Keywords
double inferior vena cava - double suprarenal veins - double right testicular veins
- anomalies
Introduction
Double superior or inferior vena cava (IVC) are congenital variations caused by an
unusual embryological development of the inferior vena cava, estimated to occur in
between 0.2 and 3% of the population.[1]
[2]
[3] Most of the cases of double IVC are incidentally found during diagnostic interventions
with computed tomography (CT) or magnetic resonance imaging (MRI).[3]
[4] Since the renal segment of the IVC has the same origin as the gonadal veins in embryogenesis,[5] variations of the IVC are often accompanied by anomalies of the gonadal vein. Double
IVC has significant clinical implications, especially during retroperitoneal surgeries
or in the treatment of thrombotic diseases.[6] Also, understanding of the variation of the left suprarenal veins (LSRVs) is clinically
important for renal transplantation, laparoscopic adrenalectomy, and adrenal venous
sampling. Laparoscopic adrenalectomy has become the technique of choice in adrenal
surgery, and its main complication is intraoperative hemorrhage.[7]
[8] Adrenal venous sampling has been used as the golden standard test to differentiate
between unilateral adrenal adenoma and bilateral adrenal cortical hyperplasia, both
of which are the most common causes of primary hyperaldosteronism.[9] Likewise, prediction of the presence of duplicate testicular veins is important
to avoid diagnostic and therapeutic errors during radiological and surgical procedures,
especially during the ligation of varicocele, because, if unnoticed, it may cause
recurrence of varicocele.[10] Double IVC with coexistent double right testicular veins (RTVs) and double LSRVs
are extremely rare, and awareness of these venous variations is necessary to reduce
severe hemorrhage in retroperitoneal surgeries, and in interventional radiology.[11] The objective of the present study was to present a case of a double IVC accompanied
by double LSRVs and double RTVs.
Case Report
During a routine cadaver dissection of the abdominal region, the retroperitoneal visceral
organs were exposed after removal of the anterior abdominal organs. The kidneys and
the adrenal glands were dissected according to the standard technique. Double IVC
was found in a 70-year-old male Thai cadaver associated with double LSRVs and double
RTVs. While the upper LSRV was a tributary of the IVC, the lower LSRV was a tributary
of the left renal vein ([Fig. 1]).
Fig. 1 (A) Photograph and (B) schematic drawing demonstrating the double inferior vena cava
(IVC) interconnecting with an interiliac vein, associated with right and left suprarenal
(LSR) and testicular venous anomalies.
In this case, the IVC presented normally on the right side of the abdominal aorta,
but another similar vein, also identified as a left IVC on the left side of the aorta,
was parallel to the normal IVC. The left renal vein joined the left IVC, which then
passed to the right and joined the right IVC. Then, the common IVC traversed the normal
retrohepatic route before passing through the diaphragm into the right atrium in the
normal anatomical position. The right renal vein drained into the right IVC. The interiliac
vein was situated ventral to the body of the 5th lumbar vertebra. The RTV was bifurcated at the height of the iliac crest, and the
medial branch drained to the right IVC below the height of the right kidney, and its
lateral branch also drained to the right IVC, but just below the point of drainage
of the right renal vein ([Fig. 1]). The renal vessels followed the normal pattern. Both ureters lied laterally to
each IVC in their course to the pelvis, with no apparent abnormalities.
Discussion
The retroperitoneal venous system develops from three paired fetal venous systems,
the posterior cardinal, the subcardinal, and the supracardinal systems.[12] The normal IVC is converted to a unilateral, right-sided system, consisting of four
components: (1) the infrarenal segment from the right supracardinal vein, (2) the
renal segment from the right supracardinal anastomosis, (3) the suprarenal segment
from the right subcardinal vein, and (4) the hepatic segment from the right hepatic
vein. Double IVC is considered to occur due to the persistence of both supracardinal
veins.[13]
[14] Chen et al (2011)[11] reviewed 109 cases of IVC anomalies and found that 87 of them had intrailiac anastomosis.
According to their classification of IVC anomalies, the case reported here is compatible
with their type 2d, double IVC connected by transversely running interiliac vein,
which is assumed to be the left common iliac vein in normal development. Double IVC
is a rare and usually clinically silent venous anomaly. Discovery of double IVC in
the operating room would lead to unexpectedly serious technical difficulties in certain
patients subjected to laparoscopic nephrectomy.[15] There are several case reports of thromboembolic events occurring in patients with
double IVC.[16] In radiology, the presence of double IVC can be mistaken as lymphadenopathy,[17] or left pyeloureteral dilatation.[18] The interiliac vein might cause some problems due to unexpected hemorrhage during
abdominopelvic surgeries including misdiagnosis among clinicians.[19] The interiliac vein is a decisive factor in determining the strategy for venous
interventional radiology, such as in IVC filter placement, because of a possible risk
factor of deep venous thrombosis.[20]
The LSRV normally receives blood from the left suprarenal gland and drains into the
left renal vein. Sebe et al examined 88 venograms and found anatomical variations
in 5% of the right and in 6% of the left suprarenal veins (SRVs).[21] In the adrenal venous sampling procedure, it is important to review the anatomy
of the SRVs from thin slices of CT scan prior to the intervention. Catheter selection
is determined according to the anatomy of the SRVs. The approach to the left SRV should
be made under a different position, according to the position of the venous anatomy.
Detailed knowledge of the variation of the LSRV, including double LSRVs, is critically
important for the effective procedural planning and sampling interpretation.[22] Also, in the laparoscopic adrenalectomy procedure, it is important to know the anatomical
variation to avoid the risk of massive intraoperative hemorrhage. Excessive traction
of an adrenal gland without control of the principal adrenal vein on the left may
injure the renal vein or the IVC.[21] The gonadal veins may be misinterpreted as a double IVC because they run close to
the ipsilateral IVC, particularly the left gonadal vein that drains into the left
renal vein.[11]
Embryologically, the SRVs are formed by the stem of the subcardinal veins.[23] In the present case, double left SRVs were identified, the upper left SRV as a tributary
of the IVC, and the lower SRV as a tributary of the left renal vein. Malposition of
the left suprarenal gland during the embryonic development might cause a small distance
of transposition of an intra-abdominal organ from their usual anatomic locations,
which in turn alters its vascular variation.[24] Recently, we have found a case of double LSRVs in a 62-year-old-male cadaver. In
this case, other vascular anomalies were not found and both left SRVs drained into
the left renal vein.[25] About the anomalies of testicular veins, bifurcation of the RTVs is very rare. The
right testicular vein develops from the lower part of the right subcardinal vein.
The terminal bifurcation of the RTV might be due to the bifurcation of the right subcardinal
vein during its development.[26]
Conclusion
To our best knowledge, this is the first record of the coexistence of double IVC,
double LSRVs, and double RTVs. Those anomalies have particular importance for the
various interventions that take place during retroperitoneal surgeries, and are essential
for venous interventional radiologists, as well as for orthopedists, to reduce the
risk of serious hemorrhage during surgical treatment and to avoid operative complications.
