Preminger, Glenn M.

Purpose: The ASPiration to Improve Renal Calculi Removal Effectiveness study showed steerable ureteroscopic renal evacuation (SURE) with CVAC that significantly reduced residual stone volume at 30 days vs standard ureteroscopy (URS). This report presents 2-year health care consumption and stone events (SE) and their link to residual stone volume and other variables ( n = 101 at primary end point; n = 93 at 2 years). Materials and Methods: Logistic regression identified predictors of health care consumption events (HCEs), that is, emergency department visits, hospitalization, surgical retreatment, and SE across the study population. Incidence was compared between the treatment groups with Kaplan–Meier survival analysis. Results: At 2 years, residual stone volume was significantly associated with both HCEs and SE. For every 100 mm 3 increase in residual stone volume, the HCE risk increased by 50% to 54%, and the SE risk increased by 70%. Stone-free rate, the number of residual fragments (RFs), and RF total stone burden (based on diameter) were not predictors. Significantly fewer HCEs occurred in the SURE group (3 vs 20 events, p = 0.0004). Survival analysis confirmed this (4.3% vs 20%, log-rank p = 0.02), with a 73% risk reduction (hazard ratio 0.27, 95% Cl 0.09–0.80, p = 0.02). Fewer SE occurred in the SURE group, although not statistically significant. These subjects also had longer event-free survival. Conclusion: High-quality volumetric analysis supports evaluation of stone removal therapies, as residual stone volume predicts HCEs and SE. SURE significantly reduces the downstream incidence and risk of HCEs compared with standard URS.

Purpose: We report the first multicenter, prospective, randomized noninferiority controlled trial of steerable ureteroscopic renal evacuation (SURE) for nephrolithiasis treatment. Materials and Methods: Candidates for laser lithotripsy ≥18 years with ≥1 renal stone ≥7 mm and 7–20 mm stone burden were randomized 1:1 SURE vs ureteroscopy (URS). SURE was performed using the CVAC Aspiration System, a novel steerable irrigation–aspiration catheter. The primary efficacy end point was noninferiority in stone-free rate (SFR) based on zero residual fragments (RFs) 30 days postprocedure on noncontrast computed tomography. Secondary end points were superiority tests, stone clearance (percent stone volume reduction), residual stone volume (RSV), SFR (no RF >2 mm), and SFR (no RF >4 mm) 30 days postprocedure. Results: Of the subjects, 123 were randomized and 101 qualified for efficacy analysis (SURE 46 vs URS 55). Despite randomization, baseline URS stone volume was higher (SURE 485.0 ± 432.5 mm 3 vs URS 713.3 ± 558.5 mm 3 ). The primary noninferiority end point was achieved (SURE SFR 48% vs URS SFR 49%, p = 0.027, −1.3% [90% confidence interval; −18%, 15%]). Stone clearance was significantly higher for SURE vs URS subjects (SURE 96.9 ± 5.6% vs URS 92.9 ± 11.6%, p = 0.036); RSV was significantly lower (SURE 14.3 ± 3 0.9 mm 3 vs URS 70.2 ± 144.9 mm 3 , p = 0.012). SURE stone clearance and RSV were independent of baseline stone volume, but for URS degraded with increasing baseline stone volume. Safety was comparable between groups. Conclusions: SFR for SURE subjects was noninferior compared with URS subjects; stone clearance and RSV were significantly better with SURE, independent of baseline stone volume.

Purpose: Cystinuria is a genetic disorder with both autosomal recessive and incompletely dominant inheritance. The disorder disrupts cystine and other dibasic amino acid transport in proximal tubules of the kidney, resulting in recurrent kidney stone formation. Currently, there are no consensus guidelines on evaluation and management of this disease. This article represents the consensus of the author panel and will provide clinicians with a stepwise framework for evaluation and clinical management of patients with cystinuria based on evidence in the existing literature. Materials and Methods: A search of MEDLINE ® /PubMed ® and Cochrane databases was performed using the following key words: “cystine nephrolithiasis,” “cystinuria,” “penicillamine, cystine,” and “tiopronin, cystine.” In total, as of May 2018, these searches yielded 2335 articles, which were then evaluated for their relevance to the topic of evaluation and management of cystinuria. Evidence was evaluated by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Results: Twenty-five articles on the topic of cystinuria or cystine nephrolithiasis were deemed suitable for inclusion in this study. The literature supports a logical evaluation process and step-wise treatment approach beginning with conservative measures: fluid intake and dietary modification. If stone formation recurs, proceed to pharmacotherapeutic options by first alkalinizing the urine and then using cystine-binding thiol drugs. Conclusions: The proposed clinical pathways provide a framework for efficient evaluation and treatment of patients with cystinuria, which should improve overall outcomes of this rare, but highly recurrent, form of nephrolithiasis.