Authors’ reply to the letter to the editor regarding “stented versus stentless pyeloplasty in adults: A systematic review of surgical outcomes and complications”

Dear Editor, We thank the correspondents for engaging with our review[1] and address each point in turn. ON DEL GIUDICE COHORT DOMINANCE Del Giudice et al.[2] indeed contributed 4872 of the 5820 patients [83.7%, Table 2]. However, we performed a narrative – not a pooled – synthesis (Methods), so the weighted effect estimate was not sample size driven. This study was also rated high risk of bias on the Newcastle–Ottawa Scale (NOS) [5/9; Table 1, one of three so rated] and did not report surgical success [Table 3: NR/NR], so it did not contribute to our primary-outcome synthesis. Its reintervention finding (25.49% vs. 20.44%) was presented at face value with the authors’ caveat that complication severity and long-term failures were unchanged. ON THE STRENGTH OF EVIDENCE UNDERPINNING THE ALGORITHM Only one randomized controlled trial (RCT)[3] was included, limiting the strength of practice recommendations. We classified all non-randomized studies by NOS [Table 1; five of nine rated ≥7/9] and called for future directions for “large-scale, multicenter randomized trials” to validate stentless techniques. Figure 4 is a clinical decision algorithm synthesizing available evidence, not a guideline requiring pooled RCT data; it’s one Level I recommendation (stent duration 1–2 weeks) is labeled as such. Beyond the paper, risk-stratified algorithms serve as interim decision aids in adult urology where RCT evidence is sparse. ON PATIENT-REPORTED OUTCOME MEASURES We are in full agreement. Our review itself identified the absence of standardized Patient-Reported Outcome Measures[1] (PROMs) as a “critical evidence gap” and made no quantitative quality-of-life claim. The symptom-reduction signal is reported only through objectively documented LUTS (64.7%–100% stented vs. 0%–3.8% stentless) and hematuria (27%–95.4% vs. 0%–4.3%) in Table 4. Standardized PROMs are accordingly recommended in our Future Directions. ON DIFFERENTIAL RENAL FUNCTION The hypothesis that better-functioning kidneys imposes greater anastomotic stress through higher urine output is mechanistically reasonable, but no such analysis is presented in our review or in the data we extracted from the included studies. The differential renal function (DRF) >35% threshold is based on the empirical observation that DRF >35% predicts 87.5% functional improvement following pyeloplasty. Critically, Figure 4 lists DRF >35% as one of the five Green-criterion variables (primary UPJO, DRF >35%, pelvic volume <50 mm3, parenchymal cortex >7.5 mm, non-dilated ureter), and even when all the five are met, the algorithm requires intraoperative confirmation of a watertight anastomosis – never DRF alone. A dedicated DRF–leakage analysis would be a valuable future contribution. ON TECHNICAL ADJUNCTS AND SUTURING The data do not support the inference that stentless success was contingent on the intraoperative adjuncts. Cross-referencing Tables 3 and 6: Bilen et al.[4] used feeding-tube saline testing yet reported the lowest stentless success (81.5%, 22/27); Sethi et al.[5] used indigo carmine (88%, 16/18); whereas Hopf et al.,[6] with “none reported,” achieved 91.5% (43/47) robotically. This is consistent with our Discussion that “outcomes appear to be more closely related to the surgical technique quality, the presence of favorable anatomy, and the surgeon’s experience.” Regarding the suturing technique (interrupted/continuous/hybrid), we acknowledge this variable was not extracted – a fair limitation we would welcome being addressed in the future subanalyses. ON THE DEFINITION OF FAILURE Our “Standardized Outcome Definitions section” adopted T1/2 >20 min as the criterion most commonly applied in the adult literature, while Table 3 footnote acknowledges that “criteria varied across the studies” and most relied on the combined clinical and imaging assessment. The correspondents correctly observe that T1/2 may exceed 20 min after pyeloplasty, particularly in the non-reductive cases without true obstruction, which is precisely why the included studies did not declare failure based on prolonged T1/2 alone, but rather on symptom resolution and renal function trends, thereby mitigating misclassification of asymptomatic patients. The newer parameters cited – gravity-assisted drainage and cortical transit time – were validated in references[7,8] in congenital and antenatally diagnosed hydronephrosis populations, respectively; adult postpyeloplasty extrapolation is plausible but, to our knowledge, not yet established for use as a synthesis criterion. We agree that better outcome definitions are needed, as we recommended in our Future Directions: “Standardized outcome definitions using composite criteria of symptoms, drainage, and function should be adopted for consistent reporting across the studies.” We thank the correspondents again. PROMs, suturing, and outcome definitions are areas that the field and our review will benefit from continuing to refine. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.