An easily missed diagnosis: flank pain and nutcracker syndrome

Outcomes of conservative management in patients with nutcracker syndrome

OBJECTIVE

This study aims to evaluate outcomes in nutcracker syndrome patients with tolerable symptoms and treated conservatively without invasive interventions.

METHODS

This prospective study included patients treated conservatively. Promoting weight gain, the endpoint of the study was spontaneous resolution of symptoms.

RESULTS

Sixteen patients (75% female and mean age 24.4 ± 3.5 years) underwent conservative management. Over a mean follow-up of 27.3 months [13-42, interquartile range (IQR)], the diameter ratio (5.5 [5-6.5, IQR] vs 4.3 [4.1-6], p = NS), the peak velocity ratio (6 [5-7, IQR] vs 4.8 [4.8-5.8], p = NS), beak angle (27° [24-30, IQR] vs 29° [24-32]; p = NS), and aortomesenteric angle (26° [23-29, IQR] vs 28° [24-30]; p = NS) exhibited no statistically significant changes. Complete resolution and improvement of symptoms were 28.5% and 31.4%, respectively, while 68.5% remained unchanged.

CONCLUSIONS

This study shows that a conservative approach contributes to the spontaneous improvement or complete resolution in young adult patients with mild symptoms.

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.

How I treat nutcracker syndrome

Anatomic compression of the left renal vein in the angle between the aorta and superior mesenteric artery may be asymptomatic or may result in symptoms, including flank pain, hematuria, or pelvic pain and/or congestion. Patients can be referred to a vascular surgeon due to symptoms and/or radiologic findings. Because symptoms of nutcracker syndrome can be vague and/or nondiagnostic, careful evaluation, assessment, and counseling with patients are required before undertaking intervention, which is often an open surgical procedure. The definitive diagnosis is ideally confirmed with diagnostic venography, including pressure measurements from the left renal vein and inferior vena cava. The optimal treatment includes open decompression of the left renal vein with renal vein transposition or gonadal vein transposition, with or without concomitant management of pelvic varicosities if symptomatic. Because most patients with nutcracker syndrome are young, long-term follow-up with scheduled ultrasound examinations should be maintained.

Nutcracker syndrome: challenges in diagnosis and surgical treatment

BACKGROUND

Nutcracker syndrome (NCS) is an uncommon syndrome that presents with signs and symptoms caused by compression of the left renal vein (LRV), whereas 'nutcracker phenomenon' is solely used to refer to the anatomical configuration without clinical symptoms. Treatment for NCS may include non-operative management, open surgical intervention and in some instances endovascular stenting. We present a single-center retrospective case series of patients who presented with NCS managed with open surgical interventions.

METHODS

Single-center, retrospective review of patients managed from 2010-2021. We diagnosed NCS via a thorough clinical examination and additional cross-sectional imaging studies including magnetic resonance venography (MRV) and/or computed tomography venography (CTV). For further confirmation of the diagnosis, duplex ultrasound was frequently combined with contrast venography.

RESULTS

Thirty-eight patients were included in our study from 2010-2021 . Twenty-one (55.3%) patients presented with symptoms including flank pain, abdominal pain, hematuria and fatigue. The remaining 17 (44.7%) patients had nutcracker phenomenon. Within the group of patients diagnosed with NCS, 11 patients underwent LRV transposition. Symptoms related to NCS improved in 10 patients. Hematuria in one patient did not improve.

CONCLUSION

Transposition of the LRV is an effective treatment for NCS. Non-operative management is an option for those patients experiencing less severe or nonspecific clinical symptoms.

Trauma-associated left renal vein thrombosis with nutcracker syndrome

Background

Nutcracker syndrome is a compression of the left renal vein between the superior mesenteric artery and aorta, resulting in thrombogenesis. While renal vein thrombosis caused by renal disease is more common, solitary left renal vein thrombosis with nutcracker syndrome is rare.

Case Presentation

We present the case of a patient with trauma-associated left renal vein thrombosis with nutcracker syndrome. A 24-year-old woman with low body mass index taking oral contraceptives was admitted for trauma. She had multiple injuries, including thoracolumbar fractures, for which elective spinal fusion surgery was scheduled. As the D-dimer level elevated to 82.5 μg/dL preoperatively, enhanced computed tomography was performed, which revealed a solitary left renal vein thrombus.

Conclusion

This is the report of solitary left renal vein thrombosis in a patient with nutcracker syndrome after trauma. Patients with low body mass index and coagulopathy might have solitary left renal vein thrombosis associated with nutcracker syndrome.

Nutcracker syndrome as the main cause of left renal vein thrombus and pulmonary thromboembolism

INTRODUCTION

Left renal vein thrombus complicating nutcracker syndrome is relatively rare. To the best of our knowledge, there have been only four previous case reports. Furthermore, there have been no reports of pulmonary thromboembolism caused by nutcracker syndrome. Herein, we report a rare case of pulmonary thromboembolism caused by nutcracker syndrome and its clinical management.

CASE PRESENTATION

A 40-year-old man was admitted to our hospital with acute left flank pain. Computed tomography angiography revealed compression of the left renal vein between the aorta and the superior mesenteric artery with a left renal vein thrombus. Furthermore, computed tomography revealed bilateral pulmonary thromboembolism. Rivaroxaban was administered as an anticoagulant. Twenty days after initiation, computed tomography revealed complete resolution of pulmonary thromboembolism and left renal vein thrombus, and repeated computed tomography showed no recurrence.

CONCLUSION

This case report highlights nutcracker syndrome as a likely cause of pulmonary thromboembolism.

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.

Coexisting nutcracker phenomenon and superior mesenteric artery syndrome in a patient with IgA nephropathy: A case report

RATIONALE

Nutcracker and superior mesenteric artery (SMA) syndrome share the same pathogenesis, but the simultaneous occurrence of both diseases is quite rare. A combination of the nutcracker syndrome and IgA nephropathy has previously been reported. Herein, we report what we believe is the first case of coexisting nutcracker and SMA syndrome in a patient with IgA nephropathy.

PATIENT CONCERNS

A 15-year-old Chinese boy who was diagnosed with IgA nephropathy at 8 years of age presented with gross hematuria, fatigue, anorexia, nausea, and recurrent abdominal distension for 1 week without any obvious evidence of preceding infection. Laboratory data showed macroscopic hematuria, heavy proteinuria, and relatively normal renal function. Doppler ultrasonography and upper gastrointestinal gastrografin study were performed, respectively. Since his renal function deteriorated after admission, repeated renal biopsy was performed.

DIAGNOSES

IgA nephropathy with nutcracker phenomenon and SMA syndrome.

INTERVENTION

Immunosuppressive therapy combined with conservative therapy for superior mesenteric artery syndrome.

OUTCOMES

One month later, his abdomen symptoms such as anorexia and abdominal distension eased a lot with body weight increase of about 3 kg. After 6 months of follow-up, his body weight increased to 57 kg, serum creatinine decreased to 63 μmol/L, and urine microscopy showed 75.5 RBC/high-power field with 0.3 g urine protein per day.

LESSONS

Although the association between vascular compression and IgA nephropathy (IgAN) has not been elucidated yet, combination of nutcracker syndrome and SMA syndrome should be considered in patients with IgAN. The combination may increase the complexity of the disease, and renal biopsy should not be hesitated for differential diagnosis.

Value of magnetic resonance imaging indices of left renal vein entrapment in the diagnosis of nutcracker syndrome in children

BACKGROUND

Nutcracker syndrome (NCS) is also known as left renal vein (LRV) compression syndrome. Magnetic resonance imaging (MRI) can better depict the anatomical structure of soft tissues in the area of compression. Diagnosis of NCS using MRI in adults is not uncommon. However, there are few studies on the diagnosis of NCS using MRI in children. Therefore, we conducted this study to evaluate the clinical value of the MRI indices of the LRV in the diagnosis of NCS in children.

METHODS

This study was a single-center retrospective analysis. One hundred seventy-four patients with suspected NCS were enrolled from January 2017 to July 2020. The inclusion criteria for suspected NCS were mainly based on clinical symptoms or signs, laboratory examinations and imaging reports. Other diseases that may cause hematuria and/or proteinuria were excluded. We grouped the patients based on the diagnostic criteria for NCS into a nutcracker group and a control group. The receiver operating characteristic (ROC) curve was constructed for evaluating the value of MRI indices in the diagnosis of NCS.

RESULTS

The majority of NCS patients presented with orthostatic proteinuria (OP) (67.2%), followed by hematuria (55.2%), abdominal pain (19.0%), and left flank pain (15.5%). The areas under the curve (AUCs) for the superior mesenteric artery (SMA) angle, beak sign, and compression ratio (CR) in the diagnosis of NCS were 0.870, 0.895, and 0.878, respectively, and the best cutoff values of the SMA angle and CR were 36.8 and 3.99, respectively. The specificities of SMA angle <36.8°, beak sign, CR >3.99, SMA angle <36.8° and beak sign, SMA angle <36.8° and CR >3.99, and beak sign and CR >3.99 were 82.5%, 93.8%, 93.8%, 97.9%, 95.9% and 97.9%, respectively.

CONCLUSIONS

Children with SMA angles less than 36.8°, beak signs and CR greater than 3.99 should be highly suspected of having NCS. Among these parameters, "beak sign" showed the highest diagnostic accuracy by MRI, and the combination of any two of the above parameters achieved a higher specificity than the single parameters.

Splenic vein enlargement, a rare cause of nutcracker syndrome

Abnormal enlargement of the splenic vein is one of the etiologies of nutcracker syndrome that should be considered when examining the causes of this syndrome. Because knowing rare etiologies can help correct diagnose and reduce mortality.

From Nutcracker Phenomenon to Nutcracker Syndrome: A Pictorial Review

Left renal vein (LRV) entrapment, also known as nutcracker phenomenon if it is asymptomatic, is characterized by abnormality of outflow from the LRV into the inferior vena cava (IVC) due to extrinsic LRV compression, often accompanied by demonstrable lateral (hilar) dilatation and medial (mesoaortic) stenosis. Nutcracker syndrome, on the other hand, includes a well-defined set of symptoms, and the severity of these clinical manifestations is related to the severity of anatomic and hemodynamic findings. With the aim of providing practical guidance for nephrologists and radiologists, we performed a review of the literature through the PubMed database, and we commented on the definition, the main clinical features, and imaging pattern of this syndrome; we also researched the main therapeutic approaches validated in the literature. Finally, from the electronic database of our institute, we have selected some characteristic cases and we have commented on the imaging pattern of this disease.

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.

Anterior nutcracker syndrome in the setting of a duplicated inferior vena cava

Nutcracker syndrome is a rare vascular disorder that involves compression of the left renal vein (LRV), most often at the level of the aortomesenteric angle. In some cases, this compression syndrome arises in the setting of unusual vascular anatomic variants. We describe the case of a 43-year-old woman with a duplicated inferior vena cava who was found to have LRV compression on magnetic resonance angiography and venography with intravascular ultrasound. The patient was successfully treated with concurrent transposition of the LRV and left-sided inferior vena cava, with complete resolution of symptoms.

Uncracking a case

Nutcracker phenomenon (NCP) refers to compression of the left renal vein (LRV), most frequently between the aorta and the superior mesenteric artery, with impaired blood outflow often accompanied by distention of the distal portion of the vein. The nutcracker syndrome (NCS) is the terminology used when the nutcracker phenomenon is accompanied by a complex of symptoms such as pain (abdominal, flank, and pelvic), hematuria and orthostatic proteinuria. Diagnosis can be made with Doppler ultrasound (DUS), computed tomography (CT), magnetic resonance imaging (MRI), and venography. We describe a case of a young female adult who was identified with NCP by DUS, after a first CT had found no abnormalities. She presented with flank pain and severe hematuria causing a drastic decrease in hemoglobin levels. The management of NCS depends upon the clinical presentation and the severity of the LRV hypertension. The treatment options range from conservative to nephrectomy. Treatment decision should be based on the age of patients, severity of symptoms, and their expected reversibility. This case describes an underreported disorder that presents with non-specific symptoms, demonstrating the difficulties of the diagnostic approach of NCS, as well as the challenges in the appropriate management, given the lack of standardized treatment.

The role of multidetector CT angiography in characterizing vascular compression syndromes of the abdomen

Background

Various abdominal vessels can compress the adjacent structures or in turn can get compressed by them. Most of these compression syndromes present with non-specific symptoms. Unlike the common causes of acute abdomen, the various vascular compression syndromes have bizarre clinical presentations and subtle imaging findings, which can easily be missed by the physicians as well as the radiologists.

Main body of the abstract

This is a retrospective study which was done for a period of 3 years from April 2015 to April 2018 using a 64-slice CT scanner. Among 2412 cases that came for evaluation, 114 patients were diagnosed to have one of the various vascular compression syndromes. These 114 cases were further managed either conservatively or surgically depending on the pathology and the severity of the compression. The syndromes discussed in this article include median arcuate ligament syndrome (29 cases), superior mesenteric artery syndrome (23 cases), portal biliopathy (3 cases), nutcracker syndrome (6 cases), pelvi-ureteric junction obstruction due to crossing of vessels (8 cases), and retrocaval ureter and May-Thurner syndrome (45 cases).

Conclusions

The primary goal of this article is to reinforce the knowledge of the radiologists of the various vascular compression syndromes and to make them possess a high degree of vigilance to detect them. This article elaborates the imaging findings of these syndromes and the role of multidetector CT angiography in diagnosing them.

Evaluation of posterior nutcracker phenomenon using multisection spiral CT

AIM

To prospectively evaluate the epidemiological, anatomical classification, clinical importance, and radiological features of posterior nutcracker phenomenon (PNP) in patients examined with multisection spiral computed tomography (MSCT).

MATERIAL AND METHODS

Patients who underwent abdominal enhanced MSCT from January 2012 to July 2016 were evaluated retrospectively. Combined with the blood, normal biochemistry, and urine tests, patients were assessed retrospectively for renal vein diameter measurements, the compression ratio of blood vessels, gender differences, anatomical classification, percentage of proteinuria and haematuria, and clinical symptoms.

RESULTS

The study included 6,225 consecutive patients, PNP was observed in 2.06% involving the CLRV in 1.22% and retro-aortic left renal vein in 0.84%. The proportion of posterior nutcracker syndrome (PNS) was lower in PNP (17.2%). There was no difference by sex and age in the prevalence of PNP (p>0.05). In patients with urological symptoms, the number of type II abnormalities was more frequent than type Ia and type Ib abnormalities. Meanwhile, the number of type II abnormalities was frequent than the other two types. There was a significant difference between PNS and asymptomatic PNP (aPNP) in all measured values (p<0.001), the ratio was >4, especially in type II abnormalities (ratio >5.0).

CONCLUSIONS

PNP is a type of left renal vein entrapment. It is exceptionally rare and might be underdiagnosed. MSCT and measured values can be useful in diagnosis and recognition.

Nutcracker syndrome associated with celiacomesentric trunk anomaly: case report

Introduction

Nutcracker syndrome is a rare disease entity that is caused by entrapment of the left renal vein between the aorta and superior mesenteric artery, usually due to abnormal branching of the superior mesenteric artery from the aorta causing renal venous hypertension. The symptoms vary from asymptomatic hematuria to severe pelvic congestion. Celiacomes-enteric trunk anomaly is a rare variation of splanchnic artery anomaly that occurs when the celiac trunk and superior mesenteric arteries have a common origin from the aorta. A disease involving the rarely encountered celiacomesenteric trunk anomaly is extremely uncommon. To our knowledge, association between nutcracker syndrome and celiacomesentric trunk anomaly has not been reported in the literature.

Case presentation

A 14-year-old boy with no significant past medical history presented with a 3-year painless hematuria. CT-angiogram revealed anterior nutcracker syndrome with celiacomesenteric trunk anomaly. The patient was managed conservatively with close follow-up.

Conclusion

Nutcracker syndrome associated with celiacomesenteric trunk anomaly is extremely uncommon and is a rare cause of hematuria in children. Whether this abnormal anatomy is the cause of nutcracker syndrome or just an association should be investigated. Moreover, awareness of this anatomical variation may help in planning therapeutic options and reducing the chance of surgical iatrogenic injuries.

Left Renal Vein Compression Syndrome: Cracking the Nut of Clinical Dilemmas - Three Cases and Review of Literature

Case series

Patient: Female, 36 • Female, 41 • Female, 36

Final Diagnosis: Left renal vein compression syndrome

Symptoms: Hematuria

Medication: —

Clinical Procedure: Percutaneous intervention • nephrectomy

Specialty: Nephrology

Venous Compression Syndromes: a Review

OPINION STATEMENT

Venous compression syndromes present a diagnostic and therapeutic challenge as the clinical presentation can be vague, diagnostic criteria are often not present, and high quality standardization of when and how to treat is not available in part due to the limited number of cases reported and also due to the limited literature available. Significant venous compression should be considered when clinical symptoms correlate to location of compression and there is evidence of hemodynamic changes including venous hypertension, collateral/variceal formation, and/or thrombus formation. In general, treatment of venous compression should address the etiology of the compression as opposed to just treating symptoms associated with it such as significant varices or anticoagulation for thrombus to avoid recurrence of symptoms.

An Unusual Course of Segmental Renal Artery Displays a Rare Case of Hilar Nutcracker Phenomenon

Nutcracker phenomenon or renal vein entrapment is classically seen as a compression of renal vein in between abdominal aorta and superior mesenteric artery with patients being asymptomatic or clinically manifested in the form of nutcracker syndrome as proteinuria, hematuria, flank pain, pelvic congestion in women, and varicocele in men. In this report, we are presenting a case of rare variant of nutcracker phenomenon along with brief review of anatomy, pathophysiology, public health, and clinical significance of nutcracker syndrome. On a routine dissection of an adult male cadaver, we noticed an unusual arrangement of the structures at the hilum of the left kidney showing entrapment of renal vein between left anterior inferior and posterior segmental renal arteries. The variation in the course of left anterior inferior segmental renal artery leads to compression of left renal vein at renal hilum. Therefore, we have named this rare abnormal anatomical entity as hilar nutcracker phenomenon. The structures in the right renal hilum are normal. The objective of this paper is to report an unusual but important variant of nutcracker phenomenon and also give collective knowledge of such anatomical variations in renal vasculature that will help in diagnosing and treating such rare renal disorder.

Treatment of nutcracker syndrome with open and endovascular interventions

OBJECTIVE

Nutcracker syndrome (NS) is a rare cause of hematuria, flank pain, and renal venous hypertension due to compression of the left renal vein (LRV) between the aorta and the superior mesenteric artery. To evaluate outcomes of open surgery and endovascular interventions, we reviewed our experience.

METHODS

A retrospective review of clinical data of all patients treated at our institution with an intervention for NS between January 1, 1994, and February 28, 2014, was performed. Primary outcomes were morbidity and mortality. Secondary outcomes included late complications, patency, freedom from reintervention, and resolution of symptoms.

RESULTS

Thirty-seven patients (30 female, seven male) with a mean age of 27 years (range, 14-62 years) were treated. The most frequent symptom was flank pain (97%); the most frequent sign was hematuria (68%). NS was diagnosed with duplex ultrasound scanning with measurement of LRV diameters and flow velocities (87%), with computed tomography or magnetic resonance venography (94%), and with contrast venography with measurement of pressure gradients (93%). Initial treatment was open surgery in 36 patients, endovascular in 1. Distal transposition of the LRV into the inferior vena cava (IVC) was performed in 31 patients. Adjunctive procedures to optimize venous outflow included great saphenous vein cuff in six patients, great saphenous vein patch in four, and both cuff and patch in four. Three patients had patch alone; two had transposition of the left gonadal vein into the IVC. Two patients had anterior reimplantation of retroaortic LRV into the IVC. There were no major early complications, renal failure, or mortality. Three patients underwent early reinterventions within 30 days (stent, two; open revision, one). All LRVs and left gonadal veins were patent at discharge. Follow-up was 36.8 ± 52.6 months (range, 1-216 months). Reinterventions after 30 days were performed in eight patients because of LRV stenosis (n = 7) or LRV occlusion (n = 1). One stent migrated into the IVC and required endovascular removal with repeated stenting. Six patients required stenting. Primary, primary assisted, and secondary patencies at 24 months were 74%, 97%, and 100%, respectively. Freedom from reintervention at 12 and 24 months was 76% and 68%, respectively. Resolution of symptoms occurred in 33 patients (87%).

CONCLUSIONS

Open surgery, mostly LRV transposition, remains a safe and effective treatment of patients with NS. However, one of three patients after open repair required reintervention, most frequently LRV stenting. Open reconstruction should be tailored to the patient's anatomy, and placement of vein cuff or patch may reduce restenosis. Although renal vein stents improved patency, the safety and durability of currently available stents need to be established.

Nutcracker syndrome complicated by left renal vein thrombosis

Isolated renal vein thrombosis is a rare entity. We present a patient whose complaint of flank pain led to the diagnosis of a renal vein thrombosis. In this case, abdominal computed tomography angiography was helpful in diagnosing the nutcracker syndrome complicated by the renal vein thrombosis. Anticoagulation was started and three weeks later, CTA showed complete disappearance of the renal vein thrombosis. To treat the Nutcracker syndrome, we proposed left renal vein transposition that the patient consented to.