Predictive value of radiological criteria for disintegration rates of extracorporeal shock wave lithotripsy.

OBJECTIVE

To evaluate routinely applicable criteria to predict fragmentation of renal calculi by extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND

METHODS

Two hundred and two consecutive patients (121 men, 81 women), median age 48 (range 19-81) years, were treated with the original Dornier HM-3 lithotriptor at a single stone center. Inclusion criteria were: solitary stones, 10-30 mm in greatest diameter, located in renal pelvis or calyces. Based on plain radiographs, the calculi were classified according to their size, form, location, density (compared to the 12th rib), structure and surface. Furthermore, age of the patient, gender and body mass index were also considered for evaluation. Disintegration was documented on day 1 after ESWL by plain X-ray. A multivariate regression analysis was applied to all preoperative parameters, based on the dual variable stone free versus residual fragments.

RESULTS

The overall disintegration rate was 95.5%; 42 patients (20.8%) were completely stone free, and 151 patients (74.7%) had clinically insignificant residual fragments (5 mm or smaller). 14.9% of men and 29.6% of women were stone free (p = 0.01). All other parameters did not reach statistical significance.

CONCLUSIONS

The disintegration rate of the HM-3 is excellent for kidney stones; women did significantly better than men. However, because of this high disintegration rate, a much larger series would be necessary to define possible differences between preinterventional parameters, if there were any at all.