Evaluation of posterior nutcracker phenomenon using multisection spiral CT

Twenty-year analysis of the rarely diagnosed nutcracker syndrome

Aim: Nutcracker syndrome is a very rare cause in patients presenting to the emergency department with abdominal pain. Early consideration in differential diagnosis will reduce the time spent for diagnosis and morbidity, as well as provide the correct treatment. We aimed to contribute to the literature by determining the clinical relations of these cases with laboratory, imaging and treatment data. Material and Method: Twenty-seven patients over the age of 16 who presented to the emergency department with abdominal pain between January 2000 and December 2020 were included in this study. The ages of the patients were between 16-39 and the mean was 25.19±7.00 years. Demographic characteristics, clinical findings, laboratory parameters, radiological evaluations, and treatment modalities of patients were evaluated retrospectively. Results: Abdominal pain and flank pain were the most common reasons for admission to the emergency department of 27 patients included in the study. In the anterior group, 17 (77%) patients had flank pain, 10 (45%) patients had dysmenorrhea, 11 (50%) hematuria, 10 (45%) proteinuria, and 9 (40%) patients hematuria and proteinuria. In the posterior group, there was no hematuria, proteinuria, anorexia, nausea and vomiting, and oral intolerance. In cases with anteior nutcracker syndrome, 12 (54%) doppler ultrasonography, 13 (59%) computed tomography, 5 (22%) magnetic resonance imaging were performed. Conservative treatment was applied to 11 (40%) patients in the anterior group and 3 (11%) patients in the posterior group. Endovascular surgery was performed on 5 (22%) female patients. Conclusion: Nutcracker syndrome should be investigated in adult patients who present to the emergency department with abdominal pain and whose diagnosis is unclear. Early diagnosis is critical in terms of treatment and morbidity.

Evaluation of renal vascular variations with computed tomography

Background

It is important to know the renal vascular variations before renal surgeries and invasive procedures. The aim of this study is to evaluate the prevalence and types of variation of renal arteries and veins.

Methods

The abdominal CT images of 460 patients, taken between 2019 and 2021, were retrospectively analyzed in axial and coronal planes. The presence and number of accessory renal arteries and early branching in the main renal artery were evaluated. Then, bilateral renal vein variations were investigated. Finally, the compression of the left renal vein by different anatomical structures was evaluated.

Results

Of the 450 patients included in the study, the mean age was 53 years. No variations were detected in 378 renal arteries on the right side (84%) and 392 renal arteries on the left side (87.1%). The most common variation in renal arteries was an accessory inferior hilar artery in 7.5% and 6% rates on the right and left, respectively. An accessory inferior renal polar artery was observed at an overall rate of 1.3%. An accessory superior renal hilar artery was found at 3.3% and 2% rates on the left and the right, respectively. An accessory superior renal polar artery was found at an overall rate of 3.5%. Multiple variations in the renal arteries were observed at a rate of 6.4%. Early branching was observed at a rate of 4.9% on the right and 2.2% on the left. The presence of two and three right renal veins was observed at rates of 13.1% and 0.6%, respectively. Retroaortic and circumaortic left renal veins were found at 3.5% and 4.4% rates, respectively. The compression on the anterior and posterior left renal veins was observed at 4.6% and 0.9% rates, respectively.

Conclusion

Considering that variations in renal arteries and veins are too many and of different types to underestimate, a CT examination for the renal vascular anatomy before and at the planning phase of renal surgery or interventional procedures will be of great benefit to avoid potential complications.

A Case of Posterior Nutcracker Syndrome Revealed in the Aerospace Environment

BACKGROUND: Nutcracker syndrome is caused by a rare anatomic variant where the left renal vein is trapped between the aorta and the superior mesenteric artery. Posterior nutcracker syndrome is an even rarer entity, characterized by the retro-aortic positioning of the renal vein, causing compression between the aorta and spinal vertebrae. Symptoms include microscopic or frank hematuria, flank pain, varicocele, pelvic congestion syndrome, and abdominal pain. A search of the literature did not reveal prior cases of nutcracker syndrome that became symptomatic and diagnosed secondary to the unique stressors of high gravitational force (G force) in the aviation environment.CASE REPORT: A 25-yr-old man training as an F-16 flight test engineer presented with left scrotal/testicular pain, varicocele, and intermittent gross hematuria. After an extensive workup, he was diagnosed with posterior nutcracker syndrome and underwent a left varicocele ligation with spermatic cord denervation. He was eventually able to be returned to flying duties with limitation to non-high performance aircraft.DISCUSSION: This case is particularly unique as its diagnosis was dependent on exposure to high G force conditions that may have otherwise remained asymptomatic without this environmental stressor. Education on the diagnosis of nutcracker syndrome as a differential in the setting of hematuria and pain is an important lesson learned. This case also illustrates the necessity of considering the effects of the stressful environment of high G force on even overall healthy individuals. Fortunately, due to the collaboration of medical-surgical expertise and familiarity with the requirements for operational readiness, this patient was able to resume his aviation career, albeit in a different capacity compatible with his condition.Chung CY, Lytle ME, Clemente Fuentes RW. A case of posterior nutcracker syndrome revealed in the aerospace environment. Aerosp Med Hum Perform. 2021; 92(1):5456.

Compression of left renal vein and left common iliac vein on CT scans: how often are they detected?

Background

The nutcracker and May-Thurner syndromes are rare and, although often underdiagnosed, they can cause limiting symptoms. They are frequently considered only after exclusion of other diagnoses and there is no consensus in the literature on prevalence, incidence, or diagnostic criteria.

Objectives

To estimate the frequency of compression of the left common iliac vein and left renal vein in CT scans of the abdomen and pelvis.

Methods

Descriptive, quantitative, cross-sectional study. The criteria used to define compression of the left renal vein were a hilar/aortomesenteric diameter ratio > 4 and aortomesenteric angle < 39° and the criterion for compression of the left common iliac vein was a diameter < 4mm.

Results

CT scans of 95 patients were analyzed; 61% were women and 39% were men. Left renal vein compression was observed in 24.2% of the sample, with a mean age of 48.8 years, occurring in 27.6% of the women and 18.9% of the men (p = 0.3366). Compression of the left common iliac vein was detected in 15.7% of the sample, with a mean age of 45.9 years, occurring in 24.1% of the women and 2.7% of the men (p = 0.0024). Both veins were compressed in 7.4% of the patients.

Conclusions

Left renal vein compression was detected in women and men at similar frequencies, whereas left common iliac vein compression was more frequent in women. Both venous compressions were most frequently found in patients aged 41 to 50 years.

Unusual Drainage of the Bifurcated Left Renal Vein Into a Dilated Lumbar Azygos Vein and Inferior Vena Cava

We report a unique case of unusual drainage of the bifurcated retroaortic left renal vein, with the cranial wider branch draining into a dilated lumbar azygos vein and caudal thinner branch connecting with the inferior vena cava. The right renal vein was duplicated. The anomaly was discovered on multimodal ¹⁸F-labeled fluorodeoxyglucose positron emission tomography/computed tomography performed for oncological purposes. The basis enabling occurrence of such variation was probably persistent developmental extra left-right venous connections, intercardinal, or intersupracardinal, depending on the theory. The embryology of the chest and abdominal veins is a complicated process and there is no unanimity concerning its concepts. The old models are currently being questioned and reevaluated. Knowledge of possible variants of renal and azygos veins course is important from clinical, imaging, and surgical points of view. The retroaortic left renal veins course may sometimes cause pain, hematuria, proteinuria, and pelvic congestion syndromes. Dilated parts of uncommonly located veins, because of assuming a nodular shape on transverse images, may be mistaken for abnormal lymph nodes, other tumors or aneurysms on imaging. During a variety of surgical procedures, including venous sampling, renal transplantation, or any retroperitoneal surgery, knowledge of an aberrant venous course may be important for the success of the procedure and may be crucial even earlier during the qualification process.