Abstract
Purpose:
An ultrasound-based real-time tracking system has been shown to improve the efficacy of lithotripsy in animal studies. This system has been implemented into an electromagnetic shockwave lithotripter (LM-9200 ELMA), and the treatment outcomes were prospectively evaluated.
Materials and Methods:
A total of 1332 patients with one renal stone were treated with LM-9200 ELMA lithotripter between December 2004 and November 2007. Fluoroscopy and ultrasound were alternately used for calculus localization and focusing first. After the calculus was focused and displayed clearly by ultrasound, the ultrasound-based real-time tracking system was applied for calculus monitoring and shockwave trigger control. All patients were followed for up to 3 months. Data regarding stone location, stone size, shockwave number, treatment time, stone free rate, and possible complications were obtained.
Results:
Of the 865 males and 467 females treated (mean stone size = 12.3 mm), the stone-free rate in 3 months was 80.0%. For all patients, neither anesthetics nor analgesics were necessary. The incidence of blood pressure and microscopic hematuria grading increment at 2 weeks after treatment was 6.8% and 13.8%, respectively. There were no subcapsular hematoma or prolonged hematuria observed. Stone size was an important factor predicting stone-free rate (9.1 ± 2.1 mm in the successful group vs. 22.0 ± 3.1 mm in the failed group, p < 0.001). The calculated efficiency quotient of this machine was 0.67.
Conclusion:
An electromagnetic shockwave lithotripter using ultrasound-based real-time tracking system showed efficient crushing of renal calculi in vivo. Our experience has shown that patients treated by this lithotripter are safe with slight microscopic hematuria and having 80% chance of stone clearance.