CLINICAL STUDIES ON PYELORENAL BACKFLOW IN EXCRETORY UROGRAPHY

Abstract

Over a period of 3 years, pyelorenal backflow (PRB) was found in 563 of 2365 excretory urograms. These cases were statistically analyzed and cases with PRB with no conceivable organic obstruction in the upper urinary tract were studied with radioisotope renography and urometry. The following informations were obtained.
1. Examinations of the clinical statistics
1) The frequency of appearance of PRB in excretory urogram was highest in DIP with abdominal ureteral compression followed by standard IVP (with combined use of ureteral compression) and further by DIP without the use of ureteral compression (Table 1).
2) According to the type of PRB, pyelotubular backflow was seen in the overwhelming majority. Among fornical backflows, pyelosinous, pyelolymphatic, pyelovenous and pyeloparenchymal types were seen in decreasing order of frequency (Table 3, 4).
3) In DIP without using ureteral compression, PRB appeared in 20.1% of the cases and 13.8% of the kidneys (Table 1).
4) PRB appeared more frequently in females, with high incidence in the 20s and 30s in both males and females (Table 2, Fig. 1, 2).
5) As to the morphology of the renal calyx and pelvis with PRB, normal shape was seen most frequently in about 80%, with narrowing in 8.5%. Dilatation of the renal calyx and pelvis was seen only in 11.7%, becoming rarer as the dilatation was more pronounced (Table 6).
6) Among 563 cases with PRB, chief complaint of pain (37.5%) and hematuria (22.5%) was found most frequently (Table 7) and diseases of the upper urinary tract such as movable kidney, renal and ureteral stone, renal tuberculosis, essential hematuria and pyeloureterospasm were frequently found (Table 9, 10).
2. Studies with radioisotope renogram and urometry
1) In the findings of renogram. stepwise changes of excretory phase exhibiting the spastic changes of renal calyx and pelvis were seen in 48.6%, and a prolongation of the excretory phase in as high as 27.0% (Table 19).
2) In the findings of urometry obtained with the combined use of DIP, the intrapelvic resting pressure of the kidney with PRB tended to be higher than that in the kidney without PRB, with frequent peristaltic contraction wave (Table 21, 22, 23). In the cystoscopic findings, the changes of the ureteral orifice such as narrowing and hyperemia, and elevation of the interureteric ridge were seen in many cases (Table 24).
3) As the reaction of the renal pelvis to drugs, the intrapelvic resting pressure, pressure amplitude of the contraction wave and frequency of contraction tended to decrease by intramuscular injection of Buscopan (Fig. 20).
According to these findings, PRB in the excretory urogram occurring in the absence of organic obstruction of the upper urinary tract is based on the pathophysiologic state mainly consisting of a state of excitation with unstable tonus of the pelvic and ureteral wall, and caused by a sudden rise of intrapelvic pressure due to the pelvic spasm. In the presence of an abnormal rise of the tonus or persistent spasm of the pelvic and ureteral wall, a state of functional obstruction takes place and this probably constitutes a factor in the occurrence of PRB as in the presence of organic obstruction. Various types of PRB are probably produced on account of the difference in the height and speed of the rise of intrapelvic pressure produced by pelvic spasm. While the pyelotubular backflow is produced by reflux into the papillary duct under a relatively low intrapelvic pressure, fornical backflow is probably produced by rupture of the wall of the fornix under a higher level of the intrapelvic pressure.