV wherein it bifurcated into anterior and posterior divisions of two uneven calibers at knee region, which then reunited at thigh region to form a single vein before its termination into the femoral vein. Locating such variations of bifurcated GSV is a challenging task for both diagnostic and therapeutic tactics, particularly in venography procedures as it might lead to iatrogenic traumatic injury of the vessel.

INTRODUCTION

The great saphenous vein (GSV) originates on the medial side of the foot as a continuation of the medial end of the dorsal venous arch. It lies anterior to medial malleolus and ascends upward on the medial side of leg accompanied by the saphenous nerve. At the knee region, it becomes superficial and continues along the medial side of the thigh. In the medial compartment of the thigh, it perforates the cribriform fascia, and through the saphenous opening, it drains into the femoral vein. It presents about 10–20 valves and receives numerous communications with the deep veins at different parts of lower limb throughout its extent, except above mid-thigh level.[1]

The typical ultrasonic “saphenous eye” appearance of GSV in the mid-thigh level marks as the easiest diagnostic approach of its identification,[2] while the “Egyptian eye” view which shows the appearance of GSV in the transverse view between the superficial and deep fascia is used to distinguish the GSV from other tributaries.[3]

Clinically, GSV or its tributaries are most frequently affected by varicosity. The ligation and stripping of the GSV and its tributaries are the standard therapeutic approach in varicose vein therapy.[4] Morphologically, duplicated GSV and persistence of accessory GSV are two most clinically significant anatomical variations of GSV. However, very often both these variations are erroneously interpreted as synonyms. From the reported scientific literature, as many as five different types of anatomical variations of GSV in the thigh[5] and knee region[6] are established which involve the presence of an accessory or duplicated GSV. However, none of these classifications mention about the bifurcated pattern of GSV, which makes this report unique.

CASE REPORT

We report herein a rare type of bifurcated GSV encountered in the right lower limb of an elderly male human cadaver during routine dissection for the medical undergraduate students. The formation of the GSV was normal from the medial end of the dorsal venous arch of the foot. The initial course of the GSV was normal till the junction between lower two-third and upper one-third of the medial side of the leg. After that, the GSV bifurcated into thick anterior and thin posterior divisions. Both divisions of GSV ascended upward parallel to each other. At the upper third of the medial surface of the thigh, both divisions of bifurcated GSV united to form a single vein which passed through the saphenous opening to open into the femoral vein [Figure 1]. Just distal to the point of bifurcation, the anterior division of the GSV received anterior leg vein and proximal to knee joint it received knee perforator vein. In between these two tributaries, it also received an anomalous superficial vein originating from the middle of the dorsum of the foot. It crossed the GSV superficially from anterior to posterior and terminated into the anterior division of bifurcated GSV. The posterior division of the GSV was accompanied by the saphenous branch of the femoral nerve [Figures 1 and 2].

Figure 1

Gross morphology (a) with a comparative schematic diagram (b) showing the bifurcation of the great saphenous vein into anterior and posterior divisions; the presence of anomalous superficial vein. Knee perforator vein and anterior leg veins draining into anterior division. FV=Femoral vein, FN=Femoral nerve, FA=Femoral artery, SN=Saphenous nerve

Figure 2

Closer view of the pattern of bifurcation of great saphenous vein into anterior and posterior divisions at the knee (a) and thigh (b) region. Anomalous superficial vein and anterior leg veins draining into anterior division. FV=Femoral vein, FN=Femoral nerve, FA=Femoral artery, SN=Saphenous nerve

DISCUSSION

Venous ultrasonography is one of the most challenging practices for sonographers because of the complexity owing to frequent venous anatomical variations. The GSV is a superficial vein of the lower limb with great clinical importance. Being superficial in location and readily accessible, it is the choice of vessel for coronary arterial bypass. Moreover, because of the rich content of muscular and elastic fibers in its wall in contrast with any other superficial veins, it can be safely harvested.[4]

Two significant anatomical variations of GSV have been mistaken very often and misinterpreted in the thigh region, i.e., the duplicated GSV and the presence of accessory GSV. In the duplication of GSV, both segments of it typically lie in the same plane and will also have similar caliber with a common drainage territory.[7] An accessory saphenous vein is usually smaller in size when compared to the corresponding normal GSV and often do not have common cutaneous drainage area. However, both veins unite just before entering the saphenofemoral junction.[3] Based on the duplex ultrasonography which is regarded as a standard for accurate phlebographic detection of true duplication of the GSV, the reported prevalence of duplication of GSV accounts for 1.6%–2%.[7] The presence of duplicated GSV has been reported together with the morphological and clinical perspectives.[89] Similarly, Waseem and Roger presented a case of duplicated GSV with multiple intercommunications both at mid-calf and mid-thigh level in the scientific literature.[10] The intermittent incompetence of the GSV is reported to be one of the frequent predisposing factors of the duplicated GSV.[11]

In the present case, the variation identified with the GSV does qualify neither with the morphological features of duplicated GSV as the caliber of both vessels was variable nor with the accessory GSV as both veins united more distally than described above. The GSV bifurcated at the knee and reunited eventually at the mid-thigh level to get terminated into the femoral vein. Hence, we termed this variant morphology of GSV as bifurcated GSV.

Bifurcation of GSV may not be a rare occurrence as it is not united distally. Bifurcation into smaller divisions if occurring at a level above the knee has a disadvantage of inadequate availability of vessel for limb bypass grafting.[12] Varicose veins are manifested more often in the veins of lower limb following the incompetence of the valves in the superficial veins that prevent the flow of blood from the deep veins to the latter. The GSV and its tributaries are the most frequent victims of varicosity and most commonly occur in the posteromedial part of the lower limb.[13] Recurrent varicose veins even after surgical intervention are one of the major complications resulting due to the persistence of duplicated GSV. This therapeutic complexity also holds good in the case of bifurcated GSV as a missed vessel can be a cause for recurrence of the condition. Therefore, bifurcated GSV should be identified and treated before surgical interventions to prevent the future risk of recurrence of venous insufficiency.

Similarly, bifurcated GSV can also set a challenge to the sonographers and other diagnostic practitioners as device introduced to such anomalous vessel could cause an iatrogenic injury. To avoid these complications, a careful look at the abnormal pattern of GSV is essential before performing any approaches aiming GSV.

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Conflicts of interest

There are no conflicts of interest.