Generation (spark) gap: developments in lithotripsy


The role of ESWL is well established in the treatment armentarium for renal tract calculi. Since the earliest outcomes reported on the use of the HM-3 machine (Dornier MedTech Europe GmbH, Wessling, Germany), lithotripters have been compared with regard to their stone-free rates (SFRs) and efficiency quotient (EQ) ratios. The recent study by Neisius et al. [1] addresses these outcomes for a third generation lithotripter, the Lithoskop® (Siemens Medical Systems, Erlangen, Germany), with a long focal length and a wide beam. The favourable results were described separately for renal and ureteric stones, and the study also reported on analgesic requirements, complication rates and re-treatment rates.

Although there has been a vogue for literature to compare the outcomes of newer lithotripters with those of the HM-3, the traditional ‘gold-standard’ device, one may actually wish to see where the newer machine stands in relation to contemporary (and therefore commercially available) products. The current study illustrates this in tables 4 and 5, and the authors also reference a fourth generation lithotripter evaluated by Nomikos et al. [2].

The published European Association of Urology/AUA guidelines [3, 4] note that modern ureteroscopy is superior to ESWL for mid- and distal ureteric stones, and for proximal ureteric stones >10 mm; and therefore the SFR and EQ for amodern lithotripter might actually even be compared with modern ureteroscopic results, especially if one is to counsel the patient fully with objective outcome data.

The definition of ‘stone-free’ remains variable, partly because of the difficulties of standardization across different healthcare systems, as alluded to by the present authors. While it would be ideal to have CT data (before and after treatment, e.g. at 3 months), this is not always practical or achievable; this is an inherent weakness of any true comparison of treatments, albeit one that is universally recognized.

Finally, one might consider whether the success of a particular approach can incorporate factors such as analgesic requirements and ancillary procedures (e.g. stenting) in a quantitative way. Just as the ‘trifecta’ described for radical prostatectomy advances the outcome measure beyond just oncological survival data [5], perhaps it is time for us to re-examine outcomes for stone treatments beyond just measuring SFR and EQ, especially as the choice of stone treatment method is affected by a number of other variables, both patient- and therapy-related. For now, there remains a range of options, and ESWL in expert hands plays a key role in the armentarium.