Wu H et al, 2015: Treatment of Renal Stones ≥20 mm with Extracorporeal Shock Wave Lithotripsy.
Wu H, Wang J, Lu J, Wang Y, Niu Z.
Department of Urology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China.
Abstract:
AIMS: To identify subgroups of patients with renal stones ≥20 mm that are more suitable for extracorporeal shock wave lithotripsy (ESWL)
monotherapy.
METHODS: A total of 376 patients with renal stones ≥20 mm underwent monotherapy with ESWL. The treatment outcome was evaluated after 3 months of follow-up. A stone-free status or fragmentation of stones to 4 mm or smaller was considered efficacious.
RESULTS: At 3 months after treatment, the overall stone-free rate was 64.4%, and the efficacy rate was 70.7%. The efficacy rate was 89.4% for patients with a residual stone surface area ≤50% of baseline after the first ESWL, while the efficacy rate was 32.4% for other patients. The efficacy was 92.2% for stones ≤400 mm2 and those with lower radiodensity, as determined by a plain (KUB) film.
CONCLUSIONS: For renal stones with a surface area ≤400 mm2 and a radiodensity equal to or less than that of the 12th rib as determined by a KUB film, ESWL may be considered the first line of treatment, even for stones with a diameter ≥20 mm. For large stones requiring repeat treatments, the surface area of the residual stones after the first ESWL is a predictor of the final treatment result.
Comments 1
It is interesting to note that some authors still find it worthwhile to go beyond the standard recommendations to use SWL only for stones with a diameter ≤20 mm (usually approximately less than ~250 mm2). From my own SWL experience the results presented in this article are not surprising, but using the surface area after the first SWL session as a predictor of final success and to decide if it is worthwhile to proceed with additional treatment sessions is an interesting idea. I can imagine, however, that it is not always easy to estimate the remaining surface area. I some cases the fragments will be spread out and in others it can be difficult to decide whether the stone at all has been disintegrated. The other predictor of success, used by the authors, was stone density less than that of the 12th rib. The described principles rather easily can be included in routine SWL.
The results give support to a non-invasive method for removal of stones with a surface area ≤ 400 mm2. It is correctly mentioned by the authors that such an approach is economically favourable compared with invasive treatment modalities.