Stepwise cystometry : a new method to investigate properties of the urinary bladder

The urinary bladder has a twofold function : 1. to store urine and 2. to expel it if necessary under complete voluntary control. The bladder can store various volumes of urine at a low and approximately constant intravesical pressure until capacity is reached. In the literature, this characteristic of the bladder was originally ascribed to reflex mechanisms (Mosso and Pellacani, 1882; Ausems, 1957). However, experimental evidence to show that inherent properties of the detrusor muscle, independent of neurogenic control, play an important role, has been put forward by some authors (Nesbit and Lapides, 1948; Tang and Ruch, 1955). Remington and Alexander (1955) have distinguished active and passive properties of the detrusor muscle. They demonstrated that viscoelastic properties of smooth muscular organs are determined primarily by passive components of the tissue. The objectives of the studies presented here can be summarized as follows: 1. To demonstrate again that the urinary bladder has viscoelastic properties. 2. To describe quantitatively the physical properties of the bladder wall in the collection phase by means of a passive model. 3. To study the influence of the active elements on passive behaviour. 4. To compare the present method with the classical cystometry with regard to its value in representing physical characteristics of the urinary bladder. 5. To propose a new cystometry method by which the physical properties of bladders can be quantitatively analysed. These properties are represented in parameters, based on passive features.