Pelviureteric junction obstruction: how much is the extent of the upper ureter with defective innervation needing resection?

Background/Purpose: It is well realized that Anderson-Hyne’s pyeloplasty fails to improve the drainage pattern and renal functional parameters in a few cases of hydronephrosis because of pelviureteric junction (PUJ) obstruction. The purpose of this study is to delineate the lower extent of the abnormally innervated pelviureteric junction by S-100 immunohistochemistry, which requires surgical removal. Methods: Thirty pelviureteric junction (PUJ) specimens were analyzed by histology and by S-100 immunohistochemistry after serial sectioning of the resected ureter and compared with the variables age, calyceal separation, parenchymal thickness, differential renal function, glomerular filtration rate (GFR), and the measured constricted ureteral segment on gross examination. Results: No significant correlation was noted ( P > .05) when the histology was analyzed to find any association with any of the variables studied. The length of the visible constricted segment ranged from 2 mm to 15 mm (mean, 5.37 mm). The abnormally innervated segment was much longer than the length of the visible constricted segment in 24 and of the same length in 5 specimens. However, in 1 case, the abnormal innervation segment was shorter than the macroscopic constriction by 3 mm. The maximum difference in length between the visible constriction and the lower limit of defective innervation was 8 mm. Conclusions: The abnormally innervated ureteral segment below the PUJ in hydronephrosis is longer than the visible constricted segment at the time of surgery, and the ureter should be excised at least 8 mm or more beyond the visible lower limit of the constricted segment in cases of Anderson-Hyne’s pyeloplasty.