Left Ovarian Vein Transposition to Restore Renal Venous Outflow in a Patient With Severe Pelvic Congestion After Multiple Endovascular and Failed Open Procedures for Nutcracker Syndrome.

A 29 year old female presented with severe pelvic pain, left flank pain, and lower limb oedema. She had no significant comorbidities and did not report a history of thrombophilia or clotting disorders. She was 168 cm tall, weighed 59 kg, and had a body mass index of 21 kg/m 2 . Her past medical history included one pregnancy by caesarean section and a diagnosis of NCS. She was referred to the clinic from a foreign institution that only provided limited information about the previous procedures she had undergone. The first procedure was performed to treat venous compression and alleviate the associated symptoms, including chronic pelvic pain and dyspareunia, through endovascular stenting of the LRV. This was immediately complicated by proximal migration of the stent into the inferior vena cava (IVC), which required an urgent surgical approach with stent removal and subsequent reconstruction of the LRV onto the IVC via midline laparotomy. The latter intervention was further complicated by a retroperitoneal haematoma that was evacuated surgically. Due to her surgical history and severe symptoms of pelvic congestion at presentation, an abdominal duplex ultrasound (DUS) was performed, showing dilatation of the LOV with severe reflux. Computed tomography venography showed thrombosis of the LRV reconstruction and severe pelvic venous congestion with multiple ectatic venous circles of the gonadal and uterine vessels, with a maximum calibre of the LOV of 20 mm that appeared to be the main renal outflow ( Fig. 1 ). Figure 1 Pre-operative computed tomography images showing collateral renal venous drainage. A–C Axial images showing a markedly dilated left ovarian vein (LOV) and extensive pelvic venous collateralisation. The reconstructed left renal vein is not visualised distally due to thrombosis. D Volume rendered three dimensional reconstruction illustrating the engorged LOV as the only outflow tract for the left kidney, with prominent pelvic venous networks. Pre-operative computed tomography images showing collateral renal venous drainage. A–C Axial images showing a markedly dilated left ovarian vein (LOV) and extensive pelvic venous collateralisation. The reconstructed left renal vein is not visualised distally due to thrombosis. D Volume rendered three dimensional reconstruction illustrating the engorged LOV as the only outflow tract for the left kidney, with prominent pelvic venous networks. During multidisciplinary discussion of the case, an endovascular approach was considered more fitting due to the multiple open operations that the patient had already sustained. She therefore underwent a phlebography of the iliocaval venous axis and LRV and gonadal vein, with unsuccessful intravascular ultrasound (IVUS) guided attempts at recanalisation of the occluded reconstructed LRV. Due to the severity of symptoms and risk of further renal complications, the patient was scheduled for open surgical repair. The procedure was performed under general anaesthesia. A left pararectal extraperitoneal approach was performed followed by medial visceral rotation. The left ureter and both the left external iliac artery and vein were isolated. After heparin administration, according to the patient's weight, mobilisation of the LOV, and ligation of the varicose collaterals, the vessel was transposed onto the LEIV by end to side anastomosis with polypropylene 5-0 sutures ( Fig. 2 ). Figure 2 Intra-operative images and illustrations of the ovarian vein transposition. A Intra-operative image showing the left ovarian vein (LOV), left external iliac artery (LEIA), left ureter (LU), and left external iliac vein (LEIV) after careful dissection and isolation. B Schematic illustration of the anatomic structures before transposition. C Intra-operative image showing the end to side anastomosis (T) of the dilated LOV to the left external iliac vein, using a running polypropylene suture. D Schematic representation of the completed ovarian vein to external iliac vein transposition, showing the restored renal outflow via the collateral pathway. Intra-operative images and illustrations of the ovarian vein transposition. A Intra-operative image showing the left ovarian vein (LOV), left external iliac artery (LEIA), left ureter (LU), and left external iliac vein (LEIV) after careful dissection and isolation. B Schematic illustration of the anatomic structures before transposition. C Intra-operative image showing the end to side anastomosis (T) of the dilated LOV to the left external iliac vein, using a running polypropylene suture. D Schematic representation of the completed ovarian vein to external iliac vein transposition, showing the restored renal outflow via the collateral pathway. The procedure was successful and recovery was uneventful. Follow up DUS showed patency of the transposed and recipient vessels. The post-operative clinical conditions were good with haemodynamic stability, gradual and progressive return of bowel function, no impairment of the urinary system, and significant improvement of the venous symptoms. The patient was discharged three days after the operation, with acetylsalicylic acid. At the four month follow up, the patient's symptoms were significantly improved with no residual pain or pelvic congestion manifestations. Computed tomography angiography (CTA) showed good outcomes of the surgical anastomosis, with renal outflow into the LOV and subsequently LEIV and IVC ( Fig. 3 ). Figure 3 Post-operative imaging confirming successful renal outflow. A Volume rendered three dimensional reconstruction of the four month post-operative computed tomography scan showing the patent transposed left ovarian vein (LOV) anastomosed to the left external iliac vein (LEIV), with no signs of compression or thrombosis. B Colour Doppler ultrasound demonstrating antegrade flow through the transposed LOV into the LEIV, confirming haemodynamic patency. Post-operative imaging confirming successful renal outflow. A Volume rendered three dimensional reconstruction of the four month post-operative computed tomography scan showing the patent transposed left ovarian vein (LOV) anastomosed to the left external iliac vein (LEIV), with no signs of compression or thrombosis. B Colour Doppler ultrasound demonstrating antegrade flow through the transposed LOV into the LEIV, confirming haemodynamic patency.

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Nutcracker syndrome can often be associated with pelvic congestion. If a patient complains of symptoms of pelvic and renal venous congestion, other more common causes need to be ruled out, such as May–Thurner syndrome, genitourinary disease, endometriosis, or neuropathies. The definitive diagnosis is made after exclusion of these differential diagnoses and confirmed by a mixture of suggestive symptoms, clinical examination, DUS, phlebography, IVUS, CTA, and magnetic resonance angiography. 1 , 2 Treatment has evolved over the last few decades, and the available management options range from conservative approaches to surgical corrections, both open or endovascular, each with different indications, advantages, and disadvantages. Conservative treatments are usually recommended for young patients and include focusing on weight gain to increase the amount of retroperitoneal fat and subsequently decreasing compression on the left renal vein, use of compressive stockings or medical therapy with acetylsalicylic acid, analgesics, or ACE inhibitors. 2 Endovascular approaches, such as the application of stents in the venous system, have emerged as one of the possible strategies in the treatment of venous problems, especially because of their reduced invasiveness with shorter recovery times compared with open surgery. 3 Although this has considerably improved patient results, it is still associated with complications, including re-stenosis, occlusion, LRV erosion or perforation, and stent fracture. One of the mostly feared complications is stent migration from its designated location to sites such as the IVC and, in extreme cases, the heart, which may lead to serious consequences, such as cardiac arrest due to dysrhythmias, perforation of myocardial tissue, damage to the tricuspid valve or the coronary arteries requiring open cardiac surgery in worst cases. 4 , 5 Venous stent migration is infrequent and has reported rates ranging 0.17–4.3% 6 due to excessive vein dilation with erosion of the surrounding structures and or undersizing of the stent length or diameter. Early detection is extremely important to avoid complications and allow repositioning and or retrieval of the stent. To minimise this risk, the stent must be ensured to conform to the patient's body, with adequate pre-operative planning and preferably placed above a fixed stenotic lesion. 4 Other options to secure the venous stent, such as proximal and distal anchoring mechanism with balloon expandable stents or fixation devices to improve stent stability, have been widely discussed in the literature. 7 It is worth noting that the initial renal vein stenting procedure, which ultimately resulted in stent migration, was performed at a different institution. Consequently, this unit was not involved in the decision making process regarding the stent selection or technical approach. In recent years, some authors have proposed the use of adjunctive techniques, such as temporary IVC filters placed at the LRV confluence or the deployment of interlocking stents, as means to reduce early stent migration risk; 7 , 8 , 9 however, these measures were not applied in this case. The absence of such strategies may have contributed to the complication encountered, ultimately requiring a complex salvage approach. Open surgical treatments are mainly reserved for cases with severe symptoms or after failure of conservative treatments and they include LRV transposition, nephropexy, gonadal vein transposition, patch venoplasty, transposition of the SMA, and renal autotransplantation, that must be tailored to each patient's anatomy and clinical features, in addition to the experience of the operating team. 2 A new hybrid approach for treating NCS has also been described in the literature, with a two stage procedure: firstly LRV stenting and later laparoscopic stent exofixation or stent suture via minilaparotomy. This ensures more stability of the stent while avoiding extensive open operations. Results are promising but more data are needed to evaluate the outcomes. 10 In this presented case, the presence of a May–Thurner syndrome was excluded with the pre-operative diagnostics, and it was decided to re-implant the LOV onto the LEIV instead of using an autologous conduit between the LRV and the IVC to avoid entering the peritoneum, which was preferable given the patient's previous laparotomies and retroperitoneal haematoma. Although the common iliac vein is typically used as the recipient vessel for LOV transposition, the EIV was chosen in this case. This choice was based on both anatomical considerations and surgical history. The EIV offered a more accessible and less adherent target via an extraperitoneal approach. Additionally, a dilated segment of the ovarian vein reached the EIV without tension, allowing for a tension free anastomosis with renal outflow and resolution of pelvic congestion. Several options can be considered in the treatment of NCS. In this case, LOV transposition on the LEIC was a safe and effective approach due to the anatomical feasibility and previous unsuccessful procedures.

Compression of the left renal vein (LRV) between the superior mesenteric artery (SMA) and aorta is commonly referred to as nutcracker phenomenon. If associated with symptoms, it is called nutcracker syndrome (NCS) and it is one of the causes of venous renal congestion. 1 Clinical findings and symptoms may include: macro- or microhaematuria, orthostatic proteinuria, varicocele, anaemia, left flank and or abdominal pain, fatigue, orthostatic intolerance, dyspareunia, and dysmenorrhoea. In severe cases, pelvic congestion can also cause manifestations in the lower extremities, such as varicosities and oedema, when the pelvic floor becomes incompetent and venous hypertension discharges through pelvic and lower escape points. In addition, pregnancies and caesarean sections complicate and may worsen cases of renal venous hypertension and pelvic congestion. 1 NCS is probably underdiagnosed; therefore, prevalence remains uncertain, but it seems to mainly affect women with symptoms that typically peak during the second and third decades of life after complete maturation of the vertebral bodies and sharpening of the angle between the SMA and aorta. 1 This case report presents a woman with NCS, who underwent three previous procedures for the treatment of this condition, and the associated complications, which resulted in a worsening and further progression of the symptoms. A left ovarian vein (LOV) transposition onto the left external iliac vein (LEIV) was performed to ease the pelvic congestion and restore renal outflow.

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