Tuesday, June 21, 2011

After Hysterectomy, Which Women Are at Risk for Developing Stress Incontinence?

Approximately 30% of women report having some form of urinary incontinence, but only those the most troubled by it, or those where fluid restriction and Kegels fail to help will be considered candidate for correcting it with a sling. We also know that many things predispose to the development of stress incontinence, among them: menopause, birth trauma, hysterectomy, and chronic straining (from high impact exercise, coughing, constipation).

But, in those women undergoing a hysterectomy how likely is it that the patient will develop stress incontinence? The majority don’t, but for those who do, it can be disheartening, embarrassing and restrictive on their quality of life.
The hysterectomy (removal of only the uterus, NOT the ovaries) operation itself leads to unavoidable damage to supportive structures of the bladder and urethra, as well as affecting the nerve supply to these structures. Can we separate the risk factors for developing stress incontinence from the risk of the hysterectomy by itself, since many women undergoing hysterectomy have some of the risk factors for stress incontinence already.

I must compliment a very ingenious and simple methodology for calculating this risk factor to Dutch researchers who devised a simple equation to predict of a woman is more likely or not going to experience stress incontinence after her surgery.
They surveyed 234 women after three years from their hysterectomy and collected data. Bothersome stress incontinence developed in 22% of the women by three years. Among the women, abdominal hysterectomy was performed in 3 times as many, vs vaginal hysterectomy.

What’s amazing, even before getting to the equation, is that 22% (!!!!!) of women by just years after surgery, developed bothersome stress incontinence. That is a lot of women.

What the researchers found is that 3 variables helped to predict the risk for stress incontinence (SUI). They are: BMI, age, and surgical route. Women with higher BMI simply have more pelvic pressure due to their higher weight that can affect the support of the urethra. Secondly, the YOUNGER the women was the more likely she was at risk for developing SUI. One would think the converse would be true, since with menopause, the risk for SUI increases. But here, if the woman is younger, she has longer to develop SUI in her lifetime where it would also be more bothersome if more physically active, versus an older woman who may have made it to an older age prior to hysterectomy with having developed SUI, and if not very active, may not experience SUI as bothersome or at all. Vaginal approach may put special strain on the bladder during dissection that is not seen with an abdominal approach. On the other hand, vaginal hysterectomy is preferred for those with dropped uteruses, who already are predisposed by virtue of this condition to developing SUI.

RISK FOR SUI score= 32 + BMI –age + (7.5 x route of surgery), where abdominal route =0, vaginal = 1.

For example, a 40 year old woman with a BMI of 25 scheduled for have an abdominal hysterectomy would have a risk score of 17. This would equate to a 23% chance of SUI at 3 yrs according to the graph developed by the researchers. If the surgery were done vaginally, the risk score would be 32 +25 – 40 + 7.5= 24.5, which would translate to a 40% risk, according to the graph developed by the researchers.

This fascinating predictive model finds its biggest utility in counseling women prior to their hysterectomy, what their risk of SU I may be. All women prior to hysterectomy should at least know that SUI is a risk, but now we can estimate just how much a risk it may be. With this knowledge in hand, those women at higher risk for SUI can be advised to begin Kegel muscle exercises more dutifully to mitigate development of SUI. Of course this represents only one researcher’s data, and to be truly accurate must be validated and repeated, but it holds potential.