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Chronic pelvic pain (CPP) is defined as pain that persists for more than 6 months and is severe enough to interfere with normal daily and occupational functioning [1,2]. Chronic pelvic pain can be associated with pelvic varicose veins and is known as pelvic venous stasis [3,4]. It is an often undiagnosed disorder of the pelvic venous circulation that causes chronic pelvic pain in premenopausal and reproductive age women [5,6].

This pathology has typical signs such as pelvic varices, pelvic pain

This pathology has typical symptoms such as pelvic varices, pelvic pain that is exacerbated by prolonged standing, sitting, after sexual intercourse, during menstruation and pregnancy [5]. The main tests to identify this pathology are non-invasive radiological examinations such as UG, CT, MRI venography, which help to rule out other causes of pain and allow minimally invasive treatment options to be considered [3].

Chronic pelvic pain in women caused by venous stasis in the pelvis is a treatable pathology. Embolic therapy of the iliac and ovarian veins is a safe and effective treatment for pelvic venous insufficiency and significantly reduces pain in women with VSD [2]. Chronic pelvic pain in women is an important and frequently encountered problem in healthcare settings [1]. Up to 10% of gynaecological consultations, about 12% of hysterectomies and up to 40% of laparoscopies are aimed at identifying the cause of the STD [2]. However, many women with LDS are not screened for VSD, which can occur in about 31% of patients [7].

Diagnosing venous stasis in the pelvis as the cause of chronic pelvic pain could save healthcare resources and improve the quality of life of patients.

VSD epidemiology

Venous stasis in the pelvis is a common undiagnosed cause of chronic pelvic pain in women. VSD is also often referred to in the literature as “pelvic pain syndrome”, “female varicocele”, “pelvic venous congestion” and “pelvic venous insufficiency”. Venous stasis in the pelvis is typically seen in young women aged 20-30 years with more than one childbirth, and can be suspected after excluding other causes of chronic pelvic pain, such as endometriosis, adenomyosis, urinary tract or gastrointestinal disorders [10]. Venous stasis in the pelvis is one of the causes of chronic pelvic pain [10].

STDs are defined as intermittent or persistent, lasting about 3-6 months, localised in the abdomen or pelvis, and unrelated to the menstrual cycle or sexual intercourse and pregnancy [5]. Pelvic varices are found in 10-30% of women with chronic pelvic pain [3].

VSD aetiology

Venous stasis in the pelvis mostly affects women of reproductive age (20-45 years). Environmental and anatomical risk factors influence the development of VSD. Environmental factors include pregnancy, history of pelvic surgery, oestrogen therapy, obesity, phlebitis, and the nature of the work, especially sitting for long periods of time or heavy lifting [11]. There is no known genetic or ethnic predisposition for the development of this pathology, but it has been reported to be more common in women who have given birth more than once [12].

Table: PCS Patient Population

Venous stasis in the pelvis can be caused by two mechanisms: reflux due to venous insufficiency and obstruction [8,9]. Congenital absence of the gonadal valves is present in about 15% of the female population and as many as 60% of these women may develop VSD [3,13]. The exact cause of venous valve insufficiency is not known, but the influence of hormones on venous stasis in the pelvis is. During pregnancy, oestradiol inhibits vasoconstriction and induces uterine enlargement and selective dilatation of the uterine and ovarian veins, resulting in increased stress on the venous valves [9]. It is thought that veins do not return to their original size after pregnancy and this may be related to venous valve insufficiency [12]. VSD has been observed to be more common in women who have given birth more than once [8,9]. Also, in patients with venous stasis in the pelvis, symptoms worsen during menstruation and pregnancy, and ease or disappear after menopause [8]. The influence of hormones on VSD is also supported by the fact that many symptoms regress in postmenopausal life [12].

Pelvic venous outflow can also be impaired by obstructive causes [9]. The most common cause of this is a blockage of the left renal vein between the superior mesenteric artery and the aorta, known as “Nutcracker” syndrome [8,9]. The incidence of this pathology is not precisely known, but it has been observed to occur most often in young, healthy individuals, mostly women aged 30-40. In this syndrome, stenosis of the left renal vein results in venous pressure, capillary pressure and haematuria [14]. There are no precise diagnostic criteria for this pathology, but it is generally accepted that a 39-degree angle between the superior mesenteric artery and the aorta, when measured by CT in the sagittal section, has a sensitivity of 92% and a specificity of 89% in symptomatic patients [8].

The normal angle between the superior mesenteric and the abdominal aorta is considered to be 45 degrees or greater [15]. The syndrome is most often found in incidentally asymptomatic patients. Other obstructive causes of venous blood flow can include congenital or acquired absence of the inferior vena cava and external venous compression due to a mass or lymphadenopathy in the abdomen or pelvis. These structural causes of VSD are rare, but should be recognised as they are important for treatment selection. Other causes of gonadal varices and pelvic varices include pelvic arteriovenous malformations [8].

VSD Clinic

Pelvic pain is usually dull, non-cyclical and can worsen depending on body position, walking, sexual intercourse and during menstruation. The pain lasts for about 6 months and is localised in the pelvis, sacrum, groin or surrounding areas [12]. Some patients report that the pain is unilateral and typically more frequent on the left than on the right side [8]. Pain is usually aggravated by prolonged standing or sitting and relieved by lying down. It also increases when intra-abdominal pressure increases, in cases such as pregnancy, before menstruation and after sexual intercourse [3,8,9,16]. Dyspareunia is usually scored 6 or more on the VAS scale and often radiates towards the anus and can last up to 24 hours [12]. Comorbidities also include a feeling of fullness in the legs, increased urge to urinate, bloating and nausea [3]. In some cases, neurological and psychosomatic symptoms such as depression, lethargy [3,12] also occur.

During the clinical examination, it is important to look for signs of cervical tenderness and ovarian and uterine tenderness on bimanual examination. Finding post-coital pain and ovarian tenderness on gynaecological examination is a combination with a sensitivity of 94% and a specificity of 77% for the diagnosis of pelvic venous insufficiency [3,12,17]. It is also important to assess varicose vein networks, which can be located in the anus, vulva, buttocks and posterior thighs. Varicose veins affect about 10% of pregnant women. It rarely occurs in the first pregnancy and usually develops in the 5th month of the second pregnancy. The risk of varicose veins increases with the number of pregnancies [12].

Ultrasound examination

Sonography is considered the first choice diagnostic test for finding venous stasis in the pelvis, as it is non-invasive, easily accessible and inexpensive, and suitable for excluding other pelvic pathologies. This test helps to rule out causes of pelvic pain, such as masses in the pelvis and urinary tract pathologies. At the same time, it can help to assess the presence of left renal vein occlusion, iliac vein compression, arteriovenous malformations, pelvic hypervascular masses, portal hypertension and other pathologies [12]. It is also possible to assess dilated uterine and ovarian veins, ovarian abnormalities and uterine enlargement [5]. Normally, the pelvic veins are straight and do not exceed 4mm in diameter [17].

Transabdominal UG (TAUG) is valuable for visualising the left ovarian vein. An ovarian vein diameter of 6 mm has a 96% predictive value for the diagnosis of pelvic varices. Transvaginal ultrasound (TVUG) is superior because it provides better visualisation of the pelvic venous plexus compared to TAUG [12].

The diagnostic criteria for SSD in TAUG and TVUG are: tortuous pelvic veins with a diameter > of 4-6 mm, slow (≤3 cm/sec), reversible blood flow, dilated curvilinear veins in the 16th myometrium associated with bilateral pelvic varices and polycystic changes in the ovary [3,8]. Polycystic ovaries are associated with VSD in 56% of cases, but usually patients do not develop hirsutism and amenorrhoea [17]. UG also has the advantage of being performed with the patient in a standing position and a provocative Valsalva sample, which best simulates anatomical conditions and enhances the visualisation of venous reflux [8].

Duplexsonography of the lower limbs should also be performed in patients with suspected VSD, especially those with atypical varicose veins. Atypical varicose veins are found in the posterior and lateral thighs and are a pathognomonic sign of pelvic venous insufficiency [12].

Ultrasound photo gallery

The role of computed tomography in the diagnosis of VSD

CT scanning may be an option when structural pathology is suspected. CT can assess the anatomy of the veins, their dilatation and varicosities [8]. The normal diameter of the ovarian veins varies between 3.2 and 3.6mm [18]. Diagnostic features of VSD: at least 4 ipsilateral dilated paraaortic veins, at least one of which is greater than 4 mm in diameter, or a gonadal vein > of 8 mm in diameter, and the absence of any other structural obstruction (No 1) [3,8].

Fig. 1 Dilated gonadal veins

The role of magnetic resonance imaging in the diagnosis of VSD

Magnetic resonance imaging provides good visualisation of the soft tissues and a good assessment of the pelvic organs [8]. On MRI, varices are usually not visible on T1 18 sequences and are seen as hyperintense on T2 sequences, but can sometimes be iso and hypointense depending on the blood flow velocity (Figure 8). Another disadvantage of this test is that it is performed while the patient is lying down, resulting in poorer visualisation of varicose veins[3].

The role of conventional venography in the diagnosis of VSD

Conventional venography is an invasive diagnostic test where a catheter is inserted into the venous system and contrast material is injected into selected areas. The anatomy, diameter and flow of the veins are examined in this way [12,20]. This test is necessary to confirm the diagnosis of VSD before embolization therapy can be applied [12]. The diagnostic criteria for conventional venography for the diagnosis of VSD are: ovarian vein diameter > 6 mm, pelvic vein diameter > 5- 10 mm, contrast retention > 20 sec, stasis of blood in the pelvic venous plexus, and filling of the vulva and thigh varices [3]. Although this test is the gold standard for the diagnosis of VSD, it should only be performed if non-invasive tests are inconclusive [9].

VSD treatment

Treatment of chronic pelvic pain caused by SSD with non-steroidal anti-inflammatory drugs (NSAIDs) or ovarian suppressants is often the first-line treatment until invasive treatment is available.

Ovarian vein coil embolization is one of the best treatments, with an efficacy rate of between 70-100% The aim of this treatment is to occlude the pelvic veins causing venous stasis and eradicate the reflux [22]. Indications for this treatment include chronic pelvic pain lasting > 6 months and dipareunia, excluding other causes of pain, and marked perineal and perianal varices [3].

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