Endovascular stenting for treatment of Nutcracker syndrome: report of 61 cases with long-term followup

Nutcracker Syndrome (a Delphi consensus)

INTRODUCTION

Nutcracker syndrome describes the symptomatic compression of the left renal vein between the aorta and superior mesenteric artery. Whereas asymptomatic compression is a common radiological finding, patients with nutcracker syndrome can report a range of symptoms. There are no specific diagnostic criteria and interventions include a range of open surgical and endovascular procedures. Therefore, we wished to develop an international consensus document covering aspects of diagnosis, management, and follow-up for patients with nutcracker syndrome.

METHODS

A three-stage modified Delphi consensus was performed. A steering committee developed 37 statements covering three categories for patients with nutcracker syndrome: diagnosis, management and follow-up. These statements were reported individually by 20 international experts in the management of venous disease, using a five-point Likert scale. Consensus was defined if ≥70% of respondents rated the statement between 1 or 2 (agreement) and between 4 or 5 (disagreement). Those statements without consensus were recirculated in a second round of voting. A third round of the questionnaire was performed with 14 additional statements to clarify diagnostic values of nutcracker syndrome.

RESULTS

Responses were achieved by 20 of 20 (100%) experts in round one and 17 of 20 (85%) in round two. Initial consensus was reached in 24 of 37 statements (65%) spread over all categories. Round two achieved a further consensus on five out of ten statements (50%). No categories reported consensus on all statements. In round two consensus was reached in the category of Follow-up (4/5 statements, 80%). The final round reached consensus on 5 out of 14 statements (36%). Experts agreed that imaging is obligated to confirm NCS. Experts did not agree on specific diagnostic cut-off values. There was a consensus that the first choice of operative treatment is left renal vein transposition and that the risk of stent migration outweighs the advantages of a percutaneous procedure.

CONCLUSION

Consensus was achieved on most statements concerning the assessment and management of nutcracker syndrome. This Delphi consensus identified those areas in which further research is needed, such as anti-platelet therapy, endovascular treatment and renal autotransplantation. A rare disease registry to improve data and reports of patient outcomes is warranted.

Diagnosis and Management of Pelvic Venous Disorders in Women

Pelvic venous reflux and obstruction can lead to chronic pelvic pain and extra-pelvic varicosities. This paper will discuss the contemporary understanding of this pathophysiology and its clinical manifestations. It will review evidence-based clinical and imaging criteria of pelvic venous disorders, data supporting benefit from venous interventions, criticisms of the available data and highlight evidence research gaps that exist. Finally, it will argue that comparative outcomes research utilizing standardized patient selection for embolization and stenting, embolization treatment strategies that eliminate the pelvic varices (at least to start), and clinically relevant outcome measures are necessary to establish the benefit of vascular treatments.

Venous Compressive Disorders

Venous compressive disorders are a heterogenous group of vascular syndromes characterized by extrinsic venous compression that can lead to complications of venous hypertension or venous thrombosis. Endovascular damage secondary to deep venous thrombosis (DVT) can result in post-thrombotic syndrome (PTS), a potentially debilitating condition that can be associated with significant morbidity in the pediatric population. Here we discuss 4 venous compressive disorders: iliac vein compression (May-Thurner syndrome [MTS]); subclavian vein compression at the venous thoracic inlet (Paget-Schroetter syndrome); left renal vein compression (nutcracker syndrome); and popliteal vein compression (popliteal entrapment syndrome) with a focus on clinical evaluation and diagnostic methods. Where endovascular therapy is appropriate, specific procedural considerations including procedure indications, equipment, procedural steps, technical challenges, complications, clinical follow-up and expected outcomes are discussed.

Nutcracker syndrome: a case-based review

The nutcracker phenomenon, also known as left renal vein entrapment, occurs when there is extrinsic compression of the left renal vein, most often between the abdominal aorta and the superior mesenteric artery. Nutcracker syndrome refers to the constellation of clinical symptoms that may arise from the nutcracker phenomenon, typically inclusive of haematuria, flank/pelvic pain, orthostatic proteinuria and (in male patients) varicocele. We provide a short review of the nutcracker syndrome including various diagnostic and therapeutic modalities. We utilise our own experience with a patient as a case study and highlight the modern management option of endovascular stenting.

Treatment of Nutcracker Syndrome with Left Renal Vein Transposition and Endovascular Stenting

BACKGROUND

Nutcracker syndrome is a rare condition that occurs as a result of the entrapment of the left renal vein (LRV) between the aorta and the superior mesenteric artery. It is typically associated with symptoms such as left flank pain, hematuria, proteinuria, and pelvic congestion. The current treatment approach may be conservative in the presence of tolerable symptoms, and surgical or hybrid and stenting procedures in the order of priority in the presence of intolerable symptoms. The aim of this study is to review our experiences to evaluate the results of both methods in this series in which we have a greater tendency toward surgery instead of stenting.

METHODS

The clinical data of consecutive patients with nutcracker syndrome who underwent LRV transposition and LRV stenting between July 2019 and October 2023 were retrospectively reviewed. The patients were divided into 2 groups based on the methods of treatment: surgical and stenting. For procedure selection, LRV transposition was primarily recommended, with stenting offered to those who declined. Primary end points were morbidity and mortality. Secondary end points included late complications, patency, freedom from reintervention, and resolution of symptoms. Standard basic statistics and survival analysis methods were employed.

RESULTS

Nineteen patients with nutcracker syndrome (female: 100%) were treated with LRV stentings (n = 5) and LRV transposition (n = 14). The mean age was 24 (20-27, interquartile range [IQR]) years. The mean follow-up was 23 (9-32, IQR) months. There were no major complications and mortality after both procedures. The most frequent sign and symptom associated with LRV entrapment were left flank pain 100% (n = 19), proteinuria 88% (n = 15), and hematuria 47% (n = 9). The mean peak velocity ratio on Doppler ultrasound was 6.13 (6-6.44, IQR). Aortomesenteric angle, beak angle (beak sign), and mean diameter ratio on computed tomography were 26° (22.6-28.5, IQR), 25° (23.9-28, IQR), and 5.3 (5-6, IQR), respectively. Venous pressure measurements were only used to confirm the diagnosis in 5 patients in the stenting group. The measured renocaval gradient was 4 (3.9-4.4, IQR) mm Hg. After both procedures, the classical symptoms, including left flank pain, proteinuria, and hematuria, resolved in 89.5% (n = 17), 57.8% (n = 11), and 82.3% (n = 15) of the cases, respectively. A total of 4 patients required reintervention, 3 patients after LRV transposition (occlusion, n = 2; stenosis, n = 1), and 1 patient after stenting (occlusion, n = 1). The 1-year and 3-year primary patency for the 19 patients was 87% and 80%, respectively. Three-year primary-assisted patency was 100%. Similarly, the 1-year and 3-year freedom from reintervention rate was 83% and 72%, respectively. Additionally, the 1-year and 3-year primary patency for the surgical group was 91% and 81%, respectively, and the 1-year and 3-year primary patency for the stenting group was 75%.

CONCLUSIONS

Nutcracker syndrome should be kept in mind in cases where flank pain and hematuria cannot be associated with kidney diseases. Radiographic evidence must be accompanied by serious symptoms to initiate the treatment of nutcracker syndrome with LRV transposition and endovascular stenting procedures. Both procedures, along with their respective advantages and disadvantages, can be preferred as primary treatments for nutcracker syndrome. Our study demonstrates that both procedures can be safely and effectively performed, yielding good outcomes.

Case presentation and review of renal autotransplantation for nutcracker syndrome

Nutcracker Syndrome (NCS) is characterized by entrapment of the left renal vein, leading hematuria, flank pain, and proteinuria. We evaluated the efficacy of renal autotransplantation as a curative treatment for NCS through a review and case report. 55 patients from 18 studies were analyzed, with a combined 91% success rate of symptom resolution or improvement post-autotransplantation. In our case report, a 25-year-old man with severe NCS received laparoscopic nephrectomy and autotransplant, resulting in symptom resolution at 3.1 years follow up. Further research should confirm these findings and refine patient selection criteria and surgical techniques.

Growing Renal Vein Aneurysm Treated by Endovascular Repair: A Case Report and Literature Review

Renal vein aneurysm (RVA) is extremely rare and often asymptomatic, disclosed only incidentally on diagnostic imaging modalities such as computed tomography and ultrasonography. Management is often just watchful follow-up, but some patients require intervention. We present the case of a 74-year-old man complaining of lower back pain in whom a 53-mm RVA was identified. He underwent successful endovascular repair using Amplatzer vascular plugs. The aneurysm had completely resolved by 12 months. Endovascular treatment of a primary RVA does not seem to have been reported previously. This is a milestone case in the management of RVA.

The disappearing act: case of a migrating left renal vein stent

INTRODUCTION

Nutcracker syndrome (NS) is a rare condition in which the abdominal aorta and superior mesenteric artery compress the left renal vein (LRV). One treatment option is the placement of an endovascular stent into the LRV, which carries the risk of stent migration.

CASE REPORT

A 30-year-old female with NS status-post LRV stenting 6 months prior presented to the emergency department with suprapubic pain. An incidental finding on abdominal computed tomography scan noted interval removal of LRV stent, which had not been surgically removed. A subsequent chest radiograph showed the stent lodged in the left pulmonary artery.

DISCUSSION

To our knowledge, this is the first documented case of LRV stent migration to the pulmonary artery. This case demonstrates the importance of physician awareness of stent migration as a potential complication after stent placement, and careful review of all imaging findings, even if unrelated to the chief complaint.

Systematic review of endovascular versus laparoscopic extravascular stenting for treatment of nutcracker syndrome

OBJECTIVE

The aim of the present study was to assess the current strategies of endovascular and laparoscopic extravascular stenting for symptomatic compression of the left renal vein (LRV), most frequently between the aorta and superior mesenteric artery (nutcracker syndrome [NCS]).

METHODS

We performed a systematic review of all studies of endovascular and laparoscopic extravascular LRV stenting for NCS using the PubMed/MEDLINE, Scopus, Embase, Cochrane, Science Citation Index Expanded, Emerging Sources Citation Index, and Epistemonikos databases. Data were collected in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analysis) guidelines. The English, Spanish, and German language literature was searched from January 1, 1946 to February 9, 2022. The outcomes assessed included symptom resolution, hematuria resolution, and reintervention at follow-up.

RESULTS

The search yielded 3498 reports. After removing the duplicates and those without the full text available, 1724 studies were screened. Of these, 11 studies were included in the present review. Of the 11 studies, 7 were on endovascular stenting and 4 on laparoscopic extravascular stenting; all 11 studies were retrospective, single-center case series. Of the 233 patients, 170 (80 women) had undergone endovascular stenting and 63 (9 women) had undergone extravascular stenting. The follow-up period varied from 1 to 60 months after endovascular stenting and 3 to 55 months after extravascular stenting. The symptoms had resolved in 76% (range, 50%-100%) after endovascular stenting and 83% (range, 71%-100%) after extravascular stenting. Hematuria had resolved in 86% (range, 60%-100%) after endovascular stenting and 89% (range, 77%-100%) after extravascular stenting. Of 185 patients, 9 had required reintervention after endovascular stenting and none after extravascular stenting.

CONCLUSIONS

Endovascular and laparoscopic extravascular stenting are less invasive and, thus, more attractive treatment options that have been more recently developed for the management of NCS. The results from the present study have shown that symptom and hematuria resolution must be provided before they can be considered preferred management options for patients affected by NCS. Given the limited number of patients involved, no definitive conclusion could be drawn regarding the superiority of one technique compared with the other.

Laparoscopic placement of left renal vein extravascular stenting in treatment of nutcracker syndrome: Techniques and long-term outcomes

OBJECTIVES

We aimed to assess the feasibility and efficacy of laparoscopic extravascular stent in treatment of nutcracker syndrome by transperitoneal or retroperitoneal approach.

METHODS

Seventy-six patients with nutcracker syndrome were retrospectively enrolled from a tertiary referral center, and underwent transperitoneal (63 patients) or retroperitoneal (13 patients) laparoscopic extravascular stent from March 2011 to December 2020. Surgical parameters, complications, imaging and clinical outcomes were collected and analyzed.

RESULTS

All procedures were successfully carried out without open conversion. The median operation time, estimated blood loss, and postoperative hospital day were 120 (interquartile range [IQR]: 90-144) min, 20 (IQR: 10-30) ml, and 7 (IQR: 6-9) days. At a median follow-up of 52 (range: 9-127) months, 60 (79%) patients had complete symptom resolution, 14 (18%) patients had significant symptom improvement, and 2 (3%) patients reported no symptom improvement. Ninety-four percent (50/53) of hematuria, 91% (30/33) of proteinuria, and 89% (25/28) of flank/abdominal pain resolved after extravascular LRV stenting. No significant differences were detected in surgery parameters and recovery rates of clinical symptoms between two approaches (each p > 0.05). However, patients with transperitoneal approach need longer to achieve complete recovery compared with retroperitoneal approach (8.7 vs. 1.5 months, p = 0.016).

CONCLUSIONS

Laparoscopic extravascular stent performed either transperitoneally or retroperitoneally is a feasible and effective option in treatment of nutcracker syndrome. Retroperitoneal laparoscopic extravascular stent required shorter time to achieve complete recovery, which should be considered whenever possible in surgical decision-making.

Nutcracker syndrome: A case report and review of the literature

Background

Nutcracker syndrome (NS) is an uncommon condition resulting from the compression of the left renal vein (LRV) between the aorta and superior mesenteric artery (SMA), resulting in symptoms such as flank pain and hematuria.

Case presentation

We present the case of a 30-year-old woman complaining of abdominal pain who was found to have nutcracker syndrome and treated with endovascular stenting of the left renal vein.

Discussion

We review the literature related to endovascular treatment of NS with focus on the distribution of the sizes of stents and rates of stent migration.

Conclusion

NC is a rare condition requiring a high index of suspicion for diagnosis. Endovascular treatment is a reasonable option, but its limitations must be considered.

Fortuitous Discovery of Nutcracker Syndrome During Acute Appendicitis: A Case Report

Nutcracker syndrome (NCS) belongs to a group of rare vascular disorders. It refers to compression of the left renal vein (LRV) generally between the abdominal aorta (AA) and the superior mesenteric artery (SMA). It is one of the most unknown causes of chronic abdominal pain. Herein, we present the case of a young patient who came to the emergency department for acute abdominal pain. Patient's history revealed an uncharacterized chronic epigastric pain evolving for 13 years. The imaging showed acute appendicitis and NCS; the latter finding was the principal explanation for the patient's chronic pain. We hope that the concise and synthetized structure of this case report will help physicians acquire the necessary reflexes to notice and diagnose this already underdiagnosed syndrome.

Interventional Management of a Rare Combination of Nutcracker and Wilkie Syndromes

Nutcracker and Wilkie syndromes are rare mesoaortic compression entities, and their association is even less common. Data on interventional treatment of these pathologies are still scarce, but results from limited case series are encouraging. We report the case of a previously healthy 45-year-old woman diagnosed with nutcracker and Wilkie syndromes who presented with macroscopic hematuria, intermittent pain in the left flank and hypogastric region, postprandial nausea, and unexplained significant weight loss. A successful endovascular approach with stent implantation in the left renal vein was performed, but the stent migrated toward the left kidney, and this acute complication was managed through an interventional strategy as well. At the three-month follow-up, the patient described a marked improvement in all symptoms, except for the macroscopic hematuria. As it was our strong belief that the approach was efficient, we further investigated the “hematuria”, which eventually led to the diagnosis of endometrial carcinoma. A hysterectomy and bilateral adnexectomy were planned, and chemoradiotherapy was initiated with the goal of preoperative tumor reduction. To our knowledge, this is the first reported case in which both Wilkie and nutcracker syndromes were effectively treated by stent implantation in the left renal vein, complicated with very early stent migration due to inadequate apposition to the less compliant venous lumen. The treatment of the duodenal compression was indirectly included in the stenting of the left renal vein, as reclaiming the venous lumen widened the aortomesenteric angle. The aim of this review is to discuss our center’s transcatheter experience with these rare disorders and explore the literature in order to establish the benefits and limitations of such an approach.

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.

A Novel Approach for the Treatment of Nutcracker Syndrome: A Case Report

We describe a case of nutcracker syndrome in a 35 year-old male that was treated with a left renal vein transposition via an open retroperitoneal approach. Our case highlights some of the advantages of the retroperitoneal approach, which may decrease the risk of postoperative complications when compared to the traditional midline abdominal transperitoneal approach. The patient agreed to publish the case details and images included below.

Atypical Posterior Nutcracker Syndrome in a 17-Year-Old Male Without Hematuria

Retro-aortic left renal vein (RLRV) is an anatomical variation, where the left renal vein (LRV) courses posterior to the aorta and anterior to the vertebrae before it eventually drains into the inferior vena cava (IVC). RLRV is a rare finding, with a prevalence of around 1%-2%, and only a small minority of RLRVs cause symptoms. RLRV symptoms occur secondary to compression of the LRV between the abdominal aorta and vertebrae, otherwise known as posterior nutcracker syndrome (PNCS). The most common symptoms of PNCS are hematuria and flank pain. We present a 17-year-old male, who came in with recurring left flank pain without hematuria, initially thought to be renal colic secondary to nephrolithiasis. On further investigations, an aberrant posterior renal vein was seen on CT suggestive of PNCS. The patient was treated successfully with RLRV vascular stent placement by interventional radiology. This case report adds to the limited number of PNCS cases observed in children and to the even rarer cases of PNCS without hematuria. This case also acts as a reminder for pediatricians to keep a wide scope of differentials in patients presenting with flank pain and provides an outline of both diagnostic and treatment modalities available for these patients.

An Uncommon Variant of Nutcracker Syndrome Secondary to Left Renal Vein Compression Between the Right Renal Artery and The Proper Hepatic Artery

Nutcracker syndrome refers to the compression of the left renal vein between the abdominal aorta and the superior mesenteric artery. The subsequent venous congestion of the left kidney, when symptomatic, could be associated with left flank pain, hematuria, varicocele, dyspareunia, dysmenorrhea, and proteinuria. Here we describe a 42-year-old female patient with simultaneous Dunbar syndrome and a rare variant of nutcracker syndrome in which the left renal vein (LRV) compression is secondary to the unusual path of the vein between the right renal artery and the proper hepatic artery. For both the nutcracker syndrome and the Dunbar syndrome, open approach by median mini-laparotomic access for transposition of LRV, and resection of the diaphragmatic pillars and arcuate ligament was attempted. During the intervention, due to anatomical issues, the LRV transposition was converted to endovascular stenting of the LRV, moreover the implanted stent was transfixed with an external non-absorbable suture to avoid migration. At the 12 months follow-up the patient was asymptomatic, and the duplex scan confirmed the patency of the celiac trunk without re-stenosis and a correct position of the LRV stent with no proximal or distal migration.

Endovascular management of nutcracker syndrome in an adolescent patient population

BACKGROUND

Nutcracker syndrome is defined as left renal vein compression with concomitant clinical symptoms that include flank pain and hematuria. Historically, pediatric and adolescent patients with mild symptoms of nutcracker syndrome were simply observed while those with more severe symptoms underwent left renal vein transposition. Endovascular stenting of the left renal vein is a potentially efficacious and less invasive alternative for managing nutcracker syndrome in adolescents.

OBJECTIVE

The purpose of this study was to investigate the technical feasibility, efficacy and safety of left renal vein stenting in adolescents with nutcracker syndrome.

MATERIALS AND METHODS

We conducted a retrospective review of electronic medical records and imaging archives to identify adolescents undergoing endovascular stenting for nutcracker syndrome. We reviewed patient demographics including age, gender, presenting symptoms and diagnostic imaging findings. We compared pre- and post-stent deployment intravascular ultrasound (IVUS) and venography and evaluated patient symptoms in clinic up to 6 months following stent placement.

RESULTS

Ten patients (average age 16 years, range 12-20 years) underwent 13 procedures. Initial symptoms included pain (n=10) and gross hematuria (n=5). Diagnostic imaging studies included CT abdomen pelvis (n=8), retroperitoneal US (n=6), MRI abdomen/pelvis (n=4), scrotal US (n=2), pelvic US (n=1) and renal Doppler US (n=2). Venography and IVUS demonstrated venous collaterals, proximal blanching at the left-renal-vein-IVC junction, pre-stenotic dilation and intraluminal compression. Most patients (n=9) experienced symptomatic resolution; however, three patients required reintervention to achieve asymptomatic status. No periprocedural complications occurred.

CONCLUSION

In this carefully selected adolescent cohort, left renal vein stenting for nutcracker syndrome was often technically feasible, safe and effective in symptom management.

A simplified surgical approach for left ovarian vein transposition for the treatment of pelvic venous disease from nutcracker syndrome

Nutcracker syndrome is becoming increasingly recognized as a cause of chronic pelvic pain. Several treatment options have been used, including renal vein or ovarian vein transposition to the more distal inferior vena cava and renal vein stenting. Concerned about the major scope of the surgical procedures as well as the implantation of a foreign body that must function for six to seven decades, we undertook to develop an all autogenous simpler surgical solution for the treatment of nutcracker syndrome. In 2013, we began performing left ovarian vein transposition to the left iliac vein. In our initial report, we used a minimally invasive robotic approach. For the past several years, we have used a simplified open approach to left ovarian vein transposition that takes advantage of the fact that the left ovarian vein naturally courses over the iliac vein. We have found this surgical treatment of nutcracker syndrome provides excellent relief from the associated symptoms.

Nutcracker Syndrome: How to Diagnose It and When/How Should It Be Treated in the Pelvic Venous Disease Population

With wider recognition of left renal vein compression / obstruction, especially as an incidental finding, the significance as it relates to the patient's symptoms needs to be evaluated in light of variable practices and results of treatment. This communication deals with problems of diagnosis, clinical significance, options and indications for treatment.

The Vici venous stent for treatment of renal vein entrapment

The nutcracker syndrome results from compression of the left renal vein between the superior mesenteric artery and the aorta. We present the first reported case of symptomatic left renal vein compression treated with balloon angioplasty and stenting with the Vici stent system.

Left Renal Vein Stenting in Nutcracker Syndrome: Outcomes and Implications

Nutcracker syndrome refers to the symptomatic extrinsic compression of the left renal vein presenting most commonly as flank pain and haematuria. While surgery remains the first-line treatment, stenting is gaining more acceptance and there are now several published case series. This article highlights the outcomes of left renal vein stenting in the setting of nutcracker syndrome.

'Full prosthetic jacket': external stenting of the renal vein

Introduction: We present a case of positional compression of the left renal vein (LRV) after right nephrectomy and caval reconstruction, treated by external stenting using a reinforced vascular prosthesis.Case report: A 69-year-old female patient presented because of swelling of the left leg. A renal cell carcinoma (RCC) was visualized on computed tomography (CT) scan in the right kidney, with a thrombus occluding the inferior caval vein (ICV) and the right renal vein (RRV). A right nephrectomy was performed, with ligation of the already occluded ICV. Venotomy allowed thrombectomy of the ICV above the level of the renal veins. Venous return from the left kidney was secured by reconstruction of the confluence of the LRV and the ICV. Postoperatively, urinary output declined, leading to anuria and elevated levels of serum creatinine. With surgical exposition of the LRV, a flow of 387 mL/min was measured. After removal of exposition, flow in the LRV dropped to 51 mL/min. The positional compression was treated with a reinforced vascular PolyTetraFluoroEthylene (PTFE) prosthesis placed around the LRV.Discussion: Besides some reports on external stenting of the renal vein in the treatment of nutcracker syndrome (NS), this is the first report describing this technique outside this clinical entity.

Endovascular treatment of anterior nutcracker syndrome and pelvic varices in a patient with an anterior and a posterior renal vein

There are few data on endovascular treatment of anterior nutcracker syndrome and pelvic varices in patients with anterior and posterior renal veins. Our objective is to report a case, identify occurrences and compare diagnosis and treatments. A 42-year-old woman presented with flank and pelvic pain and hematuria. She had anterior nutcracker syndrome and pelvic varices with an anterior and a posterior renal vein. A successful complete endovascular approach was done with stent implantation in the anterior renal vein and left gonadal vein embolisation. After 12-month follow-up, the patient remained asymptomatic with good results on CT. Only two case reports of patients with nutcracker syndrome with anterior and posterior renal veins were identified. In both, a self-expanding stent was implanted in the anterior renal vein. In conclusion, endovascular treatment represents a safe and successful option in patients with nutcracker syndrome and pelvic varices with an anterior and a posterior renal vein.

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.

Endovascular treatment of a teenager with nutcracker syndrome: a case report

The nutcracker syndrome is caused by compression of the left renal vein by the superior mesenteric artery and aorta and is associated with characteristic symptoms, such as lower abdominal pain, varicocele, and hematuria. Diagnosis is often difficult and, therefore, is often delayed. Invasive treatment is controversial, particularly in pediatric patients. However, it is indicated in cases of gross hematuria associated with anemia, renal function impairment, severe pelvic pain, or ineffective conservative treatment. We report the case of a 12-year-old boy presenting with severe hematuria for 12 hours, with no abnormal findings at a first evaluation, who progressed with severe anemia and urinary retention. Further investigation provided images suggestive of nutcracker syndrome, and endovascular stenting (smart control stent) followed by balloon dilatation was the treatment of choice. Hematuria ceased after the procedure, and the patient is still asymptomatic at 5-year follow-up.

Localized solitary left renal vein thrombus complicating nutcracker syndrome: a case report and review of the literature

Nutcracker syndrome (NCS) refers to compression of the left renal vein (LRV) between the abdominal aorta and the superior mesenteric artery (SMA). The clinical presentation of NCS includes hematuria, abdominal and left flank pain, gonadal varices, and varicocele formation. Theoretically, thrombosis can occur in the LRV in patients with NCS. However, an isolated solitary left renal vein thrombus (LRVT) complicating NCS is rare. In addition, the clinical features of an LRVT complicating NCS remain unclear. We describe a 43-year-old woman presenting with an asymptomatic LRVT complicating NCS. She was referred to our hospital for investigation of dysfunctional uterine bleeding, and detailed examination revealed endometrial cancer. Computed tomography angiography (CTA) and Doppler ultrasonography revealed compression of the LRV between the aorta and the SMA, as well as an LRVT. CTA performed 4 months after the administration of an anticoagulant showed complete disappearance of the LRVT. We have also included a review of published reports describing LRVT complicating NCS and discussed the clinical features of such a presentation.

Eighteen years of experience with pediatric nutcracker syndrome: the importance of the conservative approach

INTRODUCTION

Nutcracker syndrome (NS) defines an entity generated by the compression of the left renal vein resulting in venous hypertension, which transmitted in a retrograde direction may cause hematuria, proteinuria, and varicocele. The literature concerning exclusively pediatric patients is very rare.

OBJECTIVE

To report the authors' experience with pediatric NS in the last 18 years.

STUDY DESIGN

This is a retrospective review of the patients followed up in the authors' center with diagnosis of NS based on clinical and imaging tests (ultrasound, computed tomography/magnetic resonance imaging, and phlebography). The primary outcome was the success of the conservative approach in the study patients.

RESULTS AND DISCUSSION

A total of 21 patients were diagnosed with NS and followed up for a mean period of 52.3 months (37.1-67.5). The mean age at diagnosis was 11.7 years (9.9-13.4). The most frequent symptom of presentation was hematuria in 16 patients (76.2%), being macroscopic in 75% patients and related to physical exercise in 42.9% patients. Other symptoms were left varicocele in 7 patients (33%) and proteinuria in 6 patients (28.6%). Mild to moderate cases received conservative treatment (change of physical activity, postural hygiene), which achieved resolution of symptoms in 16 patients (76.2%). Five cases (23.8%) finally needed a more aggressive approach. Two (9.5%) of them required endovascular procedures (intravascular stent in the renal vein in 1 case and embolization of the spermatic vein in 1 case); in one (4.8%) of the patients, transposition of the left renal vein and kidney autotransplantation were performed, and 2 (9.5%) of the patients with mild cases required surgical correction of the varicocele.

CONCLUSIONS

Hematuria, usually macroscopic and related to physical exercise, is the most frequent symptom in pediatric patients with NS. The authors advocate studying the aortomesenteric junction by abdominal ultrasound in patients with varicocele or with intermittent macroscopic hematuria. Diagnosis is based on non-invasive tests; phlebography should be reserved for severe cases that require an interventionist attitude. A long period of conservative treatment is the first approach for pediatric patients with NS.

A minimally invasive alternative for the treatment of nutcracker syndrome using individualized three-dimensional printed extravascular titanium stents

BACKGROUND

This study was designed to evaluate the clinical and radiographic outcomes of patients with nutcracker syndrome (NCS) who were treated with three-dimensional printing (3DP) extravascular titanium stents (EVTSs). The 3DP EVTS was expected to release the hypertension of the left renal vein (LRV) produced by its compression between the superior mesenteric artery (SMA) and the aorta without causing any complications.

METHOD

The pre-operative kidney model of each patient was printed out to enable surgical planning. After that, the EVTS was designed based on the LRV's primitive physiologic structure using computer-aided design software, and each stent was printed out with a precision setting of 20 μm. Seventeen patients who had been suffering from NCS underwent laparoscopic 3DP EVTS placement. The surgical procedure was designed for the placement of EVTS, taking great care in positioning and fixing the stent. Surgical data, which included patient demographic characteristics as well as pre- and post-operative test results, were collected and analyzed.

RESULTS

The mean duration of surgery was 75 ± 9 min, and the mean blood loss was 20 ± 5 mL. Computed tomography examinations revealed that the pre- and post-operative angle between the SMA and the aorta ranged from 18.7° ± 4.3° to 48.0° ± 8.8° (P < 0.05); in patients with left varicocele, the mean diameter of the left spermatic vein ranged from 3.7 ± 0.5 to 1.3 ± 0.2 mm (P < 0.05). Moreover, Doppler ultrasound examinations showed that the peak velocity of blood flow at the hilar area ranged from 12.4 ± 3.3 to 18.5 ± 3.4 cm/s (P < 0.05). No side effects were observed in the 24 to 42 months following surgery.

CONCLUSION

The findings after 2 years of follow-up suggest that the 3DP EVTS is a safe and effective minimally invasive alternative for the treatment of NCS.

Salvage Renal Autotransplant Following Previous Renal Vein Stenting in Nutcracker Syndrome

OBJECTIVES

Nutcracker syndrome is rare, and a proportion of patients with this syndrome continue to have intractable pain and symptoms. Due to the heterogeneity of patients' chief complaints and symptoms, the surgeon's preferred approach may be inherently different but is of paramount importance to the outcome.

MATERIALS AND METHODS

We present 4 cases in which renal autotransplant with extraction and ligation of previously placed gonadal coils was performed following previously attempted renal vein stenting or combined renal vein transposition followed by renal vein stenting.

RESULTS

Autotransplant resulted in flank pain resolution with improvement in symptoms associated with pelvic congestion syndrome.

CONCLUSIONS

The approach to such cases requires meticulous and adequate vena cava exposure, with preparation for potential caval reconstruction. No firm inferences can be made from such a small series; however, we believe in renal autotransplant as first-line therapy, and failure after an initial renal vein stent should be salvaged by renal autotransplant over further endovascular attempts.

Robot-Assisted Laparoscopic Left Renal Vein Transposition for the Treatment of Nutcracker Syndrome: A Preliminary Experience

BACKGROUND

The aim of this study was to describe our robot-assisted laparoscopic left renal vein (LRV) transposition experiences for nutcracker syndrome treatment.

METHODS

From August 2016 through May 2017, three patients with nutcracker syndrome underwent robot-assisted laparoscopic LRV transpositions. The patient demographics, surgical outcomes, and postoperative morbidities were reviewed.

RESULTS

Successful surgical procedures were performed in all three patients. The operative times for the three cases were 150, 175, and 162 minutes, respectively, while the LRV anastomosis times were 19, 22, and 13 minutes, respectively. No major perioperative complications were encountered, and the hematuria and flank pain were resolved in all three cases. At the 6-month follow-up, the computed tomography scan showed that the LRV narrowing had disappeared in two of the patients. Although one patient still exhibited LRV flattening, his symptoms were also relieved, and the varicose tributaries spontaneously ceased.

CONCLUSIONS

Robot-assisted laparoscopic LRV transposition can be a viable minimally invasive treatment option for patients with nutcracker syndrome.

Tratamento endovascular da síndrome de quebra-nozes: relato de caso

Chronic pelvic pain is a debilitating disease that directly impacts on quality of life and generates costs for health services. Nutcracker Syndrome is an important cause of pelvic pain and consists of a set of signs secondary to compression of the left renal vein, most commonly between the superior mesenteric artery and the aorta. Treatment remains controversial and varies depending on the patient's clinical severity. However, endovascular treatment with renal vein stenting has achieved excellent results. We report the case of a 59 year-old female treated by endovascular repair with a self-expanding nitinol stent. Clinical data, details of the procedure, and follow-up results are presented. Technical success was achieved and there patient reported no postoperative complications. Short-term, there was relief from symptoms and follow-up imaging tests showed improvement.

Diagnosis and treatment of the Nutcracker syndrome: a review of the last 10 years

The nutcracker syndrome is characterized by a group of clinical manifestations caused by compression of the Left Renal Vein. The main symptoms are: macro and micro hematuria, proteinuria, and flank pain. Diagnosis is usually made after excluding other causes, because there are no clinical criteria for diagnosis. Confirmation is by Doppler ultrasonography or computed tomography. Treatment can vary, depending on patient characteristics and the severity of the symptoms, while conservative treatment, open surgery, and endovascular surgery may be employed. Currently, open surgery is still the first-line treatment, but some less invasive approaches are gaining acceptance.

Association Between Left Renal Vein Entrapment and Varicocele Recurrence: A Cohort Study in 3042 Patients

The recurrence rates after varicocelectomy vary from 0.9% to 32.2%, especially for patients with the left renal vein entrapment (LRVE). This study aims to study the association between LRVE and varicocele recurrence, and to find the risk factors of LRVE. With the design of a cohort study, we included 3042 varicocele patients who would undergo modified inguinal microscope-assisted varicocelectomy (MHMV). 858 (28.21%) patients with LRVE were as the study group, and 2184 (71.79%) patients without LRVE were as the control group. Compared with the control group, BMI was lower (p < 0.001) in study group. Totally, 18 patients had recurrence after surgery, so the recurrence rate was 0.59%. Seventeen patients (1.98%) in study group and 1 patients (0.05%) in control group had recurrence, and significant statistical difference was found between the two groups (p < 0.001). The risk ratio of LRVE for varicocele recurrence is 43.27. In conclusion, the recurrence rate of our MHMV is the lowest (0.59%). There is association between LRVE and varicocele recurrence, and varicocele patients with LRVE have higher probability of recurrence rate after varicocelectomy. BMI could be a risk factor of LRVE. Thus, for varicocele patients, especially those with lower BMI, attentions should be payed to LRVE.

Endovascular extraction of a migrated large self-expanding laser-cut renal venous stent from the right ventricle

Endovascular stent placement for decompression of an entrapped left renal vein (LRV) between the aorta and superior mesenteric artery is an alternative to surgical decompression for treating the nutcracker syndrome. However, an interventional approach may be challenging because of the unfavorable configuration of the LRV, leading to insufficient stent anchoring. We provide a case of a life-threatening stent migration from the LRV into the right ventricle 2 days after stent placement and its endovascular retrieval.

Posterior nutcracker syndrome - a systematic review

Posterior nutcracker syndrome (PNCS) is the entrapment of the left renal vein between the aorta and the vertebral column. Although uncommon, it is still an important diagnosis due to the high morbidity associated with the risk of secondary anaemia from haematuria, from long-term left renal vein hypertension, vascular thrombosis, and even blood clots in the urinary system. A literature search of PubMed and EMBASE databases was performed and 27 publications containing 27 cases were included for the final analysis. The following frequency of clinical signs and symptoms was noted: twenty-five patients had haematuria, 13 patients had flank pain, and two had hypertension. Overall, male-female distribution was balanced and there were more adult than paediatric (age < 18 years) patients. All symptoms of patients with conservative treatment were either well-controlled or under spontaneous resolution. Conservative management instead of surgical treatment should be preferred in most cases. Taken together, despite the low incidence of PNCS, its recognition and management are highly important. This systematic study explores the evidence base for conservative and medical options.

Robot-assisted laparoscopic extravascular stent for nutcracker syndrome

Minimally invasive treatment options are a safe and feasible alternative for treatment of nutcracker syndrome. Endovascular stenting has shown promising long-term resolution of symptoms but can be complicated by stent migration or thrombosis. Laparoscopic extravascular stent placement has shown promising results with the potential to avoid these complications. We report the first case of extravascular stent placement using the robotic approach for the treatment of nutcracker syndrome.

Management of left renal vein compression in patients presenting left gonadal vein reflux

Background

Compression of left renal vein is an atypical cause of reflux in pelvic veins resulting in pelvic varices that in turn causes frequently lower limb varices in many cases.

Methods

A monocentric study was undertaken to report the treatment and five-year follow up of patients presenting left renal vein compression. Embolization of refluxive gonadal/pelvic veins was performed generally as the initial procedure. Left renal vein stenting was performed in patients presenting haematuria, severe lumbar pain or persistent pelvic/lower limb varices after embolization.

Results

From 462 cases of left renal vein compression, 40 were treated by stenting as first procedure. Four hundred twenty-two were treated by gonadal/pelvic vein embolization and only 15 needed complementary stenting. After follow-up, all cases with haematuria had improved and lumbar pain was eliminated in 81.5%. Patients with recurrent or persistant varices were all improved.

Conclusion

Left renal vein stenting should be considered an effective and safe procedure, with demonstrated durable efficacy and safety and no evidence of restenosis.

Venous Compression Syndromes

Venous compression syndromes occur due to extrinsic compression causing complications of venous hypertension or venous thrombosis. This review focuses on 4 venous compression syndromes involving the left common iliac vein, subclavian vein, left renal vein, and popliteal vein. Clinical presentation, diagnostic methods, and management options are reviewed. When properly diagnosed and treated, long-term consequences can be avoided.

Nutcracker Syndrome: Case Report on the Management of Recurrent Stenosis After Stenting

Nutcracker syndrome is a clinical entity leading to renal venous hypertension due to extrinsic compression of the left renal vein by the superior mesenteric artery. Current surgical therapy involves placement of an oversized renal vein stent with partial protrusion into the inferior vena cava (IVC) to relieve stenosis and prevent stent migration. Here, we present a patient with intractable pain and hematuria secondary to nutcracker syndrome who underwent left renal vein stent placement and developed recurrent symptoms due to flow-limiting kinking at the left renal hilum, with partial obstruction of the IVC from pseudointimal hyperplasia. This was treated with stent excision and construction of a left neorenal vein bypass. Thus, given these complications, we should perhaps revisit the recommendations for oversizing of the stent.