ABSTRACT
PURPOSE: We test the hypothesis that erbium:YAG (Er:YAG) lithotripsy is more efficient than holmium:YAG (Ho:YAG) lithotripsy. MATERIALS AND METHODS: Human calculi composed of greater than 97% calcium oxalate monohydrate and cystine were studied. Calculi were irradiated in water using Er:YAG or Ho:YAG lasers. Er:YAG lithotripsy was done with a 425 microm sapphire optical fiber at a pulse energy of 50 mJ at 10 Hz. Ho:YAG lithotripsy was performed with a 365 microm low hydroxy optical fiber at a pulse energy of 500 mJ at 10 Hz or a 425 microm sapphire optical fiber at a pulse energy of 50 mJ at 10 Hz. Fragmentation was defined as the initial stone mass minus the final dominant fragment mass and normalized for incident laser fluence (energy per unit area of fiber tip). RESULTS: Mean fragmentation plus or minus standard deviation for calcium oxalate monohydrate was 38 +/- 27 mg for Er:YAG and 22 +/- 6 for Ho:YAG (low hydroxy silica fiber) versus 5 +/- 1 for Ho:YAG (sapphire fiber, p = 0.001). When fragmentation was normalized for incident laser fluence given different optical fiber sizes, mean fragmentation efficiency was 53.6 +/- 38.7 g-microm2/J for Er:YAG lithotripsy compared with 22.6 +/- 6.4 for Ho:YAG (low hydroxy silica fiber) lithotripsy (p = 0.04). Mean cystine fragmentation was 15 +/- 3 mg for Er:YAG versus 9 +/- 1 for Ho:YAG (sapphire fiber, p = 0.0005). CONCLUSIONS: Er:YAG lithotripsy is more efficient than Ho:YAG lithotripsy.
Subject(s)
Lithotripsy, Laser/methods , Urinary Calculi/therapy , HumansABSTRACT
PURPOSE: During ureteroscopic basketing of ureteral calculi a stone may become engaged in the basket and the basket impacted in the ureter. We describe an endoscopic technique of managing the impacted basket and stone. MATERIALS AND METHODS: The ureteroscope is back loaded off of the basket, and passed into the ureter beside the basket and stone. The holmium:YAG laser is used to irradiate a basket wire, fracturing the wire and releasing the stone. The basket is removed and the stone managed by holmium:YAG lithotripsy. RESULTS: We successfully treated 3 consecutive patients with this technique. No injuries were observed. CONCLUSIONS: The holmium:YAG laser may be used to free an impacted stone basket containing a ureteral calculus.
