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Quantification of urethral function based on Griffiths' model of flow through elastic tubes
Author(s) -
Spángberg Anders,
Terió Heikki,
Engberg Anders,
Ask Per
Publication year - 1989
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.1930080105
Subject(s) - urethra , flow (mathematics) , function (biology) , medicine , mechanics , anatomy , physics , evolutionary biology , biology
Griffiths' model of flow‐through elastic tubes makes it possible to relate the elastic properties of the flow‐controlling zone to the pressure/flow relation of the urethra. In this work the pressure function p(A) = P mo + K n A n , where A is cross‐sectional area, P mo the minimal opening pressure, and K n and n parameters describing urethral distensibility, describes the elastic properties of the flow‐controlling zone. By curve‐fitting in the pressure/flow plot, the three parameters p mo , K n , and n can be estimated analytically. Using this model it is possible to identify three different biomechanical changes that may cause obstruction. First, p mo may be elevated. Second, the urethra can be distended to a certain area only, corresponding to high values of K n and n. Third, the urethra can be distended but a higher‐than‐normal pressure increase above P mo is needed, K n is high, and n is low. With this model it is possible to quantify urethral function for both scientific and clinical purposes.