Is One Early Renographic Follow-Up Adequate to Measure the Success of Robotic Pyeloplasty?

PURPOSE

Diuretic renography (DRG) is commonly used to diagnose ureteropelvic junction obstruction (UPJO) and to evaluate the success of surgical repair (pyeloplasty). Duration, frequency, and interpretation of renographic follow-ups are still under dispute.

METHODS

We retrospectively reviewed 94 consecutive patients diagnosed with UPJO who underwent a minimally invasive, robotically assisted laparoscopic pyeloplasty at our institution between January 2009 and September 2015. DRG was carried out preoperatively and again routinely 4 to 6 weeks postoperatively the day after stent removal (early DRG). Patients were scheduled for repeat (late) DRG and follow-up examinations, including clinical status and ultrasonography.

RESULTS

Nineteen patients with missing preoperative DRG were excluded from the study; the remaining 75 patients were eligible for statistical evaluation. At follow-up, 98.7% reported no or only very mild and rare symptoms. On early DRG, 52.5% had T ≤ 10 min (unobstructed), 39.3% had T between 10 and 20 minutes (equivocal), and 8.2% had T ≤ 20 minutes (obstructed). At late follow-up, the DRG results had improved to 80.8% unobstructed with 19.2% remaining equivocal, and no patients were obstructed; thus, the overall success rate was 80.8%. There was only one patient who worsened from unobstructed to equivocal from early to late DRG assessment.

CONCLUSION

In case of complete symptom resolution, a nonobstructive diuretic half-time of ≤10 minutes on early DRG following stent removal suggests that further routine renographic follow-up is unnecessary. Patients with an equivocal early DRG (T between 10 and 20 minutes) require further scintigraphic follow-up, as they have a 42.1% chance of staying equivocal.