Paraureteral diverticula of children (author's transl)

Abstract

1) External protrusion of the posterolateral wall of the bladder adjacent to the ureteral orifice is called paraureteral diverticulum. Almost all cases are seen in infants and children and many are accompanied by vesicoureteral reflux. Clinicopathological studies were made on fourteen cases of paraureteral diverticula (male 9, female 5; children 12, adults 2; bilateral 6, left 3, right 5) and discussion was made about their pathogeneses, diagnoses and treatments.2) Pyelonephritis was the most common presenting sign. Urinary tract infection was present in all cases of infants and children. All cases were free from neurogenic dysfunction of the bladder and lower urinary tract obstruction.3) Paraureteral diverticula were visualized in only 3 cases on IVP but were present in all cases on voiding cystourethrography. Vesicoureteral reflux of the affected side was present in all cases. Almost all refluxes were of more than Grade III with lower ureteral stasis. Careful cystoscopy with changing vesical volume was required for final diagnosis.4) Histologically the ureterovesical junction of paraureteral diverticula lacks all three muscular components (intrinsic ureteral musculature, deep periureteral sheath and superficial periureteral sheath) which maintain normal function of UVJ. And in such condition VUR seems to occur freely. Ureteral stasis was present cranial to a few mm above the ureteral opening to the diverticula. Histologic sections of this segment universally show an increase in fibrous tissue, atrophy of smooth muscle cells, infiltration of fibrous tissue into muscle bundle and occasionally abnormal muscular arrangement. These findings are qualitatively identical to the abnormal histology of intrinsic ureteral musculature of other congenital dilated ureters.5) A refluxing ureter with a paraureteral diverticulum completely lacks in the anti-refluxing mechanism and presents ureteral stasis very frequently. Therefore, we have to treat this disease not in the same way as other primary VUR. As the effect of conservative therapy is not expected, we would like to adopt operative therapy (ureterovesiconeostomy with complete resection of diverticula and distal ureteral segment both of which present muscular abnormality).6) The relationship between paraureteral diverticula and renal dysplasia is noticed recently. We divided ureteral openings of our cases into four positions (C, D1, D2, D3) by the classification of Wickramasinghe (Fig. 8). Ureteral openings of five dysplastic cases (3 were complete duplex) were in D2 and D3 position. All the cases which maintained good renal function on IVP were in C and D1 position except one case (in D2 position). Severe renal dysplasia associated with paraureteral diverticula seems to be a total dysplasia similar to aplasia. This is different from the severe dysplasia of ectopic ureter which consists of almost mesonephric like structure.7) We do not consider paraureteral diverticula either as a simple herniation of vesical mucosa through ureteral hiatus or as simple as other forms of the vesical diverticula. Instead, we would rather like to consider these as a developmental expansion of the terminal ureteral end as evidenced by (a) the histological similarities of the ureteral end of the parau reteral diverticulum to that of the other megaloureters of known various developmental etiologies and (b) the close association between the position of the ureteral orifice and the degree of renal dysplasia which is embryologically well explicable.