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Female Urinary Incontinence
At least ten million Americans suffer from urinary incontinence. It affects 15 to 50 % of elderly individuals in the community. The annual cost spent on incontinence in America is $10 billion (this figure exceeds the annual cost of dialysis and coronary artery bypass surgery combined)(1).
Factors Involved in Maintaining Urethral Closure and Continence
Intrinsic Urethral Mechanism
The urethra consists largely of a rich vascular "sponge", lined by a moist mucosal layer and surrounded by a coat of smooth muscle, fibro-elastic tissue and striated muscle. The mucosa provides coaptation. The vascular submucosa creates the "washer effect" for the continence mechanism. Functionally, the surrounding smooth muscle coat contains this mechanism by directing submucosal expansile pressures inward towards the mucosa. Muscle tone is mediated by alpha-adreno receptors in the sympathetic nervous system. All three layers are under estrogen control.(3, 4)
Incidence of Subtypes of Urinary Incontinence in Women (5)
Genuine Stress Incontinence
|Trauma and stretching of vaginal delivery|
|Hormonal changes ( Menopause)|
As the bladder neck support is weakened, the increase in intra-abdominal pressure is no longer transmitted equally to the bladder outlet, and therefore instantaneous leakage occurs.
B). Intrinsic Sphincter Dysfunction (10 - 20% of patients)
This results from damage to the sphincter due to:
|Multiple prior operations|
|Neurogenic disorders including Diabetes Mellitus|
|Atrophic changes: lack of estrogen.|
Immediate leak after coughing or standing up is stress
Leaking after a few seconds is a detrusor contraction.
A diary kept over a 24 or 48 hour period which records the times and volumes that the patient voids will give an idea of the largest single voided volume but also of frequency and polyuria and severity of incontinence problems.
Volume voided (mL)
Wet or Dry
Volume of Incontinence
This test is essential in all incontinent women and distinguishes between true incontinence (residual urine <50 mL) and overflow incontinence (residual urine>100 mL)
Creatinine and Electrolytes, fasting Glucose and Calcium
(for patients with Polyuria).
Renal Ultrasound in patients with incomplete emptying.
A. Non-Surgical Treatment
In approximately 10 - 15% of women with symptoms that appear to indicate stress incontinence, their condition is actually due to detrusor instability (coughing can stimulate a detrusor contraction)(5) Urodynamic testing reveals that approximately 20% of women with symptoms of urge, frequency, and overactive urge incontinence actually have underlying genuine stress incontinence, rather than detrusor overactivity (This is called "sensory urgency"). Urgency is absent in 20% of patients with detrusor overactivity.(5)
1. Residual Urine
This test is essential in all incontinent women and distinguishes between True Incontinence (Residual urine < 50 mL), and Overflow Incontinence (Residual urine >100 mL).
A poor flow could be an indication of urethral obstruction and should be treated during surgery to prevent post-operative retention or difficulty to void.
3. Pressure flow study
A small catheter in the bladder measures the pressure during voiding while her flow is also measured. This helps to differentiate true urethral obstruction from underactivity of the Detrusor.
Obstruction = detrusor pressure more than 50 cm water and flow < 15 mL/s.
The pressure in the bladder and rectum is measured during bladder filling. Intra-abdominal pressure is subtracted from bladder pressure to give a real indication of Detrusor function.
5. Abdominal Leak-Point Pressure (ALPP)
This is the measurement of the total bladder pressure during coughing or valsalva manoeuvre to determine the pressure in the bladder required to induce leakage. In hypermobility of the urethra, the ALPP will be more than 60 cm water, but with Intrinsic Sphincter Dysfunction, the ALPP is less than 60 cm water and often less than 20 cm water.
To evaluate the urethral closing mechanism and to exclude other pathology.
B. Surgery for Hypermobility of the Urethra
The pathology in these patients is malposition of a normal sphincteric unit and therefore, the goal of surgery is repositioning of the bladder neck and urethra to a high retropubic position (Bladder Neck Suspension).
Burch Colposuspension is still one of the operations with the best long-term results. This operation also corrects small to moderate cystocoeles. It can be done Laparoscopically, or by open surgery, depending on the circumstances. With the Laparoscopic technique, the patient is normally discharged after two nights and could return to work within one to two weeks. Burch Colposuspension is carried out through the retropubic space and the vaginal wall and urethropelvic ligament (endopelvic fascia), is elevated and fixed to the lateral pelvic wall by attaching it to Cooper's Ligament with Ethibond Sutures. Because all loose fatty and connective tissue is stripped off the vaginal wall and urethropelvic ligament, it adheres to the pelvic wall and should cause permanent fixation in this position.
Laparoscopic Burch Colposuspension
There are more than 100 other operations, but most other suspension operations done trans-vaginal do not create the same raw surface and therefore, do not have the same amount of fixation due to fibrosis, to the pelvic wall. The failure rate is therefore higher. There is also a higher incidence of post operative retention, or difficulty passing urine, where the elevating sutures are very close to the urethra and bladder neck.
In this condition, there is damage or paralysis of the sphincteric unit which could even be in a normal position. The goal of surgery for Intrinsic Dysfunction is coaptation, support, and compression of the damaged sphincteric unit. Simple suspension of the bladder neck is unlikely to correct the problem. Urethral Sling Procedures are the best to achieve the goal.
A sling is put around the mid-urethra. There are different suburethral slings which include Sparc sling, TVT and IVS.
In patients with good support of the bladder neck, but with Intrinsic Sphincter Deficiency, injections of substances, such as Macroplastique and Collagen, can cause coaptation of the urethral mucosa.
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