A 52-year-old postmenopausal woman comes to the office due to urine leakage with coughing and sneezing. She has no dysuria, urgency, or changes in urinary frequency. The patient has had 3 spontaneous vaginal deliveries. On pelvic examination, there is mild vulvovaginal atrophy and anterior vaginal wall prolapse. The remainder of the physical examination is normal. The patient is advised to perform exercises to strengthen her pelvic floor as part of treatment for her symptoms. Which of the following structures is the most likely target of the exercise?
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This patient's loss of urine with increased intraabdominal pressure (eg, coughing, sneezing) is due to stress urinary incontinence (SUI). The bladder and urethra are typically maintained in a normal anatomic position by the pelvic floor muscles known as the levator ani muscle complex (ie, iliococcygeus, pubococcygeus, puborectalis), which form a U-shaped sling around the pelvic viscera for pelvic support.
Patients develop SUI due to chronic pressure (eg, obesity) or injury (eg, multiple vaginal deliveries) affecting the levator ani muscle complex, which results in pelvic floor weakness and laxity. Chronic pelvic floor laxity contributes to urethral hypermobility, in which the pelvic floor muscles cannot stabilize and fully compress (close) the urethra against the anterior vaginal wall during times of increased intraabdominal pressure (eg, coughing). Pelvic floor weakness can also lead to herniation of the bladder into the vagina and anterior vaginal wall prolapse (cystocele).
First-line treatment of SUI is pelvic floor muscle (Kegel) exercises, which repeatedly activate and release the levator ani muscle complex to gradually strengthen and stabilize the pelvic floor. The strengthened pelvic musculature provides a stable base for urethral compression, thereby maintaining continence.
(Choice A) The bulbospongiosus muscle is part of the superficial urogenital triangle of the perineum. It constricts the vaginal orifice and is commonly damaged during vaginal delivery. Because it is a superficial muscle, strengthening it does not improve pelvic floor support or reduce SUI.
(Choices B and C) Detrusor muscle overactivity results in urge incontinence (eg, the sudden need to urinate followed by immediate, involuntary loss of urine) rather than SUI, while stimulation of the internal urethral sphincter helps prevent urine leakage. Both are smooth muscles (ie, controlled by the autonomic nervous system); therefore, they cannot be voluntarily exercised for symptom improvement.
(Choice E) The uterosacral ligaments run along the lateral pelvic wall and elevate the uterus and vaginal apex by attaching to the sacrum. Weakening of these ligaments contributes to uterine prolapse but does not directly cause SUI or anterior vaginal wall prolapse.
Educational objective:
Stress urinary incontinence is involuntary urine leakage with increased intraabdominal pressure (eg, coughing, sneezing). Pelvic floor muscle (Kegel) exercises target and strengthen the levator ani muscle complex, improving support around the urethra and bladder and symptoms of stress urinary incontinence.