Transplantation of horseshoe kidney from living-related donors: report of two cases
Article Outline
Horseshoe kidney is one of the most common congenital renal anomalies, with an incidence estimated from childhood autopsy series of 1 per 400. In an adult series,1 the incidence was reported to range from 1 per 600 to 800. The horseshoe kidney is frequently associated with vascular and ureteral abnormalities. Ureteral duplication, ureteroceles, and ureteropelvic junction obstruction are common. Vesicoureteral reflux, hydronephrosis, urine stasis, nephrolithiasis, upper tract infection, and tumors are frequent complications of horseshoe kidneys.1
The continuing donor organ shortage has led to an expansion of the criteria for acceptability of cadaveric organs, including the use of organs from donors who are older than 55 years,2, 3 or who have underlying medical problems (e.g., diabetes mellitus or hypertension),4 or the use of organs with anatomic variations. There are reports of cadaveric donors where the horseshoe kidney has been used en bloc into a single recipient or divided, with each half transplanted successfully into two separate recipients. Use of divided horseshoe kidneys from live donors is rare; only one such case has been reported.5 We present our experience on two living-related donors, where half of horseshoe kidney was retrieved and transplanted into the recipients.
Material and methods
Case report 1
The donor was the 47-year-old sister of the recipient. Preoperative ultrasound revealed a horseshoe kidney with no hydronephrosis or calculi. Angiography revealed two renal arteries arising from right side with one from the left side. The recipient was a 51-year-old man diagnosed with diabetic nephropathy on hemodialysis, and with creatinine level of 8.3 mg%. The surgery was performed in March 1999. A donor exploration performed through a left flank incision revealed an isthmus in front of the IVC and aorta (Fig 1, Fig 2). The lower branch on right side was perfused with methylene blue and isthmus stained, confirming it as the blood supply to the isthmus. The kidney was divided at the left margin of isthmus, preserving its vascularity. The collecting system was closed and the parenchyma approximated.
Fig 1.
Illustration showing horseshoe kidney with branch from right side of aorta supplying the isthmus. Left half of kidney was removed (marked with crosses).
Fig 2.
Aortogram showing branch from left renal artery supplying the isthmus.
The transplant was performed in the right iliac fossa. The renal artery was anastsmosed to the external iliac artery, and the renal vein joined to the external iliac vein. The ureter was implanted using a Litch-Gregorine technique with a DJ stent placed in situ. The donor experienced an uneventful recovery. Color Doppler showed no evidence of arterial narrowing or venous thrombus. A drain was removed on the 7th postoperative day. A postoperative intravenous urogram on the 8th day was normal, with no leak from the isthmus. The recipient nadir creatinine levels were 1.6 mg% by the 11th postoperative day. On follow-up at 18 months, the patient had no surgical complications or rejection, while maintaining creatinine levels between 1.5 mg% and 2.5 mg%.
Case report 2
The transplant was performed in September 1999, from a donor who was the 55-year-old mother of the recipient. Ultrasonography revealed both kidneys to be medially rotated with a soft tissue isthmus extending across the midline from lower poles (Fig 3, Fig 4). DSA confirmed a horseshoe kidney with a single left renal artery supplying the left kidney and isthmus, and the right kidney supplied by a single artery. A right flank incision the blood supply to the isthmus was confirmed by injection of methylene blue into lower branch of left renal artery, A right nephrectomy was performed with closure of collecting system using parenchyma.
Fig 3.
Case II. Illustration showing horseshoe kidney, with branch from left renal artery supplying the isthmus. Right half of kidney (cross-marked area) was removed preserving blood supply to the isthmus.
Fig 4.
Intravenous urogram demonstrating medially rotated pelvis lying near the spine, characteristic of horseshoe kidney.
The transplant was performed in the right iliac fossa of the recipient using standard techniques. The renal artery was anasta- mosed to the internal iliac artery, and the renal vein to the external iliac vein. The ureter was implanted onto bladder using a Litch-Gregoine technique. The creatinine levels fell from 9.3 to 2.3 mg% by the 4th postoperative day. A Doppler study showed a normal renal artery and vein. The patient had persistent fluid drainage between 100 and 300 mL daily, with a fluid creatinine of 40 mg/dL, indicating a urine leak. Ultrasonography on the 15th postoperative day showed no fluid collection and a normal echotexture of kidney with no hydronephrosis. The patient was discharged on the 40th postoperative day with an in situ drain which had an output of about 200 mL/d. He reported back 20 days after discharge, with minimal drainage and the drain was removed. The serum creatinine had stabilized at 1.6 mg%. With a follow-up of 1 year, patient is maintaining serum creatinine levels around 2 mg%.
Discussion
A horseshoe kidney occurs at an incidence of 0.25%.1 In 95% of cases, the kidneys are fused at the lower pole, causing an incomplete rotation so that the renal pelvis and ureters are situated anteriorly rather than medially. Inability of the kidneys to ascend may also result from a failure of the blood supply to shift from the iliac arteries to the aortic segmental branches and then finally to definitive renal arteries.1 Each artery to the horseshoe kidney supplies its own area; there is no collateral circulation, so that ligation of an artery will always cause an infarct.6
Anomalous vasculature is the norm for horseshoe kidneys, with only 30% of all horseshoe kidneys having a single renal artery to each side.1 Graves7 studied the arterial anatomy of 13 horseshoe kidneys, determining that the vascular supply followed predictable patterns. The devised a classification system. To preserve multiple or anomalous renal vessels in cadaveric donors, removal of the horseshoe kidney should always be performed en bloc with a large segment of aorta and cava. In living donors, the decision as to the site to divide the kidney is best made after the vascular anatomy and the anatomy of the collecting systems and calyces has been meticulously evaluated preoperatively using angiography or spiral CT scan. The organs from cadaveric donors can be evaluated in cold saline on the back table upon perfusion of the kidney. When a large portion of functioning renal tissue is situated in the isthmus, particularly in the presence of continuity of the calyceal system, meticulous closure of the collecting system with approximation of parenchyma is mandatory. If the isthmus consists of fibrous tissue, this area can simply be ligated.9
Horseshoe kidneys have an anteriorly placed pelvis that can be mistaken for hydronephrosis. Some degree of ureteropelvic junction (UPJ) obstruction may exist in as many as 15% to 30% of all fused kidneys, the majority of which are asymptomatic.1 A horseshoe kidney may be associated with vesico-ureteral reflux, obstruction, hydronephrosis, urine stasis, nephrolithiasis, or infection. Horseshoe kidneys have an increased incidence of squamous cell carcinoma and transitional cell carcinoma in the renal pelvis, which may be related to the more common complications of stasis, infections, and stone.1 Hydronephrosis or prior urinary tract infections secondary to reflux do not necessarily preclude the use of a horseshoe kidney for transplantation.10 A stenotic UPJ can be managed by ureteropyelostomy, with long-term satisfactory results.11 Kidneys with hydronephrosis or reflux due to distal tract pathology are suitable for transplant.
Ureteroneocystostomy may be performed via standard techniques. Short ureters may require a psoas hitch to provide adequate length for a tension-free anastmosis.12 DJ stent has been used.13 The major complication after symphysiotomy are urinary fistula formation and hemorrhage. No complication has been reported following transplantation of an intact horseshoe kidney.
Most reported cases using cadaveric kidneys used either en block or separately after division have yielded encouraging results. There have been occasional reports of increased morbidity, mainly because of urinary fistula in separated kidneys, but all patients have achieved acceptable nadir creatinine levels.
Conclusion
Many transplant centers are reluctant to use horseshoe kidneys for transplantation. The rarity of a horseshoe kidney should not discourage the potential use of these organs. Our cases and a review of the literature reveal that the horseshoe kidney, although rare, can be an appropriate organ for transplantation, if free of significant urinary tract pathology and if meticulous attention is paid to technical details. We believe that the use of horseshoe kidneys as renal allografts is justified and should be encouraged.8
References
- . In: Walch PC, Retil AB, Stamey TA, et al. editor. Campbell’s Urology. 6th ed. Philadelphia: Saunders; 1992;
- . Transplant Proc. 1991;23:905
- . Transplantation. 1991;51:135
- Transplant Proc. 1990;22:378
- Jpn Urol. 1998;89:62
- . Transplant Proc. 1981;20:765
- . Br J Surg. 1969;56:533
- J Urol. 1982;139:571
- JAMA. 1979;243:1066
- Surgery. 1974;76:252
- Br J Urol. 1978;50:284
- Menezes de Goes, de Campos Freire G, Borrelli M, et al: J Urol 126:537, 1981
- . Urology. 1990;35:530
PII: S0041-1345(02)03898-8
doi:10.1016/S0041-1345(02)03898-8
© 2003 Elsevier Science Inc. All rights reserved.
