Stress urinary incontinence (SUI) refers to the involuntary leakage of urine from the external urethral meatus when abdominal pressure increases during activities such as sneezing, coughing, laughing, or exercising. Urinary incontinence is a common condition in women, with 23%–45% experiencing varying degrees of incontinence, approximately 50% of which are cases of stress urinary incontinence.
Etiology
Established risk factors include age, increased number of childbirths, vaginal delivery, pelvic organ prolapse, obesity, and racial or genetic predisposition. Potentially related risk factors include estrogen deficiency, pelvic floor surgeries such as hysterectomy, smoking, diabetes, chronic coughing, chronic constipation, and depression.
Pathophysiology
The primary mechanisms underlying stress urinary incontinence involve excessive downward displacement of the bladder neck and proximal urethra, loss of urethral support, intrinsic urethral sphincter deficiency, reduced closure capability of the urethral mucosa, and neuromuscular dysfunction affecting continence-supporting structures.
Clinical Manifestations
The primary symptom is involuntary leakage of urine during events that increase abdominal pressure, such as coughing, sneezing, laughing, jumping, or walking, with the leakage ceasing when the pressure-inducing action stops. Symptoms are typically not accompanied by bladder irritation, hematuria, or difficulty voiding.
Diagnosis and Differential Diagnosis
Physical examination should assess for vaginal atrophy, the ability of pelvic floor muscles to voluntarily contract, the presence of bladder or uterine prolapse, and any bladder-vaginal or urethra-vaginal fistula. Stress testing and urodynamic studies are useful in confirming the diagnosis. A positive stress test is indicated when urine leakage is observed from the urethral meatus during coughing in a supine or standing position, with the leakage ceasing once the coughing stops.
For differential diagnosis, conditions to consider include true incontinence caused by sphincter dysfunction, urgency incontinence due to infection, overflow incontinence caused by bladder overdistention, and bladder-vaginal fistula.
Treatment
Non-Surgical Treatment
Pelvic Floor Muscle Training
The function of the pelvic floor is improved, and urethral stability is enhanced through repeated, voluntary contraction and relaxation of the pelvic floor muscles.
Pharmacological Treatment
Selective α1-adrenergic receptor agonists, such as midodrine, activate α1 receptors in the bladder neck and posterior urethra to increase urethral resistance. Topical or oral estrogen is used to promote the proliferation of urethral mucosa, submucosal vascular plexus, and connective tissue.
Surgical Treatment
Various surgical methods are available, with the most common being tension-free mid-urethral sling (MUS) procedures and laparoscopic bladder neck suspension (Burch colposuspension). Among these, tension-free mid-urethral sling procedures are the preferred option. The retropubic approach is referred to as tension-free vaginal tape (TVT), while the transobturator approach is called tension-free vaginal tape-obturator (TVT-O).