Transmesenteric Laparoscopic Pyeloplasty in Trendelenburg Position for Horseshoe Kidney with Hydronephrosis

This case describes transmesenteric laparoscopic pyeloplasty in Trendelenburg position for a patient with horseshoe kidney and hydronephrosis, with successful symptom relief and no complications. This case shows that transmesenteric intraperitoneal laparoscopic surgery in Trendelenburg position is a feasible and safe alternative for treating UPJO in horseshoe kidney patients. The patient had UPJO caused by a crossing gonadal vein, which is relatively rare in horseshoe kidney cases.

A full abdominal inspection was performed laparoscopically to observe retroperitoneal organs and mesenteric fat thickness to assess the feasibility of transmesenteric surgery. A three to four-centimeter longitudinal incision was made through the mesentary of the descending colon using an ultrasonic scalpel to create an opening while avoiding blood vessels and the intestine. The mesenteric fascia was dissected to expose the renal pelvis and left ureter.

The ascending portion of the duodenum along the dissection plane was visualized. After mobilizing the ureteropelvic region, a crossing branch of the genital gland vein was identified as the cause of UPJ obstruction. Upon confirming it as a vein, it was ligated.

In cases of ectopic artery compression, the artery was transposed and a dismembered pyeloplasty was performed. A non-dismembered pyeloplasty was then performed by making a three to four-centimeter long incision from the lateral aspect of the proximal ureter to the renal pelvis using laparoscopic scissors. The posterior walls of the ureter and pelvis were sutured using a 4-0 absorbable running suture.

A guide wire was passed through the proximal ureter into the bladder. Then, a 4.7 French Double J Stent was passed over the guide wire into the bladder. The proximal end of the stent was placed within the renal pelvis.

The anterior anastomosis was completed by suturing the proximal pelvis and ureter with 4-0 polyglactin sutures on a half-circle needle. The ureteropelvic anastomosis was performed using 4-0 polyglactin sutures on a half-circle, round-bodied needle. The mesenteric incision was closed with running 4-0 polyglactin sutures.

The surgical field was inspected for bleeding, urine leaks, or gastrointestinal injuries. A drainage tube was placed adjacent to the mesenteric window, ensuring no contact with the anastomosis. The mesenteric approach required careful dissection to avoid intestinal injury, especially in thin patients.

This technique offers better exposure and minimizes bowel manipulation compared to traditional lateral approaches. Proper understanding of mesenteric anatomy was key to the safe execution of this technique.