OBJECTIVE To explore the therapeutic feasibility, safety and efficacy of semi-sitting astride position for extracorporeal shock wave lithotripsy (SWL) of urethral calculi. METHODS A total of 7 male cases of urethral calculi from November 1997 to August 2013 were enrolled. Their age range was 24-52 years. There were anterior (n = 1) and posterior (n = 6) urethral calculi. The diameter range of stone was 0.5 cm×0.5 cm to 1.0 cm×2.0 cm. BH-VG twin-pulse low-energy SWL was employed with a semi-sitting astride position. The average frequency was 2 500 (1 800-3 500) times. And the treatment voltage was 3-8 kV. RESULTS Both stone fragmentation rate and stone-free rate 1 hour post-SWL was 100%.No severe complications occurred. CONCLUSION Semi-sitting astride position SWL is simple, safe, effective and feasible for posterior urethral calculi.

中文翻译：

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半坐式跨坐位治疗体外冲击波碎石术治疗尿道结石的临床经验

目的探讨跨坐式半坐位治疗尿道结石体外冲击波碎石术的可行性，安全性和有效性。方法收集1997年11月至2013年8月的7例男性尿道结石病例。他们的年龄范围是24-52岁。尿道结石有前（n = 1）和后（n = 6）。石头的直径范围是0.5cm×0.5cm至1.0cm×2.0cm。BH-VG双脉冲低能SWL采用半坐式跨骑姿势。平均频率是2500（1 800-3 500）倍。处理电压为3-8kV。结果SWL后1小时的碎石率和无结石率均为100％，未发生严重并发症。结论半坐式跨骑位SWL治疗尿道后结石简单，安全，有效，可行。