The Medstone fixed, mobile, and modular configurations: impact on efficacy.
OBJECTIVE
To evaluate the efficacy of three lithotripter configurations that utilize the Medstone STS treatment head.


METHODS
From 1999 through 2002, 13,131 patients were treated with the Medstone STS fixedsite unit (STS-FIX; 52%), the mobile coach-transportable unit (STS-MOB; 26%), or the modular operating-room unit (STS-T; 22%). All units were staffed by a rotating schedule of the same ten SWL-certified radiological technicians. The treating urologists reported follow-up that included plain abdominal radiography to document stone-free rate (no residual fragments) and the need for auxiliary procedures or re-treatment. An efficiency quotient (EQ) was calculated for each unit.


RESULTS
The overall stone-free rate for the STS-FIX, STS-MOB, and the STS-T was 59%, 62%, and 65%, respectively. The STS-FIX had the lowest stone-free rate for lower-pole stones (48%) and stones 21 mm to 30 mm (30%) compared with the STS-MOB (57% and 62%, respectively) and the STS-T (59% and 54%, respectively). However, the STS-FIX had a higher stone-free rate in the middle ureter (86%) than the STS-T (67%) and STS-MOB (65%). The STS-FIX required more post-SWL procedures overall (12%) than the STSMOB (4%) and STS-T (5%). The re-treatment rates for the STS-FIX, STS-MOB, and STS-T were 7%, 6%, and 6%, respectively. The STS-T had the highest overall EQ (59) followed by the STS-MOB (56) and the STSFIX (50).


CONCLUSIONS
New configurations of the STS lithotripter have a significant positive impact on efficacy compared with the original fixed machine. Availability of real-time fluoroscopy with the STS-T may impact the higher EQ of this machine.
Nicholson
Adam
A
Department of Urologic Surgery, University of Minnesota, Minneapolis, Minnesota 55455-0392, USA.
Lee
Courtney
C
Ugarte
Roland
R
Best
Sara
S
Monga
Manoj
M
D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000628:therapy*; D008096:Lithotripsy / Q000295:instrumentation* / Q000592:standards; D011785:Quality Assurance, Health Care; D012008:Recurrence; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000000981:diagnostic imaging / Q000628:therapy*