Transmesenteric Laparoscopic Pyeloplasty in Trendelenburg Position for Horseshoe Kidney with Hydronephrosis.

Due to anomalous anatomy, pyeloplasty with a horseshoe kidney (HSK) presents a technical challenge. Previously, we reported a technique of intraperitoneal laparoscopic surgery in Trendelenburg position (ILSTP) for pyelolithotomy, pyeloplasty, and heminephrectomy in patients with HSKs. To demonstrate the procedure, the case of a 29-year-old female with HSK and left hydronephrosis who underwent pyeloplasty using transmesenteric ILSTP is presented. Magnetic resonance confirmed HSK with left-sided hydronephrosis. After opening a window in the mesentery and dissecting the renal pelvis and left ureter, a crossing vein causing ureteropelvic junction obstruction (UPJO) was identified and ligated, followed by non-dismembered pyeloplasty. The operative time was 147 min with blood loss of 5 mL. Follow-up evaluation at 8 weeks post-stent removal demonstrated significant resolution of hydronephrosis without complications. This study describes the feasible use of the transmesenteric ILSTP technique, providing an important method to perform pyeloplasty in selected HSK patients. This technique requires surgeons to possess advanced laparoscopic skills, and the method may face limitations depending on the thickness of the mesentery.