In addition to the low incidence of iatrogenic retroperitoneal hematomas secondary to CPR, the site of the lumbar vein hematoma in this patient was not near the area of chest compressions and thus makes it less likely to be the cause of the bleed.
b) Initial noncontrast CT coronal reformatted images demonstrated a large high density left retroperitoneal hematoma (dashed arrow) contiguous with high-attenuated tubular structure arising from the left side of IVC (arrow), likely a lumbar vein.
b) Contrast CT coronal reformatted image during delayed (120 sec) venous phase demonstrated hyperattenuated contrast material below the IVC filter contiguous with dilated left lumbar vein (arrow) extending to left retroperitoneal hematoma (dotted arrow).
Left lumbar vein initially ascended along the posterior abdominal wall lateral to the left kidney, turned medially at the level of the hilum of the left kidney to cross its anterior surface, finally draining into the anterior aspect of the left renal vein, lateral to the openings of left suprarenal and left ovarian veins.
It coursed laterally posterior to the left suprarenal vein (shown in the inset of figure 2) and then crossed the anterior surface of the left kidney accompanying the lumbar vein to reach the posterior abdominal wall.
According to Jack Baniel et al in their study on lumbar vessels, a lumbar vein entering the left renal vein was documented in 43% of cases.
But the lumbar azygos vein was absent (though present on the right side) and a dilated communicating vein (of almost equal thickness as the left renal vein) was seen to pass deep to the left psoas major muscle into the left para-vertebral gutter and communicate with the left ascending lumbar vein (figure 1 & 2).
The LRV is usually formed from the transverse anastomotic vessel between the left and right sub-cardinal veins and the supra-cardinal veins along with the azygos venous line (which develops subsequently) gives rise to the azygos venous system including the ascending lumbar vein.