Stone metrics: is stone volume the new king?

Stone volume represents the most accurate measure of urolithiasis burden. While this may be obvious to all, this stone metric has not yet found its way into standard clinical practice or guidelines algorithms guiding treatment strategies. Although linear measurements have their obvious limitations, they are still most commonly used in practice and reported in literature as well as guidelines. This review evaluates the current available evidence supporting stone volume as the most important stone metric.

By now, literature has been able to confidently demonstrate that stone volume is a more accurate predictor of stone free status in shockwave lithotripsy and ureteroscopy. Recent advances in three-dimensional imaging reconstruction, automated segmentation and artificial intelligence have lowered thresholds for obtaining stone volume from computed tomography imaging.

Today, historical barriers have been overcome, and fast, reproducible stone volume assessment is at our fingertips. And yet, we do not use volume in our daily practice, as we ourselves hold back evolution. While future efforts should be put towards embracing volume as a stone metric, more studies are also needed to identify volume-based thresholds for treatment success aiding in the development of new treatment algorithms.