Percutaneous Nephrolithotomy Monotherapy for Staghorn: Paradigm Shift for 'staghorn Morphometry' Based Clinical Classification

Purpose Of Review: The term staghorn is plagued by an unclear morphology There is a need for clinical definition of staghorn that could classify patients in either of the two ends of the treatment spectrum for percutaneous nephrolithotomy (PCNL) monotherapy.

Recent Findings: Staghorn morphometry was identified as a prognostic tool to predict tract(s) and stage(s) for PCNL monotherapy for staghorn. Staghorn morphometry requires a three-dimensional computed tomography urography assessment by volume rendering software. As per the detailed stone morphometric analysis, a clinically important definition of staghorn calculi based on the high odds probability of multiple tract(s) and stage(s) is proposed. Type 1 staghorn has a total stone volume of less than 5000 mm with less than 5% unfavorable calyx stone percentile volume, whereas type 3 staghorn has a total stone volume of more than 20,000 mm with greater than 10% unfavorable calyx stone percentile volume. Type 2 staghorn is in-between type 1 and 2. Based on the prediction model for achieving clearance by PCNL monotherapy, type 1 staghorn would require single tract and stage, type 2 single tract-single/multiple stages or multiple tract-single stage and type 3 multiple tract and stage.

Summary: Staghorn morphometry based clinical classification of staghorn is an exciting concept for PCNL monotherapy. Further prospective studies are required to validate the staghorn morphometry based clinical variate of staghorns. The prospective studies should take into account clinical presentations, operative complications, tract and stage required, postoperative complications, hospital stay, operative cost and stone-free status.