Optical Trocar Access for Retroperitoneal Robotic-Assisted Pyeloplasty in Children with Ureteropelvic Junction Obstruction.

Purpose: Retroperitoneal robotic-assisted pyeloplasty (ret-RAP) for ureteropelvic junction obstruction (UPJO) requires a larger retroperitoneal space (RS) to maintain specified distances between robotic (da Vinci) trocars and between trocars and the region of interest. A modified closed technique (MOT) and conventional closed technique (COT) were compared for creating an adequate RS with optical trocars. Methods: RS access in children with UPJO who underwent ret-RAP ( n  = 30) was MOT ( n  = 15) and COT ( n  = 15). All patients were positioned laterally. For MOT, a 5 mm optical trocar was inserted at the angle formed between the 12th rib and the erector spinae muscles. As the trocar was advanced under direct vision, it pierced the superficial subcutaneous layer, Scarpa's fascia, lumbar fascia, internal/external oblique and transversus abdominalis muscles, and the posterior renal fascia. Once in the RS, the tip of the scope was used for blunt dissection of perirenal fat, the tip was withdrawn until it was outside the perirenal fascia, and used to dissect toward the anterior abdomen in the pararenal fat layer. Results: Ages and weights at ret-RAP were similar (MOT: 5.6 ± 1.8 years versus COT: 7.8 ± 4.6 years; MOT: 20.6 ± 10.1 kg versus COT: 27.6 ± 13.9 kg). Times for RS access were similar (MOT: 1.6 ± 0.5 minutes versus COT: 1.9 ± 0.7 minutes), but RS expansion was significantly quicker in MOT (32.3 ± 8.7 minutes versus 52.0 ± 15.1 minutes; P  < .001). Peritoneal injury caused carbon dioxide leakage in 4 of 15 COT cases and 0 of 15 MOT cases. Conclusion: RS expansion with MOT was safer because there were no peritoneal injuries and MOT was quicker than COT.