Rigi10™ Malleable Penile Prosthesis
Also Known As
Bladder neck hypermobility, Urethrovesical junction hypermobility, Rotational descent of the vesical neck, Unstable urethral structure
Definition
Urethral hypermobility refers to a condition characterized by excessive movement of the urethra during stress maneuvers due to weakened pelvic floor support structures.1 It describes the instability of the urethra in relation to the pelvic floor muscles, where the urethra drops below the pelvic floor muscles when abdominal pressure increases.2 The condition occurs when damage to the urogenital diaphragm, which consists of ligaments, pelvic floor muscles, and surrounding connective tissue, causes the urethra to be displaced from its normal position or to have increased range of motion.3 This displacement results in lack of effective closure of the urethra and thus urinary leakage, especially during physical exertion, coughing, sneezing, or Valsalva maneuvers.3
According to Delancey’s “hammock theory” and the integral theory proposed by Petros and Ulmsten, normal voiding control mechanisms depend on the proper function of the urethral sphincter, as well as on the bladder neck, urethra, and the supporting and surrounding anatomical structures.4 Damage to the levator ani muscle or pubourethral fascia causes weakening of the vaginal pressure on the urethra and the inability to maintain closed pressure in the normal urethra, which leads to stress urinary incontinence.4
Clinical Context
Urethral hypermobility is clinically significant as one of the main etiologic factors implicated in stress urinary incontinence (SUI), which affects approximately 12.6% of women in developing countries.5 The condition is often associated with anatomical changes in the pelvis and urethral sphincter following pelvic organ prolapse as a result of tissue weakening and prolonged labor.2 Many studies have observed a relationship between the route of delivery and the risk of SUI, with vaginal delivery associated with a two-fold risk compared to cesarean section.2
Diagnosis of urethral hypermobility is typically made through several methods. The Q-tip test, first described in 1971, is a simple clinical assessment where a cotton-tipped swab is inserted into the urethra until reaching the bladder neck. Urethral hypermobility is defined as a Q-tip angle of 30 degrees or greater from the horizontal during straining.5 More advanced diagnostic methods include transperineal ultrasound (TPUS), which measures the overall rest-stress distance of the bladder neck. A rest-stress distance of more than 13.3 mm has been identified as an optimal cut-off value to predict urethral hypermobility.5 Other diagnostic modalities include urodynamic testing, voiding cystourethrography, pelvic ultrasound, and electromyography.3
Treatment approaches for urethral hypermobility begin with conservative measures such as pelvic floor muscle training under the supervision of a physical therapist, which is considered first-line treatment.1 Weight loss of 5-10% has been shown to result in mild improvement in symptoms that persists for 1-3 years.1 Pharmacological interventions may include duloxetine, a serotonin-norepinephrine reuptake inhibitor approved in Europe for treatment of stress urinary incontinence.1
Surgical interventions are considered when conservative measures fail and include procedures that use combinations of sutures, implanted synthetic mesh, and autotransplanted tissue to support and reposition the urethra. Common surgical procedures include Burch colposuspension, midurethral sling, pubovaginal sling, and mini sling.1 Less invasive procedures such as urethral bulking involve injecting an inert material into the wall of the urethra, though this has a lower cure rate than surgical options.1
The recognition of urethral hypermobility is particularly important for preoperative counseling, as it is associated with greater operative success after anti-incontinence surgery.5