Determination of renal function following urinary diversion through intestinal segments

Area of Science:

• Nephrology
• Urology
• Surgical Innovation

Background:

• Traditional renal function tests (urea, creatinine clearance) are unreliable with urinary diversion via intestinal segments.
• Intestinal segments reabsorb urinary solutes, confounding standard renal function assessments.
• Accurate assessment of renal function is critical for managing patients with urinary diversion.

Purpose of the Study:

• To evaluate the impact of ileal ureter segments on renal function measurements in a canine model.
• To determine the most reliable markers for assessing renal function in the presence of intestinal urinary diversion.

Main Methods:

• A canine model was utilized, comparing normal renal units with those employing an ileal segment as a ureter.
• Urinary clearances of urea, creatinine, and inulin were measured in both renal units.
• The effect of varying urinary flow rates (diuresis) on solute reabsorption and clearance was investigated.

Main Results:

• Ileal segments demonstrated reabsorption of urea, creatinine, and inulin, dependent on urinary flow.
• Solute clearances through the ileal ureter approached those of the normal ureter under maximal diuresis.
• Creatinine and inulin clearances during diuresis provided the most accurate assessment of renal function, showing less reabsorption than urea.

Conclusions:

• Standard renal function tests are significantly affected by solute reabsorption in intestinal segments.
• Creatinine and inulin clearances during diuretic states are superior indicators of true renal function in this model.
• Urine concentrating ability is not a reliable measure of distal tubule function with ileal diversion due to solute and water reabsorption.