Evaluation of a synchronous twin‐pulse technique for shock wave lithotripsy: a prospective randomized study of effectiveness and safety in comparison to standard single‐pulse technique

Abstract

OBJECTIVE To asses the efficacy and safety of bidirectional synchronous twin‐pulse extracorporeal shock wave lithotripsy (ESWL) compared with standard ESWL. PATIENTS AND METHODS Between March 2003 and December 2006, 240 patients with a radio‐opaque single renal stone of ≤25 mm were randomized to treatment either by the Twinheads (TH) lithotripter (FMD, Lorton, Virginia, USA) or the Dornier Lithotripter S (DLS, Dornier MedTech Europe GmbH, Germering, Germany). Before and after ESWL, urinary N‐acetyl‐B‐glucosaminidase (NAG) levels were assessed and patients were evaluated with dynamic MRI. The efficacy and complications were compared, with success defined as no residual fragments. RESULTS For stones of >10 mm the rate for the failure of disintegration was 13.3% for the DLS vs 1.4% for the TH (P = 0.009). For stones of ≤10 mm the stone‐free rate was 74.4% for the TH vs 67.7% for the DLS (P = 0.6), while for stones of >10 mm it was 78.1% and 66.7%, respectively (P = 0.14). The median (range) number of sessions in both groups was 2 (1–5). After ESWL urinary NAG levels were increased significantly in both groups; in the TH group it declined below the level before ESWL after 2 days, while in the DLS group it remained high after 7 days. In the DLS group four patients developed subcapsular or parenchymal haematoma after ESWL, vs none in the TH group. There was loss of corticomedullary differentiation after ESWL in three patients in the DLS group and only one in the TH group. In the DLS group there was a statistically significantly decrease in bilateral renal perfusion after ESWL, but no changes in the TH group. CONCLUSIONS Synchronous twin‐pulse ESWL has clinical advantages over standard ESWL in terms of safety and efficacy.

Shock wave lithotripsy: advances in technology and technique

“…Dual-head lithotripters are already being used to treat patients and despite the inherent complexity associated with twin shock sources—two potential sources of variability in coupling and acoustic output—plus concern that treatment at very fast shock-wave rate (up to 240 shock waves per min) might be injurious, initial reports suggest that such machines can be used safely and effectively 80,81. Dual-head lithotripters are not currently in widespread use, but the concept has merit and with continued refinement and further study such machines may be applied more widely in the future.…”

Removal of Kidney Stones by Extracorporeal Shock Wave Lithotripsy Is Associated with Delayed Progression of Chronic Kidney Disease

“…Taken together, ESWL trauma is regarded to cause scar formation and loss of functional renal mass 14. In contrast, however, other recent studies reported that renal function impairment associated with ESWL is largely resolved within 1 to 3 months and ESWL per se has no significant long-term effects on renal function 17,18. However, the patients included in these studies had normal renal function, and the effect of ESWL in CKD patients was not addressed.…”

Extracorporeal shock wave lithotripsy today

“…[1415] The rationale in this concept is, that “filling” the negative part of the pressure wave with a positive pressure pulse would theoretically result in improved fragmentation and reduced cavitation with reduced parenchymal damage.…”