Hydronephrosis in pediatric horseshoe kidneys: a comparative analysis of open and laparoscopic pyeloplasty and the influence of obstruction causes.

BACKGROUND: Horseshoe kidney (HSK) represents a unique challenge for performing pyeloplasty due to its anomalous anatomy. Our study aimed to report our results in treating children with hydronephrosis in HSK and to investigate the differences in prognosis based on the cause of obstruction and the surgical approach. We also aimed to share our experiences by characterizing the success rates and complications after surgery.

METHODS: We retrospectively reviewed the clinical data of hydronephrosis patients with HSK who were treated with pyeloplasty from August 2009 to June 2022. The patients were grouped according to different surgical methods and causes of obstruction, and then the clinical characteristics and outcomes were analyzed.

RESULTS: Thirty-one patients were included in this retrospective cohort observational study, and surgical success was achieved in 80.6% (25/31) of patients. There was no significant difference in complications between open pyeloplasty (OP) and laparoscopic pyeloplasty (LP) groups (2/16 vs. 4/15, P=0.374). At 6 and 12 months postoperatively, both OP and LP groups experienced a decrease in anteroposterior pelvic diameter (APD) and the ratio of APD to the thickness of renal parenchyma (P/C ratio), accompanied by an increase in renal parenchymal thickness. Two patients of reobstruction were caused by missed crossing vessels in primary operation. The success rate of patients with crossing vessels (62.5%) was significantly lower than that of patients without crossing vessels (100%) (P=0.018).

CONCLUSIONS: Our study found that intrinsic obstruction, crossing vessels, and high insertion were the main causes of hydronephrosis in HSK, with missed crossing vessels being the primary cause of reobstruction. Our results demonstrate that both OP and LP are safe and effective in treating hydronephrosis in HSK patients.