Anterior and posterior nutcracker syndrome: a report on 11 cases

Anatomical variants of the retroaortic left renal vein

BACKGROUND

Anatomical variants of the left renal vein (LRV), such as the retroaortic (RLRV) and circumaortic (CLRV) course, are of surgical importance. Different morphological and topographical possibilities of the RLRV could occur. It was aimed at documenting the anatomical variables of the RLRV.

METHOD

A retrospective study on 375 computed tomography angiograms was performed. Five different anatomical types of LRV were documented: preaortic types 1 and 2 and retroaortic types 3-5.

RESULTS

In 344/375 cases, preaortic LRVs were found. In 31/375 cases, different types of RLRV were found: type 3a - single RLRV, 41.94%; type 3b - single RLRV with bifid caval end, 9.68%; type 3c - single RLRV with trifid caval end, 3.23%; type 4a - CLRV with extrahilar origin, 29.03%; type 4b - CLRV with renal sinus origin, 12.9%; type 5 - triple LRV (one preaortic LRV and two RLRVs), 3.23%. Reference vertebral levels were recorded for the prevertebral segment of the RLVR. The vertebral level of type 3a varied from the L1/L2 disc to the upper third of the L4 vertebra. Type 3b was found in 3/31 RLRV cases; in one of these, the hemiazygos vein was inserted by two roots into the LRV and its upper caval end trunk. There was a significant statistical association between type 3b and the vertebral level, all cases being centered on the middle third of the L4 vertebra.

CONCLUSIONS

New morphological possibilities of the LRV were distinguished, and a new anatomical classification system of the RLRV results. The RLRV variant should be documented case-by-case as it has its anatomical variables.

Anterior and Posterior Nutcracker Syndrome Combined with May-Thurner Syndrome: First Report of This Unique Case

BACKGROUND

Anterior nutcracker syndrome is defined as the compression of the left renal vein (LRV) between the superior mesenteric artery (SMA) and the aorta, whereas posterior nutcracker syndrome refers to the compression of the retroaortic LRV between the aorta and the vertebral column-the presence of the circumaortic left renal vein may predispose to "combined nutcracker syndrome". May-Thurner syndrome consists of obstruction of the left common iliac vein caused by the crossing right common iliac artery. We report a unique case of combined nutcracker syndrome associated with May-Thurner syndrome.

CASE PRESENTATION

A 39-year-old Caucasian female came to our radiology unit for triple-negative breast cancer computed tomography (CT) staging. She complained of pain in hermid-back and low-back regions and intermittent abdominal pain in the left flank region. Multidetector computed tomography (MDCT) incidentally revealed a circumaortic left renal vein draining to the inferior vena cava, with bulbous dilatation of both the antero-superior and posterior-inferior branches, which was associated with pathological serpiginous dilation of the left ovarian vein with varicose pelvic veins. Axial CT imaging of the pelvis also showed compression of the left common iliac vein by the overlying right common iliac artery consistent with May-Thurner syndrome without signs of venous thrombosis.

CONCLUSION

Contrast-enhanced CT is the best imaging modality for suspected vascular compression syndromes. CT findings showed a combination of anterior and posterior nutcracker syndrome in the left circumaortic renal vein, associated with May-Thurner syndrome, which has not previously been described in the literature.

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.

Indications for and results of renal autotransplantation

PURPOSE OF REVIEW

To understand the indications and outcomes of renal autotransplantation, and when to consider this unique procedure for patients.

RECENT FINDINGS

Renal autotransplantation confers acceptably low rates of graft failure and prevents need for long-term dialysis. Renal autotransplantation remains an important management strategy in very select patients for complex renovascular disease, ureteral stricture disease, ureteral trauma, upper urinary tract urothelial carcinoma, renal cell carcinoma, and Loin-Pain Hematuria Syndrome. With advancements in minimally invasive procedures, the application of renal autotransplantation for refractory stone disease is rare but exists. Robot-assisted laparoscopic renal autotransplantation demonstrates reproducible graft success and complication rates with improved perioperative outcomes (ex. hospital length of stay) - though comparative studies are lacking. Patients would benefit from a multidisciplinary approach from renal transplant surgeons, vascular surgeons, urologists, nephrologists, dieticians, pain management providers, social workers, and psychiatrists.

SUMMARY

In experienced hands, renal autotransplantation is a reasonable treatment approach for complex and refractory renal vascular disease, Loin-Pain Hematuria Syndrome, ureteral strictures and trauma, upper urinary tract malignancy, and stone disease in highly select patients.

Nutcracker syndrome: A rare cause of chronic pelvic pain and left back pain

The Nutcracker Syndrome is a rare and often unrecognized cause of chronic pelvic pain and left back pain. These symptoms are due to the left renal vein compression between the aorta and the superior mesenteric artery (anterior nutcracker) or between the aorta and the spine (posterior nutcracker). The variety of clinical manifestations make the diagnosis difficult and commonly delayed. Therefore, imaging plays a key role in correcting the diagnosis by confirming the left renal vein stenosis and ruling out any differential diagnosis. Treatment options are discussed by a multidisciplinary team involving urologists, nephrologists and vascular surgeons for each patient. We report the case of 2 patients presenting chronic pelvic and lower back pain in whom clinical investigation and CT imaging findings were consistent with a nutcracker syndrome.

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.

Doppler US and CT Diagnosis of Nutcracker Syndrome

Nutcracker syndrome (NCS) is a syndrome caused by compression of the left renal vein (LRV), between the abdominal aorta and the superior mesenteric artery, resulting in hypertension of the LRV and hematuria. Doppler ultrasonography (US) has been commonly used for the diagnosis of NCS. However, several technical issues, such as Doppler angle and sample volume, need to be considered to obtain satisfactory results. In addition, morphologic changes of the LRV and a jetting phenomenon across the aortomesenteric portion of the LRV on contrast-enhanced computed tomography (CECT) are diagnostic clues of NCS. With proper Doppler US and CECT, NCS can be diagnosed noninvasively.

Serial ganglion impar blocks in a patient with nutcracker syndrome refractory to left renal vein transposition: a case report

Background

Nutcracker syndrome is a rare disorder caused by compression of the left renal vein, usually between the aorta and the superior mesenteric artery. It typically presents with left-sided abdominal pain and hematuria. Left renal vein transposition is the most commonly employed surgical technique to alleviate the compression.

Case presentation

A 22-year-old Caucasian man with a known diagnosis of nutcracker syndrome had undergone left renal vein transposition 1 year before presentation without any subsequent pain relief. In addition, his surgery was complicated by massive blood loss and a 1-week-long stay in an intensive care unit (ICU); as such, he was not amenable to further surgical intervention or stenting to treat his underlying pathology. His symptoms included constant sharp left-sided flank, perineal, and testicular pain. A series of ganglion impar blocks were performed every 3–4 months over the course of 5 years with substantial pain relief achieved.

Conclusions

Our case report highlights a treatment option that has not yet been described for patients with pain secondary to nutcracker syndrome refractory to surgical intervention.

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.

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.

A systematic review on management of nutcracker syndrome

OBJECTIVE

Although nutcracker syndrome (NS) is rare, patients presenting with symptoms or signs and anatomic compression of the left renal vein (LRV) can be considered for intervention. Open, laparoscopic, and endovascular techniques have been developed to decrease the venous outflow obstruction of the LRV. The paucity of data regarding the management of this uncommon disease process poses a challenge for adequate recommendations of the best treatment modality. Herein, we aim to present a systematic review for the management of NS.

METHODS

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards to systematically search the electronic databases of MEDLINE from October 1982 to July 2017 for articles about the management of NS. Included were studies in English, Spanish, and German in all age groups.

RESULTS

The literature search provided 249 references. After abstract and full review screening for inclusion, 17 references were analyzed. Eight (47%) described the open surgical approach. The LRV transposition was the most commonly reported technique, followed by renal autotransplantation. Seven (41.11%) described the endovascular technique of stent implantation, and two (11.7%) described the minimally invasive laparoscopic extravascular stent implantation.

CONCLUSIONS

NS is a rare entity. Multiple techniques have been developed for the treatment of this condition. However, the rarity of this syndrome, the paucity of data, and the short-term follow-up of the existing evidence are the disadvantages that prevent recommendations for the best treatment strategy. Up to now, open surgical intervention, specifically LRV transposition, has been considered by some experts the mainstay for treatment of NS. The endovascular approach is gaining strength as more evidence has become available. However, the long-term patency and durability of this approach remain to be elucidated. Therefore, careful selection of patients is necessary in recommending this technique.

What Each Clinical Anatomist Has to Know about Left Renal Vein Entrapment Syndrome (Nutcracker Syndrome): A Review of the Most Important Findings

Nutcracker syndrome (NCS) is the most common term for compression of the left renal vein between the superior mesenteric artery and the abdominal aorta. The development of NCS is associated with the formation of the left renal vein (LRV) from the aortic collar during the sixth to eighth week of gestation and abnormal angulation of the superior mesenteric artery from the aorta. Collateralization of venous circulation is the most significant effect of NCS. It includes mainly the left gonadal vein and the communicating lumbar vein. Undiagnosed NCS may affect retroperitoneal surgery and other radiological and vascular procedures. The clinical symptoms of NCS may generally be described as renal presentation when symptoms like haematuria, left flank pain, and proteinuria occur, but urologic presentation is also possible. Radiological methods of confirming NCS include Doppler ultrasonography as a primary test, retrograde venography, which can measure the renocaval pressure gradient, computed tomography angiography, which is faster and less traumatic, intravascular ultrasound, and magnetic resonance angiography. Treatment can be conservative or surgical, depending on the severity of symptoms and degree of LRV occlusion. Nutcracker syndrome is worth considering especially in differential diagnosis of haematuria of unknown origin.

Young woman with nutcracker syndrome without main clinic manifestation: Hematuria-Case report

INTRODUCTION

The nutcracker syndrome occurs due to the compression of the left renal vein between the aorta and the superior mesenteric artery. The diagnosis of the syndrome is often difficult and under diagnosed. The main clinical manifestations are hematuria and pelvic or back pain.

PRESENTATION OF CASE

A 25 years old female patient with severe abdominal pain in the lower abdomen without hematuria. Diagnosis with nutcracker syndrome after performing computed tomography. Presented the first episode of pain with 17 years old and was diagnosed at age 25.

DISCUSSION

In the nutcracker syndrome anatomical changes do not generate specific symptoms, causing the disease to be underdiagnosed. In this syndrome, there is increased pressure on the left renal vein, generating several signs and symptoms, and hematuria is one of present. Our patient did not have hematuria. Because of common symptoms, it makes nutcracker syndrome difficult diagnosis, confusing with other diseases, especially with nephrolithiasis. It is usually diagnosed after exclusion of other diseases.

CONCLUSION

The diagnosis of nutcracker syndrome is done after exclusion of other causes of chronic pelvic pain. In most cases, macroscopic and microscopic hematuria are present but was unobserved in this case. Making it more difficult diagnosis.

[Macroscopic hematuria secondary to nutcracker syndrome and successful endovascular treatment]

BACKGROUND

Nutcracker syndrome is a rare entity, and in the majority of cases is the result of extrinsic compression of the left renal vein between the superior mesenteric artery and the aorta, associated with functional stenosis.

OBJECTIVE

To present the case of a 19-year-old female with no significant medical history with confirmed diagnosed of nutcracker syndrome treated successfully by endovascular means.

CLINICAL CASE

She was referred to the Vascular Surgery Department with a 6-month history of macroscopic haematuria, after other aetiologies were ruled out. Abdominal computed tomography angiography revealed compression of the left renal vein; the patient underwent endovascular treatment, and a 12×16 mm balloon expandable stent was placed with immediate angiographic improvement, decreased pressure gradients and progressive resolution of haematuria. At one year, she remains symptom-free.

CONCLUSION

Nutcracker syndrome is uncommon, and a high index of suspicion is needed. Macroscopic haematuria is not always present, and in our case stent placement demonstrated effectiveness in the resolution of symptoms at 12 months' follow--up. We also present a brief review of the literature.

Robotic-Assisted Laparoscopic Donor Nephrectomy of Patient With Nutcracker Phenomenon

We report the case of a 30-year-old male patient undergoing a robotic-assisted laparoscopic left donor nephrectomy, where compression of the left renal vein between the superior mesenteric artery and aorta was noted on magnetic resonance angiography before the operation. The patient was diagnosed with nutcracker phenomenon and was noted to be asymptomatic at that time. This is the first reported case to date of a patient with nutcracker phenomenon who underwent a robotic-assisted laparoscopic donor nephrectomy. This article also reviews the current literature on nutcracker phenomenon and nutcracker syndrome.

Micro- and macroscopic hematuria caused by renal vein entrapment: systematic review of the literature

BACKGROUND

Hematuria secondary to renal vein entrapment is mentioned only passing in textbooks and reviews.

METHODS

We performed a search of the National Library of Medicine database for peer-reviewed publications using the terms "renal vein" or "nutcracker" and "hematuria".

RESULTS

We identified 187 published reports/studies that covered 736 patients, of whom 288 had microscopic hematuria and 448 had macroscopic hematuria. The patient cohort comprised 159 patients aged ≤17 years. Abdominal pain was absent in  approximately 65% of all patients, and a clinically relevant left-sided varicocele was observed in 29% of the male patients. A normal pre-aortic left renal vein and an anomalous anatomy were noted in 680 and 56 patients, respectively. The body mass index (BMI) was lower in patients with renal vein entrapment than in the controls, with a regression of hematuria correlating with an increase in BMI. A surgical procedure was attempted in 34% of the patients, of which the most common were endovascular stenting and transposition of the renal vein distally into the vena cava.

CONCLUSIONS

In cases of unexplained hematuria with or without abdominal pain, clinicians should consider the diagnosis of renal vein congestion, especially in males with varicocele. Ultrasonic Doppler flow scanning is the recommended initial diagnostic modality in these patients. Expectation management is advised in the great majority of cases.

Anterior Nutcracker Syndrome with Left Gonadal Vein Varicosities on Multiphasic Computed Tomography: An Unexpected Cause of Pyeloureteral Junction Obstruction

The anterior nutcracker syndrome is defined by the compression of the left renal vein between the aorta and superior mesenteric artery, usually related to the occurrence of hematuria. We report the case of an uncommon complication of the nutcracker syndrome. A 75-year-old woman was referred to our institution for left flank pain without hematuria. Multiphasic computer tomography urography showed a condition of left renal vein entrapment between the aorta and superior mesenteric artery with the development of left gonadal vein varicosities at the level of the renal hilum; a pyeloureteral junction compression with dilation of the pyelocalyceal system coexisted. To our knowledge, this is the first report of the association between nutcracker syndrome and pyeloureteral junction obstruction.

Three Unusual Cases of Nutcracker Syndrome Caused by Increased Blood Flow within the Left Renal Vein

Nutcracker syndrome (NCS) refers to the compression of the left renal vein (LRV) between the aorta and the superior mesenteric artery. It can cause both microscopic and gross haematuria, with or without flank pain. The diagnosis is often delayed in a majority of symptomatic patients. On the other hand, the use of CT in routine abdominal explorations has increased the detection of the compression of the LRV in healthy and asymptomatic patients, but its diagnostic value remains uncertain. In this paper, we report 3 cases of the NCS associated with an increased blood flow in the LRV, due to different conditions, which we believe could produce the appearance of clinical symptoms.

Postsurgical Follow-up for a Repaired Nutcracker Syndrome

Nutcracker syndrome is a venous entrapment phenomenon characterized by the impingement of the left renal vein between the superior mesenteric artery and abdominal aorta. Treatment, if necessary, consists of surgical intervention. In the case presented, a young female presented at an outpatient vascular surgical center for surveillance of a surgically repaired nutcracker syndrome. A renal sonogram was performed to evaluate patency and hemodynamics of the left renal vein. Color and spectral Doppler were used to evaluate the left renal vein as well as the left kidney to document appropriate renal perfusion.

[Nutcracker syndrome - treated by surgery]

The nutcracker syndrome is caused by tight compression of the left renal vein between the superior mesenteric artery and the abdominal aorta. The consequences may vary between symptomfree conditions through moderate proteinuria and hypertension to severe hematuria. All imaging modalities have been used during diagnostic workup. Wide varieties of surgical and endovascular solutions are reported aiming to achieve decompression of the renal vein like venous or arterial transposition, bypass, renal autotransplantation, stenting, nephrectomy, etc. In our case a 21-year-old man the nutcracker syndrome was successfully solved by transposition of the superior mesenteric artery into the infrarenal aorta.

Prosthetic left renocaval bypass for posterior nutcracker syndrome

A 58-year-old man presented with severe hematuria of unknown origin and intermittent left flank pain for 8 months, and he was diagnosed with posterior nutcracker syndrome. He underwent prosthetic left renocaval bypass with complete resolution of symptoms. Computed tomography showed a functional graft between the left renal vein and caval vein. This technique is a feasible choice for surgical treatment of posterior nutcracker syndrome with satisfactory results.

Unique nutcracker phenomenon involving the right renal artery and portal venous system

The nutcracker phenomenon is usually caused by compression of the left renal vein by the superior mesenteric artery anteriorly and the aorta posteriorly, although variations of this anatomy have previously been reported. We observed a nutcracker phenomenon in a 42-year-old female who underwent portal venous phase computed tomography of the body for oncologic workup. She had no documented proteinuria or hematuria. Multiplanar reconstructions demonstrated an enhancing left renal vein draining into the left ovarian vein without draining into the inferior vena cava due to external compression immediately before the renocaval junction. The left renal vein was compressed between the right renal artery and the portal vein. This type of nutcracker has not been previously reported in the literature and represents a new variation.

Nonatherosclerotic obstructive vascular diseases of the mesenteric and renal arteries

Nonatherosclerotic vascular diseases of the mesenteric and renal arteries are considered to occur less frequently than those caused by occlusive atherosclerotic disease. However, when present, they pose a significant diagnostic and therapeutic challenge. Such disorders include fibromuscular dysplasia, median arcuate ligament syndrome, the renal nutcracker syndrome, and some forms of acute and chronic mesenteric ischemia (embolic and thrombotic). This is a heterogeneous group of disorders with substantial differences in the pathogenesis and diagnostic approaches to these diseases. We provide an overview of the pathogenesis, clinical presentation, diagnosis, and current management of fibromuscular dysplasia, median arcuate ligament syndrome, and the renal nutcracker syndrome.

The roles of the liver and pancreas in renal nutcracker syndrome

INTRODUCTION

To assess the frequency and significance of presence of the liver and pancreas at the left renal vein (LRV) level in patients with suspected renal nutcracker syndrome (NCS).

MATERIALS AND METHODS

We included 101 patients with hematuria who underwent urography three-dimensional CT between April 2009 and November 2013. These patients were divided into NCS (n=25) and non-NCS (n=76) patients according to the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients were grouped according to the presence of the liver and pancreas at the LRV: group LP (both liver and pancreas), group L (only liver), group P (only pancreas), and group O (neither liver nor pancreas). The difference in the frequencies of groups was analyzed between NCS and non-NCS patients. Multivariate analysis was used to determine the independent factors between NCS and non-NCS patients.

RESULTS

The frequencies of group LP, group L, group P, and group O in NCS vs. non-NCS were 88% vs. 5.3% (p<0.001), 4.0% vs. 2.6% (p=0.75), 4.0% vs. 11.8% (p=0.45), 4.0% vs. 80.3% (p<0.001), respectively. Multivariate analysis demonstrated that group was a predictor for differential diagnosis between NCS and non-NCS (p=0.022), and group LP was an independent factor for the presence of NCS (odds ratio, 43.8; 95% confidence interval, 3.8-500.3; p<0.002; reference, group O).

CONCLUSION

The presence of the liver and pancreas at the level of the LRV was frequently found in NCS and was the independent factor for NCS.

Surgical and endovascular interventions for nutcracker syndrome

Nutcracker syndrome is a rare condition of left renal vein entrapment manifesting with hematuria, flank pain, and, occasionally, pelvic congestion in females or varicocele in males. Diagnosis requires a high index of suspicion upon careful history delineation. The gold standard for definite confirmation remains venography with renocaval pressure gradient. Treatment is mainly guided by the severity of symptoms. For the majority of centers, it appears that surgery remains the first-line therapy, however, endovascular alternatives are rapidly evolving into the field with favorable outcomes. This article reviews current concepts on nutcracker syndrome with particular focus on contemporary surgical and endovascular techniques and their outcomes.

Infrarenal abdominal aorta aneurysm: a rare cause of anterior nutcracker syndrome with associated pelvic congestion

We present a rare case of anterior nutcracker syndrome caused by an abdominal aorta aneurysm (AAA). A 61-year-old woman was admitted to our institution for computed tomography angiography. It revealed an AAA 51 mm in diameter that was lifting off of the left renal vein toward the superior mesenteric artery, causing anterior nutcracker syndrome with consequent left renal vein compression and left ovarian vein congestion. Aneurysm resection was performed, followed by left ovarian vein ligation and left adnexectomy to prevent vein conglomerate rupture. This is the first case that describes anterior nutcracker syndrome caused by AAA, which was successfully treated by aneurysm resection.

Incidental finding of the nutcracker phenomenon detected by 18F-FDG PET/CT

A 46-year-old man was found to have an increased carcinoembryonic antigen level (25.7 μg/L) during physical examination, and an (18)F-FDG PET/CT scan was subsequently performed. The PET image indicated abnormal radioactivity levels in the left kidney, and the coregistered CT revealed compression of the left renal vein between the aorta and superior mesenteric artery. An ultrasonography was then performed, which revealed that the ratio between the renal hilum and the aortomesenteric left renal vein was 3.2. Therefore, the nutcracker phenomenon was diagnosed. When abnormal radioactivity is found in the left kidney on PET/CT scanning, the nutcracker syndrome should be considered.

An unusual case of left venous renal entrapment syndrome: a new type of nutcracker phenomenon?

Left venous renal entrapment syndrome was observed during multidetector 64-row computer tomography and color Doppler ultrasonography in a 58-year-old Caucasian female hospitalized due to choledocholithiasis. The patient demonstrated no typical symptoms of nutcracker syndrome. The left renal vein (LRV) was compressed as it passed between the superior mesenteric artery and the right renal artery. The LRV lumen measured 1.7 × 7.8 mm (width × height) at the point of narrowing and 7.5 × 17 mm before this. Secondary to the nutcracker phenomenon, the course of left ovarian vein was winding and was significantly wider than the contralateral vessel.

Posterior nutcracker syndrome with left renal vein duplication: a rare cause of haematuria in a 12-year-old boy

The nutcracker syndrome (NCS) is a rare cause of haematuria. It embraces an extended nonpathognomonic spectrum of symptoms that imply a difficult diagnosis. Ultimately it may be associated with substantial morbidity and even life-threatening events. We report a rare cause if a 12-year-old boy who presented with a history of frequent intermittent episodes of painless constant haematuria. The cystoscopy showed a bloody urine ejaculate from the left ureter meatus. The Doppler ultrasonography showed turbulent pattern of venous blood flow of the posterior renal vein branch behind the aorta. The abdominopelvic computer tomography (apCT) revealed left renal vein (LRV) duplication with a dilated retroaortic branch, entrapped between the aorta and the vertebral column, promoting the renal nutcracker syndrome. The patient was initially hospitalized and managed with oral iron supplements and continuous saline bladder irrigation, not requiring additional treatment. The child is currently asymptomatic, with haemoglobin value returning to normal and therefore proposed to conservative management with close followup. The authors present a case report of episodic haematuria caused by a rare entity-posterior nutcracker syndrome with renal vein duplication.

US and MDCT diagnosis of a rare cause of haematuria in children: Posterior nutcracker syndrome

Posterior nutcracker syndrome is caused by compression of the left renal vein between the abdominal aorta and the vertebral column. We present the case of a 14-year-old girl with vague left loin pain, mild haematuria and proteinuria. Diagnosis of this rare syndrome was achieved using color Doppler US and multidetector computed tomography (MDCT) angiography.

Surgical treatment of posterior nutcracker syndrome

Posterior nutcracker syndrome (PNS) is a rare condition due to left renal vein (LRV) hypertension, caused by compression of the LRV between the vertebral column and the abdominal aorta. Diagnosis of PNS is challenging, as symptoms are variable and not specific. Therapeutic options are debated, and either conservative, open, or endovascular approaches have been advocated as both safe and effective. We report our experience with a case of PNS in a 17-year-old woman, who presented with a 2 year history of recurrent hematuria associated to severe left flank and back pain, successfully treated with anterior transposition of the LRV.

The nutcracker syndrome

Left renal vein (LRV) compression, commonly referred to as the nutcracker syndrome or renal vein entrapment syndrome, is a rare and often overlooked condition. Anatomically, the LRV traverses the space between the superior mesenteric artery and the aorta in close proximity to the origin of the artery. In affected individuals, the LRV is subjected to compression between these two structures, resulting in renal venous hypertension. A review of published data on this condition reveals either case reports or small case series. The classic symptoms of nutcracker syndrome include left flank pain with gross or microscopic hematuria. Patients are often children or young adults, with a slight predisposition for women who may also present with pelvic congestion symptoms such as pelvic pain and dyspareunia. Most patients have disease symptoms for many years and nondiagnostic investigations before proper diagnosis can be made. Appropriate diagnostic work-up and treatment may help alleviate patient morbidity from this chronic condition. Although surgical repair has been the standard of care, more recently endovascular intervention has become the first line of therapy. This tabular review compiles published cases in the adult population during the period between 1980 and 2009.

Nutcracker syndrome with urolithiasis

The nutcracker syndrome, caused by compression of the left renal vein between the superior mesenteric artery and the aorta, usually manifests with hematuria, flank pain and proteinuria. We report on a 9-year-old boy who was previously diagnosed with urolithiasis but had significant proteinuria, not explained by this diagnosis. On further investigation by renal Doppler ultrasonography it was found that he had nutcracker syndrome. We would like to emphasize that this syndrome should be considered where there is no obvious cause of proteinuria and hematuria.

Nutcracker phenomenon and nutcracker syndrome

Nutcracker phenomenon refers to compression of the left renal vein, most commonly 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 clinical equivalent of nutcracker phenomenon characterized by a complex of symptoms with substantial variations. Depending on specific manifestations, NCS may be encountered by different medical specialists. Although it may be associated with substantial morbidity, the diagnosis of NCS is often difficult and is commonly delayed. Diagnostic and treatment criteria are not well established, and the natural history of NCS is not well understood. We performed an initial review of the literature through MEDLINE, searching from 1950 to date and using the keywords nutcracker syndrome, nutcracker phenomenon, and renal vein entrapment. We performed additional reviews based on the literature citations of the identified articles. We attempted to elucidate clinical relevance of these conditions and their prominent features and to summarize professional experience.

Multidetector computed tomography findings and correlations with proteinuria in nutcracker syndrome

We evaluated the effectiveness of multidetector computed tomography (MDCT) as a diagnostic tool for nutcracker syndrome (NS) and its association with proteinuria. The angle and distance between the aorta and the superior mesenteric artery (SMA), the degree of difference in corticomedullary enhancement (DCE) between kidneys in the nephrographic phase of computed tomography, peak velocity ratio (PVR), and anteroposterior diameter ratio (APDR) in the sonogram were measured. The MDCT results, sonogram results, and the ratio of protein:creatinine were significantly different between NS patients and the controls. The area under the curve for angle, distance, and DCE were 0.895 +/- 0.058, 0.876 +/- 0.063, and 0.942 +/- 0.036, respectively. The cutoff values for angle and distance had sensitivity and specificity values of 96.2 and 80% for <22.4 degrees and 84.6 and 80% for <4.9 mm, respectively. The DCE had a sensitivity of 88.5% and a specificity of 100% for the positive scores. There were significant correlations between the degree of DCE and the ratio of protein:creatinine (r = 0.337, p = 0.031), and between distance and the ratio of protein:creatinine (r = -0.419, p = 0.006). We conclude that MDCT has diagnostic value for NS in children and that MDCT findings are correlated with proteinuria.

[Nutcracker syndrome managed by simple surveillance]

Nutcracker syndrome is caused by compression of the left renal vein between the aorta and the superior mesenteric artery where it passes in the fork formed at the bifurcation of these arteries. The phenomenon results in left renal venous hypertension. The syndrome is manifested by left flank and abdominal pain, with or without unilateral haematuria. The nutcracker syndrome has been treated in various ways. We report one case of the syndrome and discuss the place of surveillance in its management.