Surgical management of stress urinary incontinence in females: Preoperative evaluation for a primary procedure

INTRODUCTION — Stress urinary incontinence (SUI), the involuntary leakage of urine on effort or exertion, or on sneezing or coughing, affects 4 to 35 percent of women [1,2]. Conservative approaches to treatment of SUI include pelvic floor muscle training and incontinence pessaries. However, for patients who fail or decline conservative therapy, there are a variety of surgical treatments. Preoperative evaluation of women with SUI helps to exclude other diagnoses and guide the appropriate surgical procedure.

The preoperative evaluation of women with SUI will be reviewed here. General principles of evaluation of women with urinary incontinence and conservative and surgical treatment of SUI, as well as evaluation of women with recurrent SUI after surgery, are discussed separately. (See "Female urinary incontinence: Evaluation" and "Female urinary incontinence: Treatment" and "Female stress urinary incontinence: Choosing a primary surgical procedure" and "Stress urinary incontinence in females: Persistent/recurrent symptoms after surgical treatment".)

In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. We encourage the reader to consider the specific counseling and treatment needs of transgender and gender-expansive individuals.

PATHOPHYSIOLOGY — Continence is achieved when the urethra maintains a pressure greater than bladder pressure (eg, during a detrusor muscle contraction or an increase in intraabdominal pressure). Loss of the urethra's ability to maintain the required pressure results from anatomic or neurologic defects.

●The anatomic contribution to continence involves the anterior vaginal wall and overlying connective tissue, which provide the urethra with a stable base upon which to rest (hammock theory [3]). Upon an increase in bladder or intraabdominal pressure, the urethra is compressed onto this base, thereby closing the lumen and maintaining urethral pressure. When the support structures are weakened, the urethra loses its underlying support and becomes hypermobile. Thus, the normal mechanism of continence through urethral compression is compromised.

Etiologies of loss of urethral support include pregnancy/childbirth, aging, and repetitive stress on the pelvic floor (eg, repetitive heavy lifting, chronic cough, constipation, or obesity). Genetic factors may also contribute to a loss of pelvic support through deficient collagen structure.

●The neurologic component of continence is mediated through both bladder and urethral innervation. The bladder storage and filling phase is controlled through a spinal sympathetic reflex that (1) stimulates beta adrenergic receptors within the bladder wall causing relaxation of the smooth muscle and (2) activates alpha adrenergic receptors in the urethra which contract the urethra and increase its pressure. The urethra is also innervated through efferent pathways from the pudendal nerve, which increases the tone of the pelvic diaphragm and striated urethral sphincter. Pregnancy, childbirth, and aging can result in pudendal neuropathy leading to urinary incontinence.

The role of pregnancy and childbirth in the development of SUI is discussed separately. (See "Effect of pregnancy and childbirth on urinary incontinence and pelvic organ prolapse".)

CLINICAL EVALUATION — The diagnosis of SUI is made by a combination of history and urinary stress testing. Additional office testing and urodynamic studies are useful for some women who are planning continence surgery.

SUI often coexists with pelvic organ prolapse, urgency urinary incontinence, and/or anal incontinence [4-6]. The possible presence of these disorders should be assessed during the history and physical examination, as they may alter surgical decision making. (See "Pelvic organ prolapse in females: Epidemiology, risk factors, clinical manifestations, and management", section on 'Clinical manifestations' and "Fecal incontinence in adults: Etiology and evaluation", section on 'Evaluation' and "Female stress urinary incontinence: Choosing a primary surgical procedure", section on 'Choosing a procedure'.)

MEDICAL AND VOIDING HISTORY — The medical and voiding history are used to ensure that the patient's symptoms are consistent with SUI and to exclude other etiologies of urinary incontinence.

A urinary history is taken during a patient interview or using a questionnaire (figure 1). Typical symptoms of SUI are involuntary urine loss, such as leakage of urine with increased intraabdominal pressure (ie, coughing, sneezing, laughing, or physical exertion). A bladder diary (form 1) can be useful, particularly in patients in whom the etiology of urinary incontinence is uncertain. (See "Female urinary incontinence: Evaluation", section on 'Evaluation'.)

Women who leak urine without increased abdominal pressure, particularly upon standing, or have frequent nocturia (≥2 episodes per night) should be evaluated with urodynamic testing for urgency incontinence, overflow incontinence, intrinsic sphincter deficiency, or high urine output (eg, due to high fluid intake or the rare case of arginine vasopressin disorders, previously called diabetes insipidus). (See "Female stress urinary incontinence: Choosing a primary surgical procedure", section on 'Lack of urethral hypermobility and intrinsic sphincter deficiency' and "Female urinary incontinence: Evaluation", section on 'Etiology'.)

A focused medical history is taken to exclude local or systemic conditions that may cause or worsen urinary incontinence (table 1 and table 2). In addition, the history should focus on factors that impact surgical risk. (See "Overview of the principles of medical consultation and perioperative medicine" and "Female urinary incontinence: Evaluation", section on 'Evaluation'.)

PELVIC EXAMINATION — A complete pelvic examination is performed to quantify pelvic organ support according to the Pelvic Organ Prolapse Quantitation (POP-Q) system and to exclude a urethral or pelvic mass. A urethral mass could be a urethral diverticulum, benign vaginal cyst, or, rarely, a neoplasm. If pooling of urine is noted in the vagina, the patient should be evaluated for a urinary tract fistula. In addition, for women who have undergone previous pelvic surgery, the presence or absence of prior surgical materials (eg, suture, mesh) should be noted. The technique for pelvic examination and evaluation for urethral diverticulum and urinary tract fistula are discussed separately. (See "Pelvic organ prolapse in women: Diagnostic evaluation" and "The gynecologic history and pelvic examination" and "Urethral diverticulum in females" and "Urogenital tract fistulas in females".)

Physical examination to exclude systemic conditions associated with urinary incontinence is discussed separately. (See "Female urinary incontinence: Evaluation", section on 'Physical examination'.)

OFFICE TESTING

Urinary stress test — Confirmation of the diagnosis of SUI includes visualizing leakage of urine from the urethra during a urinary stress test (also referred to as a cough stress test or cough test). Instantaneous leakage with cough or Valsalva suggests SUI. Delayed leakage suggests detrusor overactivity incontinence, especially if there is a large flow of leakage that is difficult for the patient to stop.

The urinary stress test consists of having a patient with a full bladder Valsalva or cough. We routinely have patients present to the office with a comfortably full bladder. Alternatively, a patient's bladder can also be filled with sterile water using a catheter. If the bladder is filled, the patient's first bladder sensation and maximum capacity are noted. Maximum capacity in most women is 200 to 300 mL. The technique for performing a urinary stress test is discussed separately. (See "Female urinary incontinence: Evaluation", section on 'Clinical tests'.)

Assessing urethral mobility — Urethral hypermobility (also referred to as bladder neck hypermobility) is present in most women who have primary SUI. In our practice, we no longer formally test for urethral hypermobility since the presence or absence of hypermobility does not appear to change management (see 'Urodynamic testing' below and "Female stress urinary incontinence: Choosing a primary surgical procedure", section on 'Lack of urethral hypermobility and intrinsic sphincter deficiency'). Historically, the urethral cotton swab test (Q-tip test) was the most common test used to evaluate urethral mobility for gynecologists, while urology used fluoroscopy. However, the cotton swab test is uncomfortable for patients and has questionable test-retest and interobserver reliability [7-9]. It is not possible to assess the accuracy of this and other tests of urethral hypermobility since there is no accepted gold standard.

Some clinicians assess for urethral hypermobility solely by assessing the severity of point Aa prolapse (stage II or higher is a positive test). This approach appears to be most accurate in women with advanced prolapse. Studies have demonstrated that almost all (over 90 percent) women with advanced point Aa prolapse will have a positive cotton swab test [10-13]. Overall, the role of urethral hypermobility testing is currently limited and unlikely to change management.

Pelvic sonography is under investigation as a noninvasive alternative for assessing urethral hypermobility, but its role in changing surgical management is currently unclear [14].

Postvoid residual volume — Measurement of the postvoid residual volume (PVR) is performed to exclude overflow incontinence or other types of voiding dysfunction. To measure the PVR, the patient is asked to start with a full bladder and void normally (without additional effort to fully empty the bladder). The residual urine in the bladder is measured either by catheterization or bladder sonography. Normally, women should be able to void at least two-thirds to 80 percent of the total bladder volume and have residual urine less than 50 cc immediately after voiding. In general, a PVR of greater than 200 cc may be suggestive of voiding dysfunction or detrusor weakness; the range of normal values for PVR and treatment options remains controversial [15-17] (these values may vary in older adult women or those with advanced pelvic organ prolapse).

Urine testing — Urinary tract infection should be excluded in all women with urinary incontinence. If a urine sample has not yet been obtained, it should be obtained by clean catch or by catheterization if a clean catch sample cannot be obtained. Clinicians may use urinary dipstick testing or urine culture to ensure the patient does not have an active urinary tract infection. In our practice, it is routine to test the urine with an office urine dipstick followed by urine culture when necessary.

URODYNAMIC TESTING — Urodynamic evaluation is not necessary for many women with uncomplicated SUI, but certain urodynamic parameters do improve accuracy of predicting individual risks after surgery for uncomplicated SUI [18]. The main disadvantages of urodynamic testing are that it is expensive, time-consuming, and causes patient discomfort [19,20]. Urodynamic testing may be useful when symptoms are not consistent with physical examination findings or in women with complicated incontinence scenarios.

Women with uncomplicated SUI — Urodynamic testing does not improve treatment outcomes in women with uncomplicated SUI prior to midurethral sling surgery [21,22] but does improve accuracy of predicting a woman's risk of developing urge urinary incontinence and adverse events [18]. Women with uncomplicated SUI are those who do not have the characteristics of complicated SUI described in the next section.

There has been considerable debate regarding the diagnostic value and cost-effectiveness of routine urodynamic testing in women with uncomplicated SUI [15,19,23-25]. Two randomized trials have found that management based upon urodynamic testing does not improve treatment outcomes of midurethral sling procedures, which are the most common continence procedures. In one trial (n = 603), women with uncomplicated SUI were assigned to either urodynamic testing or office evaluation prior to SUI treatment (93 percent of women were treated with a midurethral sling) [26]. At 12-month follow-up, the rate of successful treatment (assessed by questionnaire) was 77 percent in both groups; office evaluation was found to be noninferior (defined as a difference of less than 11 percent). Women who had urodynamic testing were significantly less likely to receive a diagnosis of overactive bladder and more likely to receive a diagnosis of voiding-phase dysfunction, but this did not result in significant differences in treatment selection or outcomes. In the other trial, women with predominant SUI underwent urodynamics and those in whom urodynamic results were discordant with clinical assessment (n = 126) were assigned to either immediate midurethral sling surgery or treatment guided by urodynamic results [27]. In the urodynamic-guided group, surgery was performed in 92 percent of women initially and in 98 percent by 12 months. The immediate surgery and urodynamic-guided groups both had comparable improvement in a validated symptom inventory at 12 months.

The role of urodynamic testing is limited in this patient population. Urodynamic evaluation is not required to confirm the diagnosis of SUI in women with typical SUI symptoms and physical examination findings (urinary stress test consistent with SUI). However, a secondary analysis of data from the Trial of Mid-Urethral slings [28] produced several statistical models to predict risk of incontinence and adverse events 12 months after surgery [18]. These models were externally validated and were shown to accurately predict these outcomes after surgery. While adding several urodynamic parameters into the models increased the accuracy of predicting bothersome urgency urinary incontinence, stress test results, and adverse events in women after surgery, urodynamic parameters were not useful in predicting bothersome SUI.

Mixed urinary incontinence does not impact the choice of surgical procedure, and thus, these women do not require preoperative urodynamic evaluation. As noted above, these women may undergo a trial of pharmacologic therapy prior to surgery. (See "Female stress urinary incontinence: Choosing a primary surgical procedure", section on 'Mixed incontinence'.)

Occult SUI, which refers to SUI that develops after pelvic reconstructive surgery in women with advanced pelvic organ prolapse, can usually be diagnosed by repeating the urinary stress test while the prolapse is reduced by the examiner. This can be performed during pelvic examination in the office setting. However, there is limited evidence that the urinary stress test or urodynamic testing is able to classify patients as having occult SUI after surgery for advanced pelvic organ prolapse. Alternatively, combining a patient's risk factors together with results from the office stress test appears to accurately predict a woman's individual risk of developing occult SUI better than the urinary stress test and an expert's guess [29]. Using the data set (n = 457) from the Outcomes Following Vaginal Prolapse Repair and Midurethral Sling (OPUS) trial, a model containing seven clinical predictors discriminated between de novo SUI status (concordance index 0.73, 95% CI 0.65-0.80) in OPUS participants and outperformed expert clinicians (area under the curve 0.72 compared with 0.62) and preoperative urinary stress testing (area under the curve 0.72 compared with 0.54) [30]. The model has also been externally validated in a separate international cohort [31]. This individualized prediction model for occult SUI after vaginal pelvic organ prolapse surgery is provided for clinical use [32]. (See "Pelvic organ prolapse and stress urinary incontinence in females: Surgical treatment", section on 'Occult SUI'.)

Women with complicated SUI — There is a general consensus among surgeons who perform continence surgery that preoperative urodynamic evaluation is required in women with complicated SUI. These include women with a clinical diagnosis of SUI (based upon history and urinary stress testing) who have the following characteristics:

●Prior continence surgery

●Prior pelvic radiation

●Neurogenic lower urinary tract dysfunction (eg, due to spinal cord injury, multiple sclerosis)

●Suspicion of a nonstress etiology of urinary incontinence, suggested by the following components of the office evaluation:

•Leakage of urine without exertion, particularly while standing

•Nocturia (≥2 episodes per night)

•Persistently elevated postvoid residual volume (≥50 mL)

•Urinary stress test with leakage that is delayed, copious, and difficult to stop

Women with these findings may have overflow incontinence, intrinsic sphincter deficiency, or other systemic or local causes of incontinence (eg, urethral diverticulum, issues with mobility). Women with delayed leakage on the urinary stress test may have detrusor overactivity incontinence. (See "Female urinary incontinence: Evaluation", section on 'Etiology'.)

Mixed urinary incontinence (concomitant stress and urgency incontinence) is common and is not routinely considered complicated SUI. However, prior to surgery, women with urge-predominant mixed incontinence should undergo a trial of medical therapy for urge symptoms to assess whether this reduces the number of incontinence episodes. (See "Female stress urinary incontinence: Choosing a primary surgical procedure", section on 'Mixed incontinence'.)

Techniques for urodynamic testing are discussed separately. (See "Urodynamic evaluation of women with incontinence".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Incontinence surgery in women" and "Society guideline links: Urinary incontinence in adults" and "Society guideline links: Gynecologic surgery".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Beyond the Basics topics (see "Patient education: Urinary incontinence in women (Beyond the Basics)" and "Patient education: Urinary incontinence treatments for women (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Definition – Stress urinary incontinence (SUI), the involuntary leakage of urine on effort or exertion, or on sneezing or coughing, affects 4 to 35 percent of women. (See 'Introduction' above.)

●Diagnosis – The diagnosis of SUI is made by a combination of history and urinary stress testing. (See 'Clinical evaluation' above.)

•Concomitant conditions – SUI often coexists with pelvic organ prolapse, urgency urinary incontinence, and/or anal incontinence. The preoperative evaluation should include assessment for these conditions, as they may alter surgical decision making. (See 'Clinical evaluation' above.)

•Patient history – The medical and voiding history are used to ensure that the patient's symptoms are consistent with SUI and to exclude other etiologies of urinary incontinence. A focused medical history is taken to exclude local or systemic conditions that may cause or worsen urinary incontinence and to assess surgical risk. (See 'Medical and voiding history' above.)

•Role of urinary stress test – During a urinary stress test (cough stress test), instantaneous leakage with cough suggests SUI, while delayed leakage suggests detrusor overactivity incontinence, especially if there is a large flow of leakage that is difficult for the patient to stop. (See 'Urinary stress test' above.)

●Unclear role of urethral hypermobility – Urethral hypermobility is present in most women who have SUI. The clinical value of testing for urethral hypermobility is uncertain. (See 'Assessing urethral mobility' above.)

●Preoperative urodynamic testing – Preoperative urodynamics are not necessary for most women with uncomplicated SUI. However, urodynamic testing does improve the accuracy of predicting clinically important outcomes (eg, risk of future urge urinary incontinence and adverse events) after surgery for SUI when combined with an individual woman's characteristics. (See 'Urodynamic testing' above.)