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.

Patient-Reported Outcomes for Robot-Assisted Laparoscopic Extravascular Renal Vein Stent Placements for Nutcracker Syndrome.

Introduction: Nutcracker phenomenon is the compression of the left renal vein between the superior mesenteric artery (SMA) and the abdominal aorta. Nutcracker syndrome refers to the presence of nutcracker phenomenon with symptoms. Between 2016 and 2022, we performed 18 robot-assisted laparoscopic extravascular renal vein stent (RALERVS) placements. We sought to assess patient-reported outcomes of RALERVS placement by a single institution. Methods: We performed a single-center retrospective review of 18 patients with a minimum of 3 months follow-up. Symptoms were assessed utilizing a questionnaire conducted with a 5-point Likert scale at a minimum of 3 months postoperatively. Five on the Likert scale was severe while 1 was none. Primary study outcomes compared pre- and postoperative patient-reported symptom scores. Results: Twelve out of 18 patients responded to the survey. The average length of time from date of operation to completion of survey was 2.6 years. Average age of the cohort was 36 years with a mean BMI of 19.4 kg/m2. There was only one man. Mean operative time was 137 minutes and mean estimated blood loss was 12 mL. Mean preoperative SMA angle was 19° and mean postoperative SMA angle was 36°. Patients reported that flank pain, abdominal pain, nausea, headaches, back pain, pelvic pain, and early satiety improved (p < 0.05). Ten of 12 respondents would recommend RALERVS for nutcracker syndrome. Conclusion: RALERVS demonstrates an effective treatment for nutcracker syndrome. Patients reported improved symptoms at 3 months postoperatively across multiple domains. Further studies need to be conducted to assess long-term durability of the extravascular renal vein graft.

Nutcracker syndrome in pediatrics: initial findings and long-term follow-up results.

BACKGROUND: Nutcracker syndrome (NCS) describes a set of symptoms and signs resulting from compression of the left renal vein (LRV). There is a lack of knowledge about its natural course, diagnosis, and management, especially in children. Herein, we present our single-center experience with a large number of patients who have long-term follow-up results. METHODS: All patients with NCS diagnosed between January 2011 and March 2021 were included and their data were obtained retrospectively. RESULTS: A total of 123 NCS patients (85 females) were included. The median age at the time of diagnosis was 12 (IQR 10-14) years, and BMI percentiles were below 5% in 38% of the cases. At the time of diagnosis, two-thirds of the patients were asymptomatic. The most common laboratory finding was nephritic proteinuria (98%), followed by microscopic hematuria (16%). Signs of LRV compression were significantly more evident in upright position Doppler ultrasonography (DUS) examination. All patients have been followed conservatively; hematuria and/or proteinuria resolved in 43 of the 108 patients (40%) within 35.8 ± 25.8 months of follow-up. Control DUS was performed in 52 patients after a mean period of 39.1 ± 21.3 months. The median peak velocity and diameter ratios of the LRV in the upright position were found to be decreased significantly when compared to the initial assessment (p < 0.05). Normal DUS findings were noted in 13 patients at the final evaluation. CONCLUSIONS: In unexplained proteinuria and/or hematuria, NCS should be considered, especially in asthenic adolescents. Our results support conservative management in children as the first-line treatment approach.

Coexistència de la malaltia de Wilkie i la síndrome del trencanous / Coexistencia de enfermedad de Wilkie y síndrome del cascanueces / Simultaneous occurrence of Wilkie and nutcracker syndromes

Introducció. La síndrome de l’artèria mesentèrica superior,o malaltia de Wilkie, i la síndrome de compressió de lavena renal esquerra, o síndrome del trencanous, són pocfreqüents. Normalment estan provocades per una compressió extrínseca del duodè o de la vena renal esquerra, respectivament, a causa d’una disminució de l’angle entrel’artèria mesentèrica superior i l’aorta.Cas clínic. Adolescent de 15 anys que va consultar a urgències per dolor abdominal de cinc mesos d’evolució localitzata l’epigastri, acompanyat de vòmits, proteïnúria i pèrdua depes. La pacient havia consultat prèviament en altres centresi s’havien descartat patologies urgents quirúrgiques. Es vacompletar l’estudi amb una tomografia computada abdominal amb diagnòstic de síndrome de l’artèria mesentèricasuperior i síndrome del trencanous. La pacient va ingressara la planta d’hospitalització i es va tractar de forma conservadora amb una dieta hipercalòrica; el trànsit intestinal i laproteïnúria van millorar, i va poder ser remesa a domicili icontrolada ambulatòriament de forma multidisciplinària.Comentari. Els problemes secundaris a la compressió aortomesentèrica poden donar quadres compatibles amb la síndrome de l’artèria mesentèrica superior i la síndrome deltrencanous. El diagnòstic d’aquests quadres pot resultarcomplex per la incidència baixa i per la simptomatologiainespecífica que els caracteritza. El tractament conservador representa la primera línia de tractament, però en alguns casos pot no ser suficient. Per tot això és necessarifer un maneig multidisciplinari d’aquests pacients. (AU)

Introducción. El síndrome de la arteria mesentérica superior o deWilkie y el síndrome del cascanueces son poco frecuentes. Normalmente están producidos por una compresión extrínseca delduodeno o de la vena renal izquierda, respectivamente, debido a una disminución del ángulo entre la arteria mesentérica superior yla aorta.Caso clínico. Adolescente de 15 años que consultó a urgencias pordolor abdominal de cinco meses de evolución localizado en epigastrio, acompañado de vómitos, proteinuria y pérdida de peso. Lapaciente había consultado previamente en otros centros descartando patologías urgentes quirúrgicas. Se completó el estudio conuna tomografía computarizada abdominal con diagnóstico de síndrome de la arteria mesentérica superior o de Wilkie y síndrome delcascanueces. La paciente ingresó en planta de hospitalización y setrató de forma conservadora con una dieta hipercalórica con mejoría del tránsito intestinal y de la proteinuria, y pudo ser remitida adomicilio y controlada ambulatoriamente de forma multidisciplinar.Comentario. Los problemas secundarios a la compresión aortomesentérica pueden dar cuadros compatibles con el síndrome de laarteria mesentérica superior o de Wilkie y el síndrome del cascanueces. El diagnóstico de estos cuadros puede resultar complejo por subaja incidencia y por la sintomatología inespecífica que los caracteriza. El tratamiento conservador representa la primera línea de tratamiento, pero en algunos casos puede no ser suficiente. Por estosmotivos es necesario un manejo multidisciplinar de estos pacientes. (AU)

Introduction. The superior mesenteric artery syndrome or Wilkiesyndrome and the nutcracker syndrome are rare. They are normallycaused by extrinsic compression of the duodenum or the left renalvein respectively, due to a narrowing of the angle between the superior mesenteric artery and the aorta.Case report. A 15-year-old girl presented to the emergency roomwith a five-month history of abdominal pain located in the epigastrium, accompanied by vomiting, proteinuria, and weight loss. Thepatient had previously consulted in other centers, and urgent surgical conditions were ruled out. The study was completed with anabdominal computed tomography scan, which led to the diagnosisof superior mesenteric artery or Wilkie syndrome, and nutcrackersyndrome. The patient was admitted to the hospital and treatedconservatively with a hypercaloric diet with improvement in intestinal transit and proteinuria. She was discharged to continue thefollow-up with a multidisciplinary team. Comment. Problems secondary to aortomesenteric compression cangive symptoms like superior mesenteric artery or Wilkie syndromeand nutcracker syndrome. The diagnosis of these conditions canbe complex due to their low incidence and the non-specific symptomatology that characterizes them. Conservative treatment represents the first line of treatment, but in some cases it may not beenough. For these reasons, multidisciplinary management of thesepatients is necessary. (AU)

Síndrome de cascanueces: una causa infrecuente de hematuria / Nutcracker Syndrome: a Rare Cause of Hematuria

La hematuria en pediatría responde habitualmente a etiologías benignas. Una causa poco frecuente es el síndrome de cascanueces, que se define como la compresión de la vena renal izquierda entre la aorta y la arteria mesentérica superior, que deriva en una presión elevada en la vena renal izquierda con el desarrollo de venas colaterales y dilataciones varicosas. La prevalencia de este síndrome se desconoce. Cuando es sintomático ocasiona hematuria, proteinuria y dolor pélvico crónico. En la pubertad, el crecimiento rápido y el desarrollo de los cuerpos vertebrales pueden producir un estrechamiento del ángulo entre la aorta y la arteria mesentérica superior. Se describe el caso de una adolescente con diagnóstico de carcinoma mucoepitelial metastásico óseo múltiple que presenta hematuria anemizante. Se arribó al diagnóstico de síndrome de cascanueces y se discutieron las opciones de tratamiento. Finalmente, con el uso de realce del calzado para corrección de la escoliosis, se atenuó significativamente la hematuria. (AU)

In pediatrics, hematuria usually responds to benign etiologies. A rare cause is nutcracker syndrome, defined as compression of the left renal vein between the aorta and the superior mesenteric artery, resulting in elevated pressure in the left renal vein with the development of collateral veins and varicose dilatation. The prevalence of this syndrome is unknown. When symptomatic, it causes hematuria, proteinuria, and chronic pelvic pain. At puberty, the rapid growth and development of the vertebral bodies can produce a narrowing of the angle between the aorta and the superior mesenteric artery.We describe the case of a teenage girl diagnosed with multiple metastatic mucoepithelial carcinoma of bone who presented anemia-producing hematuria. The diagnosis of nutcracker syndrome was arrived at with consideration of the therapeutic options. Finally, with shoe enhancement for scoliosis correction, hematuria was significantly lessened. (AU)

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 nonoperative 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: A 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 and/or computed tomography venography. 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 1 patient did not improve. CONCLUSIONS: Transposition of the LRV is an effective treatment for NCS. Nonoperative management is an option for those patients experiencing less severe or nonspecific clinical symptoms.

Causa rara de dolor abdominal recurrente; coexistencia del síndrome de Wilkie y el síndrome del cascanueces / A rare cause of recurrent abdominal pain; the coexistence of Wilkie's syndrome and nutcracker syndrome

El síndrome del cascanueces es un síndrome que presenta síntomas clínicos como hematuria, proteinuria ortostática, congestión pélvica, varicocele del lado izquierdo, hipertensión y dolor en fosa renal. Estos síntomas se producen por la compresión de la vena renal izquierda entre la aorta y la arteria mesentérica superior. En el síndrome de Wilkie, la tercera porción del duodeno está comprimida entre la arteria mesentérica superior y la aorta abdominal, lo que provoca diversos síntomas gastrointestinales. La coexistencia de estos dos síndromes constituye una afección rara y se incluye como casos clínicos en la bibliografía. En este artículo, se presentan los resultados clínicos y radiológicos de un paciente de 17 años que presentaba dolor abdominal recurrente debido al síndrome de Wilkie, acompañado del síndrome del cascanueces que le provocaba proteinuria, por lo que el paciente fue derivado a los consultorios externos de reumatología pediátrica con un diagnóstico preliminar de fiebre mediterránea familiar.

Nutcracker syndrome is a syndrome that has clinical symptoms such as hematuria, orthostatic proteinuria, pelvic congestion, left-sided varicocele, hypertension, and flank pain. These symptoms occur because of the compression of the left renal vein between the aorta and the superior mesenteric artery. In Wilkie's syndrome, the third part of the duodenum is compressed between the superior mesenteric artery and the abdominal aorta, causing various gastrointestinal symptoms. The coexistence of these two syndromes is a rare condition and is included as case reports in the literature. This article presents the clinical and radiological results of a 17-year-old male patient who had recurrent abdominal pain due to Wilkie's syndrome, which was accompanied by nutcracker syndrome that caused proteinuria, and for this reason, the patient was referred to the Pediatric Rheumatology outpatient clinic with a preliminary diagnosis of familial Mediterranean fever.

Robotic-assisted combined transposition of left renal vein and gonadal vein as a novel treatment option for renal nutcracker syndrome: A case report.

RATIONALE: Renal nutcracker syndrome is a rare phenomenon that often causes various disability symptoms. The treatment protocol has been explored for a long time, but no consensus has been reached. PATIENT CONCERNS: Here, we report the case of a 19-year-old male suffering with nutcracker syndrome, including left-sided flank pain and intermittent gross hematuria. DIAGNOSES: The patient was diagnosed with renal nutcracker syndrome, and the pressure gradient between the left renal vein and inferior vena cava was >5 mm Hg. INTERVENTIONS: The patient underwentrobotic-assisted combined transposition of left renal vein and gonadal vein. OUTCOMES: Flank pain and gross hematuria ceased spontaneously after surgery without occurrence. LESSONS: Robotic-assisted combined transposition of the left renal vein and gonadal vein is a safe and promising option for this condition.

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.

A rare cause of recurrent abdominal pain; the coexistence of Wilkie's syndrome and nutcracker syndrome. / Causa rara de dolor abdominal recurrente; coexistencia del síndrome de Wilkie y el síndrome del cascanueces.

Nutcracker syndrome is a syndrome that has clinical symptoms such as hematuria, orthostatic proteinuria, pelvic congestion, left-sided varicocele, hypertension, and flank pain. These symptoms occur because of the compression of the left renal vein between the aorta and the superior mesenteric artery. In Wilkie's syndrome, the third part of the duodenum is compressed between the superior mesenteric artery and the abdominal aorta, causing various gastrointestinal symptoms. The coexistence of these two syndromes is a rare condition and is included as case reports in the literature. This article presents the clinical and radiological results of a 17-year-old male patient who had recurrent abdominal pain due to Wilkie's syndrome, which was accompanied by nutcracker syndrome that caused proteinuria, and for this reason, the patient was referred to the Pediatric Rheumatology outpatient clinic with a preliminary diagnosis of familial Mediterranean fever.

El síndrome del cascanueces es un síndrome que presenta síntomas clínicos como hematuria, proteinuria ortostática, congestión pélvica, varicocele del lado izquierdo, hipertensión y dolor en fosa renal. Estos síntomas se producen por la compresión de la vena renal izquierda entre la aorta y la arteria mesentérica superior. En el síndrome de Wilkie, la tercera porción del duodeno está comprimida entre la arteria mesentérica superior y la aorta abdominal, lo que provoca diversos síntomas gastrointestinales. La coexistencia de estos dos síndromes constituye una afección rara y se incluye como casos clínicos en la bibliografía. En este artículo, se presentan los resultados clínicos y radiológicos de un paciente de 17 años que presentaba dolor abdominal recurrente debido al síndrome de Wilkie, acompañado del síndrome del cascanueces que le provocaba proteinuria, por lo que el paciente fue derivado a los consultorios externos de reumatología pediátrica con un diagnóstico preliminar de fiebre mediterránea familiar.

Novel Use of Time-Resolved Magnetic Resonance Angiography to Evaluate Retrograde Lumbar Vein Flow and Epidural Venous Plexus Enhancement in Chronic Headache Patients With and Without Nutcracker Physiology.

OBJECTIVE: Compression of the left renal vein by the superior mesenteric artery, known as nutcracker phenomenon (NCP), can cause retrograde flow and congestion in communicating venous systems. It has recently been speculated that NCP can result in retrograde flow and congestion of the lumbar veins and epidural venous plexus (EVP), thereby affecting the central nervous system. This study describes the novel use of time-resolved magnetic resonance angiography (trMRA) to evaluate for retrograde left second lumbar vein (L2LV) flow and early EVP enhancement in patients with chronic daily headache (CDH) with and without NCP. METHODS: A retrospective analysis was performed of 31 patients with CDH (27 females and 4 males; median age, 38 years [range, 18-63 years]) who underwent trMRA centered over the L2LV to evaluate the direction of blood flow and presence of early EVP enhancement from May 2020 to March 2022. Descriptive statistics were performed, and anatomic associations were analyzed in patients with and without retrograde L2LV flow and early EVP enhancement. The accuracy of magnetic resonance imaging findings in detecting these flow patterns was also assessed. RESULTS: Patients with NCP who demonstrated narrowing of the left renal vein, a positive beak sign ( P = 0.052), decreased aortomesenteric distance ( P = 0.038), and decreased SMA angle demonstrated increased rates of retrograde L2LV flow and early EVP enhancement. A positive beak sign was 83% specific, and an aortomesenteric distance of ≤6.5 mm was 61% sensitive and 83% specific for identifying retrograde L2LV flow with early regional EVP enhancement in patients with CDH. CONCLUSIONS: Retrograde L2LV flow with early EVP enhancement in CDH patients can be effectively evaluated using trMRA and was seen with greater propensity in those patients with NCP.

SUCCESSFUL RESOLUTION OF NUTCRACKER SYNDROME WITH 3D PRINTED PEEK EXTRAVASCULAR STENT IN AN ADOLESCENT BOY.

Three-dimensional printed polyetheretherketone (PEEK) extravascular stent was applied to treat a 14-year-old boy with nutcracker syndrome. Digital subtraction angiography revealed a segment of the left renal vein (LRV) with reduced contrast filling immediately before its inflow into the inferior vena cava, and high-pressure gradient. The three-dimensional reconstruction model demonstrated that the LRV and the duodenum were contracted at the aortomesenteric angle, resulting in LRV compression from the abnormal high-level duodenal compartment. When duodenum courses between the abdominal aorta and superior mesenteric artery (duodenal interposition), the LRV entrapment occurs even at <90 aortomesenteric degrees. Three-dimensional printed PEEK extravascular stent was chosen to elevate the superior mesenteric artery and lower the duodenum position, thus relieving LRV compression. This extravascular application has significant advantages over open surgery, endovascular stenting and artificial vessel procedures with expanded polytetrafluoroethylene. It provides better cellular vitality by ensuring soft tissue proliferation. By reducing external acceleration and centrifugal force, a three-dimensional printed PEEK extravascular stent reduces adverse side effects. Such a stent has a distinctive personalized design, good stiffness, and durability that allows blood vessel growth, preventing stent migration and thrombosis. Therefore, it is suitable for both adult and pediatric patients. According to the abdominal ultrasound and multi-slice computed tomography scan, the postoperative follow-up results were satisfactory one year after surgery. The patient felt well, the blood flow in the LRV was not obstructed, and the blood flow velocity was average. The external stent was in place.

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

BACKGROUND: At present, researchers have obtained fruitful results in the study of nutcracker syndrome (NCS), but there is still a lack of systematic research on the overall status of this disease. This article aims to describe the past and current status of research into NCS, and predict future research trends and popular research topics. METHODS: Using bibliometric and visualization methods, 552 articles related to NCS collected from the Scopus database from 1974 to 2021 were analyzed from multiple perspectives. RESULTS: Overall, the amount of literature related to NCS is on the rise every year, and the number of citations is the turning point in 2006. The United States has the largest number of publications and has the most extensive cooperation with other countries. The main contents of the co-authored study focused on the symptoms, surgical procedures, and concomitant diseases of NCS. Keywords such as peak velocity, ultrasonography, orthostatic proteinuria, etc appeared earlier, whereas diagnosis, chronic pelvic pain, endovascular stents, etc appeared later. CONCLUSIONS: The literature utilization rate of NCS is relatively insufficient. The pathogenesis and pathological mechanisms need to be further studied, and the diagnostic criteria and surgical methods will continue to be favored by clinicians.

The Journey and Barriers to Treatment of Patients With Renal Nutcracker Syndrome.

OBJECTIVE: To better understand renal nutcracker syndrome (NCS) from a patients' perspective starting at presentation and followed through to diagnosis and management METHODS: This descriptive study was conducted on a national level via a self-selected online survey distributed via river sampling by a post on the Facebook Page 'Renal Nutcracker Syndrome Support Group.' RESULTS: Of the 22 responses collected, 95.5% were female and 91% self-identified as White. 43% experienced symptoms as teenagers and 62% were diagnosed as young adults. Prior to receiving a definitive diagnosis, over half of the respondents were worked up for kidney stones (57%) and ovarian cysts (48%) and saw at least 10-15 providers. Nearly 80% experienced constant pain throughout the day. Pain management included prescription oral pain relievers (38%), prescription patches (29%), and physical therapy (19%). Surgical procedures included nephrectomy with auto transplant (38%), left renal vein transposition (10%), and laparoscopic extravascular stent placement (10%). Respondents had high healthcare utilization for management of NCS. Nearly 30% were unable to work and had filed for disability. CONCLUSION: Awareness of NCS should increase among healthcare providers of all specialties to improve quality of care to those living with NCS. It is crucial to keep NCS within the differential diagnosis in patients presenting with gross hematuria and unusual abdominal and/or flank pain.

A systematic review on nutcracker syndrome and proposed diagnostic algorithm.

OBJECTIVE: Nutcracker syndrome (NCS) is an increasingly recognized venous compressive disease. Although people with NCS can experience debilitating symptoms, making an accurate diagnosis can often be challenging owing to the broad spectrum of clinical presentations and radiologic findings. In the present systematic review, we assessed the most frequent clinical and radiologic criteria used in establishing a diagnosis of NCS and have proposed a comprehensive framework for clinical decision-making. METHODS: We performed a systematic review to identify all observational studies or case series conducted within the previous 10 years that had studied patients with a clinical and radiologic diagnosis of NCS. The extracted data included details related to the study design, participant demographics, presenting clinical features, and radiologic criteria. These details were compared between studies and synthesized to establish a comprehensive diagnostic framework that would be applicable to clinical practice. RESULTS: In the present review, we included 14 studies with a total of 384 patients with NCS. The most common clinical features of NCS were hematuria (69.5%), left flank or abdominal pain (48.4%), pelvic pain (23.1%), and varicocele (15.8%). Computed tomography and ultrasound were the most commonly used imaging modalities, with a threshold for left renal vein stenosis of >80% the most frequently used diagnostic parameter. Eight studies had used venography, with the renocaval pressure gradient the most commonly measured parameter. Two studies had reported using intravascular ultrasound. The findings from our review have shown that a thorough clinical workup of NCS should include critical evaluation of the presenting clinical features and exclusion of alternative diagnoses. All patients should undergo duplex ultrasound with or without the addition of computed tomography or magnetic resonance imaging. Any patient considered for therapeutic intervention should also undergo diagnostic venography with measurement of the renocaval pressure gradient and, if available, intravascular ultrasound with measurement of the left renal vein diameters. CONCLUSIONS: NCS is a challenging condition in terms of the diagnosis and management both. We have proposed a comprehensive diagnostic framework based on the currently available literature to aid in clinical decision-making.

Left renal vein entrapment in postural proteinuria: the diagnostic utility of the aortomesenteric angle.

Nutcracker syndrome related to the left kidney vein compression is a cause of orthostatic proteinuria during childhood. Some studies have shown that the ratios between maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions must be more than 4 in order to make a Nutcracker syndrome diagnosis. Our aim was to investigate whether the use of a decrease in aortomesenteric angle between upright and supine positions in the presence of isolated orthostatic proteinuria can be a criterion for the diagnosis of Nutcracker syndrome. Relevant patient information, which included demographic data, clinical examination findings, laboratory data, urinary system ultrasound, and kidney color flow Doppler ultrasound results, were prospectively collected. Thirty-nine pediatric patients with orthostatic proteinuria were included in the study. Left kidney vein compression findings were demonstrated in 31 patients. The ratio of maximum velocities of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions was above 4 in only 7 of our patients. Ratio of aortomesenteric angle between upright and supine positions was significantly decreased for patients with left kidney vein compression findings.  Conclusion: The use of a decrease in the ratio of aortomesenteric angle between upright and supine positions in the presence of orthostatic proteinuria, instead of the ratios for maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments, can be more helpful for the diagnosis of Nutcracker syndrome in the differential diagnosis of orthostatic proteinuria. What is Known: • Proteinuria may be a sign of an impending kidney disease • Nutcracker syndrome is a cause of orthostatic proteinuria. What is New: • Ratio of aortomesenteric angle between upright and supine positions > 0.6 can be used for Nutcracker syndrome diagnosis.