70 W holmium: yttrium-aluminum-garnet laser in percutaneous nephrolithotomy for staghorn calculi.
OBJECTIVE
To investigate the safety and efficacy of the high-power (70 W) holmium laser in percutaneous nephrolithotripsy (PCNL) for staghorn calculi.


METHODS
From December 2004 to March 2008, 438 consecutive patients (456 renal units) with > or =4-cm staghorn stones underwent PCNL with a pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser using a 1000-microm end-firing optical fiber. For the first 106 patients (group A; average stone size 5.6 +/- 0.8 cm), a 30 W (3.0 J/pulse; 10 pulse/sec) laser was used, whereas for the other 332 patients (group B; average stone size 5.8 +/- 0.8 cm), the laser power was set at 3.0 J/pulse with a frequency of 20 pulses/sec. For stones in a calix visible with the nephroscope but unreachable with a laser, the mucosa of the calix was split with a 100 W holmium laser to fragment the stones further. Moreover, a porcine model for assessing the safety of the high-power holmium laser was developed.


RESULTS
All patients had successful PCNL. The average lithotripsy time in group B was significantly shorter than that in group A (44 +/- 11.5 minutes vs 69 +/- 14.8 minutes; P < 0.05). No patient had a severe complication. In addition, 39 patients underwent calix splitting with no hemorrhage during or after the operation. The glomerular filtration rate of the treated kidney, reexamined 6 months after the operation, had improved greatly (45.12 vs 31.91 mL/min; P < 0.05). Pathologic evaluation of porcine kidneys exposed to high-power laser firing showed no damage.


CONCLUSIONS
The high-power Ho:YAG laser enhances lithotripsy efficacy by "vaporizing" and "bursting" the stone quickly, reducing lithotripsy time significantly. This is an effective and safe treatment for patients with large renal stones.
Sun
Yinghao
Y
Department of Urology, Changhai Hospital, The Second Military Medical University, Shanghai, People's Republic of China. sunyh@medmail.com.cn
Gao
Xiaofeng
X
Zhou
Tie
T
Chen
Shushang
S
Wang
Linhui
L
Xu
Chuangliang
C
Hou
Jiangou
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D007670:Kidney Calices; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D013552:Swine; D055815:Young Adult