Improvement of renal split function in hydronephrosis with less than 10 % function

PURPOSE: The split function (SF) of hydronephrotic kidneys may dramatically decrease in the presence of severe and persistent obstruction, necessitating surgical correction. The indication for pyeloplasty versus nephrectomy is mainly based on the results of repeated renal ultrasonography (US) and MAG3-diuretic nephrography (DNG) with SF. Nephrectomy is usually recommended if SF is less than 10 %. However, recent studies with long-term follow-up indicate that even with an initial SF of 20 mm) and/or DNG demonstrated a loss of SF 40 %; group II, 7 patients with moderately impaired SF between 10 - 40 %; group III, 4 patients (aged 1 - 137 months) with a SF of > 10 %. In 2 patients, percutaneous nephrostomy (PCN) was performed, followed by AHP. Thirty patients underwent AHP without preceding PCN. In group III, SF increased from > 10 % preoperatively to 21 %, 27 %, 45 %, and 53 % postoperatively, respectively. In all patients, postoperative DNG demonstrated a significant improvement of SF from 41 %, on average, preoperatively (range 0 - 64 %) to 47 %, on average, postoperatively (range 17 - 60 %). CONCLUSION: Long-term follow-up confirms that the prognosis for renal function is excellent in patients with moderately reduced SF. The significant improvement of SF 12 months after AHP in all patients with a poor SF of less than 10 % supports our approach of performing pyeloplasty in patients even with an initial SF of > 10 %, which is in contrast to common practice.