Functional outcome after pyeloplasty in children: impact of the cause of obstruction and of the mode of presentation.

OBJECTIVE

To compare functional outcome after pyeloplasty in two groups of patients affected by hydronephrosis, which had different modalities of diagnosis. The first, asymptomatic, detected by prenatal ultrasonography and the second referred later because of clinical symptoms.

PATIENTS AND METHODS

84 patients (54 prenatally detected and 30 symptomatic) among 339 observed with hydronephrosis, operated in a single centre for ureteropelvic junction obstruction, have been retrospectively studied. Seventeen cases with prenatal diagnosis had an early treatment and thirty-seven were operated on after an initial observation. Symptomatic cases were all operated on at diagnosis. Ultrasonographic and renographic assessment were made at diagnosis, before and after surgery.

RESULTS

Renal function of prenatally detected cases was not influenced by early or delayed surgery. Insignificant functional loss was recorded among some cases operated after conservative management. Improvement in differential renal function (p<0.05) was recorded in symptomatic patients after pyeloplasty. A high percentage of obstructions secondary to lower polar crossing vessel were found among symptomatic cases (12 out of 30). Intrinsic obstructions were predominant among cases with in utero diagnosis (48 out of 54). Whenever the cause of obstruction is considered, postoperative functional improvement was limited to crossing vessels cases.

CONCLUSIONS

Renal function among antenatally diagnosed obstructions is scarcely influenced by surgery; potential risk of further renal damage cannot be excluded when expectant management is decided. Later detected, symptomatic cases show a better functional response to surgery. This seems corresponding to distinct clinical entities based on different causes of hydronephrosis. A reversible renal damage seems to be associated to extrinsic obstructions from polar vessel, which are predominant among symptomatic, later detected cases. A congenital, irreversible loss of function accompanies intrinsic obstructions, typical of prenatally diagnosed cases.