Dilatation, Stents, Diagnostic procedure, Contrast agent-intravenous, MR, CT, Catheter venography, Vascular, Interventional vascular, Abdomen, Varices
I. A. A. Vizzini, D. C. Caltabiano, A. Conti, L. Mammino, S. Palmucci, P. V. Foti, A. Basile; Catania/IT
The nutcracker phenomenon is defined as an anatomical condition characterized by extrinsic vascular compression of left renal vein (LRV) with consequent obstacle to venous outflow in the inferior vena cava (IVC).
Despite the terms nutcracker syndrome and nutcracker phenomenon are often used interchangeably,
it must be emphasized that left renal vein compression is not always associated with symptoms.
Definition of “nutcracker syndrome” (NCS) is the association of typical symptoms with morphological characteristics; instead,
the term "nutcracker phenomenon" should be used in absence of symptoms.
The most typical morphological feature of nutcracker syndrome is compression of left renal vein (LRV) between aorta and superior mesenteric artery (SMA),
known as "anterior nutcracker".
the third portion of the duodenum is placed in front of LRV,
between aorta and SMA.
The anterior nutcracker can coexist with the compression of duodenum by SMA,
known as "superior mesenteric artery syndrome" (Wilkie's syndrome) .
Retro-aortic or circumaortic renal vein can be compressed between aorta and vertebral body ("posterior nutcracker"); the anterior nutcracker can be associated in the combined nutcracker.
The right nutcracker phenomenon is possible for a venous compression by pregnant uterus .
Nutcracker syndrome has a greater predilection for women and for subjects with asthenic habitus.
It is more frequent when there is a narrow aorto-mesenteric angle,
a low origin of the SMA,
fibrous tissue at the origin of SMA,
a posterior renal ptosis and abnormally high course of LRV.
Some causes of secondary LRV compression can also occur in presence of pancreatic neoplasms,
retroperitoneal tumors or fibrolymphatic tissue between SMA and aorta [1,3].