Nonvisual laser lithotripsy aided by plasma spectral analysis: viability study and clinical application.

Abstract

Nonvisual laser lithotripsy implies laser fragmentation without the aid of endoscopic or direct vision. Using the laser delivery fiber for retrograde transmission of plasma spectrum and its analysis on an optical multichannel analyzer, we designed a project with the objective of identification and fragmentation of calculi by continuous analysis of the plasma feedback spectrum. We were successful in achieving the objectives in the in vitro and ex vivo studies. In the in vivo studies we successfully recorded the plasma spectrum of the stones from inside the ureter and monitored the process of fragmentation with the laser. We have been able to identify the problems for its clinical application. We conclude that by monitoring the feedback spectrum of plasma emission, nonvisual laser lithotripsy is reliable and safe, and can be used successfully in patients with some modifications. Its development is not to replace established endoscopic lithotripsy procedures but rather as an additional armament for the urologist in special situations. Also, the technique can be further exploited for a variety of clinical uses.