Surgical Treatment of Stress Urinary Incontinence: Is it for you?
Christopher K. Payne, M.D.
INTRODUCTION
Urinary incontinence, or the involuntary leakage of urine, is a symptom which has many different causes. Thus, there is no one "best" treatment. Rather, optimal treatment of urinary incontinence requires an accurate diagnosis and selection of therapy that is customized to the individual patient. In particular, the risks associated with surgical therapy mandate careful consideration of alternative therapy that can effectively treat many patients.
The two major types of urinary incontinence are stress incontinence and urge incontinence. In stress incontinence, physical stress (exercise, coughing, sneezing, etc.) puts pressure on the top of the bladder. The urethra is unable to stay closed and urine will leak out. In this situation, the abnormality is in the urethra. The bladder is simply holding urine as it is intended in the normal fashion. In urge incontinence, there will be an abnormal and undesired bladder contraction (the bladder should not contract until a person is at the toilet and is ready to void). This abnormal contraction pushes urine out through the urethra and cause leakage. It is typically associated with a sense of urgency, hence the name urge incontinence. In this situation, the abnormality is in the bladder because it is contracting inappropriately. The two conditions can occur together (and do so commonly); this situation is referred to as mixed urinary incontinence.
In stress urinary incontinence the urethra may be abnormal from either of two basic problems. First, the urethra may be poorly supported. The urethra should have strong support to the bones of the pelvis so that it remains in the proper position against exercise, coughing and straining. The support of the urethra comes form ligaments, tendons, and muscles. These structures can be injured by childbirth, pelvic surgery, obesity, frequent prolonged straining, strenuous exercise such as weight lifting, and aging. It is frequently associated with loss of support for the other pelvic organs, particularly the bladder. There may also be prolapse of the uterus, rectum, or small intestines into the vagina in this situation. This condition is sometimes referred to as a "dropped bladder" and the operations to correct it are often generically referred to as "bladder lifts" but it should be made clear that all suspension procedures are simply intended to restore normal anatomical urethral support. The second cause of stress incontinence is poor urethral function or intrinsic sphincter deficiency (ISD). Stress incontinence can occur even when the urethra is in a perfectly normal and well supported position. At one time it was thought that this was a rare problem that only occurred after unusual nerve injuries, radiation to the pelvis, and extensive pelvic surgery. We now appreciate that this is a much more common condition and may be associated with aging, hormonal changes, etc. In this situation, the walls of the urethra simply are not able to make an effective seal. Thus, urine will tend to drip through the urethra slowly whenever the patient is in the erect position and active. It is very much like a situation in which a faucet needs to have a washer added to correct a slow drip. It is also possible that a person may have stress incontinence with both poor support for the urethra and ISD.
EVALUATION OF INCONTINENCE
When incontinence is severe enough to cause embarrassment or any limitation of activities, you should talk to you doctor about treatment. To decide which is the best treatment for you, the doctor will take a detailed history of your general health and your bladder symptoms. It is helpful for you to be prepared for this visit by keeping a voiding record for one to two days detailing the time of each urination, the amount of the urination, and notations about the amount and circumstances of any urine leakage. The doctor will, of course, want to know about all of your medical history, particularly details of childbirth and any pelvic surgery. If you have had prior treatment for incontinence, particularly surgery, the details of this will be important in making a decision about future treatment. The doctor will perform a physical examination and a urinalysis. The doctor may catheterize you (pass a small tube through the urethra to drain the bladder) to determine if you are emptying the bladder completely. The doctor may then fill your bladder and examine you with coughing and straining to see if stress incontinence can be demonstrated. This will be an adequate evaluation for many patients and treatment can be started at this point. For other patients X-rays of the bladder, bladder function tests (urodynamic studies) which measure the bladder and urethral sphincter pressures, and cystoscopy may be required. Cystoscopy is an examination of the inside of the bladder and urethra using a small telescope. As part of an evaluation for incontinence, it is important to consider other problems that may be related or that could be corrected at the same time. The doctor will ask you about bladder infections, difficulty urinating, gynecologic problems, problems with defecation or fecal incontinence, and neurologic problems such as back injury, stroke, or other neurologic diseases.
TREATMENT OPTIONS: NON-SURGICAL
If the evaluation shows that you have stress incontinence or mixed incontinence, surgery is one possible option. Surgery is generally considered to be the most effective treatment for stress incontinence. Before discussing surgery in detail it is important to at least mention some of the alternative methods of managing urinary incontinence. When the diagnosis is mixed incontinence, many mediations can be effective in treating the urgency incontinence component. In patients with mixed incontinence it is often best to simply begin a two to four week trial of medication as initial therapy because it is may be difficult to determine whether the stress or urge leakage is most significant problem.
Bladder training is one treatment that can be effective for both stress and urge incontinence and thus is an important adjunct to the treatment of mixed incontinence. In this program, the voiding diary is used to estimate a voiding interval during which the patient is likely to remain dry. The patient will begin a program of strict timed voiding (urinating by a schedule such as every hour) and may then gradually increase the voiding interval when urinary control returns). Another option that can be effective for all types of incontinence is pelvic floor muscle rehabilitation. The muscles of the pelvic floor contribute to urinary control against physical stress and work to oppose abnormal bladder contractions. These muscles are often weak and can be strengthened through exercise. Pelvic muscle exercises, commonly called Kegel exercises, produce significant improvement in urinary control after a three to six month period. The strength of the pelvic floor muscles should be evaluated by the doctor at the time of the initial visit. If the muscle strength is poor, then there is a much better chance of improvement in urinary control then if the muscle strength is already good. If you are unable to perform a proper exercise while being examined, then home exercise therapy may be ineffective. You may require teaching from a nurse therapist. This type of treatment is called biofeedback. In this treatment, the nurse will teach you how to exercise effectively. The most common method is to place a small probe in the vagina which can detect weak muscle contractions and demonstrate them on a computer screen. In this manner, the patient learns how to identify the muscles and how to exercise more efficiently. Pelvic floor rehabilitation is an important option to consider since, if it is effective, the problem will actually be treated and corrected as opposed to a situation which medication is given to suppress the problem but it may return when the medication is discontinued.
Two other non-surgical options may be considered, at least in some patients. A new vaginal support pessary has been developed that helps to immobilize the urethra against straining. This pessary is effective for patients with stress incontinence due to excessive urethral mobility. This treatment would not cure the underlying problem but could be used indefinitely to manage the symptoms. Some patients will choose to use this device because they would prefer to postpone the surgery until sometime in the future and this may provide excellent relief of the symptoms during the interim period. Another new device is a urethral insert or plug. This is a soft silicone stent that the patient learns to place in the urethra to block urine leakage. This device can only be used by patients with pure stress incontinence. It is effective both for patients with stress incontinence due to poor support for the urethra and those with stress incontinence due to poor intrinsic function. The device can be used on an as needed basis. It is particularly acceptable to patients who have leakage only in certain situations (playing tennis, aerobics, etc.). These patients may use the device only once or twice a day, or sometimes only a few times per week. The device must be removed each time the patient needs to urinate and a new device inserted.
Another non-surgical treatment is injection of collagen around the urethral tissues. This treatment was developed to treat stress incontinence due to poor urethral function. The collagen creates a bulging of the walls of the urethra so that they will come together and create a stronger seal. The collagen does not impair normal voiding. The collagen also does not correct poor urethral support. Thus, collagen is optimally effective in patients who have pure stress incontinence due to poor intrinsic function of the urethra. There are reports where collagen has produced improvement in stress incontinence in patients who have some degree of poor urethral support particularly in the elderly. Collagen is most often administered in the office under local anesthesia and is similar to a dental procedure. There is certainly some discomfort during the actual treatment but the recovery period is extremely brief and patients are back to normal by the next day. The effect of the treatment is immediate. Most patients will require two treatments to achieve their initial optimal result and the procedure may need to be repeated several times in the future as the collagen may settle into a different position and be re-absorbed by the body.
OVERVIEW OF SURGERY FOR STRESS INCONTINENCE
Surgical treatment of stress urinary incontinence has been the mainstay of therapy, particularly in the United States, for many years. While surgery is still the most effective treatment for stress incontinence, the myriad of operations that have been described attests to the fact that there is no "one best" operation for all patients. There is a great deal of disagreement among surgeons as to the best treatment and the only way to answer this question would be through a large randomized trial comparing the different operations. This study has never been done, and probably never will be, because of very strong patient and surgeon preferences. Thus, the patient should be aware of this issue and feel free to question their doctor about other possible procedures. The American Urological Association has recently completed a large scale analysis of all the published literature about surgical treatment of stress incontinence and I concluded that there is not enough data to identify the optimal procedure.
The three basic approaches to the surgical treatment of stress incontinence have historically included the anterior colporrhaphy, a wide variety of bladder neck suspension procedures, and several pubovaginal sling procedures. The anterior colporrhaphy operation is primarily designed to treat a cystocele (bladder prolapse) and has a somewhat lower rate of curing stress incontinence than suspensions or slings. Currently, when a patient with a cystocele also has stress incontinence, it is generally recommended that a suspension or sling be performed along with the colporrhaphy to repair the cystocele. Colporrhaphy alone is no longer widely used as a treatment for incontinence.
BLADDER NECK SUSPENSION PROCEDURES
There are an enormous number of bladder neck suspension procedures, most of which are minor variations on a theme. In every case, the bladder neck suspension procedure involves placing stitches between the ligaments and tendons that support the bladder neck and urethra and tying these stitches to a strong supporting structure, usually the pubic bone or an attachment of dense fascia or a ligament right at the pubic bone. In this way, the bladder neck and urethra are stabilized against coughing, straining, and exercising so that the urethra will not open and leak. Almost all the bladder neck suspension procedures are effective treatments for stress urinary incontinence caused by urethral hypermobility (poor support). The bladder neck suspension procedures are further divided into those that are performed primarily through the vagina and those that are performed primarily through an abdominal incision.
The vaginal procedures are often referred to as needle suspension procedure because a long needle is used to transfer the sutures form the vagina to the abdominal side of the pelvis where they are tied behind the pubic bone to provide strong support. The abdominal procedures are commonly referred to as retropubic suspensions since this is the specific name of the incision and surgical approach. Most of the suspension procedures are named after the surgeons that describe the procedure. The two most popular retropubic suspensions are referred to as the Burch and Marshall Marchetti-Krantz (MMK) procedures. The most common vaginal suspensions are the Raz or modified Pereyra procedure and the Stamey or endoscopic bladder neck suspension procedure. For the past twenty years vaginal suspension procedures have become increasingly popular due to shorter hospitalization and quicker patient recovery. This trend has stabilized and may reverse since the introduction of laparoscopy which allows the retropubic procedures to be performed without a large abdominal incision and with a short hospitalization is at least comparable to the vaginal procedures. One important advantage of a vaginal approach is that many patients with stress incontinence also have associated prolapse at the pelvic organs. Correction of this prolapse often requires a vaginal operation and it is easy to combine prolapse repairs with one of the vaginal bladder neck suspension.
Another recent intervention is the use of orthopedic bone anchors to fix the suspension sutures to the bony structures on the abdominal side of suspension procedures. This technique has been used with most of the basic suspensions and is purported to provide improved results and decreased post-operative pain. The bone anchors have been used for approximately four to five years and have a good safety record. There is a small risk of introducing infection into the bone but this has been a rare occurrence. It is unlikely that bone anchors substantially change the outcome of suspension procedures. When the bladder neck suspension is technically unsuccessful it is essentially always due to poor placement of the sutures on the vaginal side. It is distinctly uncommon that the sutures pull out of the fixation on the abdominal side. On the other hand, it is possible that the bone anchors decrease post-operative pain and hospitalization. This is not been adequately determined through any prospectivetrial. On the other hand, many surgeons have advocated bone anchors and been able to perform suspension procedures on an outpatient basis. This has also been done by some surgeons using the standard vaginal suspension procedures so the true value of bone anchors is still being decided.
PUBOVAGINAL SLING PROCEDURES
The most important change in the practice of surgical treatment of stress urinary incontinence in the past ten years has been the great increase in the number of sling procedures performed. The pubovaginal sling is the oldest operation for stress urinary incontinence, having been developed at the turn of the century. The basic concept of the sling is that a piece of strong connective tissue (fascia) is harvested from one portion of the body (usually from the covering of the rectus muscle of the abdomen) and is then placed underneath the urethra and bladder neck as a supporting "hammock". The sling thus corrects the poor anatomic support of the bladder neck and additionally provides a degree of compression and coaptation to the proximal urethra, correcting intrinsic deficiency of the urethra. Slings can be composed of fascia from the abdomen (rectus), the leg, fascia lata, cadaver fascia, and synthetic material. In addition, a sling procedure has been described in which the native fascia at the bladder neck and urethra is reconstructed/re-supported, to create a local sling that extends to support and coapt the proximal urethra (the vaginal wall sling procedure). Space does not permit a full discussion of all of the pro's and con's of the different procedures. The use of cadaver fascia or synthetic material decreases operative time and postoperative pain but introduces some risk of infection, particularly with the use of synthetic materials.
The sling procedure has traditionally been used only in cases of severe stress incontinence. Although the operation has always provided an excellent cure rate for stress incontinence, even in these severe cases, it has been historically associated with a 20-50% risk of significant urinary retention. Thus, in the past only patients who are willing to perform intermittent catheterization were considered candidates for the sling. In recent years the procedure has been refined to the point where the risk of urinary retention is less than 5%. This retention is reversible with further surgery if required. More and more surgeons have adopted the sling as primary treatment for stress urinary incontinence, arguing that it will provide both a superior initial cure rate and superior long term durability because it brings fresh, strong material to the area of weakness.
Most incontinence surgeons would agree that some patients can be identified who must have a sling procedure rather than a bladder neck suspension in order to obtain reliable results. These would generally include patients with the most severe incontinence, patients with stress incontinence and good support for the urethra, patients with prior pelvic radiation or multiple prior incontinence operations, and certain criteria based on urodynamic testing. Sling procedures should produce a cure of stress incontinence in approximately 95% of patients. As with suspension procedures, there is a risk of new onset of urinary urgency and urge incontinence that is between 5% and 10% as well as a risk of re-operation for obstruction/incomplete bladder emptying of something less than 5%.
THE OPERATION AND THE POSTOPERATIVE COURSE
In the vast majority of cases, surgical procedures for stress urinary incontinence can be performed under either regional (spinal or epidural) or general anesthesia. Some surgeons have reported percutaneous bladder neck suspension procedures under local anesthesia plus sedation; this may be an option for motivated patients but is not in common practice at this time. If only incontinence surgery is performed hospitalization is typically minimal and an overnight unit is often employed. When additional operations are performed to correct pelvic prolapse then hospitalization may be somewhat longer. It is unusual for a patient to be in the hospital for more than two nights after a routine operation. At the time of discharge, the patient should be able to walk without assistance, go up and down short flights of stairs, eat a regular diet, and manage the bladder. The patient may have an indwelling urethral catheter for several days, may start on intermittent catheterization immediately after the procedure, or may use a suprapubic tube. The method of postoperative bladder drainage should be determined prior to the surgery.
Transient urinary retention may be expected for several days or up to three weeks. It is typically longer with sling procedures than with bladder neck suspensions. Patients should have no dietary restrictions and can resume light activities immediately. It is typically recommended that patients avoid heavy lifting, strenuous exercise and sexual intercourse for about three weeks. Some patients who have non-strenuous employment may be able to go back to work between one and two weeks but it is generally advised not to plan on an early return to work or to schedule any important activities in the first three weeks. Many patients have significant fatigue or discomfort that might interfere with such plans. In most cases, a patient who has only a simple incontinence operation will feel "back to normal" at two to three weeks whereas a patient who has a major prolapse repair along with incontinence surgery may take four weeks or more to regain full strength and stamina. An individual's response to the stress of surgery is of course highly variable and a person may use their response to other surgical procedures as a guideline.
CONCLUSIONS: IS SURGERY FOR YOU ?
The decision to have surgery to treat stress incontinence is often a difficult one. When there are other symptomatic problems such as a prolapse or dysfunctional uterine bleeding requiring hysterectomy, then the choice of surgery becomes easier. When a patient has only stress incontinence, the analogy to a skier with an injured knee may be helpful. The skier has an injury primarily involving the ligaments and tendons supporting the knee. This athlete may be able to compensate for the weakened ligaments by strengthening the surrounding muscles to stabilize the knee joint. This is analogous to pelvic floor exercises to help correct stress incontinence. When a person has a severe injury or wants to resume vigorous athletic activity, they are more likely to require surgical correction. Patients with less active lifestyles and less severe problems are more likely to be satisfied with physical therapy/biofeedback. The patient who has only stress urinary incontinence without significance urgency is more likely to be completely satisfied with the results of surgery, but mixed urinary incontinence is not a contraindication to surgery. Many patients with mixed urinary incontinence will not respond at all to medication but may become completely dry after successful surgery for the stress leakage. The problem is that we cannot accurately predict which of these patients will have persistent urgency after surgery and all patients should understand that this is possible and accept this as an acceptable outcome before agreeing to surgery.
In summary, any patient in reasonable health for whom stress urinary incontinence is a significant social problem should seriously consider surgical treatment. The patient should also evaluate the non-surgical alternatives and it is frequently appropriate to spend a three month period of time in a serious effort to strengthen the pelvic floor muscles prior to surgery. There are a great number of different operative procedures for the treatment of stress urinary incontinence and the patient should carefully discuss the alternatives with her physician. Patients with more severe incontinence, younger patients with very vigorous lifestyles, and patients with prior failed surgery should be considered for pubovaginal sling procedures.
