Aspiration Technologies in Flexible Ureteroscopic Urolithiasis Treatment: A Disruptive Concept in Pursuit of a Stone-Free Future

Introduction: Endoscopic innovation has played a pivotal role in advancing retrograde intrarenal surgery (RIRS). Integration of aspiration technology into flexible ureteroscopes (fURS), termed direct in-scope suction (DISS), and into ureteral access sheaths (s-UAS) are the most recent and rapidly progressing advancements. Aspiration technologies aim to augment stone-free rates (SFR) associated with traditional RIRS and may provide an alternative to retrograde management of large calculi typically managed with percutaneous nephrolithotomy (PCNL). This systematic and narrative review aims to consolidate the current evidence on aspiration devices used in RIRS. Methods: Using the Covidence platform, a literature search was conducted including the PubMed and Web of Science databases from inception to October 2024. This systematic review was registered in PROSPERO (CRD42024613059). Studies were categorized based on level of evidence and included randomized controlled trials (RCTs), comparative observational studies, and large-scale prospective studies; papers were excluded due to expired technology or absence of a traditional fURS comparator group. Results: Literature search yielded 232 articles. Following exclusion and manual review, 11 studies (1 RCT, 8 comparative cohort studies, and 2 large-scale observational studies) were selected for analysis. Assessing level 1 evidence, immediate and final SFRs were significantly higher in s-UAS groups. S-UAS was also superior to traditional fURS in achieving superior SFR for the management of renal calculi with level 3 evidence. Conclusion: Early studies utilizing contemporary aspiration technologies demonstrated superior efficacy and efficiency with respect to immediate SFR and operative times in patients undergoing fURS for renal stones between 1 and 2 cm compared with traditional fURS. Future studies adhering to standardized SFR criteria with postoperative thin-slice (2 mm) noncontrast computed tomography scanning is warranted to more precisely assess the effectiveness of aspiration technology-associated SFR values.