Intrarenal reflux—papillary morphology and pressure relationships in children's necropsy kidneys

Abstract

A radiological study of the necropsy kidneys of 100 children was made. Morphologically it was shown that compound or fixed papillae predominate in the upper group of calyces and to a lesser degree in the lower group, whilst simple papillae occurred in the middle group. Pressure studies showed that intrarenal reflux occurred in compound papillae at lower pressure than in simple papillae and that lower pressures were required to produce intrarenal reflux in the first year of life.

Papillary Morphology in Adult Human Kidneys and in Baby and Adult Pig Kidneys

“…It has been postulated that severe and persistent vesicoureteral reflux causes changes in papillary morphology such that initially nonrefluxing papillae may be converted to refluxing papillae with time [16]. We have only studied the effect of increased intra pelvic pressure twice at an interval of 30 min and found no differences in the occurrence of IRB [to be published later], Funston and Cremin [3] demonstrated during ret rograde pyelography in kidneys obtained at necropsy from children less than 12 years old that IRB occurred in all compound papillae at an intrapelvic pressure of 20 mm Hg and in all simple papillae at an intrapelvic pressure of 50 mm Hg. In general these observations are in agreement with ours.…”

“…With this classification they found a higher proportion of 'refluxing' papillae than Ransley and Risdon [8] (table III). Funston and Cremin [3] reported a higher frequency of 'refluxing' compound papillae in children especially in the upper pole. They determined the papillary morphology on retrograde pyelograms.…”

“…At moderate pressure the.orifices may close and thus prevent urine/contrast material backflow. Since there is a considerable shrinkage of sim ple papillae with increasing intrapelvic pressure [3] and since the shape of a papilla is not fixed [6], increased intrapelvic pressure may lead to a flattening of the papil la. This could stretch tissues, opening the round or oval orifices, and allow retrograde flow.…”

“…Nevertheless we found no obvious difference in the diameter of the orifices. Therefore, the relatively large size of the duct openings [2] may partly explain why chil dren below 5 years are more disposed to detectable intra renal reflux but it does not explain why IRB occurs inde pendently of age [4,5], A third possibility could be that higher intrapelvic pressure is required to produce IRB with the increasing age of the patient [3],…”

“…Opinions dif fer concerning the importance of the two different mor phologic types of papilla (simple and compound) in allowing IRB [1][2][3]6], Some authors [1,2] have sug gested that simple papillae have an anti-IRB configu ration. However, in several retrograde pyelographies, Baby Pig Kidneys.…”