• APIR;
  • closure function;
  • closure mechanism;
  • continence mechanism;
  • intra-abdominal pressure increase;
  • pressure reflectometry;
  • PTR;
  • strain;
  • SUI;
  • UPR;
  • urethra;
  • urinary incontinence;
  • urodynamics



to assess the urethral closure function by urethral pressure reflectometry (UPR) during intra-abdominal pressure-increase in SUI and continent women.


Twenty-five urodynamically proven SUI women and eight continent volunteer women were assessed by ICIQ-SF, pad-weighing test, incontinence diary, and UPR. UPR was conducted during resting and increased intra-abdominal pressure (PAbd) by straining. Related values of PAbd and urethral opening pressure (Po) were plotted into an abdomino-urethral pressuregram. Linear regression of the values was conducted, and the slope of the line (“APIR”) and the intercept with the y-axis found. By the equation of the line, Po was calculated for various values of PAbd, for example, 50 cm H2O (Po-Abd 50).


The resting Po (Po-rest) and APIR, respectively, significantly differed in SUI and continent women but could not separate the two groups. The urethral closure equation (UCE) based on Po-rest and APIR provided a more detailed characterization of a woman's closure function based on the permanent closure forces (primarily generated by the urethral sphincteric unit) and the adjunctive closure forces (primarily generated by the support system). Po-Abd 50 and UCE, respectively, which express the combined permanent and adjunctive closure forces and estimate the efficiency of the closure function, separated SUI and continent women and were highly significantly negatively correlated with ICIQ-SF, pad test, and the number of incontinence episodes.


New parameters for characterization of the urethral closure function and possible dysfunctions and its efficiency were provided. Po-Abd 50 and UCE may be used as diagnostic tests and severity measures. Neurourol. Urodynam. 32:1103–1108, 2013. © 2013 Wiley Periodicals, Inc.