DIAGNOSING INTRINSIC SPHINCTERIC DEFICIENCY - COMPARING URETHRAL CLOSURE PRESSURE, URETHRAL AXIS, AND VALSALVA LEAK POINT PRESSURES

OBJECTIVES: Our purpose was to compare three measures proposed to diag nose intrinsic sphincteric deficiency: maximum urethral closure pressu re, Valsalva leak point pressure, and straining urethral axis. STUDY D ESIGN: A total of 159 women with pure genuine stress incontinence had the three measures determined in a standardized fashion. Critical cuto ff values for the Valsalva leak point pressure (52 cm) and urethral ax is (22 degrees) were established by examining relative frequency distr ibution curves, using closure pressure of 20 as the arbitrary benchmar k value for the prevalence of intrinsic sphincteric deficiency. The di stribution of cutoff values is described and differences among tie mea sures with respect to risk factors for intrinsic sphincteric deficienc y and incontinence severity were determined. RESULTS: Half the subject s fell below at least one cutoff value, but only 10% fell below all th ree. Sixty-four percent of subjects with either low closure pressure o r leak point pressure had low values for the other, whereas 21% had di scordance between them. Only 53% of subjects with low closure pressure and 40% with low leak point pressure had an axis less than or equal t o 22 degrees. Conversely, a substantial portion (36%) of subjects with pure genuine stress incontinence without urethral hypermobility had n either low urethral or leak point pressures. All three cutoff values w ere associated with risk factors for intrinsic sphincteric deficiency, but only low closure and leak point pressures had significant associa tions with the severity of incontinence. CONCLUSIONS: Intrinsic sphinc teric deficiency should be diagnosed by a composite of historic, urody namic, anatomic, and clinical severity criteria. We would include a ma ximum urethral closure pressure less than or equal to 20, a Valsalva l eak point pressure less than or equal to 50, and a stress urethral axi s less than or equal to 20 in this composite.