High burden stones : the role of SWL

Percutaneous nephrolitotomy (PCNL), PCNL and Shock Wave Lithotripsy (SWL), SWL monotherapy and open surgery are nowadays the potential treatment alternatives for patients with staghorn stones. Several groups have proposed classification schemes to better define staghorn calculi dimensions taking into account size, morphology and composition of the stones. More recently the use of a CT imaging with three-dimensional reconstruction or of a coronal reconstruction of axial CT images was reported to obtain an accurate stone volume calculation. The difficulty in accurately assessing stone burden explains the wide range of reported stone-free rates for SWL monotherapy from 22 to 85%. A recent AUA guideline of the management of staghorn calculi stated that stone free rate is 78% for PCNL and 54% for SWL monotherapy and these values are similar to those reported in Segura guideline but the rate for combination treatment (PNL+SWL) is now lower (66% versus 81%) than in the previous guideline. This reduction is probably due to the fact that in the recent meta-analysis SWL was the last procedure and in the previous generally a sandwich therapy was performed with PCNL followed by a SWL and a secondary PCNL. Improved PCNL techniques with use of flexible nephroscopy and multitract PCNL allow to achieve complete stone clearance by PCNL alone. Complete removal of stone is crucial to eradicate infection and prevent further stone regrowth. Residual fragments may perpetuate post reatment infection and stone regrowth has been reported up to 78% in such patients after SWL monotherapy. In our previous experience (prior to 2000) we observed 45 pts with high burden stones: 31/45pts (68%) underwent combined therapy PCNL and SWL with a successful rate of 65% (stone free and fragments < 4mm). In our more recent experience ('03-'08) we treated 34 patients with high burden stones: we performed combined therapy PCNL and SWL in 11 pts (32%) with an overall success rate of 63%. PCNL was undertaken initially with the attempt to remove as much stone as possible with the aid offlexible nephroscopy and SWL was used only for residual stones because the passage, even of fragments < 4mm, does not always occur in dilated renal cavities. SWL monotherapy should not be used for most patients and may be considered only in patients with small volume staghorn stones with normal collecting system.