Pishchalnikov YA et al, 2013: Evaluation of the LithoGold LG-380 Lithotripter: In Vitro Acoustic Characterization and Assessment of Renal Injury in the Pig Model
Pishchalnikov YA, McAteer JA, Williams JC Jr, Connors BA, Handa RK, Lingeman JE, Evan AP
Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
ABSTRACT PURPOSE: Conduct a laboratory evaluation of a novel low-pressure, broad focal zone electrohydraulic lithotripter (TRT LG-380).
METHODS: Mapping of the acoustic field of the LG-380, along with a Dornier HM3, a Storz Modulith SLX, and a XiXin CS2012 (XX-ES) lithotripter was performed using a fiberoptic hydrophone. A pig model was used to assess renal response to 3000 shockwaves (SW) administered by a multistep power ramping protocol at 60 SW/min, and when animals were treated at the maximum power setting at 120 SW/min. Injury to the kidney was assessed by quantitation of lesion size and routine measures of renal function.
RESULTS: SW amplitudes for the LG-380 ranged from (P(+)/P(-)) 7/-1.8 MPa at PL-1 to 21/-4 MPa at PL-11 while focal width measured ∼20 mm, wider than the HM3 (8 mm), SLX (2.6 mm), or XX-ES (18 mm). For the LG-380, there was gradual narrowing of the focal width to ∼10 mm after 5000 SWs, but this had negligible effect on breakage of model stones, because stones positioned at the periphery of the focal volume (10 mm off-axis) broke nearly as well as stones at the target point. Kidney injury measured less than 0.1% FRV (functional renal volume) for pigs treated using a gradual power ramping protocol at 60 SW/min and when SWs were delivered at maximum power at 120 SW/min.
CONCLUSIONS:The LG-380 exhibits the acoustic characteristics of a low-pressure, wide focal zone lithotripter and has the broadest focal width of any lithotripter yet reported. Although there was a gradual narrowing of focal width as the electrode aged, the efficiency of stone breakage was not affected. Because injury to the kidney was minimal when treatment followed either the recommended slow SW-rate multistep ramping protocol or when all SWs were delivered at fast SW-rate using maximum power, this appears to be a relatively safe lithotripter.
J Endourol. 2013 Feb 6. [Epub ahead of print]
PMID:23228113 [PubMed - as supplied by publisher]. FREE ARTICLE
The authors of this report have made an interesting comparison between shock wave properties in four different lithotripters: LG-380, Dornier HM3, Storz SLX and XiXin CS2012. The characteristics of these lithotripters are shown below.
There are a lot of interesting data in this article. The most interesting is, however, the important role that the focal width has when the target is moved away from the central axis of the focus. The small lesions associated with the low power shock waves were expected.
The importance of the geometric properties of the shock wave focus has attracted deserved interest and it is obvious that we still have not seen the optimal solution in this regard. Research in lithotripter technology should have the aim of finding the best combination of focal geometry and shock wave power in the focal volume.