Controversies in treating nutcracker syndrome

Abstract

Nutcracker syndrome (NCS) is a relatively uncommon vascular condition characterized by compression of the left renal vein (LRV), resulting in a variable spectrum of nonspecific symptoms, including hematuria, flank pain, varicocele, and pelvic congestion syndrome. NCS can be classified into anterior and posterior types regarding the origin of LRV compression: anterior NCS occurs when LRV is compressed between the aorta and superior mesenteric artery, whereas posterior NCS involves LRV compression between the aorta and the spine. Despite advancements in diagnostic modalities, including Doppler ultrasound, computed tomography, magnetic resonance imaging, and invasive techniques like phlebography, there is still no globally accepted diagnostic algorithm, leading to inconsistencies in diagnosis. Moreover, due to the lack of standardized treatment guidelines, the optimal management of anterior NCS remains a topic of debate. While conservative management is usually recommended in the pediatric population, invasive treatments-including surgical options like LRV transposition and renal autotransplantation, as well as interventional radiology procedures like stenting, present challenges such as stent migration, restenosis, and long-term material durability. Nevertheless, the emergence of 3D-printed stents offers potential improvements in patient-specific treatment, particularly in the pediatric population, yet their clinical efficacy and safety remain under investigation. This brief communication addresses the current discussions regarding anterior NCS management, emphasizing the need for standardized diagnostic algorithms, a multidisciplinary approach, and continued technological advancements to refine treatment possibilities and strategies. Further research is critical to resolve these controversies and establish a consensus on best practices.

Fig. 1

CT measurements of AMA in the sagittal plane: A portal venous phase—11° AMA indicative of NCS (yellow arrow depicting severely compressed LRV) incidentally detected in a 37-year-old female patient during staging for malignant disease; B arterial phase—19° AMA indicative of NCS (yellow arrow depicting severely compressed LRV) detected in a 17-year-old female patient who presented with a long-lasting non-specific abdominal pain

Fig. 2

CT axial planes of the same patients with the ratio of the LRV diameter at the hilar and aorto-mesenteric level (the ratio > 5 indicates the presence of NCS): A portal venous phase – the ratio is 6.10; B arterial phase – the ratio is 6.91

Fig. 3

Contrast-enhanced CT examination demonstrating signs of pelvic congestion syndrome distally due to Nutcracker syndrome: A axial plane – dilated left ovarian vein (approximately 10 mm in diameter), B coronal plane – dilated left ovarian vein (arrow), C coronal plane – pelvic varices (arrow)

Fig. 4

Example of securely packed 3D-printed PEEK extravascular stent (courtesy of Zhang Bo and He Da-li)

Fig. 5

CT examination demonstrating patent 3D-printed PEEK extravascular stent due to Nutcracker syndrome (arrow): A non-contrast-enhanced, axial plane, B contrast-enhanced, axial plane, C contrast-enhanced, coronal plane

Fig. 6

The 3D-printed PEEK extravascular stent in the same patient (arrow): A B-mode ultrasound in the sagittal plane, B Doppler ultrasound in the sagittal plane