Etiological Determinants of Congenital Pelviureteric Junction Obstruction

Abstract

Congenital ureteropelvic junction obstruction is an important and treatable cause of neonatal hydronephrosis. It may be due to congenital absence of nerves leading to adynamic segment causing functional obstruction. It may also be due to defective muscular arrangement and replacement of muscles by fibrosis leading to anatomical obstruction or it may be caused by extrinsic compression by aberrant lower polar vessel. The aim of the present study is to define the etiological determinants of congenital PUJ obstruction. Objectives: To study the macroscopic abnormalities of congenital PUJ obstruction and correlating theses abnormalities with the microscopic and immunohistological findings. Material and Methods:   It was a cross sectional observational study and patients presenting to outpatients department, irrespective of age and sex, with the diagnosis of PUJ obstruction and needing surgery were included in the study. Anderson Hynes Pyeloplasty was done in all cases and resected portion of redundant pelvis and narrow segment was submitted for histopathological and immunohistological examination. Results: Congenital PUJ obstruction was more common in  males with a male to female ratio of 2:1 and it   was common on left side in 55.55% cases. Presentation was in wide age range patients (2-40 years). In 33.33% patients it was structural abnormality where we were unable to pass feeding tube and in 66.66% patients it was functional abnormality where it was distensible PUJ. Predominantly circular muscle arrangement was seen in 15(57.69%) cases. Varying degree of replacement of muscle fibers with fibrous tissue was seen in all cases and total replacement in those where kidney was nonfunctional due to PUJ obstruction. Nerves were present in 5/26 (19.23%) cases. In 4/5 (80%) cases of crossing vessels, nerves were present. Conclusion: Most cases of congenital PUJ obstruction are due to functional obstruction but anatomical obstruction also has a significant contribution (33.33%).Predominant circular muscle arrangement is the abnormality leading to impaired peristalsis. Absence of nerves leading to functional obstruction is the major defect in congenital PUJ obstruction. Crossing vessel is the real cause of PUJ obstruction mechanically compressing the PUJ in vascular tangle cases.