The classic saphenofemoral junction and its anatomical variations

Introduction

Superficial venous insufficiency (SVI) is one of the most common conditions affecting the western population. Population studies have ascertained that SVI affects up to one-third of adults in the UK.^1,2 The clinical features are distributed along a spectrum of telengectasia, varicose veins, swelling and soft tissue damage, culminating in venous ulceration. SVI has a significant impact upon health-related quality of life even at a relatively early stage. ³ Interventional treatment has been shown to be superior to conservative management and is highly cost effective. ⁴ Superficial venous anatomy is highly variable, and as most interventions involve treatment of or around the saphenofemoral junction (SFJ), an understanding of the anatomy and common variations is important to the modern venous specialist.

Methods

This observational study was performed in a university teaching hospital following approval from the regional research and ethics committee and was conducted in accordance with all the regulations set out by the Declaration of Helsinki. All patients presenting to a single surgeon between 2003 and 2005 with CEAP ⁵ clinical classification C2s or above SVI were clinically assessed and counselled regarding the options of conventional management or an intervention. Those wishing to undertake an interventional treatment underwent a duplex ultrasound scan to evaluate the pattern of SVI. Those with primary, unilateral isolated SVI of the SFJ and great saphenous vein (GSV) were offered the following options with appropriate counselling: Conservative treatment with compression, endothermal laser ablation under local anaesthesia, surgical ligation and stripping under general anaesthesia or enter into an Randomised Controlled Trial (RCT) of laser ablation versus surgery. Those choosing open surgery were offered inclusion in this study following informed consent.

Under a general anaesthesia patients underwent skin preparation and draping

A skin incision was placed 2 cm inferolateral to the pubic tubercle, parallel to the inguinal ligament, through which dissection was performed down to the SFJ. Tributaries were identified along the dissection path but not ligated nor disconnected. To ensure adequate exposure of the SFJ and all its related tributaries, the common femoral vein (CFV) was dissected clear approximately 1 cm proximal and distal to the SFJ until the surgeon was satisfied that all the branches were adequately visualised. Once sufficiently exposed, the individual tributaries were then identified and dissected away from the SFJ and subsequently ligated and disconnected in a systematic manner. The external pudendal artery (EPA) was identified in each procedure and preserved where possible. The GSV and large incompetent accessory tributaries were then stripped in a retrograde fashion to the perigenicular region. Concomitant phlebectomies were performed to remove distal varicosities.

A proforma was designed based on and demonstrating the ‘classically described’ appearance of the SFJ with its associated tributaries (Figure 1). OPEN IN VIEWER

Figure 1.

The classic appearance of the saphenofemoral junction (original drawing by Emma Wray and electronically processed into digital images by Andrea Thompson).

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Figure 2.

An anatomical variation showing SCI and ALTB tributaries as a confluence of veins draining into the GSV (original drawing by Emma Wray and electronically processed into digital images by Andrea Thompson).

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Figure 3.

An anatomical variation showing SCI, SEPi and SEP as a confluence of tributaries draining into the GSV (original drawing by Emma Wray and electronically processed into digital images by Andrea Thompson).

This was used to record the junctional anatomy as observed in each subject at the time of the procedure. The number and names of tributaries to GSV and CFV, whether they drained directly into or as a common trunk to the vein, the anatomical path in relation to the SFJ (lateral/medial), relationship of the EPA to the proximal GSV (deep/superficial) and the number of bifid systems were recorded.

Data were collated in an Excel™ spread sheet (Microsoft Office, Microsoft, Redmond, CA, 2011), and statistical analysis was performed utilising SPSS 20 (IBM).

Results

A total of 172 consecutive procedures were performed, 110 in women (64%) with a mean age of 45.3 years (range 21–77) and 62 in men (36%) with a mean age of 50 years (range 25–74).

The median number of GSV tributaries was 4 (range 0–7), and these joined as either individual tributaries or as a coalescence of smaller tributaries. In 85 cases (49.4%), there were less than or equal to three GSV tributaries, whereas in 81 cases (47.1%), there were four to five tributaries. More than five tributaries were identified in only six cases (3.5%). In two cases (1.2%), there were no tributaries to the GSV (Figure 4). OPEN IN VIEWER

The most consistent GSV tributary identified was the superficial circumflex iliac vein (SCI), which was present in 162 cases (94.2%), entering laterally. In 79 of these cases (48.8%), the SCI was part of a coalescence of veins into a single trunk prior to entering the junction, commonly the superficial epigastric (SEPi) vein (n = 37, 46.8%) and the superficial external pudendal (SEP) vein (n = 30, 38%) (Figure 5). OPEN IN VIEWER

The median number of tributaries draining directly into the CFV was 0 (range 0–3) with 102 cases (59.3%) having no tributaries draining into the CFV (Figure 6). The commonest tributary draining directly to the CFV was the deep external pudendal vein present in 68 cases (39.5%) (Figure 7). OPEN IN VIEWER

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Figure 7.

Number of times tributary to CFV.

The presence of a true bifid system was confirmed with ultrasound and was present in four cases (2.3%). The EPA was identified in 150 cases (87.2%), passing deep to the GSV in only 114 (66.3%).

In 16 cases, we were able to identify the six named tributaries; however, the ‘classically described’ anatomy and orientation of six tributaries was seen in only six of these cases (3.5% of the total number of cases). At least one or more tributaries were not identified in the remaining cases (Figure 8). OPEN IN VIEWER

Discussion

Intervention for SVI remains amongst the most common elective curative procedures performed in the UK, with numbers reaching over 90,000 operations per year. ⁶ Evidence suggests that intervention significantly improves quality of life and reduces associated complications,^7–9 and in addition, failure to treatment may result in disease progression. ¹⁰

The most common axis involved in SVI is that of the GSV, which is involved in isolation in 60% and in combination with another axis in 77%. ¹¹ Typically in cases of GSV insufficiency, the GSV is ablated or stripped from the SFJ, ideally to the lowest point of reflux. The conventional principle of open surgical ligation is that of a meticulous dissection and division of every groin tributary in an attempt to reduce the rates of early recurrence.^12–14 Given this, it is easy to see the place for anatomical knowledge; however, things have moved on.

Minimally invasive treatments such as endothermal ablation and ultrasound guided foam sclerotherapy are gaining in popularity and offer a superior recovery when compared with surgical ligation and stripping under general anaesthesia.^7,15–17 NICE guidelines state that treatment should be with endothermal by preference, then foam and then surgery. ¹⁸ Some may conclude that detailed anatomical knowledge of the junction is unnecessary in endovenous treatment; however, the groin anatomy chapter of the venous book is yet to be closed. Despite NICE guidelines, around 50% of procedures in the UK still involve open surgery. Furthermore, one of the most common causes of early recurrence following endothermal ablation is from neoreflux in non-ablated groin tributaries.^7,15,17 A proportion of cases is not suitable for endothermal ablation, for instance, due to a saphena varix or tortuosity. Foam sclerotherapy is available; however, commonly reported efficacy rates fall much below surgical ligation^19,20 and there is therefore uncertainty as to how best to manage a large vein which is highly tortuous all the way to its confluence with the deep vein. Perhaps, an underestimated proportion of patients has venous disease of the pelvis leaving the groin tributaries the vehicle for reflux entering the leg rather than the innocent bystanders that some would have us believe. Finally, there is little high-quality data beyond five years indicating the natural history of untouched groin tributaries following ablation and the incidence or management of late recurrence. It seems a little premature to consign venous ligation and stripping to the history books, and indeed in future, this procedure is likely to fall into the hands of surgeons less familiar with the procedure and anatomy than today. An understanding of the anatomy and common variation of the SFJ therefore remains important.

It is recognised that the anatomy of the SFJ varies greatly, and indeed some anatomy texts refer to six independent tributaries,^21,22 whilst some authors only name the SEPi, SCI and SEP whilst acknowledging the possible existence of others.^21–23 Operative surgery texts suggest that division of up to seven tributaries may be necessary during a ‘typical’ GSV high tie and strip procedure. ²⁴

Previous studies have also identified the extent of anatomical variance at the SFJ by recording the anatomy encountered either at open surgical procedures or in cadaveric dissections.^25–31 The largest prospective study of SFJ anatomy examined 2089 consecutive groin dissections, ²⁷ and found 57.4% of patients had less than three proximal GSV tributaries and 40.2% of patients had tributaries which drained directly into the CFV. In our study, the majority of patients (55.7%) had four to five proximal tributaries and 99.4% had a tributary that drained directly into the CFV (Figure 2). These differences may be accounted for by the relatively small sample size within our study, but equally Donnelly et al. did not include tributaries which coalesced into a single trunk prior to entering an axial vein; thus, this discrepancy could relate to differing recording systems and methods of anatomical identification. In our study, all tributaries which joined the main axial trunks (CFV, GSV) were documented. Individual tributaries which amalgamated into one common trunk and drained into the CFV and GSV were also recorded.

A bifid system was encountered in only 2.3% of the cases in this series and all had been identified pre-operatively on Duplex ultrasound. This is consistent with the 1% incidence of a bifid system as reported by Zamboni et al.; ³² however, Donnelly et al. reported a bifid GSV system in 18.1% of their cases and a true duplex GSV spanning from the SFJ to the knee in 9% of cases. Other studies report an incidence of bifid GSV systems ranging from 5% ²⁶ to 24% of cases.^30,31 The discrepancy between these large previously published studies and data presented here may be due to discrepancies in nomenclature. In the true bifid system, the two GSV lie within the saphenous fascia in the same plane parallel to the skin. They are of the same calibre and drain a common cutaneous area. A common reporting error is that of the anterior accessory saphenous vein, which drains a different territory to the GSV, being falsely identified as a second GSV. ³³

In this study, the EPA was visualised in 87.2% of the cases. Previous studies have reported EPA identification in between 27.9% ²⁷ and 100% of cases. The EPA commonly passes between the GSV and the SFJ often positioned medially to the CFV ²³ (Figure 3). In bifid GSV systems, it crossed between the two trunks. It has been previously suggested that the EPA could be an anatomical landmark in identifying the SFJ during surgery; ³⁴ however, given the considerable inconsistencies in its identification and position, such practice cannot be supported.

As demonstrated, the number and entry of tributaries vary widely, and thus, adequate exploration and dissection of the SFJ are paramount in the identification of all tributaries. Therefore, knowledge of the potential position of the EPA is important as in inexperienced hands, if accidentally divided, it can result in poor visibility within the operative field and potentially suboptimal outcomes.

In summary, this study demonstrates the variability of the SFJ and CFV anatomy. The precise location of tributaries in relation to SFJ, GSV and CFV is far from uniform in the population. This supports the consensus that attentive, accurate dissection of the SFJ may limit local complications and there is evidence to suggest that this same diligence could prevent future recurrence.