Purpose: The latest digital ureteroscope, the DUR-D (Gyrus ACMI Inc., Southborough, Massachusetts) offers image quality that greatly exceeds current analog image capabilities. The purpose of this report was to document the applicability of this device in studying the earliest stages of stone formation.
Materials and methods: Symptomatic patients with nephrolithiasis (less than 1 cm in diameter) were prospectively enrolled and their renal papilla digitally mapped prior to stone removal. Recovered stones were photographed and analyzed using micro-computerized tomography. If the procedure could not be completed with the DUR-D, a conventional ureteroscope was used. Minors, pregnant patients and those with systemic disorders were excluded.
Results: Eight patients (10 renal units), 2 cystine and 6 calcium oxalate stone formers, were studied with a mean age of 50.1 years. Excellent images were collected for all papilla except in 2 cases; a proximal ureteral stricture and acute angulation of the lower pole collecting system, respectively. There were no mechanical device failures. Of the 10 renal units 7 had stents postoperatively and there were no patient complications.
Conclusions: The ease of use and high quality images of digital ureterorenoscopy will allow the documentation of the earliest stages of calcium oxalate stone formation and, thereby, advance our understanding of the pathogenesis of calcium oxalate stone formation.