EDITORIAL COMMENT

By the early 1990s management of renal calculi had, for themost part, become straightforward. Relatively small stones, thatis less than 2 cm., were managed with extracorporeal shock wavelithotripsy, while larger stones were treated percutaneously. How-ever, at that time management of lower caliceal calculi gainedinterest when some investigators suggested that the incidence oflower pole stones might be increasing. In fact, although there wasno real evidence to support that suggestion, it probably was truethat the incidence of lower pole stones managed with shock wavelithotripsy was increasing. There is no doubt that this result wasdue to earlier treatment of a backlog of more symptomatic renalpelvic or otherwise obstructing stones and the rapidly expandingsupply of lithotriptors. In any case the increasing number ofpatients presenting with lower pole stones for shock wave litho-tripsy and the seemingly inferior results achieved in that settingultimately led to a heightened interest in the study of lower polelithotripsy outcomes.

With the exception of the ongoing Lower Pole Study Group, essen-tially all such studies, including this one by Obek et al, have beenretrospective. However, the retrospective nature of this study doesnot suggest that the findings should be dismissed or even discounted.There are in fact several aspects of this report worth noting. It wasperformed at a single center by a single surgeon. Therefore, patientselection, treatment and re-treatment criteria, followup evaluation,

and determination of stone-free status were probably consistent.Like others, Obek et al found that although the results of extracor-poreal for lower pole stones were inferior to those initially reportedfor renal pelvic stones, results in this caliceal location were notsignificantly different than those achieved in any other. This findingsuggests that there is no inherent problem with infundibular drain-age from the lower calices. Despite all the recent time and effortspent on studies evaluating the impact of lower infundibular angle,length, width and more, none has found any to have a significantimpact when evaluated prospectively.

The findings and recommendations of Obek et al are essentiallyconsistent with those accepted by contemporary practice for extra-corporeal shock wave lithotripsy. In the absence of any unusualanatomical abnormality stones less than 1 cm.2 can surely be treatedprimarily with shock wave lithotripsy, while stones greater than 2cm.2 generally require percutaneous management. Those stones 1 to2 cm.2, whether they are in the renal pelvis, or upper, mid or lowercalices, can often be managed with shock wave lithotripsy. However,such cases need to be individualized with attention to individualanatomy, co-morbid medical conditions, overall and ipsilateral renalfunction, and presumed stone composition and fragility.

Stevan B. StreemDepartment of UrologyCleveland ClinicCleveland, Ohio

SHOCK WAVE LITHOTRIPSY FOR ISOLATED CALICEAL STONE DISEASE 2085