[In vitro study of the process of urinary calculi fragmentation with endoscopy, light microscopy, and scanning electron microscopy]. / Estudio in vitro del proceso de fragmentación de los cálculos urinarios con endoscopia, microscopio óptico y microscopio electrónico de barrido.

Stones with different compositions respond differently to shock wave lithofragmentation. Likewise, the various lithotrity systems used may have different effects on the stones. To determine the relationships between stone composition and their fragmentation patterns, we conducted an in vitro study using endoscopy, magnifying glass, light microscope and scanning electron microscope on fragments obtained after lithotrity of 60 pure stone with different compositions: calcium oxalate monohydrate and dihydrate (OXMH and OXDH), phosphocarbonate (PC), ammonium magnesium phosphate (AMF) and uric acid (UA). Fragmentation was carried out with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulse laser). No morphologic differences in the fractures induced by the various lithofragmenting sources were demonstrated. OXMH and UA stones basically break up by intercrystalline fracture and splitting of their concentric plates. OXDH breaks up mainly by intercrystalline fractures aided by the fibrillar organic material and phosphocarbonates found in the intercrystalline spaces. Fragmentation in infective stones (AMF and PC) occurs across the intercrystalline surfaces and by intracrystalline fracture. Ammonium urate fragments break up by intracrystalline fractures that run across the equatorial plane of its characteristic acicular microspheres.

[In vitro study of urinary calculi fragmentation with 4 different systems of lithofragmentation]. / Estudio in vitro de la fragmentación de los cálculos urinarios con cuatro sistemas de litofragmentación diferentes.

The results of shockwave lithofragmentation are conditioned by stone composition. Similarly, the different types of lithofragmenting energy can have different effects on the calculi. The purpose of this experimental study is to establish a relationship between calculi composition and type of energy used for fragmentation, with the results of the lithotriptsy treatment. 60 calculi, 12 for each pure composition selected (calcium oxalate mono and dihydrate, phosphocarbonate, ammonium magnesium phosphate and uric acid) underwent in vitro lithofragmentation with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulsed laser). It was carried out a study of fragmentation in particles under 3 mm and pulverization in particles under 0.5 mm, analyzing post-lithotriptsy fragments with scanning electron microscopy associated to X-ray dispersion energy. No relationship was shown between calculi composition and amount of energy supplied for the fragmentation. The lithiasic composition correlates to the fragmentation pattern, so that oxalocalcium calculi undergoes good fragmentation and poor pulverization, infective calculi have poor fragmentation but good pulverization and uric acid calculi show poor fragmentation and pulverization.

[In vitro study with techniques of imaging of the composition of urinary calculi]. / Estudio in vitro mediante técnicas de imagen de la composición de los cálculos urinarios.

Pre-treatment knowledge of the lithiasic composition can be useful to design the most appropriate therapeutic scheme for each kind of stone. The relationship between the stone's densitometry information provided by the different imaging techniques, conventional radiology (RX), computerized axial tomography (CAT) and dual energy radiographic densitometry (DO) is analyzed, as well as the elemental composition determined by the microanalysis of fragments obtained post-lithotrity using a scanning electronic microscope (SEM) associated to X-ray dispersion energy (XDE). 60 stones, 12 for each pure composition selected (calcium oxalate mono and dihydro, phosphocarbonate, magnesium ammonium phosphate and uric acid), were studied with XR, CAT and DO and were later subjected to lithofragmentation in vitro. Fragments analysis was carried out post-lithotrity with SEM associated to XDE. The X-ray does not allow to establish the composition of some calculi. CAT quantifies the mineral contents of the oxalocalcic and infective calculi and differentiates the uric acid from the other compositions because the mean density values are under 500 Hounsfield Units. DO evaluates the lithiasic content in phosphocarbonate salts which are structurally similar to bone hydroxyapatite.