The smooth muscle ratio at the renal pelvis in adults: does it predict surgical outcome?

INTRODUCTION

Patients with ureteropelvic junction obstruction occasionally remain undiagnosed until adulthood. There are no objective criteria to predict the results of pyeloplasty in adult patients. We have evaluated the results of pyeloplasty in adult patients and investigated whether these results are correlated with the histopathology of the surgical specimen.

MATERIALS AND

METHODS

Histological sections from 26 patients with ureteropelvic junction obstruction were analyzed. Their mean age was 25.1 years. Diethylenetriamine-pentaacetic acid scans were used to determine the degree of renal obstruction and postoperative healing. Improvement in diuretic renography was defined as a greater than 20% decrease in the half-time of the preoperative value. To examine smooth muscle and collagen tissue, sections were stained using Masson's trichrome. Smooth muscle ratio was identified by color image analysis.

RESULTS

18 patients (69.2%) fulfilled the criteria of healing. Patients with an improved scan had a mean smooth muscle percent (SMP) of 1.85+/-0.87 while subjects with no significant change in their diuretic scans had a mean SMP of 0.36+/-0.03 (p=0.001). There was a strong correlation between the SMP and the improvement.

CONCLUSIONS

Adult pyeloplasty was found successful in about 70% of the cases. The SMP of the renal pelvis seems to be helpful in predicting the surgical outcome.