Nanoparticle-Enhanced Laser Lithotripsy for Kidney Stones

Summary

More efficient kidney-stone fragmentation with the potential to reduce laser energy, procedure time, and heat-related tissue risk is the goal of a nanoparticle-enhanced irrigation fluid that increases near-infrared laser absorption during ureteroscopic lithotripsy.

The Unmet Need

Kidney-stone laser treatment must balance effective fragmentation against thermal injury

Ureteroscopic laser lithotripsy is an established treatment, but effective stone dusting—particularly high-power pop-dusting—must be balanced against heat buildup and potential kidney-tissue damage. Clinicians have limited reliable means to monitor tissue heating, while conventional improvements primarily rely on changing laser settings and surgical technique. The technology assessment reports approximately US$10 billion spent on urinary-stone management in the United States between 2011 and 2018, including about US$1.5 billion for ureteroscopic laser lithotripsy, and roughly 300,000 procedures annually.

Advances in endoscopic stone treatment are creating opportunities for adjunctive approaches that improve energy delivery without relying solely on operator-selected settings. Nanoparticle suspensions designed to tune near-infrared absorption could enhance laser-fluid interactions, while the field’s focus on biocompatibility, visibility, irrigation performance, and thermal safety underscores the need for carefully validated materials and formulations.

The Proposed Solution

Nanoparticle-enhanced irrigation fluid tunes near-infrared absorption to strengthen laser-driven stone fragmentation

The proposed nanofluid adds biocompatible nanoparticles to saline irrigation used during ureteroscopic laser lithotripsy, tuning particle size, shape, concentration, and material properties to absorb light from Holmium:YAG or thulium fiber lasers. Candidate materials include PEDOT:PSS conducting-polymer nanoparticles and, as an alternative, heavily doped semiconductors such as indium tin oxide. Unlike approaches centered on adjusting laser settings or surgical technique, the formulation alters light absorption in the irrigation fluid and aims to enhance cavitation and stone dusting with less laser energy or treatment time while limiting heat buildup. Preliminary modeling and experiments support the concept: simulations predict more than tenfold absorption enhancement at a modeled 0.2% particle volume fraction, and experiments report increased absorption and stone-crater volume compared with water. 

Key Advantages

• Enhanced laser energy absorption
• Improved stone dusting performance
• Potentially reduced laser exposure
• Lower heat-related tissue risk
• Performance at greater fiber distances
• Compatibility with two laser types

Applications

• Ureteroscopic lithotripsy for urinary stones
• Pop-dusting of larger kidney stones
• Holmium:YAG or thulium fiber laser stone treatment