Characterization of Fluid Dynamics and Temperature Profiles During Ureteroscopy with Laser Activation in a Model Ureter

Louters, Marne; Kim, Hyung Joon; Dau, Julie J; Hall, Timothy L.; Ghani, Khurshid R.; Roberts, William W.

doi:10.1089/end.2022.0275

Cited by 6 publications

(5 citation statements)

References 24 publications

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“…Lowering ODC decreases the IRT and thermal dose by a greater proportion of the cycle without firing, as shown in an in vitro calyceal model [55]. Another in vitro experiment reported ODC utilization as a method to limit the IRT increase in small cavities, such the ureter or minor calyxes [57,58].…”

Section: Type Of Laser Activation: Operator Duty Cycle or Continuousmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

“…Burst laser lithotripsy with high frequencies (>30 Hz) with ODC >50% are suggested to increase IRT and thermal dose whereas low power-low frequencies and continuous activation do not expose to thermal damage [56]. Moreover, maintaining low power settings in narrow volumes (minor calyxes or ureter) helps to avoid direct thermal damage and to reduce the irrigation flow, lowering IRP as a consequence [34,58]. At same laser settings temperature rise was significantly higher with low irrigation flow At same irrigation flow, temperature rise was higher using 20 W compared to 10 W None of the groups with irrigation reached the 438C threshold.…”

Section: Andandmentioning

confidence: 99%

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Retrograde intra renal surgery and safety: pressure and temperature. A systematic review

Panthier

Pauchard

Traxer

2023

Current Opinion in Urology

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Purpose of reviewRetrograde intra renal surgery (RIRS) with laser lithotripsy represents the gold-standard to treat renal stones up to 20 mm. Controlling intraoperative parameters such as intrarenal pressure (IRP) and temperature (IRT) is mandatory to avoid complications. This article reviews advances in IRP and IRT over the last 2 years. Recent findingsWe conducted a PubMed/Embase search and reviewed publications that include temperature and pressure during RIRS. Thirty-four articles have been published which met the inclusion criteria. Regarding IRP, a consensus has emerged to control IRP during RIRS, in order to avoid (barotraumatic and septic) complications. Several monitoring devices are under evaluation but none of them are clinically approved for RIRS. Ureteral access sheath, low irrigation pressure and occupied working channel help to maintain a low IRP. Robotic systems and suction devices would improve IRP intraoperative management and monitoring. IRT determinants are the irrigation flow and laser settings. Low power settings(<20 W) with minimal irrigation flow (5--10 ml/min) are sufficient to maintain low IRT and allows continuous laser activation. SummaryRecent evidence suggests that IRP and IRT are closely related. IRP depends on inflow and outflow rates. Continuous monitoring would help to avoid surgical and infectious complications. IRT depends on the laser settings and the irrigation flow.

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Section: Type Of Laser Activation: Operator Duty Cycle or Continuousmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Andandmentioning

confidence: 99%

See 1 more Smart Citation

Retrograde intra renal surgery and safety: pressure and temperature. A systematic review

Panthier

Pauchard

Traxer

2023

Current Opinion in Urology

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“…Conversely, lower flow rates might risk elevating intra-urethral fluid temperature and causing renal injuries [29]. Therefore, during the experiments, we maintained a flow rate of 40 mL/min to prevent heat accumulation and complications [8,20].…”

Section: Discussionmentioning

confidence: 99%

“…1B). Room temperature irrigation with a controlled flow rate of 40 mL/min [19,20] was employed using a peristaltic pump (Masterflex®) to ensure visibility during the LL procedure. To assess the potential risk of thermal injury, the thermal dose [21], evaluated by cumulative equivalent minutes at 43°C (CEM43°C), was calculated using the following equation:

CEM 43 ° C = \int_{0}^{t_{final}} {normalR}^{43 - (Δ T + 37)} d t,

where R is 0.25 for T < 43°C and 0.5 for T ≥ 43°C.…”

Section: Methodsmentioning

confidence: 99%

Exploring optimal settings for safe and effective thulium fibre laser lithotripsy in a kidney model

Mishra,

Medairos,

Chen

et al. 2023

BJU International

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ObjectivesTo explore the optimal laser settings and treatment strategies for thulium fibre laser (TFL) lithotripsy, namely, those with the highest treatment efficiency, lowest thermal injury risk, and shortest procedure time.Materials and MethodsAn in vitro kidney model was used to assess the efficacy of TFL lithotripsy in the upper calyx. Stone ablation experiments were performed on BegoStone phantoms at different combinations of pulse energy (EP) and frequency (F) to determine the optimal settings. Temperature changes and thermal injury risks were monitored using embedded thermocouples. Experiments were also performed on calcium oxalate monohydrate (COM) stones to validate the optimal settings.ResultsHigh EP/low F settings demonstrated superior treatment efficiency compared to low EP/high F settings using the same power. Specifically, 0.8 J/12 Hz was the optimal setting, resulting in a twofold increase in treatment efficiency, a 39% reduction in energy expenditure per unit of ablated stone mass, a 35% reduction in residual fragments, and a 36% reduction in total procedure time compared to the 0.2 J/50 Hz setting for COM stones. Thermal injury risk assessment indicated that 10 W power settings with high EP/low F combinations remained below the threshold for tissue injury, while higher power settings (>10 W) consistently exceeded the safety threshold.ConclusionsOur findings suggest that high EP/low F settings, such as 0.8 J/12 Hz, are optimal for TFL lithotripsy in the treatment of COM stones. These settings demonstrated significantly improved treatment efficiency with reduced residual fragments compared to conventional settings while keeping the thermal dose below the injury threshold. This study highlights the importance of using the high EP/low F combination with low power settings, which maximizes treatment efficiency and minimizes potential thermal injury. Further studies are warranted to determine the optimal settings for TFL for treating kidney stones with different compositions.

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Factors affecting the thermal effects of lasers in lithotripsy: A literature review

Krishnaprasad,

Pathi,

Nazar

2024

Asian Journal of Urology

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Characterization of Fluid Dynamics and Temperature Profiles During Ureteroscopy with Laser Activation in a Model Ureter

Cited by 6 publications

References 24 publications

Retrograde intra renal surgery and safety: pressure and temperature. A systematic review

Retrograde intra renal surgery and safety: pressure and temperature. A systematic review

Exploring optimal settings for safe and effective thulium fibre laser lithotripsy in a kidney model

Factors affecting the thermal effects of lasers in lithotripsy: A literature review

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