"Pass the ball!" Simultaneous flexible nephroscopy and retrograde intrarenal surgery for large residual upper-pole staghorn stone.

Complex staghorn calculi have conventionally been treated with percutaneous nephrolithotomy, extracorporeal lithotripsy, or, occasionally, open surgery. Access to branched calculi is difficult through a single percutaneous track. We tested and make a case for a synchronous bidirectional technique combining the use of flexible instruments through percutaneous and retrograde approaches. We present a case of "pass the ball," which may have a place in tackling large, complex, or branched staghorn calculi without the need for multiple percutaneous punctures, removing larger fragments than is possible through the ureter and avoiding multiple passes through the ureter, saving time and decreasing the possibility of iatrogenic ureteral injury.