High-frequency in laser lithotripsy: do we truly know what it means?

Area of Science:

• Urology and Endourology
• Laser Technology in Medicine
• Nephrolithiasis Treatment

Background:

• The definition of high frequency (HF) in laser lithotripsy is inconsistent.
• This ambiguity may affect clinical outcomes and patient safety during stone removal procedures.
• Understanding HF parameters is crucial for optimizing Holmium:YAG (Ho:YAG), Thulium Fiber Laser (TFL), and pulsed Thulium:YAG (p-Tm:YAG) applications.

Purpose of the Study:

• To systematically review and analyze the existing evidence on the definition of high frequency (HF) in laser lithotripsy.
• To identify variations in HF definitions across different geographical regions, laser types, and manufacturers.
• To propose standardized HF definitions for improved consistency and safety in clinical practice.

Main Methods:

• Conducted a comprehensive literature search of MEDLINE, Scopus, and Cochrane databases up to November 2024.
• Included studies focusing on Ho:YAG, TFL, and p-Tm:YAG lasers for ureteral and renal endoscopic procedures.
• Analyzed user manuals from laser manufacturers and data from artificial intelligence (AI) platforms for HF definitions.

Main Results:

• 106 studies were included, with most originating from Europe, North America, and Asia.
• HF definitions were poorly documented in 25% of studies, showing significant variation (10-200 Hz) across regions.
• Manufacturer guidelines were limited, and AI platforms provided broad ranges (e.g., 15-100 Hz for Ho:YAG, 50-2000 Hz for TFL).

Conclusions:

• A lack of consensus exists regarding HF definitions in laser lithotripsy.
• Standardized terminology is essential for consistent clinical application and patient safety.
• Proposed HF definitions: >30 Hz for renal and >15 Hz for ureteral procedures; HF settings may not be essential for dusting/popcorning with current technology.