Correlation of Imaging and Hemodynamic Findings with Clinical Outcomes for Diagnosis of Left Renal Vein Compression Syndrome.

PURPOSE: Left renal vein compression syndrome (LRVCS) remains a challenging diagnosis. This study aimed to correlate imaging and hemodynamic findings with clinical outcomes for patients with LRVCS. MATERIALS AND METHODS: A retrospective review of 66 renal venography procedures with or without intravascular ultrasound (IVUS) was performed from 2017 to 2023 at a single institution. Patients with prior LRVCS treatment or other indications were excluded (n = 11). Primary outcome measure was correlation of catheter-based endovascular (CBE) findings with clinical outcomes (n = 55). Secondary outcome measures included correlation of CBE findings and LRV (i.e., beak) angle > 32°, beak sign, aortomesenteric angle (AMA < 41°), and hilar-to-aortomesenteric ratio (HTAMR ≥ 4.9) on cross sectional imaging. Descriptive statistics, chi-square testing, and ROC analyses were used. RESULTS: Of the 55 patients, 52 (94.5%) were females (median age 31, range 14-72) and 56.4% (n = 31) had a diagnosis of LRVCS on CBE evaluation. A renocaval pressure gradient of ≥ 3 mmHg, presence of collaterals, and > 50% area stenosis on IVUS were significantly associated with CBE diagnosis of LRVCS (p < 0.001). Surgical treatment (renal autotransplantation or LRV transposition) was recommended to all patients with CBE diagnosis of LRVCS (n = 31). 81.2% (18/22) of patients who underwent surgery reported symptom resolution or improvement. When the cross sectional imaging measurements were compared with CBE evaluation, AMA was the most sensitive (100%), HTAMR and beak sign were highly specific (93.3%), and beak angle was the most predictive (77.4% sensitivity; 86.7% specificity). CONCLUSION: CBE diagnosis of LRVCS was highly predictive of surgical candidacy and post-surgical symptom resolution. The presence of collaterals, > 50% area stenosis on IVUS, or a renocaval pressure gradient ≥ 3 mmHg had a significant association with a CBE diagnosis of LRVCS.

Beyond Abdominal Pain: Decoding the Mysteries of Nutcracker Syndrome.

Nutcracker syndrome (NCS), a rare but impactful vascular condition, emerges from the compression of the left renal vein by adjacent major arteries, leading to a diverse array of symptoms such as hematuria, flank pain, and renal challenges. Highlighting the case of a 30-year-old male with an atypical presentation of NCS, this report explores the diagnostic complexities arising from its varied presentations and therapeutic options. It emphasizes the critical role of computed tomography (CT) in unveiling the underlying vascular constriction. Through this lens, the case underscores the necessity of considering NCS in the differential diagnosis of abdominal pain, advocating for a prompt and accurate diagnosis to guide effective management strategies, ranging from conservative approaches to surgical intervention. This stresses the importance of heightened awareness and ongoing research for optimizing patient outcomes in the face of this elusive condition.

Navigating Complexities: A Case of Multiple Abdominopelvic Vascular Compression Syndromes in Ehlers-Danlos Syndrome.

Abdominopelvic vascular compression syndromes (VCS) refer to conditions where blood vessels in the abdomen or pelvis are compressed by nearby structures, leading to various symptoms and complications. These conditions include superior mesenteric artery syndrome (SMAS), nutcracker syndrome (NCS), May-Thurner syndrome (MTS), and median arcuate ligament syndrome (MALS). Each syndrome is characterized by specific compressions of blood vessels, resulting in symptoms such as pain, nausea, vomiting, weight loss, leg swelling, and other related issues. Ehlers-Danlos syndrome (EDS), characterized by hyperelasticity, altered collagen, and mobility of the viscera, has been associated with VCS, although the exact prevalence is unknown. We report a case of a patient with EDS who presented with multiple VCS, including NCS, MTS, SMAS, and MALS.

A unique posterior nutcracker syndrome combined with Wilkie syndrome: A singular case.

Left renal vein variants are not commonly observed in the general population. Usually, the renal vein runs in front of the aorta before entering the inferior vena cava, while the most common variants include the presence of a circumaortic or retroaortic renal vein. However, when present, left venal rein variants are important to recognize due to their potential clinical and surgical relevance. In this regard, CE-CT is an instrument with high sensitivity and specificity in detecting vascular anomalies and can certainly help diagnose. In this article, we present a unique case of a left venal rein compressed between the left iliac artery and vertebral bodies associated with the presence of a superior mesenteric artery Syndrome, another rare entity that occurs when the duodenum is compressed between the aorta and the superior mesenteric artery.

Nutcracker Syndrome Revealed by Hematuria in a Young Woman: A Case Report and Literature Review.

Nutcracker syndrome is a rare condition that arises from the left renal vein getting compressed between the aorta and the superior mesenteric artery. Despite its clinical significance, this syndrome is often challenging to diagnose and is frequently overlooked. Its key clinical presentations include hematuria and pelvic or back pain. This condition involves elevated pressure on the left renal vein, leading to various signs and symptoms, with hematuria being a common manifestation. Herein, we report a 28-year-old woman with no medical history who presented with hematuria for two months. Abdominal CT revealed compression of the left renal vein between the superior mesenteric artery and abdominal aorta, with dilated left ovarian vein and pelvic varices, consistent with nutcracker syndrome.

Bilateral Renal Hilar Nutcracker Phenomenon in a Male Cadaver.

Nutcracker phenomenon (NCP) typically refers to the entrapment of the left renal vein (LRV) between the aorta and the superior mesenteric artery. Similar to the classic NCP, the renal vein can also get entrapped between the segmental branches of the renal artery at the renal hilum, which has been referred to as 'renal hilar nutcracker phenomenon (RHNP).' During routine dissection of a male cadaver of 67 years, the renal veins of both sides at the renal hilum were seen between the segmental branches of renal arteries, which we identified as the 'renal hilar nutcracker phenomenon.' The disposition of the rest of the perihilar structures was normal. 'Renal hilar nutcracker phenomenon' can have similar clinical presentation like that of the nutcracker phenomenon. Hence, knowledge of such anatomical variation at the renal hilum is desirable.

Case Report; Concomitant Left Nutcracker Syndrome and Right Ureteropelvic Junction Obstruction.

We report rare case of concomitant left nutcracker syndrome and right ureteropelvic junction obstruction (UPJO) on adult female patient diagnosed by CT urogram after she presented with intermittent bilateral flank pain. For this we did Anderson-Hynes pyeloplasty for right ureteropelvic obstruction, it was laparoscopic initially but due to difficulty of stenting it is changed to open. She had smooth post-op course then discharged on 3rd post-op day. Symptoms of nutcracker syndrome are not that much bothersome for the patient so we planned to follow her conservatively.

A new notable compression source of left renal vein entrapment: right renal artery.

PURPOSE: To estimate the incidences of left renal vein (LRV) entrapment by right renal artery (RRA), a phenomenon primarily reported as case reports. METHODS: The cross-sectional study consecutively screened renal vessel CT data of 38 (Renal) patients with nephropathy and 305 (Non-renal) patients with peripheral arterial diseases in a teaching hospital in northeast China between November 2018 and March 2023. The LRV compression by adjacent anatomical structures, including but not limited to RRA and multiple compression-related parameters, were investigated through multiplanar analysis of the CT data. RESULTS: The overall LRV entrapment rates by adjacent structures were 41.93% (12/31) and 24.00% (6/25), the rates of RRA-sourced LRV compression 22.58% (7/31) and 20.00% (5/25), and the rates of compression by superior mesenteric artery (SMA) 16.13% (5/31) and 4.00% (1/25) in the Renal and Non-renal groups, respectively, with no significance. The venous segments distal to the RRA-compressed site had a significantly larger transectional lumen area than those of the non-compressed veins in both groups (3.09 ± 1.29 vs. 1.82 ± 0.23, p < 0.001 and 4.30 ± 2.65 vs. 2.12 ± 0.55, p = 0.006; maximum-to-minimum area ratios in Renal and Non-renal groups, respectively). Nearly 80% of RRAs were found arising anteriorly rightwards instead of passing straight to the right. CONCLUSION: RRA-sourced LRV compression was not rare, and its incidence was higher than that of the compression by SMA in both patient cohorts. RRA could be a more common compression source than SMA concerning LRV entrapment. Further investigations involving different populations, including healthy individuals, are needed.

The Da Vinci Single-Port (SP) Treatment of Nutcracker Syndrome: A Case Report of a Novel Approach.

Nutcracker syndrome (NCS) is a rare disease affecting the left kidney. Surgical management is the only choice of treatment. Minimal invasive surgeries can be effective and may prevent complications of the major surgery. We present the case of a 33-year-old woman suffering from chronic left flank pain, diagnosed with NCS and treated with extravascular stents. Robotic-assisted extravascular stent insertion was performed using the Da Vinci single-port (SP) (Intuitive Surgical, Inc., Sunnyvale, USA) system. This approach offers the advantages of minimal invasiveness, precise stent placement, and reduced operative time. To our knowledge, this is the first case of using Da Vinci SP for this indication. Further studies are needed to evaluate the long-term outcomes and safety.

Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review.

Vascular compression syndromes are a diverse group of pathologies that can manifest asymptomatically and incidentally in otherwise healthy individuals or symptomatically with a spectrum of presentations. Due to their relative rarity, these syndromes are often poorly understood and overlooked. Early identification of these syndromes can have a significant impact on subsequent clinical management. This pictorial review provides a concise summary of seven vascular compression syndromes within the abdomen and pelvis including median arcuate ligament (MAL) syndrome, superior mesenteric artery (SMA) syndrome, nutcracker syndrome (NCS), May-Thurner syndrome (MTS), ureteropelvic junction obstruction (UPJO), vascular compression of the ureter, and portal biliopathy. The demographics, pathophysiology, predisposing factors, and expected treatment for each compression syndrome are reviewed. Salient imaging features of each entity are illustrated through imaging examples using multiple modalities including ultrasound, fluoroscopy, CT, and MRI.

Robotic Renal Vein Bypass: A Novel Technique for Treating a Challenging Case of Nutcracker Syndrome.

This case report highlights the successful application of a robotic-assisted surgical approach in managing Nutcracker syndrome. The patient, a 36-year-old female presented with severe symptoms and underwent robotic left renal vein transposition after failing conservative management. The procedure was performed through a minimally invasive approach utilizing the Da Vinci robotic system™ which offers enhanced visualization and precision. However, challenges arose during the renal vein anastomosis due to tension and poor flow through the transposition, requiring two revisions with a bovine pericardial patch. Ultimately, an 8 mm ringed PTFE bypass was anastomosed from the distal left renal vein to the Inferior Vena Cava. Despite these challenges, the patient experienced a successful outcome with complete symptom resolution of this complicated pathology.

Endovascular retrieval of a migrated covered stent from the pulmonary artery.

Stent migration is a rare but significant complication following endovascular procedures. Techniques for managing dislodged stents have included surgical, endovascular, and conservative approaches. This case details a patient who had a covered stent placed within the left renal vein which later migrated to the pulmonary artery causing damage to the tricuspid valve. The migrated stent was successfully removed using a percutaneous endovascular approach utilizing fluoroscopy and transesophageal echocardiogram guidance.

Hemodynamics in nutcracker syndrome: implications for diagnosis.

BACKGROUND: Nutcracker syndrome is a disease characterized by complex symptoms, making its diagnosis challenging and often delayed, often resulting in a painful experience for the patients. OBJECTIVE: This study aimed to investigate the pathogenesis of nutcracker syndrome through the perspective of hemodynamics by simulating blood flow with varying compression degrees of the left renal vein. METHODS: 3D patient-specific vascular models of the abdominal aorta, superior mesenteric artery and left renal vein were constructed based on CT images of patients suspected of having nutcracker syndrome. A hemodynamic simulation was then conducted using computational fluid dynamics to identify the correlation between alterations in hemodynamic parameters and varying degrees of compression. RESULTS: The study indicated the presence of an evident gradient in velocity distribution over the left renal vein with relatively high degrees of stenosis (α ≤ 50°), with maximum velocity in the central region of the stenosis. Additionally, when the compression degree of the left renal vein increases, the pressure distribution of the left renal vein presents an increasing number of gradient layers. Furthermore, the wall shear stress shows a correlation with the variation of blood flow velocity, i.e., the increase of wall shear stress correlates with the acceleration of the blood flow velocity. CONCLUSIONS: Using computational fluid dynamics as a non-invasive instrument to obtain the hemodynamic characteristics of nutcracker syndrome is feasible and could provide insights into the pathological mechanisms of the nutcracker syndrome supporting clinicians in diagnosis.

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.

A Possible Newly Defined and Treatable Secondary Cause of Early Morning Wake-Up Headaches in an Older Hypermobile Woman: Nutcracker Physiology with Spinal Epidural Venous Congestion.

Introduction: Left renal vein compression (nutcracker physiology) with secondary spinal epidural venous congestion is a newly recognized cause of daily persistent headache. Presently, only women with underlying symptomatic hypermobility issues appear to develop headache from this anatomic issue. The hypothesized etiology is an abnormal reset of the patient's cerebrospinal fluid (CSF) pressure to an elevated state. Headaches that occur during sleep can have a varied differential diagnosis, one of which is elevated CSF pressure. We present the case of an older woman who began to develop severe wake-up headaches at midnight. She was found to have left renal vein compression and spinal epidural venous congestion on imaging. After treatment with lumbar vein coil embolization, which alleviated the spinal cord venous congestion, her headaches alleviated. Case Report: A 61-year-old woman with a history of hypermobile Ehlers-Danlos syndrome began to be awakened with severe head pain at midnight at least several times per week. The headache was a holocranial, pressure sensation, which worsened in the supine position. The headaches were mostly eliminated with acetazolamide. Because of her hypermobility issues and pressure-like headache, she was investigated for underlying nutcracker physiology and spinal epidural venous congestion. This was confirmed using magnetic resonance (MR) angiography and conventional venography, and after lumbar vein coil embolization her wake-up headaches ceased. Conclusion: The case report suggests a possible new underlying and treatable cause for early morning, wake-up headaches: nutcracker physiology with secondary spinal epidural venous congestion. The case expands on the clinical headache presentation of nutcracker physiology.

Coronal vertical fracture of vertebral body following minimally invasive lateral lumbar interbody fusion: risk factor analysis in consecutive case series.

BACKGROUND: To investigate the incidence and risk factors of coronal vertical vertebral body fracture (CV-VBF) during lateral lumbar interbody fusion (LLIF) for degenerative lumbar disease. METHODS: Clinical data, including age, sex, body mass index, and bone mineral density, were reviewed. Radiological assessments, such as facet joint arthrosis, intervertebral disc motion, index disc height, and cage profiles, were conducted. Posterior instrumentation was performed using either a single or staged procedure after LLIF. Demographic and surgical data were compared between patients with and without VBF. RESULTS: Out of 273 patients (552 levels), 7 (2.6%) experienced CV-VBF. Among the 552 levels, VBF occured in 7 levels (1.3%). All VBF cases developed intraoperatively during LLIF, with no instances caused by cage subsidence during the follow-up period. Sagittal motion in segments adjacent to VBF was smaller than in others (4.6° ± 2.6° versus 6.5° ± 3.9°, P = 0.031). The average grade of facet arthrosis was 2.5 ± 0.7, indicating severe facet arthrosis. All fractures developed due to oblique placement of a trial or cage into the index disc space, leading to a nutcracker effect. These factors were not related to bone quality. CONCLUSIONS: CV-VBF after LLIF occurred in 2.6% of patients, accounting for 1.3% of all LLIF levels. A potential risk factor for VBF involves the nutcracker-impinging effect due to the oblique placement of a cage. Thorough preoperative evaluations and surgical procedures are needed to avoid VBF when considering LLIF in patients with less mobile spine.

Nutcracker syndrome unveiled by severe Typhoid fever: A rare case report.

Typhoid fever, caused by Salmonella Typhi, is a severe bacterial infection prevalent in developing countries, and can result in life-threatening complications if untreated. Nutcracker Syndrome is a rare vascular disorder involving compression of the left renal vein between the aorta and the superior mesenteric artery. It can lead to various symptoms and poses diagnostic and management challenges. We present a case study of a patient diagnosed with typhoid fever in a Unit of Critical Emergency Care. Coincidentally, the evaluation through CT-scan revealed the presence of Nutcracker Syndrome. This report underscores the incidental discovery of Nutcracker Syndrome during the assessment of a patient with typhoid fever in a critical emergency care setting.

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.

Paired acoustic recordings and point count surveys reveal Clark's nutcracker and whitebark pine associations across Glacier National Park.

Global declines in tree populations have led to dramatic shifts in forest ecosystem composition, biodiversity, and functioning. These changes have consequences for both forest plant and wildlife communities, particularly when declining species are involved in coevolved mutualisms. Whitebark pine (Pinus albicaulis) is a declining keystone species in western North American high-elevation ecosystems and an obligate mutualist of Clark's nutcracker (Nucifraga columbiana), an avian seed predator and disperser. By leveraging traditional point count surveys and passive acoustic monitoring, we investigated how stand characteristics of whitebark pine in a protected area (Glacier National Park, Montana, USA) influenced occupancy and vocal activity patterns in Clark's nutcracker. Using Bayesian spatial occupancy models and generalized linear mixed models, we found that habitat use of Clark's nutcracker was primarily supported by greater cone density and increasing diameter of live whitebark pine. Additionally, we demonstrated the value of performing parallel analyses with traditional point count surveys and passive acoustic monitoring to provide multiple lines of evidence for relationships between Clark's nutcracker and whitebark pine forest characteristics. Our findings allow managers to gauge the whitebark pine conditions important for retaining high nutcracker visitation and prioritize management efforts in whitebark pine ecosystems with low nutcracker visitation.