LOSS OF ELASTICITY IN DYSFUNCTIONAL BLADDERS - URODYNAMIC AND HISTOCHEMICAL CORRELATION

To store adequate volumes of urine at low safe pressures an elastic bl adder wall is required. We developed 2 new techniques to measure this ability in our urodynamic laboratory: pressure specific bladder volume , which measures the bladder capacity at a given pressure, and dynamic analysis of bladder compliance. Recently, morphometric and histochemi cal techniques have been used to determine the relative volume of conn ective tissue in the bladder wall and to measure the 2 major types (I and III) of collagen within the bladder wall. These methods quantitate 3 parameters of bladder ultrastructure: 1) relative volume of per cen t connective tissue, 2) ratio of connective tissue to smooth muscle an d 3) ratio of type III to type I collagen. These parameters have been shown to be abnormally elevated in patients with dysfunctional bladder s compared to normals. The purpose of the study was to describe the ul trastructural changes that occur in the wall of dysfunctional bladders and to determine the ability of these new urodynamic techniques to de tect reliably the clinical effect of these histological changes. The s tudy included 29 consecutive patients with dysfunctional bladders nece ssitating bladder augmentation. All patients had upper tract changes a nd/or were incontinent despite treatment with clean intermittent cathe terization and pharmacotherapy. Preoperative urodynamic evaluation inc luded measurement of the total bladder capacity, pressure specific bla dder volume and dynamic analysis of bladder compliance. Full thickness bladder biopsies were obtained from the dome of the bladders during a ugmentation. The percent connective tissue and the ratio of connective tissue to smooth muscle were determined for all patients, and 4 unsel ected patients from this group had the ratio of type III to type I col lagen determined. These histological results were compared to previous ly established normal values. All 29 patients had a decreased pressure specific bladder volume and dynamic analysis of bladder compliance, w hereas 9 had a normal total bladder capacity. The per cent connective tissue was 35.19 +/- 2.84 and ratio of connective tissue to smooth mus cle was 0.60 +/- 0.08 compared to normal values of 10.6 +/- 0.020 and 0.131 +/- 0.021, respectively (p < 0.05). Ratio of type III to type I collagen was also significantly elevated in the 4 samples analyzed (30 .53 +/- 1.37 versus 24.00 +/- 2.50, p < 0.05). We conclude that poor s torage function of poorly compliant bladders is secondary to an altera tion in the connective tissue content of the bladder wall. Furthermore , these pathological ultrastnuctural changes are universally reflected by an abnormally low pressure specific bladder volume and dynamic ana lysis of bladder compliance. This strong association validates the use of these parameters and suggests that they are urodynamic indicators of a loss of elasticity in bladder wall.