{
  "abstract": "Negative-pressure aspiration ureteral access sheaths (NP-UAS) outperform traditional sheaths in retrograde intrarenal surgery (RIRS), but whether the two designs-the intelligent pressure-controlled type (real-time intrarenal pressure monitoring) and the flexible negative-pressure type (steerable tip)-differ in clinical outcomes is unknown. Three head-to-head comparisons exist, all using clinically insignificant residual fragment (CIRF)-based stone-free rate (SFR) definitions, with no systematic synthesis. This study aimed to determine whether the two designs differ in clinically relevant outcomes after RIRS. This study combined a single-center retrospective cohort (264 patients; 147 intelligent, 117 flexible NP-UAS) with a meta-analysis of all published head-to-head comparisons (4 studies, 539 patients). The primary outcome was SFR, defined as zero residual fragments on 1-mm computed tomography (CT) within 48 hours to maximize sensitivity to between-group differences. Confounding by indication was addressed with multivariable regression, propensity score matching (PSM), inverse probability of treatment weighting (IPTW), Firth penalized likelihood, and E-value analysis; the meta-analysis used a restricted maximum likelihood (REML) random-effects model. Certainty was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Crude SFR was 24.5% (intelligent) versus 14.5% (flexible) [odds ratio (OR) 1.91, 95% confidence interval (CI): 1.02-3.68, P=0.047], attenuating to non-significance after sequential adjustment (operative time excluded: OR 1.72, 95% CI: 0.83-3.68, P=0.15), with consistent results across PSM (OR 1.67), IPTW (OR 1.49), and Firth regression (OR 1.65); E-values were 3.23 (crude) and 2.83 (adjusted). Operative time was shorter with the flexible sheath (crude -25.9 min), but mediation analysis showed it did not mediate the sheath-SFR relationship [average causal mediation effect (ACME) P=0.30]. Postoperative infection did not differ between groups. In the exploratory meta-analysis, subgrouping by SFR definition reduced I2 from 75.7% to 0.7%, though confounded with study center. GRADE certainty was very low for all outcomes. Across five analytical methods and meta-analysis, the evidence is insufficient to establish a clinically meaningful SFR difference between intelligent and flexible NP-UAS. The flexible sheath is associated with shorter operative time, but without differential stone clearance, and GRADE certainty is very low. A non-inferiority randomized controlled trial (RCT) (approximately 500 patients) with standardized zero-fragment CT SFR is required.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Urology, Xiangxi Tujia and Miao Autonomous People's Hospital, Jishou, China."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Wenyang Xiao",
      "orcid": "0009-0008-2292-9677"
    },
    {
      "affs": [
        0
      ],
      "name": "Nanyang Luo"
    },
    {
      "affs": [
        0
      ],
      "name": "Junyu Yan"
    },
    {
      "affs": [
        0
      ],
      "name": "Xiuhong Huang"
    },
    {
      "affs": [
        0
      ],
      "name": "Qi Huang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fnygv46x8w503.bib",
  "cited_by": 0,
  "doi": "10.21037/tau-2026-0611",
  "fulltext_url": "https://europepmc.org/articles/PMC13741069",
  "id": "fnygv46x8w503",
  "issns": [
    "2223-4691"
  ],
  "landing_url": "https://europepmc.org/article/MED/42997147",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2748|Kidney Stones and Urolithiasis Treatments"
    ]
  ],
  "openalex": "W7223924586",
  "pdf_url": "https://europepmc.org/articles/PMC13741069?pdf=render",
  "pmcid": "PMC13741069",
  "pmid": "42997147",
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fnygv46x8w503.ris",
  "sources": [
    {
      "first_seen": "2026-11-09T15:20:41Z",
      "native_id": "MED:42997147",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42997147"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2748|Kidney Stones and Urolithiasis Treatments",
      "subfield": "general"
    }
  ],
  "title": "Intelligent versus flexible negative-pressure aspiration sheath for ureteroscopic lithotripsy: a single-center retrospective study with systematic review and meta-analysis.",
  "title_text": "Intelligent versus flexible negative-pressure aspiration sheath for ureteroscopic lithotripsy: a single-center retrospective study with systematic review and meta-analysis.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T15:20:41Z",
  "url": "https://research.draconitic.com/paper/fnygv46x8w503",
  "venue": "Translational andrology and urology",
  "versions": []
}