Scintigraphic renal function after unilateral pyeloplasty in children: a systematic review

OBJECTIVE: To systematically review previous reports and thus determine the functional outcome after pyeloplasty in children with unilateral hydronephrosis due to pelvi-ureteric junction obstruction, and the possible variables that could affect it. METHODS: We searched Medline/PubMed, Embase, and Web of Science for articles in English published from 1966 to 2007, using both 'medical subject headings' and 'free text' protocols. Abstracts, full texts, and bibliographies of pertinent papers were reviewed to select studies of scintigraphic renal function before and after pyeloplasty. The postoperative change in scintigraphic renal function was assessed in relation to presentation (antenatal vs postnatal), timing of surgery (early vs delayed), age at surgery, and preoperative ultrasonography (US) and scintigraphic findings. RESULTS: Thirty-six studies (2.1% of the initial search) were eventually selected for review. Studies were generally of poor scientific quality and very heterogeneous in their indications for surgery and follow-up protocols. Postoperative function showed a wide variability. Symptomatic patients diagnosed postnatally seemed to have a greater chance of functional improvement after surgery than asymptomatic patients diagnosed antenatally. The chance of improvement seemed also to be greater in patients with moderately rather than severely impaired preoperative function. Otherwise, the improvement seemed unrelated to the age at surgery, the preoperative US findings, or the excretion pattern on renal scintigraphy. Of patients having delayed surgery >97.5% had preserved function afterward. CONCLUSIONS: Patients with moderately impaired preoperative function and those diagnosed postnatally because of symptoms are those with the greatest likelihood of having a functional improvement after surgery.