RE: Percutaneous nephrolithotomy for isolated calyceal stones: How important is the stone location?

Abstract

I read with great interest the article “Percutaneous nephrolithotomy for isolated calyceal stones: How important is the stone location?” by Ozgor et al.[1] This article highlights an interesting outcome of isolated calyceal stones which were managed by percutaneous nephrolithotomy (PCNL). The isolated upper pole calyceal stone has been shown to have statistically significant difference in term of thoracic complications, longer nephrostomy duration, and hospital stay in comparison to middle calyceal stone. Besides that, post-operative bleeding also appeared to be higher and stone clearance rate was lower in upper pole puncture but there was no statistically significant difference between the groups. All those parameters suggest that the direct puncture for treating isolated upper pole calyceal stone has higher risks with lower effectiveness. In my opinion a definite conclusion cannot be drawn from this study as it was a retrospective review which had some limitations. In this study various modifications of conventional PCNL as a special measure was not clearly elaborated. The use of balloon dilatation and single stage dilatation with Amplatz dilator was found to have less bleeding in comparison to serial Amplatz dilatation.[2] Whereas properly selected site and timing of the puncture was found to reduce the thoracic complications. Ko et al.[3] found that careful placing the puncture site at lateral half of the ribs will avoid pleural and supracostal puncture. Whereas, puncturing kidney during fully expiration will push the lung base two interspaces higher. Both tricks will avoid from puncturing pleura, thus reduce thoracic complications. On the other hand, Raza et al.[2] found that the efficacy of upper pole puncture was significantly higher than mid-pole and lower pole punctures in managing staghorn calculi whose incidence rates were 83%, 78% and 65%, respectively. They postulated that the ability of direct access to upper pole, pelvis and upper ureter contributed to higher stone-free rate.[2] Besides that, they also found that the upper pole puncture had no significant increase in complication rates.[2] Thus in my opinion upper pole puncture had more advantages provided that careful precautions are taken during the procedure.