Clinical Scorecard: Comparative Analysis of Steady-State and Burst Lasing Methods in Thulium Fiber Laser Applications

At a Glance

Key Highlights

• TFL offers potential advantages over Ho:YAG lasers in lithotripsy but safety concerns remain, especially thermal injury risks at high power settings.
• Burst lasing mode uses intermittent laser activation (5s on/5s off) to reduce thermal buildup and improve visibility compared to steady-state continuous lasing.
• Thermal injury to ureteral tissue is assessed by a 3-point scale (no lesion, impacts/holes, burns) using an in vitro ureteral model.

Guideline-Based Recommendations

Diagnosis

• Use ureteroscopic visualization to guide laser lithotripsy and monitor stone fragmentation.

Management

• Employ TFL with appropriate laser settings balancing power and frequency to optimize stone ablation while minimizing thermal injury.
• Consider burst lasing mode to intermittently stop laser emission, allowing irrigation to cool tissue and reduce thermal damage.
• Maintain adequate irrigation pressure (e.g., gravity irrigation at 40 cmH2O) during lithotripsy to aid cooling.

Monitoring & Follow-up

• Monitor laser active time and cumulative energy delivered to avoid exceeding safe thresholds (e.g., 20W standard presets).
• Observe for intraoperative signs of thermal injury or ureteral strictures postoperatively.
• Use timers or alarms to guide burst lasing intervals and prevent uncontrolled continuous lasing.

Risks

• High-power and high-frequency laser settings can cause thermal injury leading to ureteral strictures.
• Uncontrolled lasing during burst mode may increase risk of tissue damage.
• Thermal injury risk is heightened by exceeding manufacturer-recommended power settings.

Patient & Prescribing Data

Patients undergoing ureteroscopic lithotripsy for ureteral stones

Steady-state lasing provides continuous stone dusting but may increase thermal injury risk; burst lasing reduces thermal buildup by intermittent activation, potentially improving safety.

Clinical Best Practices

• Use a standardized in vitro ureteral model to evaluate laser settings before clinical application.
• Employ a 3-point ureteral damage scale to assess thermal injury severity.
• Ensure operator training on burst lasing timing using timers to optimize safety and efficacy.
• Maintain continuous irrigation during laser activation to dissipate heat.
• Adhere to manufacturer power and energy guidelines to minimize risk of thermal injury.

References

• FDA Class 2 Device Recall for Olympus related to thermal injury
• Studies comparing TFL and Ho:YAG lasers in lithotripsy
• In vitro ureteral model and stone phantom fabrication