Clinical and Urodynamic Determinants of Earlier Time to Failure for the Artificial Urinary Sphincter

Characterizing and Quantifying Material Fatigue of the Artificial Urinary Sphincter Pressure Regulating Balloon

OBJECTIVE

To characterize and quantify changes in elastic properties and in vivo pressure characteristics of pressure regulating balloons (PRB) over time, we conducted an analysis of the mechanical characteristics of the PRB after removal from patients for revision surgery.

METHODS

Pressure and elasticity characteristics of new and used 61-70 cm H2O PRBs were analyzed. Pressure-volume curves were generated using commercially available urodynamics equipment. PRB pressures were measured at a standard fill volume (23 cc). Elastance was calculated by the slope of the tangent line at the inflection point of the pressure-volume curve. Tests were repeated 5 times per PRB and intraclass correlations were used to gauge test-retest reliability. Regression models were used for continuous variables based on data distribution.

RESULTS

Twenty-seven used PRBs were analyzed after excluding 3 for alternative pressure ratings and 2 for occult pinpoint leaks. Time from artificial urinary sphincter placement to removal ranged from 0.02-17.6 years (median 8.4, interquartile range (IQR) 5.7-10.0). The mean pressure of all extracted PRBs: 58.8 cm H=O (± 7.4), 17 (62.9%) below the standard operating range. Each year of use in-vivo was associated with 1.09 cm H2O pressure loss on linear regression (P <.01 CI -1.52 to -0.65). PRB pressures were not significantly different according to indication for removal (1-way analysis of variance (ANOVA) P = .11). Loss of elastance was non-linear, decreasing by 1.9% per year on Poisson regression (P <.01, CI -0.03 to -0.01). When accounting for PRB age, PRB pressure was independently associated with detrusor overactivity.

CONCLUSION

In PRBs tested for pressure-volume characteristics, increasing PRB age was associated with decreased pressure and elasticity.

Factors Influencing Postoperative Overactive Bladder after Adjustable Trans-Obturator Male System Implantation for Male Stress Incontinence following Prostatectomy

We aimed to determine the risk factors for postoperative overactive bladder (OAB) in patients treated with an adjustable trans-obturator male system (ATOMS) for stress incontinence after radical treatment of prostate cancer. A prospective study was performed on 56 patients implanted with an ATOMS for PPI. Clinical and urodynamic information was recorded before and after ATOMS implantation. We built a multivariate model to find out the clinical and urodynamic factors that independently influenced postoperative OAB and the prognostic factors that influenced the efficacy of medical treatment of OAB. We found that the clinical risk factors were the preoperative intensity of urinary incontinence (number of daily pads used and amount of urinary leakage), International Consultation on Incontinence Questionnaire (ICIQ) score, postoperative number of ATOMS adjustments, final cushion volume, and incontinence cure. The urodynamic data associated with OAB were cystometric bladder capacity, voided volume, volume at initial involuntary contraction (IC), maximum flow rate, bladder contractility index (BCI), and urethral resistance (URA). The prognostic factors for the efficacy of oral treatment of OAB were the volume at the first IC (direct relationship) and the maximum abdominal voiding pressure (inverse relationship). The multivariate model showed that the independent clinical risk factors were the daily pad count before the implantation and the ICIQ score at baseline and after treatment. The independent urodynamic data were the volume at the first IC (inverse relationship) and the URA value (direct relationship). Both predictive factors of treatment efficacy were found to be independent. Detrusor overactivity plays an important role in postoperative OAB, although other urodynamic and clinical factors such as the degree of urethral resistance and abdominal strength may influence this condition.

[Use of implants to treat male urinary incontinence]

Treatments for benign and malignant pathologies of the prostate can compromise urine control. Urinary incontinence (UI) affects the quality of life of patients and limits their ability to carry out usual activities. The degree of impact of UI is variable and the associated discomforts make patients seek treatment for it. At the center of the management of urinary incontinence in men are surgical interventions that seek to replace the affected sphincter function through implants. The artificial urinary sphincter since its development in the 1970s has been considered the standard of treatment for UI in men. More recently artificial sphincter and slings have been shown to be effective in a selected group of incontinent men. The goals of surgical treatment of incontinence include the preservation of bladder function, the ability to improve the strength of the urinary sphincter, and to reduce or eliminate urine leakage, and thereby improve the quality of life. The aim of the article is to present various implants for the correction of male urinary incontinence.