From July 1988 to August 1991, 174 stone treatments were attempted on
112 stones in 86 patients using a Therasonics dagger lithotriptor. Mea
n stone diameter was 13 mm. (range 4 to 60). The success rate (defined
as no debris or fragments less than 4 mm. in an asymptomatic patient)
was 49% and the retreatment rate was 63%. Subjects reported moderate
to severe pain during 70 treatment sessions (42%) despite sedation wit
h parenteral narcotics (50 to 100 mg. meperidine and 50 mg. hydroxyzin
e intramuscularly). One patient had perirenal bleeding requiring a 7-u
nit blood transfusion. Of the treatments 24 (13%) were aborted, 10 due
to pain and 13 because of inability of the operator to position the p
atient or localize the stone. These results appear to be inferior to t
hose reported with alternative lithotriptors. Modifications that have
been made in the Therasonics system may improve stone localization and
treatment results.