Shizuichi Kageyama

Clinical Application of Extracorporeal Shock Wave Lithotripsy using Microexplosions

Extracorporeal stone disintegration using a chemical explosive (10 mg. lead azide) as an energy source of underwater shock waves was performed in 105 patients 11 to 72 years old who had stones in the upper urinary tract. We used a prototype disintegrator in this series. The over-all rate free of stones 3 months after treatment was 82 per cent. Shock wave therapy was performed alone in 77 patients (73 per cent), while the remainder required combined treatment with percutaneous and/or transurethral lithotripsy. The most common complications were colic pain (30 per cent) and fever (23 per cent). In 4 patients other complications, that is bacteremia, gastrointestinal bleeding, ureteral injury and subcapsular renal hematoma, were observed but they were treated conservatively with no serious adverse effects. Our study demonstrates the safe use of this method for clinical treatment.

Computed tomography and composition of renal calculi

SummaryThe attenuation values of computed tomography were studied in 50 recovered renal calculi of more than 10 mm in diameter, in the hope of determining the composition of calculi in situ. The attenuation value of various calculi (mean±s.d.) in a 5 mm slice with a maximal rectangular region of interest was as follow (Hounsfield units); mixed calcium oxalate and phosphate 1,555±193 (n=22), magnesium ammonium phosphate 1,285±284 (n=18), calcium oxalate 1,690 (n=1), calcium phosphate 1,400 (n=2), cystine 757±114 (n=5) and uric acid 480 (n=2). Attenuation values ranging from 500 to 1,600 overlapped for various calculi, except those composed of uric acid calculi. There was no correlation between the attenuation value and the mineral content such as calcium or magnesium per unit weight of calculus. The mineral content per unit volume seemed to be attributable to the attenuation value. From the present results we conclude that the determination of calculous composition by the attenuation value is possible only for oxalate calculi of more than 1,600 and uric acid calculi of less than 500 attenuation value, provided that the proper CT slice location, the region of interest and the appropriate calculus size can be determined.