Abstract
Stress urinary incontinence is a common, but frequently unreported, problem for women. This article explores the management and treatment options that are available.
Introduction
Stress urinary incontinence (SUI) is a common problem for middle age women in the United Kingdom. One study in Leicestershire suggested that approximately one-third of all women will complain of clinically significant urinary symptoms of this nature at some time.
SUI needs to be distinguished from urgency, frequency and nocturia as well as from true incontinence (due to a fistula).
SUI usually affects women who are parous (who have had children) and is most common in women under the age of 50 years. With age, other bladder problems, particularly over-active bladder conditions, become more common. However, it is probable that many women with SUI, and other types of incontinence quietly put up with their symptoms rather than seek medical attention. Indeed incontinence is one of the last taboo subjects: while we all happily talk about other aspects of our health and daily life that used to be considered very personal and private, urinary incontinence remains a subject that is not frequently discussed over the dinner table.
Investigation
A really good and accurate history is essential. Classically women with SUI complain of leaking small amounts of urine when they move, laugh, cough, sneeze, or jump up and down. These symptoms need to be distinguished from the sense of having to rush to the loo (urgency), going frequently (frequency) and getting up at night to pass urine (nocturia). It is important also to ask about enuresis (bed wetting) and urinary incontinence with sexual activity.
Many women complain of minor degrees of urinary incontinence for which they may not desire, or require, treatment. Others may have SUI which is generally minor but is dramatically worsened during bouts of coughing or sneezing. This means that sufferers from hayfever and asthma may find that their SUI is exacerbated by their other conditions.
It is important to ascertain the effect of the urinary incontinence on a woman's life style and on how she copes with her condition without medical treatment. Many women will avoid activities that initiate SUI, others will cope by wearing an incontinence pad on most days. While many women put up with very minor degrees of incontinence and do not wish to have treatment, others unnecessarily tolerate severe symptoms unaware that effective and safe treatment is available to them.
There remains some controversy about the role of urodynamic investigations. While some women may give such a good and clear cut history of SUI that urodynamic investigation may not be necessary, the majority of gynaecologists will wish to see the results of urodynamic investigation before undertaking treatment and certainly before undertaking invasive surgical treatment.
Causes of SUI
The precise patho-physiological mechanisms of SUI in women are complex and remain poorly understood.
A small number of women seem to have a congenitally weak pelvic floor and a small number suffer from urinary incontinence in childhood. For the majority of women, vaginal childbirth plays an important role in the development of SUI and it is thought that damage to the pelvic floor occasioned by childbirth is largely responsible. Growing older is accompanied by a weakening of many of the pelvic floor tissues and this becomes particularly severe after the menopause when a lack of oestrogen comes into play. Growing older is also often accompanied by putting on weight; obesity probably places an additional strain on the pelvic floor.
Treatments
There is universal agreement that life style interventions are particularly important before invasive surgical management. Weight loss, exercise and improvement in physical fitness are particularly important. Cessation of smoking, alteration of fluid management and the relief of constipation are frequently suggested as methods of reducing the level of urinary incontinence. Although weight loss in the very overweight woman has been shown to be effective in treating urinary incontinence the effect of cessation of smoking and management of constipation are of unproven value.
Pelvic floor exercises
Pelvic floor muscle training is commonly suggested for treatment for urinary incontinence with or without the adjunct of bio feedback or electrical stimulation. Perhaps 50% of women will benefit from pelvic floor exercises. Pelvic floor exercise is most valuable in the younger woman, particularly after childbirth.
Pelvic floor exercises can be taught by either a physiotherapist with an interest in urinary incontinence or by urinary incontinence nurses. Weighted vaginal cones are, as their name suggests, plastic cone shaped weights intended to be placed in the vagina by the patient and held in place by pelvic muscle contraction. They may be a helpful self-treatment technique although there is little scientific evidence for their value.
Drug treatment
Drug treatment has only been relatively recently available for the treatment of SUI. Duloxetine has been shown in most phase 2 and phase 3 trials to be effective in the treatment of SUI, with a dose of 40 mg twice daily producing an improvement in the level of SUI in approximately 50% of women who take it. The most common side-effect is nausea but some women experience a dry mouth, fatigue, insomnia or constipation. Duloxetine is a selective seratonin re-uptake inhibitor of the type that is used in the treatment of moderate to severe depression. Despite this, there is little evidence that Duloxetine in women with urinary incontinence leads to any alteration in mood. In the later phase 3 studies of Duloxetine, women who were on the waiting list for surgery were offered Duloxetine which was studied against placebo. Approximately one-fifth of women who were taking Duloxetine opted to continue with medication rather than have surgical treatment. The remaining 80% continued with their initial intention to have surgery.
Surgery
There are many surgical techniques aimed at treating urinary incontinence but all should be reserved for those women in whom conservative management has been unsuccessful. It is important to remember that the aim of surgery is to reduce or abolish urinary incontinence and improve the quality of a woman's life. When making a decision about surgical intervention it is, therefore, important to understand how urinary incontinence has affected the woman's quality of life, how much benefit she can realistically expect to get from surgery and what the risks and possible side-effects of the surgery might be.
For many women, urinary incontinence is accompanied by prolapse and surgery may aim to treat both. It is important to recognize, however, that surgery aimed simply at treating prolapse is unlikely to benefit the symptoms of SUI unless a specific bladder neck, anti-incontinence procedure is also performed.
A number of historical operations for SUI such as urethral buttressing, anterior repair and needle suspension operations have largely disappeared from the repertoire of surgical techniques used to treat SUI because of their poor long-term outcome.
Burch colposuspension
Burch colposuspension for many years has been the gold standard by which all other treatments have been judged. The operation has been available for many years and there are a number of studies showing both short- and long-term success and complication rates. Colposuspension is generally quoted as curing 85% of women after five years, dropping to 70% by 10–15 years. Major complications are difficulty in passing urine and de-novo bladder over-activity. Genital prolapse of portions of the vagina not supported by the colposuspension may also become apparent.
The operation of Burch colposuspension can be performed through an open transverse incision or laparoscopically. When performed laparoscopically, the operation may be trans-peritoneal or entirely extra peritoneal. Laparoscopic surgery is assumed to have the advantage of avoiding a large incision and perhaps resulting in a shorter hospital stay. However the procedure is technically demanding and the operative time is longer. In some patients, laparoscopic surgery may be technically impossible, especially if there are adhesions from previous incontinence surgery.
Sling procedures
The most common procedures performed today for SUI are all sling operations of which there are a variety of different types. The classic open bladder neck sling can be performed with either synthetic tapes or by using strips of the patient's own rectus sheath or fascia. More recently tension-free vaginal tapes (TVT) have become the most common surgical procedure for SUI.
Tension-free vaginal tape is a synthetic mesh tape passed under the mid portion of the urethra. There is considerable scientific evidence to support the use of Gynaecare TVT, manufactured by Ethicon Incorporated from a type 1 mesh. The tape is inserted vaginally at the level of the mid urethra, with exit points on either side of the midline of the abdomen, in the supra-pubic region. Trials have reported an 85% success rate overall with long-term results equivalent to the results produced by open colposuspension. There is a low rate of voiding difficulty and only a small incidence of postoperative urgency. One serious complication that may be suffered after mesh insertions is that of mesh erosion. If the mesh becomes infected, this can lead to major long-term problems with difficulty in curing the infection without removal of the mesh.
Insertion of a TVT, as a procedure, is a relatively straightforward operation to perform after appropriate training. The operation can be performed under general, regional or local anaesthesia. Many practitioners prefer the patient to be awake so that the patient can cough intraoperatively to confirm that the tape is effective in relieving the problem of SUI.
Since the introduction of the TVT tape by Gynaecare there have been a number of very similar tapes produced by other manufacturers. The most important feature of the tape is that the mesh itself should be a mono filamentous type 1 mesh, with other mesh types probably having a much higher complication rate.
One potential very serious complication of the TVT tape may occur if the surgeon inadvertently passes the tape too far laterally. This risks damage to the neurovascular bundle passing to the leg. In the event that such damage occurs, the results can be calamitous and major surgery is required to correct it. Such an injury would usually be due to substandard surgical technique.
More commonly, inadvertent bladder damage by passing the trocar and tape through the bladder, is a well described problem that should be recognized intraoperatively by cystoscopy. Bladder perforation will virtually never cause long-term problems provided it is recognized and the tape immediately removed and repositioned.
The procedure of TVT tape insertion can be performed on a day-case basis although many practitioners prefer to keep the patient in overnight until they are confident that they are voiding properly and emptying their bladder completely.
Other sling procedures
Since the introduction of the TVT tape in the mid 1990s there have been a large number of other tapes manufactured and marketed by different manufacturers. There has also been development of other tapes such as the trans-obturator tape which passes through the obturator fossa and simply acts as a shelf on which the mid urethra can rest. One particular advantage of this type of tape is that it completely avoids risking damage to the neurovascular bundle to the leg and should completely avoid the risk of damaging the bladder. However, this type of tape has been associated with groin and leg pain and has now, largely, fallen from favour.
There is a growing interest in short tapes which can be passed underneath the mid urethral area which maybe an even less invasive procedure than a TVT tape. At the moment, long-term objective outcomes are not available and there are few randomized studies available for such tapes.
Periurethral bulking agents
Bulking agents, either synthetic or natural, may be injected into the urethral sub mucosa distal to the bladder neck to create a degree of urethral obstruction. Success rates vary hugely and the success of the procedure invariably seems to deteriorate with time with a maximum of 50% success after two years. The particular advantage of the procedure is its low morbidity and it may have a role when the woman is unfit for other surgery and urinary incontinence is a major problem.
Prolapse and recurrence of incontinence
It is still unclear as to which type of surgery should be performed when there is genital prolapse associated with SUI, or when there has been a previous surgical procedure that has failed.
While standard anti-prolapse surgery and standard anti-incontinence surgery is well within the remit of the ordinary gynaecologist, there is no doubt that repeat surgery for a previously failed procedure (a secondary operation) should be performed by an experienced urogynaecologist probably in a specialized referral centre.
Medicolegal issues
All operations have complications and those for SUI are no exception. In common with many operations, bleeding and infection are well-recognized complications. In terms of reducing infection rates, most practitioners would regard prophylactic antibiotics as mandatory. A synthetic tape such as TVT tape should not be inserted in the presence of pre-existing infection. Care should be taken in patients who are colonized with MRSA before inserting a TVT tape and it would generally be considered good practice to de-colonize the patient before surgery is performed.
Most of the serious intra-operative complications relate to performing the procedure correctly. There is a real risk of causing damage to the bladder and/or urethra; provided that this damage is recognized in the course of the surgery and correctly repaired, such damage should rarely cause long-term problems. During the insertion of the TVT, a cystoscopy is usually performed intraoperatively to ensure that the tape has not inadvertently traversed the bladder; if it has, then the tape needs to be removed and replaced correctly. This complication would rarely be negligent provided it was recognized and managed correctly. Damage to the neurovascular bundle passing to the leg is calamitous. In the event that such damage occurs, major surgery is required to correct it. Such an injury would usually be due to substandard surgical technique.
The two commonest postoperative complications are urinary retention and bladder over-activity. Urinary retention and voiding difficulties seem much less of a problem after a TVT procedure than with a colposuspension. The onset of de-novo bladder over-activity is a problem that occurs in approximately 5–10% of women, depending upon what sort of procedure they have had performed. Usually it is a short-term symptom but in some patients, long-term medication may be required. Neither of these complications is necessarily due to substandard care.
Summary
There are various treatment options available for women with SUI. Surgical options have moved to less invasive procedures and these continue to be refined and developed. It is important that new treatments should be subjected to rigorous clinical trials and long-term follow-up.