Evaluation of hydronephrosis with tubeless cutaneous ureterostomy using Tc-99m MAG3 diuretic renography.

PURPOSE: To assess hydronephrosis of tubeless cutaneous ureterostomy using Tc-99m mercaptoacetyltriglycine (MAG3) diuretic renogram. MATERIALS AND METHODS: Cutaneous ureterostomy with a unilateral stomal creation was performed in 15 patients (27 renal units) with a minimum follow-up period of 6 months. Stomal obstruction was evaluated with Tc-99m MAG3 diuretic renography 3 months after the surgery. The data analyses were performed with half-times to tracer clearance (T1/2) after furosemide (0.5 mg/kg) administration. RESULTS: T1/2 means were 7.27 +/- 7.11, 5.69 +/- 4.63, and 8.96 +/- 8.37 minutes for total, ipsilateral, and contralateral kidneys, respectively, in side relationships between ureter and stoma. There were no statistical differences among the groups. Six months after the surgery, of 26 renal units (96.3%) that had achieved a tubeless condition, and 25 renal units (92.6%) had no hydronephrosis. T1/2 was within 20 minutes in these 25 renal units, and of 25 renal units 23 (92%) revealed less than 15 minutes in T1/2, suggesting that the upper limit of T1/2 for nonobstructed systems after construction of a cutaneous ureterostomy might be 15 minutes. Mild hydronephrosis without the need for intervention was present in 1 renal unit (T1/2, 31.70 minutes). Catheterization was performed in one renal unit (T1/2, 21.04 minutes) due to acute pyelonephritis and persistence of grade 2 hydronephrosis 5 months after the surgery. Only these 2 renal units showed more than 20 minutes in T1/2, resulting in an obstructive pattern on diuretic renography. CONCLUSION: Tc-99m MAG3 diuretic renography with T1/2 assessment is useful to evaluate stomal stenosis in tubeless cutaneous ureterostomy.