Nephrectomy is indicated in conditions with complete or near-complete absence of renal function, and is usually performed to prevent infection due to urinary stasis or to limit the risk of hypertension resulting from renal damage due to the associated condition. While malignancies are a clear indication for nephrectomy, these applications have not been conducted in children using laparoscopic techniques in any relevant numbers to date. Pretransplantation nephrectomy is indicated for a variety of reasons, including infection, hypertension, and size of the patient. The most frequent indications for nephrectomy or nephroureterectomy (Table 87.1) are vesicoureteral reflux and obstruction with non-function of the kidney. The latter is usually due to severe ureteropelvic junction obstruction or primary megaureter, but may also be due to an obstructing ectopic ureter or ureterocele. A single-system ectopic ureter that drains into the vagina or perineum and causes incontinence is a very satisfying indication for nephrectomy in that these patients become dry after surgery. The challenge is in making that diagnosis (Borer et al. 1998). Other possible indications include severe, unreconstructable ureteral strictures and poor renal function, or any cause of renal functional loss associated with ureteral obstruction distal to the midureter. Selection criteria and the pathophysiology of these various conditions are detailed elsewhere, but, in general, there is little benefit to reconstructing a renal unit with less than 10% of total function on a radionuclide renal scan. There are no data to indicate the "correct" cutoff below which nephrectomy should be performed, but it should be recognized that in most cases associated with a congenital condition, function less than 1015% will seldom increase despite successful surgery (McAleer and Kaplan 1999). The actual threshold used varies widely and is largely a matter of individual preference. The complete absence of function on a renal scan is a good indication that it is reasonable to remove the affected unit. If it is more practical to simply achieve urinary drainage or absence of reflux, then removal is not considered essential. The long-term risks of leaving a poorly functioning renal unit remain incompletely defined and for this reason some surgeons elect to remove the affected renal unit. The concept of whether an affected unit would be able to prevent dialysis if the contralateral unit were lost is used by some, and while this may be excessively stringent, it is generally felt that 30% function is required to prevent dialysis. Perhaps optimistically, our practice has been to use a level of 10% of total uptake as the cutoff for renal salvage versus removal. It must be recognized that this is in fact an arbitrary distinction that is not based on any outcome data.
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