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.

Urethral Stricture Formation After Artificial Urinary Sphincter Cuff Erosion Is Uncommon in the Absence of Pelvic Radiation.

PURPOSE: Reported rates of urethral stricture development after artificial urinary sphincter erosion are highly variable. We hypothesized that the risk of stricture is commensurate with the degree of erosion. MATERIALS AND METHODS: We reviewed our prospectively maintained quality improvement database for all patients with artificial urinary sphincter erosion from 2011 to 2022. The incidence of postoperative stricture development was compared to the severity of erosion using a graded scale: 1, <25% circumference; 2, 25%-50% circumference; 3, >50% and <100% circumference; and 4, 100% circumference. From 862 artificial urinary sphincter surgeries, 102 erosion cases were identified, and 63 with documented erosion severity were included for analysis. Additional analysis was performed on 28 cases without documented erosion severity for validation. RESULTS: Within the main cohort, urethral stricture developed in 22 (34.9%) patients. The incidence of stricture did not vary by grade of erosion (P = .73) and was not significantly higher in men with grade 4 erosion vs lower-grade erosions (32.7% vs 50.0%, P = .34). Radiation exposure was associated with a 41.1% higher incidence of stricture (P < .01) and nearly every stricture occurred in the setting of prior radiation (21 of 22; 95.5%). In the validation group, 10 (35.7%) developed stricture, mostly in the setting of radiation (8 of 10; 80%). Overall, 29 of 32 (90.6%) cases of stricture involved a history of radiation. CONCLUSIONS: Artificial urinary sphincter erosion does not lead to urethral stricture formation in most cases and is not associated with degree of erosion. Those who develop strictures nearly always have a history of pelvic radiation.

A multimodality review of male urethral imaging: pearls and pitfalls with an update on urethral stricture treatment.

Optimum radiological assessment of the male urethra requires knowledge of the normal urethral anatomy and ideal imaging techniques based on the specific clinical scenario. Retrograde urethrography is the workhorse examination for male urethral imaging, usually utilized as the initial, and often solitary, modality of choice not only in the setting of trauma, but also in the pre- and post-operative evaluation of urethral strictures. There is, however, growing interest in utilization of ultrasound and magnetic resonance for evaluation of the male urethra owing to lack of ionizing radiation and improved delineation of the adjacent tissue. We review the various modalities utilized for imaging of the male urethra for a variety of known or suspected disorders, and provide an update on current treatments of urethral strictures. Additionally, we detail the key information needed by urologists to guide management of urethral strictures. We conclude with a brief discussion of neophallus urethral diseases following female-to-male sexual confirmation surgery.