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Transplantation of Crossed Fused Renal Ectopia

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Abstract

Crossed fused renal ectopia is a type of congenital fused anomaly of the kidney. This type of kidney, when encountered, can be used as a donor organ to provide useful solution to the critical shortage of available organs for transplantation.
Case Report
82 ASIAN JOURNAL OF SURGERY VOL 30 • NO 1 • JANUARY 2007
© 2007 Elsevier. All rights reserved.
Transplantation of Crossed Fused Renal Ectopia
Soon-Khai Lee, Bibombe Patrice Mwipatayi, Manzoor Abbas, Sathya Narayan and Kishore Sieunarine,
Department of Vascular Surgery, Royal Perth Hospital, Perth, Western Australia, Australia.
Crossed fused renal ectopia is a type of congenital fused anomaly of the kidney. This type of kidney, when
encountered, can be used as a donor organ to provide useful solution to the critical shortage of available
organs for transplantation. [Asian J Surg 2007;30(1):82–4]
Key Words: crossed fused renal ectopia transplantation, organ shortage
Introduction
The incidence of crossed fused renal ectopia worldwide is
about one in 1,000 and it is the second most common
renal fusion anomaly after horseshoe kidney.
1,2
The aver-
age wait for a kidney from a deceased donor is about
4 years in most Australian states.
2
Due to this critical
shortage of available organs for renal transplant, a cadav-
eric crossed fused ectopic kidney, when encountered, may
have to be used as a donor organ. We report a successful
case of crossed fused renal ectopia transplantation. We
discuss the variations of this fused renal anomaly and the
various surgical options to allow best use of this anomaly
as a donor organ both as a cadaveric kidney and as a living
donor kidney.
Case report
A 56-year-old man on the Organ Donation Registry for
kidney donation was diagnosed to have a single right kid-
ney on abdominal ultrasound. He had normal renal func-
tion and serum creatinine was 80 μmol/L (normal, 60–150).
His human leucocyte antigen (HLA) typing was A1, 2; B8,
24; DR4, 103 and he was also found to be cytomegalo-
virus positive. He had no known history of urinary tract
infection, renal calculi or other congenital defects.
He succumbed to head injury from a gunshot wound
in a suicide and was pronounced brain dead in the intensive
care unit.
During organ harvest, the kidney was noted to be a
crossed fused ectopic kidney, lying entirely on the right
with its lower pole encroaching the pelvic brim. It was
harvested en bloc with complete aorta and inferior vena
cava segments (Figure 1).
The recipient was a 38-year-old man with end stage
renal disease secondary to glomerulonephritis. His HLA
typing is A1, 24; C62, 57; DR1, 4. Two Ags matched with
the donor’s kidney. His preoperative serum creatinine and
urea were 878 μmol/L and 19.1 mmol/L, respectively.
Bench dissection of the harvested kidney demonstrated
two main renal arteries arising from the aortic segment.
The proximal renal artery had three main branches to the
isthmus, while the distal renal artery ran solely to the
lower part. There was a single dominant renal vein draining
into the inferior vena cava. Two ureters were noted to arise
from the renal pelvis (Figure 2).
The distal end of the aortic segment was sutured and
all other branches of the aorta like lumbar arteries were lig-
ated. The proximal aortic segment was sutured to the right
external iliac artery in an end-to-side manner providing
revascularization of both the renal arteries. The renal vein
was sutured end-to-side to the right external iliac vein.
Address correspondence and reprint requests to Dr Soon-Khai Lee, Department of Surgery, Kuala Lumpur Hospital,
50586 Jalan Pahang, Kuala Lumpur, Malaysia.
E-mail: eskaylee2@hotmail.com
Date of acceptance: 16 January 2006
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TRANSPLANTATION OF CROSSED FUSED RENAL ECTOPIA
ASIAN JOURNAL OF SURGERY VOL 30 • NO 1 • JANUARY 2007 83
The two ureters were sutured separately to the dome of the
urinary bladder (Figure 3). Two 6F, 10 cm stents (Percuflex,
Boston Scientific Corp.) were placed in the ureters at the
time of the anastomoses.
Total cold ischaemic time was 10 hours, and serum
creatinine and urea on the 5
th
postoperative day were
decreased to 94 μmol/L and 7.4 mmol/L, respectively.
Postoperative ultrasound showed a well-perfused
fused kidney. There were at least three major arteries sup-
plying the kidney and all were patent with appropriate
waveforms (resistive indices, 0.5–0.7). Arterial and venous
waveforms within the renal transplant were normal.
There was no evidence of obstruction or perinephric
collection. He was discharged home well on the 6
th
post-
operative day.
Discussion
Congenital anomalies of the kidneys include a group
called fusion anomalies, in which both kidneys are fused
together in early embryonic life. Fusion anomalies of the
kidneys can generally be categorized into two varieties:
horseshoe kidney and crossed fused ectopic kidney.
3
The most common fusion anomaly is horseshoe kidney
followed by crossed fused renal ectopia. The incidence is one
in 400 persons and one in 1,000 persons worldwide, respec-
tively. Both are twice as common in males as it is in females.
2
We present a case of transplantation of a crossed fused
ectopic kidney with successful result.
Crossed fused renal ectopia is generally differentiated
from horseshoe kidney in which both fused kidneys lie on
one side of the spine. The ureter of the crossed kidney
crosses the midline to enter the bladder.
Left to right ectopia is three times more common than
right to left, and the crossed kidney usually lies inferiorly
to the other kidney. This was illustrated by our donor’s
kidneys.
Six variations of crossed fusion have been described.
In descending order of frequency, they are:
1
Type 1: Inferior crossed fused ectopia, the commonest
type. The crossed kidney lies inferiorly. The upper pole
of the crossed kidney is fused to the lower pole of the
other kidney and both the pelves are directed anteriorly.
Proximal ureter
Renal vein
Aorta with proximal
and distal renal arter
y
Distal ureter
Crossed fused renal ecto
p
ia
Distal ureter
Proximal ureter
Recipient aorta
Recipient IVC
Donor renal vein
Donor aorta
Urinary bladde
r
Ureteric stent
Figure 1. Prepared crossed fused renal ectopia prior to
transplantation.
Figure 2. Diagrammatic representation of the prepared specimen.
Figure 3. Transplantation of the kidney. The distal end of the
aortic segment was sutured and the proximal aortic segment was
anastomosed end-to-side to the right external iliac artery. The
renal vein was sutured end-to-side to the right external iliac vein.
The two ureters were sutured separately to the dome of the uri-
nary bladder with two 6F, 10 cm stents in place. IVC = inferior
vena cava.
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LEE et al
84 ASIAN JOURNAL OF SURGERY VOL 30 • NO 1 • JANUARY 2007
Type 2: Sigmoid or S-shaped kidney. The crossed kidney
lies inferiorly with its pelvis directed laterally. The pelvis
of the other kidney is directed medially.
Type 3: Unilateral lump kidney. The two kidneys are
completely fused to form an irregular lump. Both renal
pelves are directed anteriorly.
Type 4: Unilateral disc kidney. The kidneys are fused
along their medial border. The crossed renal pelvis is
directed laterally. The renal pelvis of the normal kidney
is directed anteromedially.
Type 5: L-shaped kidney. The crossed kidney lies inferi-
orly and transversely.
Type 6: Superior crossed fused ectopia. The crossed kid-
ney lies superior to the other kidney. Both renal pelves
are anteriorly rotated.
The fusion of two kidneys is believed to result from
the fusion of the metanephric blastema across the mid-
line at around the 4
th
week of gestation. Fusion probably
occurs at this embryonic stage when the kidneys are in the
true pelvis and the renal capsule has not yet matured.
Lateral flexion of the lumbosacral spine may push one of
the developing kidneys to the opposite side causing
fusion. Some have suggested that teratogenic factors are
responsible for the abnormal migration of nephrogenic
and fusion.
4
Besides the abnormal location and fusion, they often
have abnormal vasculature and ureteral abnormalities. It is
important to recognize the abnormality during organ pro-
curement in order to preserve them for transplantation.
Transplantation of a crossed fused renal ectopic kid-
ney can be performed en bloc in one individual or it can be
split and transplanted into two recipients, depending on
the number and location of the vessels and the anatomy
of the urinary collecting system.
The kidneys should be removed en bloc with a large seg-
ment of the aorta and vena cava. The course and number
of ureters should be identified and, to obtain maximal
ureteral length for reimplantation, they should be divided
at the level of the bladder.
The decision to split the organs depends on many vari-
ables such as the vascular and urinary collecting system
anatomy and the degree of fusion of the renal parenchyma.
The fusion defects may range from thin fibrous band, an
isthmus that contains functional renal tissue to extensive
parenchyma intermingling. Later, it will preclude the
separation of the two organs.
In our harvested kidneys, bench dissection showed
a pair of short proximal and distal renal arteries, single
renal vein and two reasonably long ureters. The kidneys
showed fused parenchymal tissue and, as a result, it was
transplanted en bloc.
The aorta can be used as a tube whereby the distal end
of the aortic segment is sutured, and the proximal aortic
segment sutured to the recipient aorta or iliac artery in an
end-to-side manner providing revascularization of both
the renal arteries. This can be an alternative solution to a
short donor renal artery.
The renal vein was sutured end-to-side to the recipient
iliac vein or the vena cava. Similarly, the donor vena cava
can be used as a tube if the donor renal veins are short.
Although the number of patients awaiting kidney
transplantation is rapidly increasing, with a 6% growth
rate in dialysis programmes each year, kidney availability
in Australia remains low. The trend seems to be worsening,
with 6.8% of those on dialysis receiving transplants in
2002 compared with 11.7% a decade earlier. In most
Australian states, the average wait for a kidney from a
deceased donor is about 4 years, and some patients wait
much longer.
2
In an attempt to increase this pool, kidneys
with congenital anomalies such as crossed fused ectopia
can provide a useful solution to the ever-increasing gap
between demand and supply.
References
1. Medcyclopedia/medical/volumeIV: Crossed fused ectopic, renal.
(http://www.amershamhealth.com/medcyclopaedia/medical/
article.asp?vol =Volume%20IV%202&article=CROSSED_FUSED_
ECTOPIA_RENAL)
2. Mathew T, Faull R, Snelling P. The shortage of kidneys for trans-
plantation in Australia. Desperate people seek desperate reme-
dies. Med J Aust 2005;182:204–5.
3. Decter R. Renal duplication and fusion anomalies. Pediatr Clin
North Am 1997;44:1323–41.
4. Bauer SB. Anomalies of the kidney and ureteropelvic junction.
Campbell’s Urology. Philadelphia: Saunders, 1998:1709–39.
Downloaded from ClinicalKey.com.au at Royal Australasian College of Surgeons JC April 14, 2016.
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... Crossed-fused ectopic kidneys can even be utilized as donor organs for transplantation. [25] ...
Article
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Rationale: Crossed renal ectopia (CRE) is a rare congenital anomaly that is frequently associated with gastrointestinal, cardiovascular, genital and bone malformations. To the best of our knowledge, only 35 cases of crossed renal ectopia involving calculi and 30 cases of CRE associated with renal carcinoma have been reported to date. Patient concerns: Here, we present 2 cases of crossed renal ectopia. A 59-year-old woman with diabetes presented to our hospital with abdominal pain. The second patient was a 24-year-old woman who complained with abdominal pain with a duration of 1 day. Diagnoses: On the basis of abdominal ultrasonography, we suspected a solitary kidney both in the two patients. Combined with retrograde pyelography and 3D computed tomography, case 1 was diagnosed as an S-shaped right-to-left crossed-fused ectopic kidney with many stones in the left (normal) renal pelvis and case 2 was confirmed to have lump right-to-left crossed-fused renal ectopia with two 3-mm stones in the renal pelvis of the 2 kidneys. Interventions: Case 1 underwent percutaneous nephrolithotomy while case 2 refused to undergo surgery and underwent conservative treatment for pain relief. Outcomes: Two patients have been followed up and have no stones recurrence. Lessons: Crossed fused renal ectopia is easily misdiagnosed as a solitary kidney. CRE is so rare that the recognition of the disease needs to be improved and effective treatment should be taken timely. According to the two cases and literature review, minimally invasive surgery has become increasingly common to treat CRE with stones and carcinoma.
... 2,9,10 Several centers have successfully transplanted grafts with rare forms of congenital fusion anomaly (eg, crossed fused renal ectopia). 3,[11][12][13][14][15] Reported techniques to improve vascular identification of such anatomically complex grafts include preoperative donor imaging. 3 However, without prior imaging, one may not identify a fusion anomaly until organ recovery, because these patients are often asymptomatic. ...
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The shortage of kidneys for trans-plantation in Australia. Desperate people seek desperate reme-dies
  • Mathew T R Faull
  • Snelling
Mathew T, Faull R, Snelling P. The shortage of kidneys for trans-plantation in Australia. Desperate people seek desperate reme-dies. Med J Aust 2005;182:204–5.
Anomalies of the kidney and ureteropelvic junction
  • Bauer
Bauer SB. Anomalies of the kidney and ureteropelvic junction.
Philadelphia: Saunders
  • Campbell
Campbell's Urology. Philadelphia: Saunders, 1998:1709–39.
Anomalies of the kidney and ureteropelvic junction. Campbell's Urology. Philadelphia: Saunders
  • S B Bauer
Bauer SB. Anomalies of the kidney and ureteropelvic junction. Campbell's Urology. Philadelphia: Saunders, 1998:1709-39.
The shortage of kidneys for transplantation in Australia. Desperate people seek desperate remedies
  • Mathew