ASERNIP S Australian Safety and Efficacy Register of New Interventional Procedures Surgical Consumer summary Minimally invasive techniques for the relief of stress urinary incontinence (Adapted from the report of the Review Group for consumer use by Ms E. Ahern) To navigate in this document in Word: Click on the word (underlined in blue) to link to glossary. Use back arrow on tool bar to return to original place in document. Introduction New surgical techniques have been developed for treating stress urinary incontinence in women. ASERNIP-S has reviewed the available published evidence to compare the safety and effectiveness of these procedures with the more established methods of surgery. What is 'stress urinary incontinence'? The urethra is the tube leading from the bladder through which urine passes to the outside of the body. Three sets of muscles control urine flow: the bladder muscle, the sphincter muscles that surround the urethra which open and close the tube, and the pelvic floor muscles (Figure 1). Changes to these muscles may occur as a 1
result of childbirth by vaginal delivery, particularly if instruments have been used, advancing years, falling levels of hormones in the blood, obesity and constipation. As a result, the woman may be unable to hold her urine until she gets to the toilet. This is called urinary incontinence. Stress urinary incontinence is the condition where a usually small amount of urine escapes from the urethra during coughing, laughing, sneezing and other physical activity. There are two main theories explaining this condition. Firstly, typical stress incontinence results from either a loosening up of the supports for the urethra (urethral hypermobility) and/or a slackening off of the muscular wall of the urethra (intrinsic urethral sphincter deficiency). In such patients a sudden cough or sneeze has the effect of pushing down the urethra rather than shutting it off. This is the Passive Transmission Theory. Overstretching or damage to the nerves supplying the pelvic floor muscles, which support the bladder and other organs, may also be an important factor. Secondly, the Integral Theory attributes stress urinary incontinence to connective tissue weakness in the vagina itself or its supporting ligaments. Established treatments for stress urinary incontinence Women with this condition should receive a basic evaluation from a doctor to determine what treatment, if any, is appropriate. Tests are required to confirm the existence of genuine stress incontinence as opposed to another condition, urge urinary incontinence. In this condition inappropriate bladder contractions can lead 2
to a sudden and/or frequent desire to urinate (urgency and/or frequency) and requires a different style of management. The most common procedure for the control of stress incontinence due to urethral hypermobility is the Burch procedure. The normal anatomy of the female pelvis without stress incontinence is seen in Figure 2. The urethra lies in a natural hammock of vaginal tissue, which provides support. In a patient suffering from urethral hypermobility, however, the supports for the urethra have become loose. During the Burch procedure a cut (incision) is made in the lower part of the abdomen and the top edges of the vagina are pulled up and stitched to ligaments connected to the pubic bone. The urethra is thus once again held upwards in a hammock of vaginal tissue. The Pubo-vaginal sling procedure is the treatment most commonly applied for stress incontinence resulting from intrinsic sphincter deficiency. Here the incision is again made through the lower part of the abdomen, although a vaginal approach can be used. A sling is constructed, either from artificial material or from strips of abdominal connective tissue, which passes from the inner face of the abdominal wall down under the top end of the urethra and up to the other side (Figure 3). These standard procedures produce the best-documented long-term results for stress incontinence, and are known to be safe and effective if undertaken for the 3
Figure 1: Muscles controlling urine flow Figure 2: Female pelvic anatomy 4
correct reasons. Around 4% of patients who have the Burch procedure will experience a major complication following the surgery, while minor complications will occur in approximately 14% of patients. Complications can include obstruction of urine outflow; blood in the urine (haematuria); urinary tract infection; changes to the wall of the bowel, rectum or urinary tract (anatomic alteration); inability to urinate (urinary retention); difficulty in urinating (micturition difficulty); and the development of urge incontinence. The risk of dying from the Burch procedure is about 0.05% (i.e. 5 patients in every 10,000). With the Pubo-vaginal sling procedure, around 7% of patients will experience a major complication following surgery, while minor complications will occur in around 12% of patients. These complications can include difficulty in emptying the bladder (voiding difficulty); anatomic alteration; urinary retention; urgency; and sling-related complications such as infection and damage to the vagina and/or urethra. The risk of dying from the Pubo-vaginal sling procedure is approximately 0.05% (i.e. 5 patients in every 10,000). How do more recent surgical treatments for stress urinary incontinence compare to the standard procedures? In 1987 a new form of minimally invasive surgery, called Intravaginal Slingplasty (IVS), was developed to treat this condition. This operation was less invasive as smaller incisions were used. The IVS technique led to the development of two independent surgical treatments, the two-stage IVS procedure and the Tension- 5
free Vaginal Tape (TVT) procedure. According to the Integral Theory mentioned above, stress urinary incontinence occurs mainly when connective tissue weakness in the vagina, supporting ligaments and pelvic floor muscles fail to support and close off the urethra from behind. In addition, when the vagina is lax the bladder is signalled to empty at a lower bladder volume than normal, causing urge incontinence. During the two-stage IVS and TVT procedures, a tension-free tape is placed below the middle third of the urethra, where the ligaments from the pubis attach (Figure 4); this produces a collagen scar around the site of the tape which supports the urethra. This approach differs from the standard procedures, as they increase the support of the urethra at the point where the urethra meets the bladder. Further, with the new procedures the new support for the urethra (tape) is not secured and is left "tension-free". The standard procedures secure their supports for the urethra with suturing. 1. Two-stage Intravaginal Slingplasty (IVS) This technique is performed under light sedation and local anaesthesia or epidural or general anaesthesia. Using two vaginal incisions and a small incision in the abdominal wall, a U-shaped sling made of nylon tape is inserted under the middle third of the urethra. The tape is passed on either side up to the inner face of the abdomen and left without fixation. The vaginal hammock is then strengthened by being attached to the ligaments and muscles near the urethra. This procedure may also be effective at curing urge incontinence. 6
Figure 3: Pubo-vaginal sling procedure Figure 4: Two-stage IVS/TVT procedures 7
2. Tension-free Vaginal Tape (TVT) This technique is usually performed under light sedation and local anaesthesia. This allows a cough stress test to be done during the operation, which checks that the operation has worked. Using two small abdominal incisions and one in the vaginal wall a tension-free Prolene sling is inserted under the middle third of the urethra. The tape is passed on either side up to the inner face of the abdomen and left without fixation. The lack of reliable evidence at the time of this review allowed only a rough comparison to be made between the tension-free tape and standard procedures. In terms of safety, there appeared to be few differences. As yet there have been no reported deaths from the new tension-free tape operations. Complication rates were more difficult to compare as not all complications were reliably reported. While the risk of tearing the bladder (bladder laceration), haemorrhage, and urinary tract infection were similar for the tension-free tape and standard procedures, the risk of blood transfusion was slightly higher for the latter. The risk of urinary retention, outflow obstruction and difficulty in urinating appeared slightly higher for the Burch procedure and the Pubo-vaginal sling procedure. This could be due to the fixed lifting up of the urethra in the standard procedures. The incidence of wound infection and defective vaginal healing were similarly low for the tension-free tape and the Pubo-vaginal sling procedures. There were no reports of infection or erosion caused by the Prolene tape. One 8
study indicated that the risk of developing urge incontinence was higher for tension-free tape procedures, whereas in other reports the opposite was observed. In terms of effectiveness, there is evidence that tension-free tape procedures were associated with shorter operating times, less need for catheters after the operation and faster return to urination control than either of the standard procedures. Recovery time was shorter for the tension-free tape procedures, measured by length of hospital stay and speed of return to normal activities and work. The short (<12 months) and medium term (1-3 years) cure rates for stress incontinence for the tension-free procedures appeared to be very similar to the Burch procedure, and perhaps slightly higher than for the Pubo-vaginal sling. Long term data on the cure of stress urinary incontinence has not yet been published. What are the recommended procedures for treating stress urinary incontinence? Due to the lack of reliable evidence, it is not possible at this stage to decide whether the tension-free tape procedures are as safe and effective as the standard operations for treating stress urinary incontinence. However, advantages offered by the newer methods, such as reduced recovery time, should be weighed up carefully by the patient and the surgeon before choosing the most suitable operation. The Royal Australasian College of Surgeons recommends that the new surgical procedures be performed in the setting of a monitored trial or study. 9
Key words: urinary incontinence surgery, intravaginal sling (or IVS) surgery, tension-free vaginal tape (or TVT) surgery, tension-free urethropexy June 2001 Important Note: The information contained in this report is a distillation of the best available evidence located at the time the searches were completed as stated in the protocol. Please consult with your medical practitioner if you have further questions relating to the information provided, as the clinical context may vary from patient to patient. For further information about ASERNIP-S Contact Professor Guy Maddern, ASERNIP-S Surgical Director, PO Box 688, North Adelaide, SA 5006, ph. (08) 82391144, fax (08) 82391244, or visit the website (www.surgeons.org/asernip-s). If you would like to provide feedback on this consumer summary, please contact us at consumer.asernip@surgeons.org. ASERNIP-S is a programme of the Royal Australasian College of Surgeons (RACS). 10
Glossary anatomic alteration: in this paper refers to surgical changes to the wall of the bowel, rectum or urinary tract bladder laceration: tearing of the bladder connective tissue: tissue which connects, supports or surrounds other tissues or organs frequency: the frequent desire to urinate haematuria: blood in the urine haemorrhage: major bleeding incision: cut intrinsic urethral sphincter deficiency: a slackening off of the muscular wall of the urethra ligaments: strong bands connecting bones or cartilage and strengthening joints micturition difficulty: difficulty in urination pelvic floor muscles: the muscles which line the bottom of the pelvis and support the uterus, rectum and bladder urethral hypermobility: a loosening up of the supports for the urethra urgency: the sudden desire to urinate urinary retention: inability to urinate or empty full bladder voiding difficulty: difficulty in passing urine 11