Extracorporeal shock wave lithotripsy monotherapy for selected staghorn stones

To define a subgroup of staghorn stones that is amenable to extracorporeal shockwave lithotripsy (ESWL) monotherapy and review the need for prophylactic ureteric stents.

Fifty-eight renal units with staghorn calculi in 56 patients (30 males and 26 females) were treated by ESWL monotherapy on the EDAP LT-01 lithotripter. The stones were grouped as complete staghorn (11, 19%), partial staghorn (34, 59%) and borderline staghorn (13, 22%). Results of treatment were analysed in relation to subgroup and calyceal dilatation. Post-treatment complications were studied and the influence of prophylactic ureteric stents examined.

The average number of ESWL sessions was 3.1 (range: 1 to 8). The mean follow-up period was 13 months. Stone-free rate at 10 months was 52%. When clinically insignificant residual fragments less than 4mm were included, the overall clearance rate was 75%. Favourable factors influencing treatment outcome included smaller stone burden, peripheral distribution of stone mass and absence of pelvicalyceal dilatation. The overall complication rate was 39% with urosepsis being the commonest. Complications were related to stone burden. More than half of the renal units with complete staghorn stones developed one or more complications. Auxiliary procedures were required in 18% of the renal units. Twenty of 39 renal units with a stone burden (sum of length and width) greater than 50mm had pretreatment ureteric stenting using the double-J (DJ) siliastic stent. A urosepsis rate of 50% was noted in those with ureteric stents compared to 26% in those not stented. The stents did not offer any advantage in preventing post-treatment obstruction by fragments. Six of 7 renal units with post-treatment obstruction had in-situ stents.

ESWL monotherapy is suitable for selected staghorn stones. Prophylactic ureteric stents do not offer any advantage and may predispose to urosepsis.