Mechanical testing of urinary calculi

Cohen, Nicholas; Whitfield, H. N.

doi:10.1007/bf00182165

Cited by 30 publications

(22 citation statements)

References 19 publications

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“…Mechanical properties A variety of mechanical stone parameters have been examined in kidney and gallstones. Microhardness testing of kidney stones revealed Knoop hardnesses of 210-990MPa with calcium oxalate monohydrate stones being in the higher range and cystine stones in the lower range (Johrde and Cocks 1985a;Singh and Agarwal 1990;Zhong et al 1992;Cohen and Whitfield 1993). When these values were compared to the ease of fragmentation by a lithotripter, no clear relation could be established (Dretler 1989).…”

Section: Stone Propertiesmentioning

confidence: 97%

“…The tensile strength of gallstones was found to vary in a relatively narrow range of 0.4-1.0 MPa. The dynamic Young's moduli of elasticity were 8-30 GPa in kidney stones (Cohen and Whitfield 1993) and 4.6-7.1 GPa in gallstones (Holtum 1993); higher quasi-static elasticities were reported in those kidney stones which were more difficult to fragment (Zhong el;). …”

Section: Stone Propertiesmentioning

confidence: 97%

“…Kidney stones have an exchangeable water content of 2-15 % (Cohen and Whitfield 1993) and gallstones of 20 % (Holtum 1993). Very low porosities of kidney stones were found in cystine and brushite stones, types which are difficult to fragment.…”

Section: Chemical Propertiesmentioning

confidence: 99%

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Medical applications and bioeffects of extracorporeal shock waves

Delius¹

1994

Shock Waves

163

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Abstract. Lithotripter shock waves are pressure pulses of microsecond duration with peak pressures of 35-120MPa fotlowed by a tensile wave. They are an established treatment modality for kidney and gallstone disease. Further applications are pancreatic and salivary stones, as well as delayed fracture healing. The latter are either on their way to become established treatments or are currently under investigation. Shock waves generate tissue damage as a side effect which has been extensively investigated in the kidney, the liver, and the gallbladder. The primary adverse effects are local destruction of blood vessels, bleedings, and formation of blood clots in vessels. Investigations on the mechanism of shock wave action revealed that lithotripters generate cavitation both in vitro and in vivo. An increase in tissue damage at higher pulse administration rates, and also at shock wave application with concomitant gas bubble injection suggested that cavitation is a major mechanism of tissue damage. Disturbances of the heart rhythm and excitation of nerves are further biological effects of shock waves; both are probably also mediated by cavitation. On the cellular level, shock waves induce damage to cell organelles; its extent is related to their energy density. They also cause a transient increase in membrane permeability which does not lead to celJ death. Administered either alone or in combination with drugs, shock waves have been shown to delay the growth of small animal tumors and even induce tumor remissions. While the role of cavitation in biological effects is widely accepted, the mechanism of stone fragmentation by shock waves is still controversial. Cavitation is detected around the stone and hyperbaric pressure suppresses fragmentation; yet major cracks are formed early before cavitation bubble collapse is observed. The latter has been regarded as evidence for a direct shock wave effect.

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Section: Stone Propertiesmentioning

confidence: 97%

Section: Stone Propertiesmentioning

confidence: 97%

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Medical applications and bioeffects of extracorporeal shock waves

Delius¹

1994

Shock Waves

163

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“…Mechanical testing of urinary calculi was previously discussed by Cohen and Whitfield [41]. Chauhan and Joshi [42] carried out Vickers micro-hardness study and related mechanical properties of struvite crystals, which may provide useful information for the fragmentation of the struvite stones using appropriate parameters in ESWL management without causing any damage to the kidney and urinary tract.…”

Section: Vickers Micro-hardness Studymentioning

confidence: 99%

In vitro crystallization, characterization and growth-inhibition study of urinary type struvite crystals

Chauhan

Joshi

2013

Journal of Crystal Growth

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“…However, microhardness test allows the repeated measurements of a single sample at different regions, allowing differentiated characterization at different region of a single sample. Cohen and Whitfield [12] proposed that chemical composition was related to stone strength and determined through experimentations that denser and more uniform calculi would be more resistant to ESWL.…”

Section: Introductionmentioning

confidence: 99%

Characterization of kidney stones using thermogravimetric analysis with electron dispersive spectroscopy

2011

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Urinary calculi are formed from a result of biological mal-adjustment of urine leading to deposits of salt and mineral crystals along the urinary collecting system. They are usually multiphasic material with complex compositions. The objective of this study is to identify and characterize a series of urinary calculi samples using a combination of thermogravimetric analysis (TGA) with electron dispersive spectroscopy (EDS). These samples were retrieved during percutaneous nephrolithotripsy. Additional characterization by hardness value and microstructure is also carried out for co-relation study. The samples are found to be uric acid, calcium oxalates and magnesium ammonium phosphate hexahydrate. TGA is indeed one of the viable analytical tools for urinary calculi as it is fast and simple. The combinational application of EDS is beneficial when there is a need for differentiated qualitative chemical composition detection at the identified nuclei position for urinary calculi with spatial variation in composition. The combination of TGA and EDS will thus facilitate the correct diagnosis and treatment by clinicians.

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Mechanical testing of urinary calculi

Cited by 30 publications

References 19 publications

Medical applications and bioeffects of extracorporeal shock waves

Medical applications and bioeffects of extracorporeal shock waves

In vitro crystallization, characterization and growth-inhibition study of urinary type struvite crystals

Characterization of kidney stones using thermogravimetric analysis with electron dispersive spectroscopy

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