DISS Studies

Summary: 

This retrospective study from Sf. Ioan Clinical Hospital (Bucharest) compared three single-use flexible ureteroscopes across 75 consecutive patients treated for renal stones: a 7.5 Fr scope without suction (Group A), a 7.5 Fr scope with direct in-scope suction (Group B), and the newer 9.2 Fr Pusen PU400 with a 5.1 Fr working channel and DISS (Group C). 

Baseline stone characteristics (size, volume, density, location) were comparable across groups. Residual fragment rates trended lower with increasing scope caliber and suction (24.0% in Group A, 16.0% in Group B, 4.0% in Group C), though the difference did not reach statistical significance (P = 0.132), likely due to sample size. The PU400 (Group C) achieved significantly higher subjective visualization scores (mean 3.72) than both 7.5 Fr devices (3.04 and 3.20; P < 0.001), with no significant difference between Groups A and B. Operative time, hospitalization duration, and complication rates were similar across all three groups.

Key takeaways:

• The 9.2 Fr PU400 (5.1 Fr working channel, DISS) delivered significantly better intrarenal visualization than both 7.5 Fr scopes, with or without suction
• A numerical trend toward fewer residual fragments with larger caliber and suction did not reach statistical significance in this sample
• Operative time, hospitalization stay, and complication rates were comparable across all three device types — added suction and caliber did not prolong surgery or increase morbidity
• Findings are hypothesis-generating given the retrospective, non-randomized design (group allocation was based on device availability, not randomization) and modest sample size (n=25 per group)
• Authors note the higher cost of single-use devices remains a key real-world consideration despite the visualization benefits

Published: May 2026

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Summary: 

This multicentre registry study (540 patients, 16 centres, 14 countries) compared DISS-assisted flexible ureteroscopy with vs. without a ureteral access sheath (UAS), looking at stone-free rates and complications.

Both approaches achieved high stone-free rates, but the non-UAS group had a modestly higher overall stone-free rate (95.9% vs 88.9%). That's explained by case selection: the UAS group tackled larger, more complex, multi-stone cases with more pre-stenting, and took longer in surgery. UAS use was linked to more fever and a higher 30-day complication rate, but no sepsis occurred in either group.

Key takeaways:

• Non-UAS DISS: high stone-free rates, fewer complications — best suited to smaller, simpler stones
• UAS + DISS: better suited for larger, multiple, or more complex stones, despite longer operative time and higher complication odds
• No sepsis in either group
• Bottom line: UAS use should be tailored to case complexity, not applied by default. 

Published: May 2026

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Summary:
This prospective audit (64 patients, 2 institutions) introduces the FIRST procedure — combining a Flexible and Navigable Suction Access Sheath (FANS) with a DISS ureteroscope — and compares it against DISS used with a conventional access sheath (C-UAS).

Despite handling a significantly larger stone burden, the FIRST group achieved a higher 30-day stone-free rate (83.8% vs 70.4%) and notably better 3-month outcomes, with zero residual fragments in 100% of patients versus 22.2% in the conventional group — translating to zero reinterventions in the FIRST group. Surgeons also rated ergonomics and visibility significantly better with FIRST. Complication rates were comparable between groups, with no severe complications in either.

Key takeaways:

• FIRST procedure (FANS + DISS) outperformed DISS + conventional sheath on stone-free rate at both 30 days and 3 months
• FIRST group had zero reinterventions at 3 months vs 22.2% residual fragments in the comparison group
• Achieved despite FIRST group having a larger, more complex stone burden
• Surgeon-rated ergonomics and visibility favored FIRST
• Complication rates similar between groups; no high-grade complications in either

Published: June 2026

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Summary:
This retrospective study (81 patients, Hospital Alemán, Buenos Aires) evaluated whether DISS could work safely and effectively without a ureteral access sheath and without pre-stenting — in patients with non-complex kidney stones.

Using the 7.5 Fr DISS scope, the study achieved a Grade A stone-free rate of 86.4% (zero residual fragments) and Grade B of 13.6% (fragments ≤2mm), with no patients left with larger residual fragments. Complications were low (8.6%) and none were major. A postoperative stent was still placed in the large majority of cases (84.3%), even though a pre-operative stent was not used.

Key takeaways:

• Sheathless, non-prestented DISS achieved a 100% combined stone-free rate (Grade A + B) in this cohort
• Complication rate was low (8.6%), with no major complications
• Most patients (84.3%) still received a post-operative stent, even without pre-stenting
• This is an initial single-centre experience — authors call for further trials to confirm the findings

Published: January 2026

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Summary: 

This ex vivo study compared two DISS-enabled flexible ureteroscopes — the 7.5 Fr PU3033AH and 9.2 Fr PU400A — measuring irrigation flow, intrarenal pressure (IRP), and how quickly the kidney's collecting system responds to suction, both with an empty channel and with laser fibers or a basket inserted.

The 9.2 Fr scope delivered higher flow rates and IRP (peak of 34 mmHg), and collapsed/recovered faster than the 7.5 Fr scope. In both scopes, inserting instruments reduced performance across the board — but the effect was smaller in the 9.2 Fr scope, thanks to its wider 5.1 Fr working channel.

Key Takeaways: 

• 9.2 Fr (PU400A) outperformed 7.5 Fr (PU3033AH) on flow rate, IRP, and collapse/recovery speed
• Inserting working instruments reduced performance in both scopes
• The wider-channel 9.2 Fr scope was less affected by instrument insertion
• Thicker instruments had a bigger negative impact on flow and pressure recovery

Published: August 2025

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Summary: 

This ex vivo study tested whether a novel single-use flexible cystoscope with DISS (PC200) could fragment and clear bladder stones — both in a straight scope position and at an extreme 180° bend simulating a diverticulum.

Laser lithotripsy succeeded in all trials. Fragmentation and clearance were faster with the scope straight; in the bent position, continuous suction and irrigation still allowed fragments to be flushed out of the simulated diverticulum into the main bladder.

Key takeaways:

• DISS-enabled bladder stone lithotripsy is feasible, including at extreme scope angles (~180°)
• Straight-position lithotripsy was faster than the bent/diverticulum simulation
• Suction aided both visibility (via fluid/dust clearance) and scope maneuverability
• Small study — only 3 trials per condition

Published: August 2025

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Summary: 

This bench study compared two DISS ureteroscopes (5.1 Fr and 3.6 Fr) against a conventional ureteroscope for suctioning fluid and stone dust, testing multiple deflection angles and channel conditions.

The 5.1 Fr DISS scope was the standout performer — it was the only scope able to evacuate 0.5mm stone fragments, and it cleared dust and fluid faster than both the 3.6 Fr DISS and conventional scopes across all angles. Both DISS scopes beat the conventional scope on fluid suction speed. No scope could handle 1mm fragments without clogging.

Results

Both DISS-U had significantly higher suction rates than the CU 3.6 with an empty channel, or with either a guidewire, or a 2.2 Fr NCircle® in the working channel, at all measured angles (p < 0.001 for all; Table 1). The DISS-U 5.1 had the highest suction rate in all measured categories (p < 0.001 for all; Table 1). When suctioning with the CU 3.6 at 0°, the use of a 2.2-Fr basket decreased the suction rate by 71.7% (p < 0.001), and the use of a 0.038 guidewire decreased the flow rate by 93.9% (p < 0.001). With the DISS-U 3.6 at 0°, the use of a 2.2-Fr basket decreased the suction rate by 66.0% (p < 0.001). The use of a 0.038 guidewire decreased the flow rate by 95.8% (p < 0.001). With the 5.1-Fr DISS-U at 0°, the use of a 2.2-Fr basket decreased the suction rate by 28.6% (p < 0.001), with the use of a 0.038 guidewire decreasing the flow rate by 51.3% (p < 0.001).

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Summary: 

This ex vivo porcine study compared intrarenal pressure (IRP) between the 7.5 Fr and 9.2 Fr DISS ureteroscopes across different irrigation methods and suction patterns.

The 9.2 Fr scope consistently produced higher IRPs than the 7.5 Fr scope, with the highest reading (45 mmHg) seen using manual pump irrigation with no suction. However, the 9.2 Fr scope's wider 5.1 Fr channel also let it regain baseline pressure faster after suctioning. The study notes — for the first time experimentally — that a wider working channel raises baseline IRP faster than a standard 3.6 Fr channel.

Key takeaways:

• 9.2 Fr scope: higher IRPs overall, but faster pressure recovery after suction
• 7.5 Fr scope: lower IRPs, particularly with automated pump at 40 mmHg
• Novel finding: wider (5.1 Fr) working channels raise baseline IRP faster via irrigation — a trade-off, not just an advantage
• Authors flag this needs clinical (not just ex vivo) validation before drawing safety conclusions

Published: August 2025

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Summary: 

This bibliometric analysis reviewed 3,693 articles (2015–2024) from the Web of Science database to map global research trends in minimally invasive kidney stone treatments — PCNL, RIRS, SWL, and ECIRS.

Publication volume grew significantly over the decade, led by China, Turkey, and the USA (with the USA topping total citations). PCNL remains the most-studied procedure and current gold standard for large stones, while RIRS is gaining ground thanks to laser and flexible ureteroscopy advances. Interest in SWL is declining, while ECIRS and multimodal approaches are rising.

Key takeaways:

• PCNL: most-studied, remains gold standard for large stones
• RIRS: growing fast, driven by laser tech and flexible ureteroscopy advances
• SWL: declining research interest
• ECIRS and multimodal approaches: emerging trend
• Future research focus flagged: AI decision-support tools, international collaboration

Published: June 2025

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Summary: 

This in vitro study tested how quickly the 7.5 Fr single-use suction ureteroscope (PU3033AH) drops intrarenal pressure below 40 mmHg, and how it handles stones and fragments during suction.

Continuous suction with irrigation on was the fastest way to lower pressure — reaching 40 mmHg in a median of about 3.5 seconds. The scope could aspirate stone fragments under 1 mm, and could reposition (though not fully aspirate) larger stones from 1–5 mm when suctioning continuously in an obstacle-free setup.

Key takeaways:

• Continuous suction + irrigation on = fastest pressure reduction (~3.5s median to reach 40 mmHg)
• Fragments under 1 mm: successfully aspirated out of the system
• Stones 1–5 mm: could be relocated/displaced, not necessarily removed
• Testing was in vitro with no obstacles — a simplified setup, not a real renal anatomy

Published: November 2024

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Summary:
This prospective study (105 patients, single Bucharest centre) compared three setups using the Pusen 7.5Fr scope: standard access sheath alone, DISS + standard sheath, and DISS + a suction-enabled access sheath.

The combined DISS + suction sheath group performed best across nearly every measure — lowest residual fragment rate (2.85% vs 17.14% with no suction), fewest postoperative stents needed (5.71% vs 25.71%), shortest hospital stay, and the highest surgeon-rated visibility score (9/10 vs 6/10). All complications across all groups were low-grade (Clavien I–II).

Key takeaways:

• DISS + suction access sheath combo outperformed DISS alone and standard sheath alone on nearly every metric
• Residual fragment rate: 2.85% (combined) vs 17.14% (no suction at all)
• No severe complications in any group
• Single-centre, single-surgeon design — authors call for larger multicentre trials to confirm

Published: November 2024

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Summary:
This prospective multicentre study (6 tertiary centres across Europe and Asia) was the first clinical evaluation of the Pusen DISS 7.5Fr ureteroscope (PU3033AH), assessing manoeuvrability, suction quality, visibility, and clinical efficiency across 57 procedures.

Surgeons rated integrated suction as helpful in 94.7% of cases. The scope performed well across visibility, manoeuvrability, and suction quality, with the authors concluding it delivered "excellent operative results" — though they note larger comparative cohorts are still needed to fully understand suction's added value.

Key takeaways:

• First published clinical evaluation of the Pusen DISS 7.5Fr scope
• 94.7% of surgeons rated integrated suction as helpful
• Multicentre, international (Europe + Asia), reputable author group (Somani, Castellani, Gauhar et al.)
• Authors explicitly flag the need for larger comparative studies — good "honest limits" framing

Published: October 2024

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