Abstract
Introduction A decrease in the anteroposterior diameter (APD) of the renal pelvis on ultrasound
has been postulated to be indicative of sufficient pelvic drainage after pyeloplasty.
Traditionally, pyeloplasty is combined with a reduction of the renal pelvis. We have
recently demonstrated that resection of the pelvis during pyeloplasty is not necessary.
We aimed to evaluate the efficacy of ultrasound APD measurements during follow-up
to identify sufficient pelvic drainage in these patients.
Materials and Methods Data from children (0–16 years) who underwent pelvis-sparing pyeloplasty in our institution
from 2007 to 2018 were analyzed retrospectively. We included only those patients for
whom pre- and postoperative ultrasound and renal scan data were available. Patients
with a decrease versus patients with an increase in APD were analyzed with regard
to urinary drainage and reoperation.
Results Seventy-three patients who underwent follow-up at a mean of 3 months after operation
were included; 61 showed a decrease in APD. Renal scan showed sufficient urinary drainage
in 58 of them, with none requiring reoperation. Twelve patients had an increase in
APD. Six of these showed free urinary drainage on renal scan; another six showed insufficient
drainage, of whom five required reoperation. The positive predictive value of a decrease
in APD was 1, and the negative predictive value of increase in APD was 0.42.
Conclusion To our knowledge, this is the first study evaluating the efficacy of ultrasound measurements
to identify patients with decompensated urinary drainage during early follow-up after
pyeloplasty with pelvis sparing. Post- versus preoperative decrease in renal pelvis
diameter appears to be sufficient to rule out recurrence of obstruction. Renal scan
seems to be indicated only in cases with post- versus preoperative increase in the
APD of the renal pelvis on ultrasound.
Keywords
pyeloplasty - hydronephrosis - anteroposterior diameter - ultrasound monitoring
