Posterior nutcracker syndrome - a systematic review

Bibliometric and visual analysis of research on nutcracker syndrome from 1974 to 2021: A systematic review

BACKGROUND

At present, researchers have obtained fruitful results in the study of nutcracker syndrome (NCS), but there is still a lack of systematic research on the overall status of this disease. This article aims to describe the past and current status of research into NCS, and predict future research trends and popular research topics.

METHODS

Using bibliometric and visualization methods, 552 articles related to NCS collected from the Scopus database from 1974 to 2021 were analyzed from multiple perspectives.

RESULTS

Overall, the amount of literature related to NCS is on the rise every year, and the number of citations is the turning point in 2006. The United States has the largest number of publications and has the most extensive cooperation with other countries. The main contents of the co-authored study focused on the symptoms, surgical procedures, and concomitant diseases of NCS. Keywords such as peak velocity, ultrasonography, orthostatic proteinuria, etc appeared earlier, whereas diagnosis, chronic pelvic pain, endovascular stents, etc appeared later.

CONCLUSIONS

The literature utilization rate of NCS is relatively insufficient. The pathogenesis and pathological mechanisms need to be further studied, and the diagnostic criteria and surgical methods will continue to be favored by clinicians.

Endovascular treatment of a patient with nutcracker syndrome and pelvic varices involving anterior and posterior renal veins

We have reported a case of a 36-year-old woman with flank and pelvic pain and hematuria. She had posterior nutcracker syndrome and pelvic varices involving one anterior and three posterior renal veins (including one major vein). We used a complete endovascular approach, which included stent implantation in the major posterior renal vein and left gonadal vein embolization. During a 12-month follow-up period, the patient had had no symptoms and good computed tomography results. Endovascular treatment represents a safe and successful option for patients with nutcracker syndrome and pelvic varices involving the anterior and posterior renal veins.

Nutcracker syndrome: diagnosis and therapy

Nutcracker syndrome (NCS) is an extrinsic compression of the left renal vein (LRV) by the superior mesenteric artery (SMA) anteriorly and aorta posteriorly resulting in renal vascular congestion manifesting as hematuria, proteinuria, orthostatic hypotension, pain, or even renal dysfunction. Long-standing venous compression can encourage collateral drainage pathways through gonadal and pelvic veins, which may explain reported symptom and syndrome overlap with pelvic congestion syndrome. Diagnosis can be challenging and variable, frequently involving a combination of ultrasound Doppler, cross-sectional, and invasive imaging. Often, intravascular pressure measurements are required to prove a renocaval pressure gradient to aid in a definitive diagnosis. Conservative management is appropriate, especially in children, who tend to outgrow the disorder. In the interim, medical management with angiotensin converting enzyme inhibitors (ACEIs) is a useful therapy to manage orthostatic hypotension in the pediatric population. In adults, invasive therapies are more frequently pursued. These are aimed at relieving the extrinsic compression on the LRV. The standard of care is renal vein transposition, with renal autotransplantation reserved for recalcitrant cases. Endovascular stenting is a less invasive option. Laparoscopic placement of an exovascular stent is a newer therapy intended to minimize trauma to the LRV. In this review, we will discuss the clinical manifestations, diagnostic criterion, imaging features, and conservative and surgical therapies for this condition.

Wilkie Syndrome and Pseudo-Nutcracker Syndrome a Rare Combination: Description of a Case

Wilkie's syndrome is a very rare vascular alteration caused by congenital or acquired reduction of space between the superior mesenteric artery (SMA) and aorta. In acquired form, it is caused by perivascular adipose tissue reduction due to rapid weight loss and, if symptomatic, causes postprandial vomiting and weight loss. The left renal vein (LRV) when it has a retro-aortic course can be compressed in aorto-vertebral space (AVS); if the stenosis is severe it can cause venous congestion symptoms with left flank pain, microhematuria, and thrombosis, this vascular alteration is known as a pseudo-nutcracker syndrome. The combination of Wilkie's and pseudo-nutcracker's syndrome (PNCS) is very rare and has not yet been described in the literature. We describe a case of a 62-year-old woman who presented symptoms and alterations typical of two syndromes.

Left double polar renal arteries, left triplicate (preaortic, accessory and retroaortic) renal veins associated with extrinsic pelviureteric junction obstruction and posterior nutcracker phenomenon

The renal vasculature and its various congenital anomalies have been studied and documented widely in the literature. However, the concomitant occurrence of renovascular morphological anomalies with vascular compression phenomena in a single patient is a rarity. This is a case of a patient with double left renal arteries, preaortic, accessory and retroaortic left renal veins. There was also associated with vascular compression phenomena in the form of posterior nutcracker phenomenon and pelviureteric junction obstruction (PUJ) due to the double-crossing inferior left polar renal artery and retroaortic vein.

Left renal vein transposition for posterior Nutcracker syndrome

Nutcracker syndrome (NCS) is a rare cause of pelvic venous congestion syndrome and is secondary to either compression of the left renal vein in its normal anatomic position by the superior mesenteric artery and aorta or less commonly when the left renal vein is in a retroaortic position, compressed between the aorta and the spine. We herein present a unique case of NCS in a female patient with a history of chronic pelvic pain and venous congestion. We also review the literature and discuss the diagnostic modalities, differential diagnosis, and various open surgical and endovascular options for NCS.

RENAL VEIN THROMBOSIS DUE TO POSTERIOR NUTCRACKER SYNDROME

Thrombosis of the left renal vein (LRV) is a rare occurrence usually associated with hypercoagulable disorders. It may also be caused by extrinsic compression due to anatomical variations. Such variations, known as nutcracker phenomenon (NP), are usually completely asymptomatic, and they have been described in three variants: a narrowed aortomesenteric angle (AMA) with entrapment of the LRV; a second, rarer variant with an anomalous retro aortic LRV compressed between the abdominal aorta (AA) and the spine (posterior nutcracker syndrome, PNCS); and a third variant with a duplicated LRV with a pre- and retroaortic course, compressed both anteriorly and posteriorly. The development of symptoms secondary to NP is mainly due to renal congestion, often difficult to identify, and includes flank pain, ipsilateral varicocele, hematuria, and orthostatic proteinuria, among others. The most severe complication of NCS is LRV thrombosis with or without associated predisposing prothrombotic factors. The present case associates a PNCS to LRV thrombosis with a floating thrombus in the inferior vena cava and pulmonary embolism.

3D-Printed PEEK Extravascular Stent in the Treatment of Nutcracker Syndrome: Imaging Evaluation and Short-Term Clinical Outcome

Minimally invasive options are safe and reliable alternatives for the treatment of nutcracker syndrome (NCS). After continued efforts, our team successfully devised a new and effective therapeutic method: 3D-printed extravascular stenting of the left renal vein. From December 2017 to May 2019, 28 patients (25 men and 3 women) from different parts of China between 18 and 37 years old (mean, 23.6 years) diagnosed with NCS were admitted for laparoscopic 3D-printed extravascular stenting treatment. The post-operative follow-up duration was 6-24 months (median, 16.3 months). Technical success of the operation was achieved in all patients. After treatment, the NCS symptoms all patients resolved or improved during the follow-up period, without relapse. Most symptoms, including macro-/microhematuria, proteinuria, and flank/abdominal pain, tended to resolve within 3-6 months after the surgery; other symptoms, such as left-sided varicocele, also showed varying degrees of improvement at different times post-operatively. Perioperative complications were noted in two patients, including transient and mild lymphatic leakage, without any adverse effects. All extravascular stents were visualized on computed tomography and Doppler ultrasound scans, and no migration or any side effects occurred during the entire follow-up period. Compared to endovascular stenting or polytetrafluoroethylene artificial vessel procedures, 3D-printed polyetheretherketone extravascular stenting has more advantages in terms of stent design and rigidity and approach rationality while successfully preventing stent migration and thrombosis. Therefore, this method may serve as an accurate and effective treatment for NCS patients.

Unusual Drainage of the Bifurcated Left Renal Vein Into a Dilated Lumbar Azygos Vein and Inferior Vena Cava

We report a unique case of unusual drainage of the bifurcated retroaortic left renal vein, with the cranial wider branch draining into a dilated lumbar azygos vein and caudal thinner branch connecting with the inferior vena cava. The right renal vein was duplicated. The anomaly was discovered on multimodal ¹⁸F-labeled fluorodeoxyglucose positron emission tomography/computed tomography performed for oncological purposes. The basis enabling occurrence of such variation was probably persistent developmental extra left-right venous connections, intercardinal, or intersupracardinal, depending on the theory. The embryology of the chest and abdominal veins is a complicated process and there is no unanimity concerning its concepts. The old models are currently being questioned and reevaluated. Knowledge of possible variants of renal and azygos veins course is important from clinical, imaging, and surgical points of view. The retroaortic left renal veins course may sometimes cause pain, hematuria, proteinuria, and pelvic congestion syndromes. Dilated parts of uncommonly located veins, because of assuming a nodular shape on transverse images, may be mistaken for abnormal lymph nodes, other tumors or aneurysms on imaging. During a variety of surgical procedures, including venous sampling, renal transplantation, or any retroperitoneal surgery, knowledge of an aberrant venous course may be important for the success of the procedure and may be crucial even earlier during the qualification process.