UroToday - The group from the Scottish Lithotriptor Centre provides an extensive and thoughtful retrospective analysis of their SWL experience with over 3000 patients undergoing lithotripsy for stones < 1.5 cm, spanning nearly a 20 year period.

During this time, three different lithotriptors were used: Piezolith 2300 (piezoelectric shock wave), MPL 9000 (electrohydraulic), and Compact Delta (electromagnetic). In addition, the authors divided stones by size and location and calculated the effectiveness quotient (EQ) for each stone location and size (1-5, 6-10, and 11-15 mm).

The effectiveness quotient reveals what % of patients become stone free with a single SWL treatment unaccompanied by retreatment or any auxiliary procedures. The original HM3 routinely had an EQ in the 70% range and stone free rates of 80% and above. What is most telling in this article is that in no case did any of these machines exceed an effectiveness quotient of 60% or a stone free rate (based on KUB or ultrasound) of 65%. Indeed, if one looks at the most common stones: lower calyx (all 3 sizes), renal pelvis (6-10 and 11-15 mm), and upper ureter (6-10mm), the EQ rate for the Compact Delta ranges from 15-32% with an average of 24%, for the MPL 9000 from 15-59% with an average of 34%, and for the Piezolith from 14%-51% with an average of 28%. This means that over 2/3rds of patients, regardless of the type of lithotriptor used, required a retreatment or auxiliary procedure. Lastly, in their multivariate analysis, the MPL 9000 electrohydraulic SWL proved better than the piezoelectric or the electromagnetic lithotiptors.

Bottom line, after two decades of SWL, nothing beats an HM-3! The pathetic paucity of progress in SWL continues; the only response left to the urologist is to pick up ureteroscopes and nephroscopes and return to the more invasive means of the past to treat stone disease. As Yogi Berra would have said: "This is like déjà vu all over again!" Sad….

By Ralph V. Clayman

Reference:
Journal of Endourology 20: 1-8, January 2006
Link Here.
Ng CF, Thompson TJ, McLornan L, Tolley DA

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