Urolithiasis in children is often associated with underlying conditions such as metabolic abnormalities or genitourinary anomalies . As no metabolic abnormalities were detected in our case, the possibility that a renal stone that was impacted at the ureteropelvic junction may have caused the renal dilatation rather than UPJO could not be ruled out. However, since urine stasis due to UPJO predisposes to the development of renal calculi [9, 10], we considered that pyeloplasty with pyelolithotomy, rather than percutaneous or transurethral lithotripsy alone, would be a more appropriate treatment in this case, in order to avoid the recurrence of renal calculi. Due to the completely intrarenal pelvis in the affected kidney, UC was consequently performed concurrently with laparoscopic pyelolithotomy in this 10-year-old female patient.
UC was initially reported by Neuwirt in 1948 . Mesrobian et al. described that the indications for this procedure included previously unsuccessful pyeloplasty, UPJO associated with anomalies of renal rotation or ascent, an intrarenal pelvis or a short ureter . The advantage of UC is that it provides dependent urinary drainage from the lower calyx into the ureter. However, bleeding from the incised renal parenchyma and the risk of anastomotic stricture are limitations of this procedure. Matlaga et al. reported 11 patients with successful open UC . No patients experienced significant perioperative complications. Renal function in the affected kidney improved from a mean of 54.6% preoperatively to 60.1% postoperatively. Osman et al. reported that the success rate of 22 open UCs was 73% after a mean follow-up of 26.7 months . They demonstrated that preoperative factors affecting the outcome of UC were a history of endopyelotomy or pyelonephritis, renal parenchymal thickening, split renal function and the extent of scarring score. Although only a few case series with limited numbers have been reported, open UC has shown favorable outcomes and was well-tolerated in the selected cases.
Laparoscopic UC in adults was first described by Gill et al. . Subsequently, several case series about laparoscopic UC have been reported [5,6,7]. However, these were small series because the number of patients in whom UC is required is limited and because advanced laparoscopic skills, including the use of tension-free sutures and the ability to control bleeding of the incised renal parenchyma, are required for this procedure. Satisfactory outcomes were described in these reports as a low incidence of anastomotic stricture and improvements of drainage or renal function in the affected kidney after surgery.
Few reports regarding laparoscopic UC in the pediatric population have been published to date. Among 13 children described by Radford et al. an open approach and a laparoscopically assisted technique were indicated in 12 patients and in 1 patient, respectively . To our knowledge, only 2 pediatric cases in a series by Arap et al. were treated via pure laparoscopic UC . These patients were 2 and 8 years old and underwent the procedure after failed pyeloplasty. No intraoperative complications were observed. Each patient had a patent anastomosis and resolution of symptoms without significant worsening of split renal function.
In performing laparoscopic UC, control of bleeding from the anastomotic site is one of the most crucial issues . In our case, the renal parenchyma at the lower calyx was thin enough to incise without hilar occlusion. Although there is no evidence of how thin the renal parenchyma should be for laparoscopic UC without hilar occlusion, this is a key factor in patient selection for laparoscopic UC. If laparoscopic UC is considered in cases with thick parenchyma at the anastomotic site, hilar occlusion as performed in partial nephrectomy  or open procedures should be indicated.
The other crucial issue for performing laparoscopic UC is a tension-free uretero-caliceal anastomosis. For this purpose, mobilization of the ureter while preserving vascular supply and a reliable suturing technique are essential. Recently, robotic-assisted laparoscopic UC has been reported [13, 14]. The advantages of robotics are three-dimensional visualization and increased freedom of movement compared to conventional laparoscopy. Accordingly, robotic-assisted laparoscopic UC may be a promising option even in the pediatric population, although it remains expensive.