For decades, the Anderson-Hynes dismembered pyeloplasty has been widely recognized as the gold standard for surgical treatment of ureteropelvic junction (UPJ) obstruction (UPJO). Despite the well reported safety and outcomes of the open approach or the robot-assisted laparoscopic (RAL) approach in pediatrics, surgeons may face rare instances where alternative surgical techniques may need to be considered. Since first described in 1947, ureterocalycostomy (UC) has been recognized as an alternative surgical option for patients with recurrent UPJO or unfavorable anatomical features that may pose a challenge in creating a reliable anastomosis and ureteropelvic drainage.¹

UC can offer significant advantage over pyeloplasty in patients with recurrent UPJ after failed pyeloplasty, in which commonly seen scarring and fibrosis at the UPJ can prevent adequate repair via the gold standard approach. Anatomical features that favor UC over pyeloplasty include intrarenal pelvis, malrotated pelvis, high ureteral insertion, short ureteral length, in addition to a thinned renal parenchyma to allow for appropriate anastomosis.^2–8

While the adoption of UC has evolved from open approach to minimally invasive surgery including laparoscopic and RAL approach, the reported cases of UC in literature is rare, with majority of the cases concerning the adult population.^9,10 There are only a few series specific to the application of this technique within the pediatric population.

We recently reported a retrospective 3-center multi-institutional cohort of pediatric patients undergoing robot-assisted laparoscopic ureterocalycostomy (RALUC) with a 92% success rate in improvement of postoperative hydronephrosis without the need for further intervention.¹¹ This is in accordance with the success rates reported in pediatric UC cases which have ranged from anywhere between 70% and 92%.^3–6 While UC is often considered for complex redo procedures, 3 out of 24 patients from our cohort underwent UC as their primary reconstructive procedure, in which a planned pyeloplasty was intraoperatively converted to RALUC due to complexity and extensive scarring. From our cohort, intrarenal pelvis was noted in 50% of patients, malrotated pelvis in 13%, inadequate ureteral length in 13%, and high ureteral insertion in 13%. In all cases, a small amount of renal parenchyma was removed to create an adequate window into the calyx of the lower pole.

Figure. Anastomosis of the ureter and lower pole calyx.

Key steps when performing RALUC to ensure satisfactory surgical outcomes include proximal ureteral and kidney mobilization, defining the UPJ, proximal ureteral ligation, creation of a calycostomy, ureteral spatulation, and finally the anastomosis. As most UCs are generally performed as a redo procedure, adhesions and scarring are often notable during the initial mobilization of the kidney and ureter. The lower pole of the kidney should be mobilized prior to defining the UPJ, as many patients undergoing UC often have a previous nephrostomy tube which can pose difficulties in the dissection. Once the UPJ is defined and the proximal ureter is transected, the ureter should be further mobilized distally to create a tension-free anastomosis. The area around the lower pole is scored with cautery to remove the cap of the parenchyma and the calyx is opened wide to allow for anastomosis with the medially spatulated ureter (see Figure). When possible, an omental flap is utilized to circumferentially drape across the repair. Our institutional experience with the robotic platform has allowed for great visualization of this area for precise suture placement and anastomosis.

Our work along with others published in the literature demonstrates the feasibility, safety, and success of RALUC as a salvage operation after failed pyeloplasty or as a primary surgical option for patients with complex and rare urological anatomies. While the low number of reported UC cases in pediatrics may be due to the rarity of these complex anatomies and low rate of initial pyeloplasty failure, evidence for clinical efficacy of this technique is an import factor to permit consideration of adopting a novel technique within an institution. In addition, it is important to note and consider the significant learning curve in adopting this complex surgery, particularly in a minimally invasive approach, as there are broad implications for resource utilization, institutional costs, and patient outcomes. Ongoing research of this surgical technique in pediatrics is important to understand its application with unfavorable complex urological anomalies and its role in pediatrics in comparison to RAL pyeloplasty.