Abstract
Purpose:
To assess the potential effect of simple renal cysts (SRC) on stone fragmentation during shockwave lithotripsy (SWL) in an in vitro model.
Materials and Methods:
The in vitro model was constructed using 10% ordnance gelatin (OG). Models were created to mimic four scenarios: Model A—with an air-filled cavity (suboptimal for stone fragmentation); model B—without a cavity (normal anatomy); model C—with a 3-cm serum filled cavity (to represent a small SRC); model D—with a 4-cm serum filled cavity (to represent a larger SRC). SWL was applied to 24 standardized phantom stones (weight of 2 ± 0.1 g) in each model using a standardized protocol. Stone fragments were retrieved, then dried overnight at room air temperature. Fragmentation coefficient (FC) was calculated for each stone, for fragments <4 mm and <2 mm.
Results:
The OG in vitro model was robust enough for the proposed research. There was no fragmentation evident in model A as expected. The mean FC was 29.7 (± 20.5) and 39.7 (± 23.7) for <4 mm fragments (P = 0.069) and 7.6 (± 4.1) and 10.6 (± 6.7) for <2 mm fragments (P = 0.047), for noncystic and cystic models, respectively. The mean FC was 29.7 (± 20.5), 38.8 (± 26.2) and 40.7 (± 21.3) for <4 mm fragments (P = 0.213) and 7.6 (± 4.1), 11.1 (± 8) and 10.2 (± 5.3) for <2 mm fragments (P = 0.138), for models B, C, and D, respectively.
Conclusion:
Our in vitro experiment confirms better stone fragmentation associated with SWL in the presence of adjacent SRC.
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