Stress Incontinence

Introduction

Sometimes a loss of urine occurs as a result of a cough, sneeze, laugh, or vigorous exercise—a condition known as stress urinary incontinence.

The International Continence SOciety (ICS) Opens in new window defines stress incontinence in terms of a symptom, a sign, and a condition. The symptom is described as the affected person’s complaint of involuntary escape (loss) of urine during any type of physical exercise. This includes changing positions, coughing, and sneezing. The sign denotes demonstrable loss of urine with physical exertion.

Although uncommon in men, stress incontinence occurs frequently in women, especially after childbirth, and in the elderly population. Interestingly, in a survey of female university athletes, and a survey of adult women randomly selected from the general population, the prevalence of stress incontinence was approximately 20–30 per cent (Wall 1997; Nygaard et al 1990; Andersson 1988).

The symptom of stress incontinence, the most common form of transurethral incontinence in women, presents clinically as the involuntary loss of urine during coughing, sneezing, laughing, or other physical activities that increase intra-abdominal pressure. Typical features include the following:

• daytime leakage of small to modest amount of urine,
• occasional nocturnal incontinence; and, in the absence of a large vesical hernia (cystocele),
• low residual volume after bladder emptying
(Resnick and Yalla, 1997).

Stress incontinence got its name because the pressure or strain from a laugh or cough results in a loss of urine. The bladder and urethra are normally held firmly in place by muscles and connecting tissue in the pelvis (see Anatomy of the Lower Urinary Tract Opens in new window).

During physical exertion such as coughing, the pressure inside the abdomen increases, and the pressure pushes on the bladder and urethra. If the supporting pelvic muscles or connecting tissues have been damaged or weakened, they may not be able to withstand the force of the cough. The pressure then forces the urethra to open, and urine leaks out. Many activities that you ordinarily wouldn’t even think about can cause increased pressure in the abdomen and the bladder. Coughing, straining to lift a heavy piece of luggage, aerobic exercise, or even a hiccup can challenge a woman with this problem.

What Causes Stress Incontinence?

The most common cause of stress incontinence in women is urethral hypermobility, or significant displacement of the urethra and bladder neck during exertion when intra-abdominal pressure is raised.

stress incontinence may also be caused by an intrinsic sphincter deficiency (ISD) Opens in new window, a condition in which the urethral sphincter is unable to coapt and generate enough resting urethral closing pressure to retain urine in the bladder; which may be due to congenital sphincter weakness in patients with myelomeningocele, epispadias, or pelvic denervation, or may be acquired after prostatectomy, trauma, radiation therapy, or a sacral cord lesion.

In women, ISD is commonly associated with multiple incontinence surgical procedures, as well as with hypoestrogenism, aging, or both. In this condition, the urethral sphincter is unable to generate enough resistance to retain urine in the bladder, especially during stress maneuvers (Blaivas, 1985; Staskin, Zimmern, Hadley, et al., 1985). Patients with ISD often leak continuously or with minimal exertion in some patients, stress incontinence results from coexisting ISD and hypermobility of the urethra and bladder neck.

Treatment of Stress Incontinence: Urethral Sphincter Insufficiency

The rationale for pharmacologic therapy for urinary incontinence due to urethral sphincter insufficiency prevalent in stress incontinence or stress urinary incontinence (SUI) is based on selection of agents that affect the high concentration of alpha-adrenergic receptors in the bladder neck, bladder base, and proximal urethra. Sympathomimetic drugs with alpha-adrenergic agonist activity presumably cause muscle contraction in these areas and thereby increase bladder outlet resistance.

Pharmacotherapeutic strategies that are designed to increase bladder outlet resistance include the use of drugs with direct alpha-adrenergic agonist activity, estrogen supplementation both for direct effect on urethral mucosal and periuethral tissues and for enhancement of alpha-adrenergic response, and beta-adrenegic-blocking drugs that may allow unopposed stimulation of alpha-receptor-mediated contractile muscle responses.

1. Alpha-Adrenergic Agonist Drugs

Phenylpropanolamine (PPA) or pseudoephedrine is the first-line pharmacologic therapy for women with SUI who have no contraindications for its use, particularly hypertension. The recommended dosage for PPA is 25–100 mg in sustained-release form, administered orally, twice daily. The usual dosage of pseudoephedrine is 15–30 mg, orally, three times daily. (Strength of Evidence = A.)

Summary of Findings

PPA in sustained-release form is the alpha-adrenergic agonist drug studied in women with stress incontinence. According to data, the side effects were minimal and included nausea, xerostomia, insomnia, rash, itching, and restlessness. PPA did not cause significant increase in blood pressure during the evaluation period.

Pharmacologic therapy of incontinence caused by sphincter insufficiency (stress incontinence) using PPA appears to result in few cures or dryness (0–14 percent) but may cause subjective improvement in 20–60 percent of patients over placebo response.

It is unclear whether patient age or the severity of leakage affects the likelihood of response. Possible side effects from alpha-adrenergic agonist drugs include anxiety, insomnia, agitation, respiratory difficulty, headache, sweating, hypertension, and cardiac arrhythmias, all of which my occur more commonly in elderly patients.

The risk of PPA use in hypertensive women and its efficacy in women taking antihypertensive drugs have not been determined. PPA should be used with caution in patients with hypertension, hyperthyroidism, cardiac arrhythmias, and angima. The sustained-release form is advocated because of its routine use by investigators in clinical trials. Whether the immediate-release form produces similar results has not been established at the time of this findings.

2. Estrogen Therapy

Estrogen (oral or vaginal) may be considered as an adjunctive pharmacologic agent for postmenopausal women with SUI or mixed incontinence. Conjugated estrogen is usually administered either orally (0.3–1.25 mg/day) or vaginally (2 g or fraction/day). Progestin (e.g., medroxyprogesterone 2.5–10 mg/day) may be given continuously or intermittently. (Strength of Evidence = B.)

Summary of Findings

Because the vagina and urethra are of similar embryologic origin, estrogen supplementation in postmenopausal women may restore urethral mucosal coaptation and increase vascularity, tone, and the alpha-adrenergic responsiveness of urethral muscle, which in turn may increase bladder outlet resistance and decrease stress incontinence. However, the exact role of estrogen, as well as its mechanism of action, is still unknown and deserves further research.

3. Alpha-Adrenergic Agonist and Estrogen Supplementation Combined

Combination therapy of oral or vaginal estrogens and PPA is recommended in the treatment of SUI in postmenopausal women when initial single-drug therapy has proven inadequate. (Strength of Evidence = A.)

Summary of Findings

The rationale supporting combined estrogen supplementation and alpha-adrenergic agonist therapy in postmenopausal women with incontinence due to sphincteric insufficiency is based on an estrogen-induced increased number, sensitivity of alpha-adrenergic receptors in the urethra, or both, which potentiates the alpha-adrenergic contractile response to drug stimulation.

Review of four controlled studies that combined estrogen and alpha-adrenergic agonist therapy suggests that the combined therapy may be more effective than alpha-adrenergic agonist therapy alone (Ek, Andersson, Gullberg, et al., 1978, 1980; Hilton, Tweddell, and Mayne, 1990; Walter, Kjaeergaard, Lose, et al., 1990). However, the studies are limited, and based on these results, combination therapy should be considered when initial single-drug therapy fails. The possible risks of alpha-adrenergic agonist drugs and estrogen do not appear to be increased when used together. Patients should be carefully monitored when combination therapy is prescribed, however.

4. Other Drugs of Possible Benefit

Imipramine is recommended as an alternative pharmacologic therapy for SUI when first-line agents have proven unsatisfactory. (Strength of Evidence = C.)

Summary of Findings

Imipramine—A tricyclic antidepressant that possesses both alpha-adrenergic agonist activity (presumably mediated by blocking reuptake of norepinephrine) and anticholinergic properties has been reported to benefit women with stress incontinence.

In a nonrandomized, uncontrolled study, 30 women (28–64 years old) with pure stress incontinence received imipramine at 75 mg daily for 4 weeks; 21 of the 30 (70 percent) claimed continence (Gilja, Radej, Kovacic, et al., 1984). Side effects reported included nausea, insomnia, weakness, fatigue, and postural hypotension. Prospective controlled studies are not available, and thus further research is necessary.

Surgical Treatment

Surgery is recommended for treatment of stress incontinence in men and women and may be recommended as first-line treatment for appropriately selected patients who are unable to comply with other nonsurgical therapies. (Strength of Evidence = B.)

Stress Incontinence in Women: Hypermobility or Intrinsic Sphincter Deficiency

The surgical objective in cases of hypermobility is to improve the support of the sphincter unit without obstruction. On the other hand, the goal of surgery for ISD is to increase urethral coaptation and resistance. Although many operations result in both improved support and compression of the proximal urethra, a primarily supportive procedure is less likely to succeed for a patient with ISD than for a patient with only hypermobility.

Preoperative Evaluation

A preoperative evaluation is important to ensure proper patient selection and to determine the appropriate surgical procedure.

The evaluation should include a comprehensive history, physical examination, urinalysis, urine culture, and measurement of PVR volume. It is important to document the incontinence objectively by direct observation of a positive stress test (direct visualization).

Some multiparous women may have stress incontinence on physical examination but are not troubled by this; therefore, the patient should be asked if the incontinence visible on examination is the type of incontinence that led her to seek care.

To select the appropriate surgical procedure, one must assess the position of the urethra and the degree of axial urethral mobility by physical examination, cystogram, ultrasound, or cystoscopy. Factors that may be associated with an increased risk of failure, such as symptomatic DI, obesity, prior surgery, hypoestrogenism, chronic cough, strenuous physical activity, previous radiation therapy, advanced age, or poor nutrition, must be identified.

Pelvic organ prolapse Opens in new window or other pathology that would require surgical treatment at the same time as the anti-incontinence procedure should also be identified. The approach required to treat the concurrent pathology will influence the choice of approach for the anti-incontinence procedure. The extent of the evaluation depends on the complexity of the presentation.

The degree of ISD should be assessed preoperatively using a combination assessment tools. In the history, patients who have only hypermobility describe leakage with vigorous activity, whereas patients with ISD tend to have leakage with minimal activity.

On physical examination, patients with incontinence due to hypermobility have descent of the urethra and bladder neck during stress maneuvers. On the other hand, reproducible demonstration of stress incontinence through a normally supported urethra is suggestive of ISD.

Corroboration of ISD may be established by a variety of tests, including leak point pressure, passive urethral profilometry, imaging techniques such as fluoroscopy, and on occasion cystoscopic assessment. Most of these assessment tools do not provide a definitive diagnostic alone, especially if the patient has coexistent DI, which can cause a functional opening of the bladder neck at rest. Therefore, the entire clinical presentation must be considered.

Procedures for Hypermobility

After complete evaluation, if the primary pathophysiologic defect appears to be urethral hypermobility or displacement, three main types of procedures are used:

• Retropubic suspension.
• Needle bladder neck suspension.
• Anterior vaginal repair.

1. Retropubic suspension

Retropubic suspension procedures include several different techniques performed through a low abdominal incision (i.e., retropubic approach). All techniques have in common elevation of the lower urinary tract, particularly the urethrovesical junction, within the retropubic space.

The procedures differ according to what structures are used to achieve the elevation. For the Marshall-Marchetti-Krantz procedure, the periurethral tissue is approximated to the symphysis pubis. For the Burch colposuspension, the vaginal wall lateral to the urethra and bladder neck is elevated toward Cooper’s ligament. The paravaginal repair involves reapproximating the endopelvic fascia to the pelvic wall at the arcus tendineus.

2. Needle bladder neck suspension

Another type of anatomic correction employs needle suspension of the bladder neck. Variations of this procedure are all performed through a vaginal approach, and most utilize small suprapubic skin incisions (Cobb and Ragde, 1978; Gittes and Laughlin, 1987; Pereyra, Lebherz, Growdon, et al., 1982). Anchoring tissues adjacent to the urethra and bladder neck are held by suspending sutures.

3. Anterior vaginal repair

The anterior vaginal repair category of treatments includes several modifications of the original Kelly plication. All techniques include some degree of dissection of the anterior vaginal wall from the overlying bladder base and urethra, and plication of the pubocervical fascia.

The extent of the dissection and the location and extent of the placating (elevating) sutures vary substantially among these techniques. Although the success of these operations as a group is somewhat lower than retropubic or needle suspensions, some specific techniques achieve excellent success on objective follow-up, indicating the need to discriminate the actual technical details of each of these different operations before making generalizations (Beck, McCormick, and Nordstrom, 1991).

Retropubic or needle suspension is recommended for women with hypermobility when SUI is the primary indication for surgery. On the basis of greater efficacy, these procedures are recommended over anterior vaginal repair for hypermobility. (Strength of Evidence = B.)

Procedures for Intrinsic Sphincter Deficiency

Procedures for management of ISD include:

• Sling procedures.
• Periurethral bulking injections.
• Placement of an artificial sphincter.

1. Sling procedures

The various sling procedures all involve placing a sling, made of either autologous or heterologous material, under the urethrovesical junction and anchoring it to retropubic or abdominal structures or both. The operation can be performed through an abdominal approach, a vaginal approach, or a combined abdominal and vaginal approach. Sling operations are often performed in women with complicated incontinence, many of whom have failed previous attempts at surgical correction. The success and complication rate should be viewed with this fact in mind.

Data from a series of 9 studies of 434 patients with fascial slings indicated that 89 percent were “cured,” and 92 percent were “cured” or improved. Combined analysis of 298 patients from six studies that used a synthetic sling indicated that 78 percent were “cured,” and 84 percent were “cured” or improved (Brieger & Korda, 1992).

Although the total complication rate given for the facial sling series was higher than that for the synthetic sling series, the synthetic sling caused more severe complications, many of which were directly attributable to local effects of the sling (i.e., erosion, nonhealing of the vaginal wall, abscess, vesicovaginal fistula). Fascial slings are preferable to synthetic slings because of the lower rate of local complications.

Data from 32 patients treated with the vaginal wall sling showed that 81 percent were dry, 9 percent were improved, and 9 percent showed no improvement (Ogundipe and Rosenzweig, 1992; Ridley, 1966). Complications included urinary retention and new onset of irritative voiding symptoms.

2. Periurethral bulking injections

Periurethral bulking injections involve the injection of materials such as polytetrafluoroethylene (PTFE), collagen, or autologous fat under cystoscopic guidance into an incompetent periurethral area. Patients being considered for periurethral collagen injection require a skin test for sensitivity to the material.

Injection of the material appears to be technically easier because the number of patients requiring anesthesia or sedation is less than that reported with PTFE. The longevity of PTFE versus collagen has not been studied.

Urinary tract infection and transient urethral irritation are the most common side effects after periurethral collagen injection. Combined data from 15 studies of 528 women indicate that after follow-up for up to 2 years 49 percent of patients were “cured” (range = 8–100 percent), and 67 percent were either “cured” or improved (Eckford and Abrams, 1991). Complications included urgency, UTI, and urinary retention.

Although documentation of Teflon migration to the lung persisted (Claes and Stroobants, 1989) adverse reactions to this material in other sites has not been found. Increasing experience with collagen has established its efficacy in the short term, but, as with Teflon injection, long-term results beyond 5 years are not available.

3. Artificial sphincter

Artificial sphincter placement, described below in the section on ISD in men, has been used for women with ISD. Combined data from 8 studies of 192 women with ISD treated with artificial sphincter placement indicated that 77 percent were dry, and 80 percent were “cured” or improved (Parulkar and Barrett, 1990). Complications included fluid leak, loose cuff, erosion or atrophy of the cuff site, tubing kink, and infection.

Sling procedures are recommended for women who have ISD with coexisting hypermobility or as first-line treatment for ISD. (Strength of Evidence = B.)

Periurethral bulking injections are recommended as first-line treatment for women with ISD who do not have coexisting hypermobility. (Strength of Evidence = B.)

Artificial sphincter is recommended for ISD patients who are unable to perform intermittent catherization and have sever SUI that is unresponsive to other surgical treatments. Because of the high complication rate, this treatment is rarely used as primary therapy. (Strength of Evidence = B.)

Stress Incontinence in Men: Intrinsic Sphincter Deficiency

An underactive outlet in men may result from a congenital defect or from direct or indirect trauma to the anatomy or physiology of the bladder outlet.

Direct trauma due to prostatectomy is the most common cause of sphincter insufficiency. Neurologic dysfunction (e.g., sympathetic innervations to the bladder neck, pelvic nerve to the intrinsic sphincter, pudendal nerve to the external sphincter) may be a primary or contributory etiology.

Devascularization or fibrosis, most commonly following radiation therapy or surgery, may also contribute to decreased closure pressure of the bladder outlet. The high incidence of mixed incontinence requires that an alteration in bladder function be considered and diagnosed before surgical intervention for decreased outlet resistance. Postprostatectomy incontinence is not always due to sphincter insufficiency but sometimes to detrusor dysfunction or both. Patients must be evaluated for other possible causes of incontinence, including obstruction, DI, and poor bladder compliance.

The choices for surgical treatment of male sphincter insufficiency include:

• Periurethral bulking injections.
• Placement of an artificial sphincter.

The preoperative evaluation may require a cystoscopy, and a simple cystometry or complex videouodynamic studies, depending on the suspected etiology. Special care and follow-up are required in neurologically impaired individuals due to a significant incidence of bladder compliance changes following therapy to increase outlet resistance. Before injection or sphincter implantation, it is advisable to wait at least 6 months to a year and to have the patient undergo behavioral and pharmacologic intervention during the intervening months. If an artificial sphincter is being considered, it is important to assess whether the patient has enough manual dexterity and ability to operate the device.

1. Periurethral Bulking Injections

Periurethral bulking injections are recommended as a first-line surgical treatment for men with ISD. (Strength of Evidence = B.)

Periurethral bulking injections can improve urinary loss in men with stress incontinence. The mechanism for improvement after injection therapy is still unclear but may reflect an improvement in urethral coaptation and possibly compression. Periurethral injections are less likely to succeed in male than in female patients and in all patients who have undergone pelvic radiation therapy or who have extensive periurethral scarring. Success is more common in patients who have stress incontinence after transurethral or open prostatectomy than in those after radical prostatectomy. The literature does not support the use of bulking agents in men with severe postprostatectomy incontinence (Appell, 1994).

Experience and follow-up are limited for treatments by injections with collagen and fat, which are absorbed by patients over time. There are no randomized studies comparing the efficacy of different materials or of injection therapy with other forms of treatment.

The analysis included 9 studies of 1,005 men treated with periurethral injection (McGuire and Appell, 1994). Sample sizes ranged from a minimum of 3 to a maximum of 720. The mean age was 69 years, and mean follow-up time was 2.0 years. The “cure” rate was reported in eight studies and ranged from 0 to 66 percent, with a mean of 20 percent. The “cure”–improvement rate was reported in nine studies and ranged from 0 to 81 percent, with a mean of 42 percent.

Complications reported with PTFE included infection, urinary retention, fever, temporary erectile dysfunction, periurethral inflammatory reaction, extrusion of the material into the urine or perineal area, and burning sensation or perineal discomfort. Particles of PTFE have been found in patients’ lungs after periurethral injection of PTFE, but the exact incidence and the clinical significance of this migration are not known.

2. Placement of an Artificial Sphincter

Artificial sphincter may be elected for ISD during the 6 months after prostatectomy. Behavioral intervention should also be tried during this period. (Strength of Evidence = B.)

Before periurethral injection therapy became available, placement of an artificial urinary sphincter was the most commonly used surgical procedure for the treatment of underactive outlet in men. Data on the current rate of comparative utilization of these two techniques are not available. Before implantation, urodynamic evaluation to confirm a stable, compliant, low pressure bladder is critical.

The analysis included 10 studies that presented data on 346 men, with sample sizes ranging from 11 to 96 (Nordling, Holm-Bentzen, and Hald, 1986). The average age of the patients was 61.4 years. The “cure” rate was presented in nine studies and ranged from 33 to 88 percent, with a mean of 66 percent. The “cure” or improvement rate in the 10 studies ranged from 75 to 94.5 percent, with a mean of 85.3 percent.

Initial preoperative complications are mainly associated with urethral or bladder injury during implantation. Delayed complications included mechanical problems such as pump malfunction, fluid leak, or tubing kink; infection; or cuff-related site atrophy, incomplete compression, or erosion. In addition, urethral injury, pump erosion, and herniated reservoir were reported in fewer patients.

The utilization of the artificial urinary sphincter in patients after radiation therapy, cryotherapy, or pelvic fracture with urethroplasty is controversial because of concern about compromising the urethral blood supply. Also controversial is the use of intermittent catherization after sphincter implantation. The experience of the implanting surgeon may be related to the incidence of complications.