Login to Access Video or Poster Abstract: MP19-05
Sources of Funding: None

Introduction

The role of renal collecting system anatomy as it pertains to passage of stone material has been well studied, especially in the post-intervention setting. Current understanding of anatomic factors in the genesis of calculi is more limited, however. Here, we undertake the first computational fluid dynamic simulation of the renal collecting system in a known stone forming individual in order to correlate urine stagnation with calculogenesis.

Methods

In this IRB exempt study, a CT urogram was 3D reconstructed from a patient with renal calculi attached to papillae. Computational fluid dynamics were performed to simulate flow within the collecting system assuming a urine production of 0.5 mL/s with "open" inlet conditions. The non-contrast phase of the CT scan was then compared to the simulated model in order to correlate simulated flowrate with stone location.

Results

A 48-year-old first time stone former was identified with three renal calculi attached to papilla in three separate lower pole calyces. 3-D reconstruction identified stones in calyces which were labeled "5+6" (compound calyx), "8", and "9". Flow simulation produced relative volumetric flow rates for each calyx as follows: "3" - 29.38% of total, "7" - 20.10%, "1+10+2" - 16.76%, "8" - 16.61%, "9" - 8.75%, "5+6" - 7.85%, and "4" 0.55% .

Conclusions

The location of renal calculi appear to correlate with calyces with low flow rates. We offer this as supporting evidence to the idea that intrarenal anatomy plays a role in crystal retention and growth. Further work is required to perform more realistic urologic physiologic simulations.

Funding

None