Objective   To study the application of guide wire and puncture needle in percutaneous nephrolithotomy for improving the stone free rate.  Methods   Nineteen patients (11 males and 8 females) with staghorn stones admitted to our department from October 2008 to December 2009 were enrolled in this study. Their average age was 42.8 years. CT and pyelography showed staghorn stones in the left kidney of 11 patients and in the right ki

dney of 9 patients. General anesthesia was performed in all patients. Puncture was performed in the area under the costal margin 12 between the posterior axillary line and subscapular line using a 18F needle under the guidance of ultrasound. The puncture channel was dilated to the F

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  where  the peel-away sheath of the needle was left. A ureteroscope was inserted and the visible stones were fragmented using Holmium laser and then removed out of the body. If there were residual stones in any calyx inaccessible with the ureteroscope， another puncture was made under the guidance of ultrasound to the calyx with residual stones. The guide wire was inserted through the needle to the pelvic，and the ureteroscope was inserted through the first puncture channel to find the guide wire， along which the calyx calculi were observed. The renal calyx neck was split if necessary. The guide wire was withdrawn if the stones could not be touched by the guide wire because of a bad angle

and the surface of calyx calculi was directly punctured with a puncture needle under the guidance of ultrasound. The stones were slightly pushed away from the calyx to renal pelvic and fragmented.  Results   Two-channel fragmentation of stones was performed in 2 patients due to a large pelvic and a small calyx with a narrow calyx neck. Lithotripsy was successful in the other 17 patients with a stone free rate of 100%. The average operation time was 83.2 min and the mean estimated intraoperative blood loss was 100 ml. The mean postoperative hospital stay time of the patients was 5.6 d. Fever occurred in 3 patients after operation and was alleviated after treatment with antibiotics. No urinary leakage，pleural injury，hemorrhage and other complications occurred.  Conclusion   Guide wire and puncture needle can significantly improve the stone free rate of percutaneous nephrolithotomy

decrease the blood loss in patients with staghorn stones and post-operative complications such as infection. 