Ex vivo biomechanical properties of the female urethra in a rat model of birth trauma.

Stress urinary incontinence (SUI) is the involuntary release of urine during sudden increases in abdominal pressures. SUI is common in women after vaginal delivery or pelvic trauma and may alter the biomechanical properties of the urethra. Thus we hypothesize that injury due to vaginal distension (VD) decreases urethral basal tone and passive stiffness.

Functional analysis of active urethral closure mechanisms under sneeze induced stress condition in a rat model of birth trauma.

Purpose: We evaluated changes in the urethral closure mechanism under a sneeze induced stress condition in a rat model of birth trauma.

Materials And Methods: Four days after vaginal distention induced by balloon catheter inflation in the vagina sneezing was induced while recording intravesical pressure with the rat under urethane anesthesia to evaluate sneeze induced leak point pressure, defined as the lowest pressure inducing fluid leakage from the urethral meatus during sneezing. Sneeze induced responses in the bladder and proximal or mid urethra were also measured using microtip transducer catheters.

Biomechanical characterization of the urethral musculature.

Rigorous study of the associations between urethral structural anatomy and biomechanical function is necessary to advance the understanding of the development, progression, and treatment of urethral pathologies. An ex vivo model was utilized to define the relative biomechanical contributions of the active (muscle) elements of the female urethra relative to its passive (noncontractile) elements. Whole urethras from female, adult rats were tested under a range of applied intraluminal pressures (0 to 20 mmHg) as a laser micrometer simultaneously measured midurethral outer diameter.

Development of an experimental system for the study of urethral biomechanical function.

Despite its principal mechanical function in the storage and release of urine, the biomechanical properties of the urethra have remained largely unexplored. The purpose of this study was to develop and validate an experimental model that can be used for evaluating whole urethral tissue in such a manner. Bladder-urethral specimens were excised from halothane-anesthetized female rats and mounted at in vivo length within the experimental apparatus consisting of a tissue perfusion chamber, an adjustable fluid column, and a laser micrometer.