Impact of type of anesthesia on efficacy of medstone STS lithotripter.
OBJECTIVE
To evaluate the impact of the type of anesthesia on treatment efficacy, using a comparison of general anesthesia (GEN) and monitored anesthesia care with intravenous sedation (MAC), for patients undergoing extracorporeal shockwave lithotripsy (SWL) on the Medstone STS lithotripter.


METHODS
A case-control study was conducted of 660 patients treated from 1986 to 2002. General anesthesia and MAC were utilized in 330 procedures each. Case matching was performed for stone size, stone location, and body mass index. All lithotripter units were staffed by a rotating schedule of the same 10 SWL-certified radiologic technicians. Patient characteristics, treatment parameters, complications, repeat procedures, and secondary procedures were recorded. Stone-free success rates (no residual fragments) were reported by the treating physician on the basis of plain radiographs. Chi-square analysis was used to compare patients in the two groups.


RESULTS
The overall stone-free rate was better with GEN (67%) than MAC (55%; P = 0.04). Stone-free rates were not affected for stones <or=10 mm (GEN 69%, MAC 63%; P = 0.42). The type of anesthetic impacted stone-free rates in the upper calix (GEN 75%, MAC27%; P = 0.05).


CONCLUSIONS
This study helps define that population that may benefit most from the use of GEN: those with stones >10 mm or in an upper calix. General anesthesia may decrease excursion of the calculus out of the focal area secondary to breathing or patient movement.
Lee
Courtney
C
Department of Urologic Surgery, University of Minnesota, Minneapolis, Minnesota 55455-0392, USA.
Weiland
Derek
D
Ryndin
Igor
I
Ugarte
Roland
R
Monga
Manoj
M
D000758:Anesthesia; D000768:Anesthesia, General; D015992:Body Mass Index; D016022:Case-Control Studies; D016292:Procedural Sedation; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000295:instrumentation* / Q000379:methods; D009068:Movement; D012119:Respiration; D012189:Retrospective Studies; D016896:Treatment Outcome