{"id":29530,"date":"2025-08-28T22:26:08","date_gmt":"2025-08-28T22:26:08","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/29530\/"},"modified":"2025-08-28T22:26:08","modified_gmt":"2025-08-28T22:26:08","slug":"safety-and-efficacy-of-flexible-and-navigable-suction-combined-with-retrograde-flexible-ureteroscopy-in-the-management-of-infectious-stones-bmc-infectious-diseases","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/29530\/","title":{"rendered":"Safety and efficacy of flexible and navigable suction combined with retrograde flexible ureteroscopy in the management of infectious stones | BMC Infectious Diseases"},"content":{"rendered":"

The formation and growth of infectious stones were closely associated with bacterial presence, and persistent bacterial colonization further complicated treatment [4<\/a>]. Pathogenic bacteria induced highly alkaline urine and elevated urinary ammonia concentrations, disrupting glycosaminoglycans that protected urothelial cells from bacterial invasion [10<\/a>]. Bacterial biofilms formed on the mucosal surfaces of the renal pelvis and calyces reduced antibiotic efficacy and promoted antimicrobial resistance. Studies identified common bacteria in infectious stones, such as Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae, based on stone culture results [4<\/a>]. In our study, the initial bacterial culture positivity rate was higher in the infectious stone group than in the non-infectious group, though without statistical significance. E.coli predominated in the infectious group (35%, 7\/20), while P. mirabilis accounted for only 5% (1\/20). This discrepancy might have stemmed from our limited sample size and reliance on urine culture results with lower sensitivity. The internal biofilm of infectious stones harbored extremely high bacterial loads. These stones were not mere mineral deposits but complex structures composed of bacterial biofilms and crystalline matrices [11<\/a>]. Notably, bacterial distribution was highly heterogeneous, with dormant populations residing in hypoxic microenvironments within deeper stone layers [12<\/a>]. Consequently, even with standardized antimicrobial therapy, complete eradication of intrastone bacteria remained unattainable.<\/p>\n

The \u201cblast effect\u201d induced by intraoperative laser lithotripsy, as previously described in literature, represents a clinically relevant consideration in stone surgery [13<\/a>]. This phenomenon, whereby lithotripsy may release bacteria, bacterial debris, and endotoxins from stone matrices, has been associated with potential infection risks\u2014given that stone fragments post-lithotripsy have been shown to harbor bacterial loads that may exceed preoperative urine culture levels [13<\/a>]. These microorganisms and their byproducts might enter the bloodstream directly through damaged renal pelvic mucosa or via pyelovenous backflow, or disseminate through perirenal lymphatic pathways [14<\/a>]. Additionally, excessive irrigation pressure (>\u200930 mmHg) during surgery could force bacteria and toxins into the bloodstream, while negative-pressure suction systems significantly mitigated this risk [15<\/a>]. Clinical data indicated a 3\u20135% intraoperative sepsis rate for RIRS without negative-pressure management, whereas negative-pressure technology reduced this risk to 7]. In our study, no cases of sepsis occurred in the infectious group, and the non-infectious group had only a 0.5% incidence. The negative-pressure flexible ureteroscope maintained continuous low-pressure irrigation but required constant monitoring of outflow patency. As non-intelligent pressure control platforms lacked automatic irrigation cessation, surgeons had to observe fluid circulation in the visual field and immediately retract the scope while stopping irrigation if obstruction occurred. Stone culture was not performed due to laboratory constraints, limiting direct evidence of intrastone bacterial load. Future studies should include stone culture to clarify the link between intrastone bacteria and post-lithotripsy infection risk.<\/p>\n

Traditional flexible ureteroscope sheaths exhibited poor reflux efficiency, relying on slow irrigation flow and basket retrieval for limited stone fragment removal, with most fragments dependent on postoperative spontaneous passage [7<\/a>]. Residual stones served as nidi for recurrence and infection, enabling rapid regrowth, which emphasized the critical importance of immediate postoperative SFR [3<\/a>]. The negative-pressure ureteroscope system employed a flexible distal suction sheath to rapidly evacuate fragments via hydrodynamic forces. Our study achieved 90.2% immediate SFR in the infectious group, with no change at 3-month follow-up. Analysis of residual stone cases revealed two located in lower calyces with moderate-to-severe hydronephrosis. The expanded renal pelvis during irrigation prevented UAS tip advancement to lower calyces, while mucosal apposition in contracted pelvicalyceal systems increased retention risk. Thus, preoperative feasibility assessment remained crucial for patients with moderate-to-severe hydronephrosis, even with negative-pressure RIRS. Two other residual cases involved diverticular stones with narrow infundibula, no hydronephrosis, infection, or malignancy, warranting conservative management. Due to the limited follow-up duration, conclusions regarding long-term recurrence reduction remained elusive.<\/p>\n

Stone physicochemical properties influenced surgical outcomes, including operative time and renal pelvic pressure. Magnesium ammonium phosphate hexahydrate stones, commonly observed in infections, contained an abundant organic matrix and exhibited poor friability [16<\/a>]. During lithotripsy, debris mixed with pus in obstructed calyces necessitated initial pus clearance to minimize endotoxin absorption. Carbonate apatite stones (95.1% in our cohort), although hard, generated substantial dust during fragmentation, impairing visualization and increasing the risk of ureteroscope-ureteral access sheath (UAS) entrapment, thereby elevating pelvic pressure. Regular scope withdrawal every 1\u20132\u00a0min, fragment clearance, optimized irrigation flow, and enhanced suction were essential for maintaining visualization.<\/p>\n

Postoperative surveillance and adjuvant therapy were critical for reducing recurrence. A daily fluid intake of 2\u20132.5\u00a0L, culture-guided antibiotics, and urinary acidification (pH\u20095]. Postoperative acetohydroxamic acid (AHA), a urease inhibitor, demonstrated anti-recurrence efficacy but carried risks of thromboembolism and tremor. While three randomized trials confirmed AHA\u2019s ability to retard stone growth, it could not dissolve existing calculi [3<\/a>].<\/p>\n

Notably, our preoperative baseline analysis revealed a significantly higher proportion of severe hydronephrosis in the infectious stone group than in the non-infectious stone group (p\u2009=\u20090.037). This difference was biologically plausible, as infectious stones were more likely to be associated with prolonged obstruction or inflammation, which might have contributed to the development of severe hydronephrosis. Severe hydronephrosis could theoretically have acted as a confounding factor, potentially increasing operative difficulty or promoting intrarenal stasis, which might have influenced infection-related outcomes or SFR. However, our results showed no significant differences in key clinical outcomes\u2014including SFR, infectious complications (SIRS\/sepsis), operative time, or hospital stay\u2014between the two groups, suggesting that despite the imbalance in hydronephrosis severity, FANS-RIRS remained effective and safe in both cohorts. Nevertheless, we had to acknowledge the uncertainty introduced by this baseline difference; given the retrospective nature of the study, we had been unable to adjust or balance this variable post-hoc, which might have introduced selection bias, and the potential impact of severe hydronephrosis on long-term outcomes (e.g., stone recurrence) had also remained unaddressed due to our short follow-up period.<\/p>\n

This study has inherent limitations, including its retrospective, single-center design and the relatively small sample size of the infectious stone group (n\u2009=\u200961), which may restrict statistical power for rare complications such as sepsis. The 3-month follow-up period is insufficient to assess long-term stone recurrence, a critical endpoint for infectious stones given their high recurrence risk. Due to the study\u2019s time frame (November 2023\u2013December 2024), longer follow-up was not feasible; however, future studies should extend follow-up to 12\u201324 months to evaluate recurrence in infectious stone patients. We strongly recommend prospective, multicenter trials with larger cohorts to validate our findings and further evaluate long-term outcomes.Stone culture was unavailable due to laboratory constraints. Emerging techniques like radiomics and intraoperative image deep learning might enable noninvasive stone composition analysis, facilitating future prospective validation.<\/p>\n","protected":false},"excerpt":{"rendered":"The formation and growth of infectious stones were closely associated with bacterial presence, and persistent bacterial colonization further…\n","protected":false},"author":2,"featured_media":29531,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[78],"tags":[18,23547,135,19,4381,23549,1911,17,4383,4382,23548,4384],"class_list":{"0":"post-29530","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-eire","9":"tag-flexible-and-navigable-suction","10":"tag-health","11":"tag-ie","12":"tag-infectious-diseases","13":"tag-infectious-stones","14":"tag-internal-medicine","15":"tag-ireland","16":"tag-medical-microbiology","17":"tag-parasitology","18":"tag-retrograde-intrarenal-surgery","19":"tag-tropical-medicine"},"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/29530","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=29530"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/29530\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/29531"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=29530"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=29530"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=29530"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}