Optimization of the artificial urinary sphincter: modelling and experimental validation.

Abstract:

:The artificial urinary sphincter should be long enough to prevent strangulation effects of the urethral tissue and short enough to avoid the improper dissection of the surrounding tissue. To optimize the sphincter length, the empirical three-parameter urethra compression model is proposed based on the mechanical properties of the urethra: wall pressure, tissue response rim force and sphincter periphery length. In vitro studies using explanted animal or human urethras and different artificial sphincters demonstrate its applicability. The pressure of the sphincter to close the urethra is shown to be a linear function of the bladder pressure. The force to close the urethra depends on the sphincter length linearly. Human urethras display the same dependences as the urethras of pig, dog, sheep and calf. Quantitatively, however, sow urethras resemble best the human ones. For the human urethras, the mean wall pressure corresponds to (-12.6 +/- 0.9) cmH2O and (-8.7 +/- 1.1) cmH2O, the rim length to (3.0 +/- 0.3) mm and (5.1 +/- 0.3) mm and the rim force to (60 +/- 20) mN and (100 +/- 20) mN for urethra opening and closing, respectively. Assuming an intravesical pressure of 40 cmH2O, and an external pressure on the urethra of 60 cmH2O, the model leads to the optimized sphincter length of (17.3 +/- 3.8) mm.

journal_name

Phys Med Biol

authors

Marti F,Leippold T,John H,Blunschi N,Müller B

doi

10.1088/0031-9155/51/5/023

subject

Has Abstract

pub_date

2006-03-07 00:00:00

pages

1361-75

issue

5

eissn

0031-9155

issn

1361-6560

pii

S0031-9155(06)11400-1

journal_volume

51

pub_type

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