Efficacy and Safety of Flexible Ureteroscopy With Flexible Navigable Suction Ureteral Access Sheath Versus Mini-Percutaneous Nephrolithotomy With Vacuum-Assisted Access Sheath

Overview

Mini-percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) are both effective treatment modalities for renal calculi measuring up to 2.5 cm in pediatric patients, demonstrating similar efficacy and complication profiles. Suction has emerged as a potentially transformative adjunct in both percutaneous nephrolithotomy (PCNL) and RIRS. Recent studies evaluating various suction mechanisms during RIRS and mini-PCNL have demonstrated multiple benefits, including reduced operative time, higher stone-free rates (SFR), decreased intrarenal pressure (IRP) and temperature, as well as enhanced intraoperative visualization. Both FANS-UAS in RIRS and VAAS in Mini-PCNL have shown promising outcomes in the pediatric population. Taken together, these findings suggest that suction-assisted technologies whether in RIRS or Mini-PCNL enhance both efficacy and safety in pediatric stone management.

In children, renal stones commonly result from congenital anatomical defects, metabolic abnormalities, or recurrent urinary tract infections. Consequently, urolithiasis is more frequent in this age group and often requires more than one surgical intervention for complete management. Mini-percutaneous nephrolithotomy (mini-PCNL) and retrograde intrarenal surgery (RIRS) are both effective treatment modalities for renal calculi measuring up to 2.5 cm in pediatric patients, demonstrating similar efficacy and complication profiles . Currently, the majority of pediatric renal stones can be managed effectively using shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), or percutaneous nephrolithotomy (PCNL). Surgical interventions such as open, laparoscopic, or robotic surgery are reserved for a minority of cases involving anatomical abnormalities. As spontaneous passage of residual fragments occurs in only 20-25% of cases, achieving complete stone clearance is essential to minimize the risk of recurrence and additional interventions. Technological advancements in endourological instrumentation have primarily aimed at minimizing procedure-related morbidity, including blood loss, postoperative pain, and renal injury. Consequently, miniaturized endoscopes and reduced-caliber access tracts (11-20 Fr) were developed, leading to the emergence of Mini-PCNL techniques specifically adapted for the management of large renal stones in pediatric patients. The use of retrograde surgical approaches has expanded the capability to treat larger renal stones, despite often resulting in extended operative times. Due to its favorable safety profile and reduced complication rates, RIRS has gained acceptance as a preferred option for managing larger stones in pediatric patients. For stones larger than 20 mm, RIRS monotherapy is associated with lower stone-free rate (SFR) compared to Mini-PCNL. However, RIRS offers advantages including reduced radiation exposure, fewer complications, and shorter hospital stay. The Mini-PCNL and RIRS provide comparable efficacy and complication rates in the treatment of pediatric renal stones up to 2.5 cm. Furthermore, the study found that RIRS was associated with significantly shorter hospital stays, reduced radiation exposure, and decreased fluoroscopy time compared to Mini-PCNL. Suction has been utilized in endourology for over 25 years, primarily in conjunction with ultrasound and ballistic lithotripsy devices, and more recently through the use of suction sheaths during PCNL. Intraoperative suction has been introduced as an effective method to remove residual fragments (RFs), thereby reducing the need for manual extraction with baskets. Suction has also been employed in RIRS, providing multiple advantages including improved stone fragmentation and dusting, enhanced removal of debris and fragments, reduction of intra-renal temperature and pressure, as well as better intraoperative visualization. In a prospective multicenter trial, Gauhar et al. demonstrated that the flexible and navigable suction ureteral access sheath (FANS-UAS) is safe and effective for use in pediatric RIRS, yielding high stone-free rates with low complication rates. This supports its emerging role as a valuable innovation in pediatric endourological procedures. The initial experience using a semi-closed-circuit vacuum-assisted mini-percutaneous nephrolithotomy (Mini-PCNL) system in pediatric patients, achieving an 80% stone-free rate with no intraoperative complications and only minor postoperative events. This technique, which integrates continuous irrigation inflow with suction-controlled outflow, was found to be a safe and effective option for managing complex renal stones in children while maintaining acceptable operative times.