Biomechanics of urinary bladder: slow-filling and slow-emptying cystometry and accommodation

Main Article Content

Wim A. van Duyl

Keywords

accommodation, compliance, contractions, micromotions, urinary bladder

Abstract

OBJECTIVE: In a concept of accommodation of detrusor pressure to volume as an autonomous potency of the bladder, a crucial physiological biomechanical role has been attributed to spontaneous contraction activity. This concept is experimentally investigated on pig bladder in vitro.
METHODS: Slowly emptying of not-stimulated pig bladders via a flow resistor has been recorded and the effect of spontaneous contractions on the tonic pressure during emptying by expulsion has been studied.
RESULTS: The expulsed volume can be separated in a reduction of elastic volume and of rest volume. Tonic pressure is determined by the elastic volume in combination with elastic compliance. In an accommodated state completely transient superimposed pressure waves affect rest volume not elastic volume. Accommodation of tonic detrusor pressure to bladder volume is based on equilibration between passive elongations and active transient contractions distributed in bladder wall.
CONCLUSION: Maintenance of a tonic accommodated detrusor pressure to a constant or slowly varying volume, obtained by a process of equilibration between passive elongations and active contractions, can be understood as an autonomous potency of a bladder. The earlier presented concept of active accommodation has been validated by the experiments. The pressure-volume relation of the bladder is fundamentally revised. Total volume V can be virtually separated in an elastic volume VE and a plastic or rest volume VR. Both parts change with V and in changing ratio. Tonic pressure marks a border between VE and VR.

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References

1 Duyl W.A. van and Coolsaet BLRA (2021): Biomechanics of urinary bladder: spontaneous contraction activity and micromotions related to accommodation. Int Urology and Nephrology 53(7),1345-1353. PMID: 33713288 DOI: 10.1007/s11255-021-02814-w
2 Duyl WA van (1985): A model for both the passive and active properties of urinary bladder tissue related to bladder function. NeuroUrol Urodyn 275-283.DOI: 10.1002/nau.1930040404
3 Mastrigt R van, Coolsaet BLRA, Duyl WA van (1978): Passive properties of the urinary bladder in the collection phase. Med.Biol.Eng.Comput. 16:471-482. PMID: 309982 DOI: 10.1007/BF02457796
4 I.C.S. (1988) The standardization of terminology of low urinary tract function. The International Continence Society Committee on Standardisation of Terminology Sc. J. Urol. Nephrol. Suppl. 114, 5-19. PMID: 3201169
5 Wyndaele JJ, Gammie A, Bruschini H, De Wachter S, Fry C H, Jabr RI, Kirschner-Hermanns R, Madersbacher H. (2011) Bladder compliance what does it represent: can we measure it, and is it clinically relevant? NeuroUrol Urodyn June 2011 30,5 714-722. PMID: 21661019 DOI: 10.1002/nau.21129
6 Hill AV (1926) The viscous properties of smooth muscle. Proc. Roy Soc. 100, 108-115 doi: 10.1098/rspb.1926.0036
7 Duyl WA van, Coolsaet BLRA Mastrigt Rvan (1978): A new clinical parameter for the assessment of the contractility of the urinary bladder. Urol Int 33, 31-39. DOI:10.1159/000280173
8 Griffiths DJ (2004): Detrusor contractility, order out of chaos Scand. J Urol Nephrol Suppl. 215. PMID: 15545203 DOI: 10.1080/03008880410015426
9 Mastrigt R van, Tauecchio EA (1982): Series-elastic properties of strips of smooth muscle from pig urinary bladder. Med. and Biol. and Comput. 20,585-594. PMID: 7176715 DOI: 10.1007/BF02443406
10 Huxley AF (1957): Muscle structure and theories of contraction. Progress in Biophysics and Chemistry 7,255-318. PMID: 13485191
11 Duyl WA van (1985): Spontaneous contractions in urinary bladder smooth muscle: preliminary results. NeuroUrol Urodyn 4:301-307. https://doi.org/10.1002/nau.1930040406
12 Coolsaet BLRA, Duyl WA van, Mastrigt R van, Zwart A van der (1975): Viscoelastic properties of the bladder wall. Urol Int, 30,16-26. PMID: 1118945 DOI: 10.1159/000279953
13 Trapman JP (1997): Blaas mechanica; trainee report (in Dutch) MMD-group Erasmus University Rotterdam.
14 Eddinger TJ (2017): Reversible plasticity of detrusor smooth muscle: evidence for a key role of “slipping” actomyosin crossbridges in the control of urinary bladder compliance. Am J Physiol Renal Physiol, May. PMID: 28490527 DOI: 10.1152/ajprenal.00227.2017