Considerations in the modern management of stress urinary incontinence resulting from intrinsic sphincter deficiency

Intrinsic sphincter deficiency (ISD) is a common cause of stress urinary incontinence and is associated with more severe symptoms, often being associated with failed previous surgery. Due to the impaired sphincteric function, alternative surgical approaches are often required. The purpose of this review is to appraise the contemporary literature on the diagnosis and management of ISD. A PubMed search was performed to identify articles published between 1990 and 2014 using the following terms: ISD, stress urinary incontinence and type III stress urinary incontinence. Publications were screened for relevance, and full manuscripts were retrieved. Most studies base the diagnosis of ISD upon urodynamic appearances using recognized criteria (Valsalva leak point pressure < 60 cm H2O or a maximum urethral closure pressure < 20 cm H2O) in addition to clinical features. A range of non-surgical and surgical treatment options are available for the patient. Pubovaginal slings are more effective than retropubic colposuspensions with outcomes comparable to those reported with midurethral slings. The artificial urinary sphincter provides long-term cure rates; however, it is associated with specific morbidity including device erosion, mechanical failure and revision. The benefits of bulking agents, however, are not sustained beyond 1 year. There are few randomized controlled trials that compare accepted treatments specifically for patients with ISD. The lack of standardization in the definition and diagnostic criteria used limits inter-study comparisons. An assessment of urethral pressure profile when combined with the clinical features may help predict outcomes of surgical intervention.