Horseshoe Kidney Treatment & Management
- Author: Robert C Allen, Jr, MD, FACS; Chief Editor: Bradley Fields Schwartz, DO, FACS more...
The horseshoe kidney is susceptible to medical renal disease. These diseases, if present, are treated as indicated. A metabolic evaluation should be performed because metabolic causes for kidney stone disease are no less common in the patient with horseshoe kidney than in the general population with kidney stone disease. Any identified metabolic abnormality should be treated. Metabolic evaluation includes a 24-hour stone risk assessment and serum studies, including calcium, uric acid, and phosphorous.
Surgical treatment is based on the disease process and standard surgical indications. The anomalous vascular supply to the kidney should be kept at the forefront of the surgeon's mind when planning the surgical approach. Generally, the midline abdominal incision provides access to both sides of the horseshoe kidney and vessels.
Ureteropelvic junction obstruction
UPJ obstruction is usually treated with open pyeloureteroplasty or ureterocalicostomy. With the advent of and surgeon familiarization with laparoscopic techniques, the preferred approach has become laparoscopic dismembered pyeloplasty. More recently, robotic dismembered pyeloplasty using the da Vinci surgical system has been successfully performed.[5, 6] Endopyelotomy is an option but yields success rates that are inferior to those of open or laparoscopic techniques.
In bilateral UPJ obstruction, the midline transperitoneal incision provides access to both sides of the horseshoe kidney and the vessels. Symphysiotomy (division of the isthmus) is controversial and was recommended routinely after pyeloplasty to improve drainage. However, it is associated with an increased risk of hemorrhage, fistula, and renal infarction. In addition, after division of the isthmus, the kidneys, because of their abnormal vasculature, return to their original position. Therefore, symphysiotomy is rarely, if ever, indicated in conjunction with pyeloplasty.
Kidney stones can be treated with ESWL, endoscopy, or open surgery. If pyeloplasty is to be performed, stones can be removed concomitantly with a flexible nephroscope and stone basket. Treatment decisions and indications are similar to those for a normal kidney. The presence of untreated obstruction or hydronephrosis precludes ESWL. Concomitant percutaneous nephrostolithotomy with endopyelotomy has been used successfully in the treatment of stones with obstruction. Alternatively, successful retrograde therapy of the UPJ with an "Accusize" cutting-balloon dilator followed by ESWL has also been performed.
Guided by the angiographic findings, interruption of the blood supply of the tissue to be resected is the first step. This prevents significant hemorrhage during dissection and tissue removal. In cancer surgery, the isthmus usually needs to be divided to gain access to the tumor and surrounding lymph nodes.
Problems may arise when operating on the great vessels, eg, with abdominal aortic aneurysm repair. Horseshoe kidney complicates aortic aneurysm surgery in 1 out of 200 cases. The most important aspect of abdominal aneurysm repair in association with horseshoe kidney is appropriate surgical management of the common renal artery anomalies. Survival in these patients is predicated on preservation of renal function. Renal artery continuity can be established via branch grafts or reimplantation into the aortic graft. The approach can be midline-abdominal or retroperitoneal through a low-left thoracoabdominal incision. Successful endoluminal transfemoral repair via stent placement has also been described.
Horseshoe kidneys can be used for transplantation. They can be transplanted into a single recipient en bloc or can be divided and transplanted into two individuals. Dividing the isthmus can increase the risk of urinary fistula.
The donor’s medical history must be obtained to preclude complications such as hydronephrosis, renal calculi, and urinary tract infection. The decision to transplant a horseshoe kidney en bloc depends on renal isthmus morphology and vascular anatomy, as well as the medical and functional status of the kidney.
Because of the anomalous and variable vascular supply to the horseshoe kidney, authorities recommend preoperative arteriography to delineate the vascular anatomy in addition to the routine diagnostic procedures. Accessory and aberrant arteries to the parenchyma and the tumor are the rule.
Because of the anomalous vasculature, the blood supply to the kidney must be identified and preserved.
Outcome and Prognosis
The horseshoe kidney does not complicate pregnancy or delivery. Importantly, note that the presence of the horseshoe kidney alone does not affect survival. As mentioned above, the horseshoe kidney does have a higher propensity to become diseased. Therefore, survival depends on the disease process that the affected horseshoe kidney may harbor or develop.
Future and Controversies
Despite the increased incidence of Wilms tumor in children with horseshoe kidney and carcinoid tumor in adults with horseshoe kidney, no recommendations regarding periodic surveillance to detect occult malignancies have been made.
Performing periodic renal ultrasonography in children with horseshoe kidney seems prudent for early detection of Wilms tumor. Periodic renal ultrasonography in the adult may also be prudent, especially in patients with hydronephrosis. All patients with horseshoe kidneys and stones should undergo 24-hour urine tests for kidney stone prophylaxis. Otherwise, surveillance should be performed as indicated based on the clinical situation.
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