Clinical and urodynamic features of intrinsic sphincter deficiency

A prospective analysis of 92 patients with genuine stress incontinence was performed to identify the clinical and urodynamic features of intrinsic sphincter deficiency (ISD). Methods: We divided the patients into two categories: 50 patients affected by pure ISD as they had severe stress incontinence and no urethral mobility; 42 patients suffering from stress urinary incontinence without ISD as they had mild stress incontinence and marked urethral hypermobility. Cystometry was normal in all patients. The presence/absence of ISD was considered the dependent variable and was correlated against the following independent variables: age, vaginal deliveries, menopause, previous urogynecological surgery and/or hysterectomy, supine stress test, irritative and/or obstructive symptoms, Valsalva leak point pressure (VLPP), maximum urethral closure pressure (MUCP), urethral functional length (UFL), and leakage during cystometry. Results: The statistical analysis showed close correlations between ISD and age (P < 0.001), menopausal status (P < 0.001), previous surgery (P < 0.0001), supine stress test (P < 0.0001), leakage during cystometry (P < 0.001), and UFL (P < 0.01). The VLPP was below the cut-off value (less than or equal to60 cm H2O) in 70% of ISD patients (P < 0.0001), whereas the MUCP in 50% of ISD patients (P < 0.0001). Multiple logistic analysis showed that lower VLPP, lower MUCP, and previous surgery correlate more significantly with ISD. After backward conditional stepwise logistic regression, the odds ratio of having ISD were VLPP = 2.3, MUCP = 7.7, VLPP + MUCP = 62.8. Conclusions: ISD is related to the presence of a more severe clinical picture and case history, but the most significant independent variables are the VLPP and MUCP.