The estimation of urine bolus volume for patients with congenital hydronephrosis.

A new examination (bolusmetry) to evaluate the urine transport function of the ureteropelvic system was performed in 7 adult patients with congenital unilateral hydronephrosis. Whistle-tipped Fr. 5 catheters were introduced to each ureter about 5 cm proximal from the ureteral orifice by transurethral endoscopic technique. Bolus volume and frequency, and changes in them caused by furosemide injection, were estimated by using a drop counter which was connected to the terminal end of the ureteral catheter. Bolusmetry was performed comparing the hydronephrotic side and the healthy side, pre and postoperatively, and these results were then compared with a conventional examination. We obtained the following results: Bolus volume of the hydronephrotic side was 0.05 +/- 0.02 (mean +/- S.D.) ml at oliguric state, and it was significantly lower than the value of the healthy side which was 0.19 +/- 0.07 ml. Injection of diuretics increased the bolus volume of the healthy side ten times or more. On the other hand, the bolus volume of the hydronephrotic side was increased only slightly by the injection of furosemide, it being approximately one-fourth of the value of the healthy side. The value of bolus frequency was similar to peristaltic frequency which was measured by the electromyogram. The tendency of a decrease was noticed in bolus frequency of the hydronephrotic side but it was not significant. Of patients with severe hydronephrosis, the bolus volume of the hydronephrotic side was decreased and the response to the diuretics was not so significant. By bolusmetry, functional or organic obstruction of the ureteropelvic junction was detected. Of 3 patients who had nephrectomy or nephrostomy, the kidney function had deteriorated severely. The bolus volume was lower than 0.25 ml at the diuretic state. Bolus volume was increased postoperatively in 3 of 4 patients who had received pelvioplasty. One patient did not show the formation of bolus by the injection of diuretics, and the cause of the hydronephrosis was functional obstruction of the pelvioureteric junction. We concluded that bolusmetry is a valuable method for evaluation of the function of urine transport in the ureteropelvic system. Especially in hydronephrosis, bolusmetry is a useful in the choice of operative procedure, and for postoperative evaluation.