Compression of the vena cava inferior by/against the lumbar spine and the diaphragm
During the workup of patient with the compression syndromes a compression of the vena cava inferior or is frequently found in combination with other compression syndromes-mainly May Thurner syndrome and lordogenetic left renal vein compression aka nutcracker syndrome.
The review of the medical literature does not retrieve any scientific papers describing the situation.
Thus, I am going to report my own experiences with compression of the vena cava in different body and breathing postures.
A compression can only be exerted by neighbouring structures. So, the vena cava can be compressed by the spine with its vertebra and intervertebral discs, the small and large bowel, the liver, the diaphragm, the right common iliac artery and the right renal artery. Within the thorax the pericardium, the pleura and lung structures may compress the vena cava.
Beside these normal anatomic structures tumors, abscessi and malformations due to their variable location may compress the vena cava. Such conditions are not taken into consideration in the following description.
The right kidney lies too far dorsally to compress the vena cava, especially if the lordotic curvature of the spine is exaggerated, the pancreas lies left to the vena cava stretching across the midline to the left, and the abdominal wall usually does not the vena cava in contrary to the aorta since the vena cava lies at the right circumference of the vertebrae and their lateral processi whereas the aorta usually lies only slightly left to the midline and more prominent at the ventral surface of the vertebra thus being the first structure of the retroperitoneum been touched by the abdominal wall is an increased lordosis is pushing the retroperitoneal structures ventrally.
Compression of the vena cava inferior by the spine
The vena cava is frequently compressed running along the lordotic curvature of the lumbar spine if this curvature is exaggerated. This can best be evaluated not by x-ray but ultrasound or MRI or CT. The hallmark of an exaggerated lordosis in the context of vascular compression syndromes is a substantial narrowing of the abdominal cavity in front of the lumbar spine.
In patients with a relevant compression of the vena cava inferior the minimum distance from the ventral surface of the spine or the frequently protruding intervertebral disc (mostly L2/L3 or L3/L4) at the apex of the lordotic curvature towards the inner lining of the abdominal wall is often less than 2 cm. Not rarely it may undercut 1 cm!
In these patients the vena cava is quite frequently compressed at typical locations. The numbers also indicate the frequency of the occurrence of the compression:
While the first compression sites are usually found in a supine posture-the patient is lying on his/her back-the compression at the cranial slope of the lordotic curvature can usually be only found while the trunk is an upright position-standing or sitting.
The symptoms may encompass the symptoms of the nutcracker syndrome and the may Thurner syndrome plus localized pain at the compression site.
Thus, main symptoms are usually :
The diagnosis is straightforward with a functional colour Doppler sonographic ultrasound examination and is most precise while using the PixelFlux technique. The most important obstacle for a correct diagnosis of a vena cava compression is not taking it into consideration.
The following images demonstrate typical findings in patients with vena cava inferior compression
The treatment of these conditions is not easy and sometimes unexpected changes occur.
The easiest way to influenced congestion of the vena cava is a changing body posture.
In selected cases an operation to decompress the vena cava might be contemplated.