To identify how many patients with symptoms of pure stress urinary incontinence (SUI) do not require any surgical treatment on the basis of urodynamics (UDS) and how many patients still do not require surgery 1 year after UDS.
To assess the outcomes of these patients at 12-month follow-up.
Patients and methods
Women with pure SUI received UDS and were prospectively divided into four groups, comprising women with: urodynamic stress incontinence (USI); detrusor overactivity (DO); USI + DO; and inconclusive UDS.
Women with USI underwent a Tension Free Vaginal Tape (Obturator) (TVT-O) procedure (Gynecare; Ethicon Inc., Somerville, NJ, USA), whereas women with DO ±/− USI were recommended 24-week antimuscarinic therapy.
Follow-up was scheduled at 3 and 12 months. To define subjective outcomes, all patients completed the International Consultation on Incontinence Questionnaire – short form, the Patient Global Impression – Improvement and the Urinary Distress Inventory.
Patients were considered cured if they presented a negative stress test, a score reduction of at least 80% on the Urinary Distress Inventory and a response of ‘much better’ or ‘very much better’ on the Patient Global Impression – Improvement.
Of the 263 women with pure SUI, 74.5% had a urodynamic diagnosis of USI, 10.6% had DO, 8% had USI + DO and 6.8% had inconclusive UDS.
At 12-month follow-up, 165/181 (91.6%) women in group 1 were considered cured post-TVT-O; in the other groups, 33/67 (49.2%) patients were considered cured simply as a result of taking antimuscarinics; 13 of these 67 patients required TVT-O.
UDS is able to show that several patients with symptoms of pure SUI present an underlying DO and do not require surgery, even 1 year after UDS.
In these patients, antimuscarinic treatment appears to ensure a good rate of cure; thus, UDS could lead to the avoidance of several surgical procedures.
The reliability and clinical impact of urodynamics (UDS) remains one of the most debated issues in urogynaecology. The latest recommendations of the International Consultation on Incontinence and also the findings reported by some recent large studies [1, 2] have shown the importance of preoperative urodynamic testing in women with stress urinary incontinence (SUI) and relevant concomitant genital prolapse. Conversely, the available data on the use of UDS in cases of uncomplicated and pure SUI are conflicting and heterogeneous [3-5]. At present, retropubic and transobturator tension-free mid-urethral slings represent the most popular and effective long-term procedures for the surgical treatment of SUI and are therefore considered as the gold standard [6-8].
Very recently, two randomized trials evaluated whether UDS can improve objective and subjective surgical outcomes in the treatment of SUI, focusing on mid-urethral sling procedures: it was concluded that a basic preoperative outpatient evaluation comprises a sufficient evaluation for women with SUI because their incontinence surgery outcomes were not inferior to those of women who underwent urodynamic testing [9, 10].
However, these trials enrolled both women with pure SUI and women with mixed incontinence. Moreover, these interesting studies also reported some notable biases regarding the accuracy of the randomization procedure and the real clinical impact of the data obtained. By contrast, several studies have identified different urodynamic parameters that are able to predict sling outcomes in terms of efficacy [11, 12] and postsurgical voiding dysfunction risk [13, 14], thus attributing an important role to UDS with respect to offering more accurate preoperative counselling to patients. A large retrospective study by Digesu et al.  showed that urodynamic investigations provide useful information in the assessment of women with a history of pure SUI because 20% of them may not require surgery. Preoperative UDS in women with symptoms of pure SUI can identify a group of women with detrusor overactivity (DO) that can be treated by anticholinergic therapy and that does not require any surgical procedure. Very recently, Jeong et al.  reported that several women with pure SUI symptoms and a positive stress test exhibit a pathophysiology that could affect surgical outcome and therefore that urodynamic evaluation should be considered necessary before anti-incontinence surgery in a population that could benefit from a pharmacological treatment. However, Jeong et al.  did not report on the cure rate of antimuscarinics in this group of women and, to the best of our knowledge, no available study in the literature has specifically evaluated this aspect.
The present prospective study aimed: (i) to identify how many patients with symptoms of pure SUI do not require any surgical treatment on the basis of UDS and how many patients still do not require surgery 1 year after UDS and (ii) to assess the outcomes of these patients at 12-month follow-up.
Patients and Methods
The present prospective study was performed in a single urogynecological unit at the University of Insubria, Italy. Between January 2006 and January 2011, we enrolled all consecutive women who complained of pure SUI symptoms without any other urinary disorder. Exclusion criteria were: women with a previous history of anti-incontinence or radical pelvic surgery or who were previously irradiated; psychiatric and neurological disorders; concomitant vaginal prolapse beyond the first stage according to the Pelvic Organ Prolapse Quantification System ; overactive bladder symptoms (urgency, urgency incontinence, frequency or nocturia), obstructive symptoms, postvoid residual urine volume >150 mL. To be included, conservative therapy (lifestyle interventions and pelvic floor muscle training) must have failed or been refused.
In all cases, urogynaecological evaluation included medical history, symptoms and physical examination, a 3-day frequency–volume chart, urine analysis, ultrasonographic evaluation, residual urine measurement and complete urodynamic testing.
Physical examination was performed with the patient in the lithotomic position and pelvic organ prolapse was described during a maximal Valsalva according to the Pelvic Organ Prolapse Quantification System . All women were evaluated with UDS as described previously  (including uroflowmetry, filling cystometry, Valsalva leak point pressure [VLPP] measurement and pressure/flow study) by a trained urogynaecologist, using a standardized protocol in accordance with the Good Urodynamic Practice Guidelines of the ICS . Each woman was asked to attend for UDS with a comfortably full bladder. Uroflowmetry was performed with the woman voiding in private and recorded on a gravimetric flowmeter. Dual channel cystometry was performed with woman supine, with the bladder filled, through a 10-F filling catheter and a fluid-filled 4.5-F catheter was used to measure the intravesical and abdominal pressures. The bladder was filled with room temperature saline at 50 mL/min. We stopped the filling phase when the patient developed a strong desire to void or 500 mL had been infused into the bladder. Provocative manoeuvres were employed with the woman standing, asking the woman to cough once, three and five times with maximal effort, to listen to running water and to wash hands in cold water. Finally, the women were seated for a pressure-flow study, which was performed in private and the postvoid residual urine volume was measured by ultrasonography. Urethral hypermobility was defined in case of a Q-tip test >30°. All methods, definitions and units were updated in agreement with the latest ICS standardization of terminology .
All patients also completed the International Consultation on Incontinence Questionnaire – short form  and the Urinary Distress Inventory (UDI), which is the urinary subscale of the Pelvic Floor Distress Inventory .
After urodynamic evaluation, patients were divided into four groups: women with urodynamic stress incontinence (USI) (group 1); women with DO (group 2); women with USI + DO (group 3); and women with inconclusive UDS (no urodynamic abnormality) (group 4).
Women with USI (group 1) were scheduled for a Tension Free Vaginal Tape (Obturator) (TVT-O) procedure (Gynecare; Ethicon Inc., Somerville, NJ, USA). All of the TVT-O procedures were performed by two experienced surgeons, as previously described by de Leval . The type of anaesthesia used was general or spinal, in accordance with the anaesthesiological requirements and/or patient preference, as reported previously . In women with DO or USI + DO (when antimuscarinic medication was not contraindicated by any medical condition), we recommended fluid restriction and 24-week antimuscarinic therapy with 5 mg of oral solifenacin daily. All women with inconclusive UDS were investigated further by ambulatory UDS.
Follow-up evaluations were scheduled at 3 and 12 months; these included anamnestic and physical examination, a cough test, and evaluation of subjective satisfaction. The objective cure of USI was defined as the absence of urine leakage during a cough test performed in the lithotomic and upright positions with a full bladder (ultrasonographic measurement of at least 400 mL). To define the subjective outcomes at 3 and 12 months, all patients completed the International Consultation on Incontinence Questionnaire – short form, the Patient Global Impression – Improvement (PGI-I) Scale (a seven-point scale, with a range of responses from 1 ‘very much improved’ through 7 ‘very much worse’)  and the UDI subscales.
Patients were defined as ‘cured’ if they presented a negative stress test, a score reduction of at least 80% on the UDI and a response of ‘much better’ or ‘very much better’ on the PGI-I.
Women in groups 2 and 3 at 3-month follow-up who showed no benefit from antimuscarinic treatment or who had abandoned this therapy because of side effects could be scheduled for a TVT-O procedure.
Institutional review board approval and written informed consent were obtained in all cases.
Statistical analysis was performed with SPSS, version 17 (SPSS Inc., Chicago, IL, USA). Continuous variables were reported as the median and range, and chi-squared and Fisher's exact tests were used to analyze proportions, as appropriate. Student's t-test and the the Mann–Whitney U-test were performed to compare continuous parametric and non-parametric variables, as appropriate. P < 0.05 was considered statistically significant.
During the study period, a total of 2143 consecutive women were assessed for urinary incontinence at our Department. Among these patients, 857 were excluded: 113 had a postvoid residual urine volume of more than 150 mL on ultrasonography or catheterization; 681 had concomitant evidence of pelvic organ prolapse beyond the first stage; and 63 patients were excluded for other reasons. Finally, 1286 incontinent patients were considered, of whom 263 reported symptoms of pure SUI and were therefore included in the present study. Figure 1 displays the overall study population. The baseline characteristics of the study population are summarized in Tables 1 and 2.
Table 1. Study population (N = 263) baseline characteristics
ICIQ-SF, International Consultation on Incontinence Questionnaire – short form. *Q-tip test >30°.
Urogenital distress Inventory score, median (range)
In the study group, 74.5% (196/263) women who complained of pure SUI alone had a urodynamic diagnosis of USI, 10.6% (28/263) had DO, 8% (21/263) had USI + DO, and 6.8% (18/263) had inconclusive UDS (no urodynamic abnormality) (Table S1). In women with inconclusive UDS, ambulatory UDS diagnosed DO in all cases and therefore all these patients also received fluid restriction and solifenacin. In group 1, 15/196 (7.7%) patients did not accept TVT-O or were lost to follow-up. Therefore, 92.3% (181/196) of patients underwent TVT-O: their objective and subjective outcomes at 3- and 12-month follow-up are summarized in Table 3. In this group, 165/181 (91.6%) women were considered cured at 12-month follow-up. Patients in groups 2, 3 and 4 (n = 67) were studied together for statistical analysis because they all followed the same management as shown in Fig. 1. Table 4 summarizes their outcomes. In these groups, 36/67 (53.7%) and 33/67 (49.2%) patients were considered as cured simply as a result of taking antimuscarinics at 3- and 12-month follow-up, respectively, without the need of any surgical procedure; at 12-month follow-up, among the remnant 34 patients, 13(38.2%) underwent TVT-O, with a cure rate of 84.6% (11/13). Table S2 summarizes the intra-operative and postoperative complications in women who underwent TVT-O. Overall, in the present study population, amongst women with symptoms of pure SUI after UDS evaluation, TVT-O was required only in 196/263 (74.5%) as the first-line treatment and in 73.7% at 12-month follow-up, respectively. In total, 12.5% of patients were considered cured at the 12-month follow-up visit as a result of receiving antimuscarinic therapy.
Table 3. Group 1 outcomes at 3 and 12 months after a Tension Free Vaginal Tape (Obturator) procedure
3 months (N = 181)
12 months (N = 181)
ICIQ-SF, International Consultation on Incontinence Questionnaire – short form; PGI-I, Patient Global Impression – Improvement; UDI, Urinary Distress Inventory.
Negative stress test, n (%)
ICIQ-SF, median (range)
‘Very much better’ or ‘much better’ on PGI-I, n (%)
80% reduction in UDI score, n (%)
Global cure rate, n (%)
Table 4. Group 2 + 3 + 4 (N = 67) outcomes at 3- and 12-month follow-up
The present study confirms how the ‘bladder could be an unreliable witness’, as previously noted by Bates et al. . In total, 25% of patients complaining of pure SUI, without overactive bladder symptoms, present DO at UDS evaluation and do not require surgery as first-line treatment. Moreover, an even more relevant and interesting finding is that 26.3% of women with symptoms of pure SUI did not undergo a TVT-O procedure and 12.5% of these patients were considered cured simply as a result of taking antimuscarinics, 1 year after the initial evaluation. This does not appear to be in agreement with other recently published articles on the role of UDS in the assessment of female SUI. In a multicentre, randomized non-inferiority trial aiming to evaluate whether UDS is able to improve objective and subjective surgical outcomes in the treatment of SUI, Nager et al.  compared two groups of patients at 12-month follow-up: 315 women underwent urodynamic testing before surgery, whereas another 315 women only underwent office evaluation. Both objective (stress test) and subjective (UDI and PGI-I) postoperative outcomes were not significantly different within the two groups. Nager et al.  concluded that a basic preoperative outpatient evaluation is sufficient for women with SUI, considering that the outcome of surgery for SUI in women who underwent only outpatient evaluation was non-inferior to the one in those women who underwent urodynamic testing. However, the interesting study presents some biases, enrolling either stress or mixed incontinence and allowing many different surgical procedures (retropubic or transobturator mid-urethral sling, mini-sling, traditional slings and other). On the whole, both issues are methodologically questionable because patients with stress and mixed incontinence have quite different outcomes and major differences in efficacy also exist among the different surgical therapies. Moreover, the two study arms were imbalanced for many important variables (including the duration and severity of symptoms, previous treatment of incontinence, absence of oestrogen therapy and urethral hypermobility).
Van Leijsen et al.  reported a similar trial that did not only include women with mixed urinary incontinence, although it was not specified how predominant stress incontinence had been defined. Furthermore, only 59 women with SUI were enrolled, which comprises a very small subset of patients mostly originating from ten different hospitals, thus resulting in a very low statistical power for a minimal clinically significant difference. It is important to consider that several studies have identified both new and classical urodynamic parameters that are able to predict sling outcomes (MUCP, VLPP, open vesical pressure) [11, 12] and offer patients more accurate preoperative counselling. In addition, the role of preoperative variables that predict the risk voiding dysfunction after SUI surgery is still debated and controversial. Although some studies did not find any urodynamic parameter significantly related to postoperative voiding disorders , others have reported, as an independent preoperative risk factor, a significant rate of postoperative, mostly asymptomatic, voiding dysfunction correlated with preoperative maximal peak flow rate [13, 14].
In the present study, we have, for the first time, included only women with pure SUI symptoms, showing that a considerable percentage of women with SUI not only present a urodynamically proven DO, but also can strongly benefit from antimuscarinic treatment. The present study confirms that mid-urethral sling (TVT-O in particular) represents a very effective and safe treatment for female SUI, although it is evident that a significant percentage of women with pure SUI do not require any surgical procedure.
In a recently published literature review, Patel and Chapple  concluded that ‘… the evidence (while not overwhelming) points to the utility of urodynamics in diagnosis, preoperative planning, severity assessment and prognosis of surgery for SUI …’ and they also note ‘… large-scale randomized controlled trials have been performed to fully assess the role of urodynamics …’ . This statement is still true, although it is essential to stress that ‘primum non nocere’ should be the first aim of every clinician, making it mandatory to avoid, as much as possible, useless or potentially damaging surgical procedures.
The strengths of the present study are: (i) a highly homogeneous study population as a result of the exclusion of women with mixed urinary incontinence and the performance of only one surgical procedure; (ii) the different standardized tools used to measure the subjective and objective outcomes; and (iii) the large study population, enrolled in only one centre.
Conversely, we acknowledge that the employment of TVT-O, regardless of urethral mobility or VLPP, may be considered as a limitation of the present study. Maximum urethral closure pressure was not taken into account and this may be a questionable issue, although we do not consider it to be a real limitation because any standardized threshold of this urodynamic parameter for predicting failure does not exist. Other possible limitations could be that: (i) all the DO and ‘mixed’ incontinence patients were analyzed together; (ii) the study was performed in a single centre; and (iii) the assessors were not blinded.
In conclusion, urodynamic evaluation is able to show that several patients with symptoms of pure SUI could present an underlying DO and do not require surgery, even 1 year after UDS. Conservative therapy, such as antimuscarinic treatment, appears to result in a good cure rate in these patients; thus, urodynamic evaluation could lead to the avoidance of a significant percentage of surgical procedures.
The authors wish to sincerely thank Mrs Rosalind Roberts for the English revision of the paper. The manufacturer of solifenacin (Astellas Pharma, Tokyo, Japan) was not involved in the present study and did not provide any funding or drugs.
Conflict of Interest
The authors declare that there are no conflicts of interest.