The orthotopic kidney is protected against external force by muscles, Gerota's fascia, and perinephric fat. A renal graft is located in the lower pelvis in the iliac fossa through a retroperitoneal incision anastomosed to the iliac artery and vein and therefore is more susceptible to injury, especially from direct blows to the abdomen.
The transplanted kidney, unlike the native kidney, is fixed in position by a thick fibrosis capsule that develops after transplantation and is not really suspended by the renal vessels (Barone et al. 1997). Consequently, deceleration events that cause pedicle injury to a native kidney are less likely to affect a transplanted kidney. As transplant recipients return to more active lifestyles, including becoming a significant risk for becoming a trauma victim, a renal graft is liable to be severely affected by trauma that may not cause any injury to a native kidney.
In transplant recipients, it is very important to know the patients' baseline renal function. The knowledge of an abnormal renal baseline may prevent unnecessary extensive diagnostic evaluation. Radiographic evaluation should proceed as for the native kidney. The increased risk for contrast nephrotoxicity can be minimized with adequate hydration. A CT scan is the test of choice for a stable injured transplant recipient, as it will identify renal and associated intraabdominal injuries but it will also indirectly assess renal blood flow and function. A renal Duplex examination can be also very helpful for identifying isolated trauma to the transplanted kidney and for identifying renal blood flow. Radionuclide scans may reveal urine leaks and are good for assessing overall blood flow and renal function, while angiography can assess blood flow and identify specific arterial injuries.
The surgical management of an injured transplanted kidney is a complex procedure. A very short vascular pedicle and ureter, dense scarring, and a fibrous capsule may prevent any attempts at the direct repair of parenchymal, collecting system, and vascular pedicle injuries. Grade 1-3 injuries can be managed nonope-ratively with adequate hydration and observation. Grade 4-5 injuries may require exploration with de-bridement and drainage or simply a subcapsular ne-phrectomy if associated with life-threatening bleeding. Isolated vascular injuries have a poor prognosis. Renal arteriography may be helpful with embolization of the main artery to stop bleeding or with more selective embolization to salvage part of the kidney. When renal graft injury occurs, saving the patient's life is the first priority but the saving of the graft is also very important to maintain renal function.
Obstructive uropathy in a renal graft is a serious complication caused by calculi, tumors, or ureteral strictures. Percutaneous access and antegrade intervention are regarded as the gold standard for the management of such complications. Ureteroscopy is a reliable alternative with acceptable outcomes and minimal morbidity. (Del Pizzo et al. 1998)
Iatrogenic vascular injuries of renal transplants can be managed by embolization. Angiographically successful embolization is not necessarily associated with clinical success, as nephrectomy in some cases is inevi table and the complication rate is high (Dorffner et al. 1998). On the contrary, transcatheter embolization is highly effective for biopsy-related vascular injury in the transplant kidney (Perini et al. 1998).
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