Open surgical measures may be undertaken in the treatment of some complex calculi and manoeuvres such as extended pyelolithotomy or nephrolithotomy may be necessary. In an attempt to improve surgical results with less morbidity and maximum ease, we used the Swiss Lithoclast to disintegrate large stones presenting as hard cases. Five patients with renal pelvic stones associated with calyceal stones in two and two further cases with staghorn stones were treated surgically using the pneumatic lithotriptor probe with less dissection and without nephrotomy. Only one of the patients with staghorn stones had residual fragments which were then treated with ESWL. We believe that when open surgical treatment is considered in hard cases, especially in those with small renal pelvises, the best results may be achieved with minimum surgical intervention if it is combined with pneumatic lithotripsy.