THE VESICOURETHRAL PRESSUREGRAM ANALYSIS OF URETHRAL FUNCTION UNDER STRESS

About one-third of older multiparous women are prone to stress urinary incontinence (SUI): unwanted urine loss during activities which sudde nly raise intra-abdominal pressure. In this paper we describe and test a method for visualizing and analyzing the function of the urinary co ntinence control system (CCS) under stress. Intravesical and intrauret hral pressure changes from the resting state were recorded at proximal , mid-, and distal urethral locations during increasingly severe cough s and cross-plotted on a 'vesico-urethral pressuregram.' The slope (al pha) and intercept (chi(0)) resulting from a linear regression analysi s of these data were used to develop a continence equation which can b e used to predict the equilibrium point pressure (P-E): the intravesic al pressure at which urine will leak to the intraurethral pressure rec ording site. We tested the null hypothesis that these parameters would not differ in six young, nulliparous continent women (mean +/- S.D. a ge: 30 +/- 3.5 yr) and six multiparous SUI women (52.3 +/- 8.0 yr, par ity: 1.7 +/- 0.8), or between urethral locations. Significant differen ces in continence equation parameters were found between groups and in different urethral locations. In the SUI group static factors calcula ted from the term (1 - alpha) contributed 27% of the mean (S.D.) midur ethral P-E value, 145 (46) cm H2O, while dynamic factors, estimated fr om alpha, contributed 73% of this value. Valuable insights for improvi ng the diagnosis and treatment of SUI may be obtained by analyzing the relative contributions of alpha and chi(0) to urethral closure during physical stress. Copyright (C) 1996 Elsevier Science Ltd.