Prone versus supine lasix renal scan to assess surgical success after laparoscopic and robot-assisted pyeloplasty.

PURPOSE: Success after laparoscopic pyeloplasty (LP) for ureteropelvic junction obstruction is determined based on renal scan (RS) results and patient symptoms ± ultrasonography. The upright or prone position during RS may facilitate drainage. This study reports on outcomes after LP and robot-assisted pyeloplasty (RALP) and determines if patient position (supine vs prone) alters the results of the postoperative RS and surgical "success."

PATIENTS AND METHODS: A retrospective review of LP and RALP performed by one surgeon between 2005 and 2012 was performed. Follow-up consisted of RS ± ultrasonography. The paired t test was used to assess for a significant difference between mean T1/2 for supine vs prone scans in each patient. Linear regression was used to determine if preoperative split renal function on the affected side or degree of preoperative hydronephrosis predicted difference in supine vs prone T1/2.

RESULTS: There were 11 LP and 81 RALP performed; 84 had follow-up data. There were four (4.3%) failures. Thirty-eight patients had sufficient supine and prone RS for analysis. The difference in T1/2 between supine and prone RS was significant (mean difference 10.18 ± 27.28 min, P = 0.03). Strict success increased to 65.8% from 44.7% and combined strict plus technical success increased to 78.9% from 63.1% on prone vs supine RS. Split function and degree of hydronephrosis were not predictors of difference in RS results.

CONCLUSIONS: LP and RALP have good technical results. Prone position for RS may facilitate drainage and may be a more accurate representation of postoperative outcome after pyeloplasty, particularly in equivocal cases.