Pelvic Prime's Anatomy Academy Series

Stress Urinary Incontinence

The main job of the urethral sphincter is to keep urine from leaking out, with help from the levator ani muscle and the endopelvic fascia. Problems usually show up when there’s extra stress, such as coughing hard. During a cough, the diaphragm and abdominal muscles push down hard, increasing the pressure inside the abdomen. This can cause the urethra to move downwards. 


When the abdominal pressure goes up, the bladder neck and nearby tissues move and stretch. The pelvic floor then has to slow down this movement. The increased pressure pushes the urethra against the supportive tissues, helping to keep it closed and prevent leaks.


With correct pelvic floor exercises, the pelvic muscles can get stronger and provide more resistance. But if the endopelvic fascia is damaged or the levator ani muscle is injured, these support tissues become more flexible and less effective, making leaks more likely during stress or increased pressure. 

Garden Hose on a Trampoline Analogy


Imagine stepping on a garden hose that's sitting on a trampoline. If the trampoline is firm, the hose flattens, and the water stops. But if the trampoline is very stretchy, stepping on the hose makes the hose and trampoline move down together, so the water keeps flowing until the trampoline starts to resist.


 The same thing happens in the body; if the supportive tissues are too flexible, the pressure from the abdomen can't close the urethra quickly, causing leaks.

Urethral Support System


For normal function, the levator ani muscle supports the urethra through the endopelvic fascia. With coughing, this muscle contracts along with the diaphragm and abdominal muscles to build pressure. This contraction helps tighten the layer under the urethra, reducing bladder neck movement and increasing urethral compression.


As people age, the levator ani muscle takes longer to increase it strength and the muscle's maximum strength decreases by about 35%.  However, the levator ani muscle doesn’t lose much volume with age because it has more slow-twitch fibers.


If the levator ani muscle is damaged or its nerves are impaired, it takes even longer to develop force, decreasing its strength and stiffness. If the connection between the muscle and the fascia is broken, the muscle can't function properly during a cough. 

Urethrovesical Pressure Dynamics

Understanding how urine stays in the bladder and how it might leak out involves looking at two main things: 


Understanding these pressures helps in figuring out why incontinence happens and what can be done about it. Unfortunately, measuring these pressures accurately is difficult because the urethra moves around a lot during a cough.

Exercises for pelvic muscles can help treat Stress Urinary Incontinence. Simple tests like coughing with a full bladder can show how much urine is leaking. If a someone can contract their pelvic muscles during a cough and reduce leakage, then learning to do these exercises regularly can be an effective treatment.

However, if the pelvic muscles are damaged, exercises might not be enough. People need to be taught when and how to use these muscles to prevent leaks. Strengthening the muscles and using them correctly during activities that increase abdominal pressure, like coughing, is key. 

Prevalence for Stress Urinary Incontinence

Knowing how common a condition is helps us plan for the needs of a population. Many studies on urinary incontinence in women have shown varying results because of different definitions and study methods. Two important studies in Europe and the United States defined urinary incontinence as any leakage in the past 30 days. 


However, many women with symptoms don't seek treatment, so the actual number may be higher.

Risk Factors for Stress Urinary Incontinence

Causes of Stress Urinary Incontinence

Stress urinary incontinence happens when bladder pressure exceeds urethral pressure. Normally, this doesn't occur because the bladder and urethra adapt to pressure changes. The external urinary sphincter is crucial in maintaining urinary control and any weakness leads to incontinence.  


Weak support structures for the urethra can also lead to incontinence. These include damage to the pubourethral ligament, lateral supports, endopelvic fascia, and pelvic floor muscles. 

Mixed Urinary Incontinence

Mixed urinary incontinence is harder to understand and involves both overactive bladder and sphincter defects. It's challenging to distinguish between stress and urgency incontinence because symptoms are based on patient responses. Pelvic floor muscle training can help with all types of incontinence, and many patients see improvement after stress incontinence surgery. 

Lifestyle Choices Associated with Urinary Incontinence

Studies have shown that symptoms like frequent urination, urgency, and incontinence can be linked to certain lifestyle choices, which are changeable. Healthcare professionals can use this information to help patients by recommending changes in behavior to lessen these symptoms. Common factors include obesity, physical activity, smoking, and diet.

Keep in mind that while some lifestyle changes might help, there is not enough strong evidence to make specific recommendations for most cases.

Obesity

Increased body weight, especially around the waist, can increase pressure on the bladder and pelvic floor. Studies show that losing weight can help reduce symptoms of urinary incontinence, especially for women who are overweight or obese. A review found that moderate weight loss should be considered a first-line treatment for incontinence in women.

Physical Activity

Regular physical activity is important for overall health. However, some high-impact activities might increase abdominal pressure and worsen pelvic floor dysfunction. Studies suggest that moderate exercise can reduce the risk of incontinence, but more research is needed to fully understand the effects of different types of physical activity.

Smoking

Smoking is linked to chronic coughing, which increases abdominal pressure and can lead to incontinence. Nicotine can also affect bladder function. While there is evidence that smoking can worsen incontinence, no studies have shown that quitting smoking improves incontinence symptoms. More research is needed.

Diet and Fluid Intake

Certain dietary factors, like caffeine and fluid intake, can influence incontinence symptoms. Reducing caffeine intake has been shown to decrease symptoms like urgency and frequency. Fluid intake should be balanced; too much or too little can cause problems. High fluid intake isn't linked to increased incontinence risk, but reducing excessive intake might help.

Encouraging Lifestyle Changes in Clinical Practice

There are various models and theories to help people adopt healthy behaviors and understand how behavior changes happen. A theory is a set of ideas that explain how something works and can guide actions. Just knowing about a health problem usually isn't enough to make people change their habits. Many healthcare workers think that telling patients about their health issues will motivate them to change, but this isn’t true.

For example, if knowing the dangers of smoking were enough, very few people would still smoke. The same goes for problems related to high BMI. People receive a lot of health information, which they understand based on their experiences, beliefs, and values. Human behavior is complex, so encouraging people to change their habits is also complicated.


Various theories from fields like sociology, psychology, management, and marketing help understand and promote health behavior changes. These models guide the creation of plans to encourage healthy habits. For example, for bladder health, patients might be advised to reduce caffeine, exercise more, and watch their waist size. However, simply telling someone to lose weight usually doesn’t work without behavior change strategies. 

Motivational interviewing is a good way to help patients change their behavior. Originally used for substance abuse, it’s now adapted for other lifestyle changes and has shown to be effective in areas like diet, exercise, diabetes, and smoking. Motivational interviewing focuses on the patient’s readiness to change, understanding that their decision can vary over time. Patients are more likely to accept advice when they are ready. This approach builds rapport, explores the patient’s view on behavior change, and boosts their confidence.  Motivational interviewing uses skills like active listening and empathy, with a mix of open and closed questions. This method makes discussions about behavior change less confrontational and more effective. However, it requires proper training and ongoing practice for healthcare professionals to use it effectively. 

Physical Therapist Clinical Recommendations: Interviewing techniques in promoting continence


These steps help patients become active participants in changing their health behaviors. It’s important for specialized healthcare providers to know when to refer patients to other experts, like dietitians for weight loss.

References: Bo, K., Berghmans, B., Mørkved, S., & Van Kampen, M. (Eds.). (2023). Evidence-Based Physical Therapy for the Pelvic Floor (3rd ed.). Elsevier.