Assessment of bladder neck mobility is an important step in the evaluation of women with stress urinary incontinence. Most stress urinary incontinence evaluation algorithms include evaluation of urethral sphincteric function and bladder neck mobility. Studies have shown that traditional antiincontinence procedures are more likely to fail if a patient lacks urethral hypermobility. This appears to be a critical parameter regardless of the type of procedure performed (retropubic urethropexy, needle suspension, or sling procedure). 1–3
Because the degree of bladder neck mobility is important in a clinician's choice of antiincontinence therapy and its ultimate outcome, it is important that practitioners have an accurate evaluation method. A number of methods have been used for this determination, including ultrasound, radiographic studies, and the Q-tip test. Because the Q-tip test is simple to perform and inexpensive, it has become a widely used component of the urogynecologic evaluation.
Crystle et al 4 introduced the Q-tip test and reported that its angle of deflection with straining reflected urethral axis rotation. By comparing the results of radiographic bead chain studies, they found that patients with good urethral support had rotational angles of less than 20° from the horizontal axis. Hence, rotational angles of greater than 30° have generally been considered excessive. However, few data exist to differentiate “normal” from “abnormal” Q-tip assessments. 5,6
Although the Q-tip test is commonly used and widely accepted, its method has not been uniformly standardized. Variations in Q-tip test method and interpretation have included baseline from which to measure excursion, 7 patient positioning, 8 and location of the cotton swab end. 6 The Q-tip test should be performed in a standardized fashion and interpreted uniformly to allow its use in the triage of a patient with urinary incontinence. Most protocols for Q-tip test performance entail positioning the patient in the lithotomy position with the back completely horizontal, placing the cotton swab end at the bladder neck, and measuring maximal excursion from the horizontal plane. The goal of the current study is to evaluate the effect of vaginal prolapse and its reduction, as well as bladder fullness, on Q-tip angle measurement.
MATERIALS AND METHODS
This prospective study included 26 women who presented with urogynecologic complaints and who were undergoing multichannel urodynamic evaluation. All women had prolapse to or beyond the hymenal ring of at least one segment of the vaginal canal (vault, cystocele, rectocele, and/or enterocele). The subjects were placed in a birthing chair in the horizontal, 0° position. A lubricated, sterile Q-tip was placed transurethrally into the bladder and then withdrawn into the urethra until resistance was met. A goniometer with a carpenter's level was used to measure the maximum angle of deflection with maximum Valsalva straining. The Q-tip angle was designated as the maximum excursion angle from the horizontal axis (0°). Measurements were obtained with the bladder empty and at maximum cystometric capacity after filling the bladder at 80 mL per minute during multichannel cystometry. In addition, the measurements were recorded with and without the prolapse reduced. The measurements were all obtained by a single observer. Therefore, four Q-tip measurements, in this order, were taken for each patient: bladder empty and prolapse not reduced, bladder empty and prolapse reduced, bladder full and prolapse reduced, and bladder full and prolapse not reduced.
The prolapse was reduced using the posterior blade of a Graves speculum. Care was taken to support the vaginal vault with the speculum without stretching or compressing the anterior wall or impeding its mobility.
A Wilcoxon signed rank test was used to compare the measured Q-tip angles with an empty and full bladder and with and without the prolapse reduced. A Wilcoxon rank-sum test was used to evaluate the impact of the compartment of prolapse and the presence of a positive cough profile on the Q-tip angle measurements.
The mean age of the study population was 58 years. Fifteen percent (four of 26) had postvoid residuals greater than 100 mL. Sixty-nine percent (18 of 26) had a positive dynamic cough urethral pressure profile with pressure transmission ratios less than 90% in the proximal urethra. As measured by the Baden–Walker system, 9 the greatest segment of prolapse was cystocele in 35% (nine of 26), enterocele in 3% (one of 26), rectocele in 31% (eight of 26), and vault in 15% (four of 26). Fifteen percent (four of 26) had two segments with equal degrees of prolapse.
The measured Q-tip angle was significantly altered by the reduction of vaginal prolapse. Regardless of bladder fullness, the mean Q-tip angle measured with the prolapse reduced was significantly less than that measured without reduction (Ps < .001). Similarly, regardless of prolapse reduction, the mean Q-tip angle with an empty bladder was greater than that with a full bladder (Ps < .001) (see Table 1 for comparisons).
The differences in Q-tip angles with and without the prolapse reduced and with a full versus empty bladder were not impacted by the compartment of prolapse (vault, cystocele, enterocele, rectocele; Ps = .09–.99). In addition, the differences in Q-tip angle were not affected by the presence of stress urinary incontinence as defined by a positive dynamic cough profile (Ps = .60–.99). In four patients (15%) the Q-tip angle was more than 30° without the prolapse reduced and less than 30° with the prolapse reduced.
The simplicity and availability of the Q-tip test have made it a widely used assessment of urethral mobility. Many clinicians use the results of this test to make treatment recommendations for patients. For example, at our center a woman with intrinsic sphincter deficiency and urethral hypermobility will receive a recommendation to undergo a suburethral sling procedure. If the urethra is not hypermobile, urethral bulking agents would be recommended in the presence of intrinsic sphincteric deficiency.
Because of the high incidence of occult stress incontinence masked by the advanced degrees of genital prolapse, preoperative assessment of such patients should include evaluation for stress incontinence. Various investigators have suggested performing preoperative urodynamic and provocative testing while reducing the prolapse with a pessary or speculum. This is important, as the urethra may become “unkinked” and reveal underlying stress incontinence. 10,11 Richardson et al 10 showed that 80% of symptomatically continent patients with advanced prolapse demonstrated stress incontinence by a cough urethral pressure profile after a pessary was placed. Additionally, the resting urethral pressure profiles with and without the pessary in place were different.
Severe genital prolapse may also mask an occult unstable bladder. Rosenzweig et al 12 found occult incontinence by urodynamic testing in 59% of women with severe genitourinary prolapse. Thirty-one percent of these women had stress incontinence, 31% had evidence of detrusor instability, and 38% had mixed stress incontinence and an unstable bladder.
Yalcin et al 13 studied 60 patients with a grade 3 or 4 cystocele. They reduced the cystocele with vaginal packing and found decreased postvoid residual volumes and increased urinary leakage on a pad test after the packing was placed. In addition, they noted increases in the posterior urethrovesical angle and the Q-tip angle after the cystocele was reduced with the vaginal packing. Although these results differed from our findings, the differences in technique used to reduce prolapse (vaginal packing versus posterior blade of a Grave speculum) make direct comparison difficult. Furthermore, they studied women with only cystoceles, whereas our patients had varying types of prolapse, including vault prolapse and large rectoceles, which might also explain the differences.
Hence, previous studies have demonstrated the impact of prolapse reduction on urodynamic and provocative testing and its ability to reveal occult urinary incontinence. Additionally, some authors have suggested that patients with stress incontinence or the potential for stress incontinence should have an antiincontinence procedure combined with the repair for vaginal prolapse. 14,15
This study focused on the impact of prolapse reduction on the assessment of bladder neck mobility. Q-tip measurement differences were demonstrated with and without the prolapse reduced and with an empty versus a full bladder. We conclude that measurement of urethral mobility by the Q-tip test is affected by pelvic organ prolapse and bladder fullness because the Q-tip angle was significantly lower with prolapse reduction and bladder fullness.
Looking at each factor separately, how can we interpret the finding that prolapse reduction impacts the measurement of bladder neck mobility? Inferring from our data, reconstructive vaginal surgery (much like prolapse reduction) may restore the vaginal axis and artificially demonstrate improved bladder neck mobility without actually restoring bladder neck support. In addition, after comparing the pelvic organ prolapse quantification system 16 with the Q-tip test, Cogan et al 17 concluded that anterior vaginal topography does not necessarily represent the dynamics of the urethrovesical junction. It is possible that stress urinary incontinence would become clinically evident in the postoperative phase if bladder neck support was not appropriately restored. A randomized series would be necessary to demonstrate different clinical outcomes in patients whose bladder neck hypermobility was normalized with only prolapse reduction, versus those patients who underwent additional procedures to support the bladder neck. In addition, because Yalcin et al 13 demonstrated increased bladder neck mobility once a cystocele was reduced with vaginal packing, it would be worthwhile to compare the effects of prolapse reduction using a speculum versus the pessary and packing. Because patients with severe genital prolapse have a weakened endopelvic fascia, it is likely that mere normalization of the vaginal axis, without specific correction of bladder neck support, is not sufficient to avoid development of postoperative stress urinary incontinence. We therefore suggest using the unreduced Q-tip angle when making decisions about surgical management.
The second factor we evaluated was the effect of bladder fullness on Q-tip measurement. In this study, the measured Q-tip angle with a full bladder was less than the measurement taken with an empty bladder. The clinical impact of bladder fullness on bladder neck mobility assessment is unclear. For instance, although we showed an effect of bladder fullness on Q-tip measurement, Karram and Bhatia 6 failed to do so. However, they measured Q-tip angles with less than 150 mL in the bladder and with a symptomatically full bladder, whereas we measured them with an empty bladder and at maximum cystometric capacity. Discomfort resulting from having a full bladder or fear of urine loss with Valsalva may inhibit a patient from performing a maximal Valsalva effort, thus limiting the accuracy of the test. Additionally, cystometric bladder capacity may not be representative of symptomatic bladder fullness, as many patients who experience stress incontinence will not allow themselves to achieve such bladder volumes. We therefore suggest performing the Q-tip angle with an empty bladder.
The shortcomings of this series are primarily related to the small sample size. However, statistical analysis revealed significant differences in measured Q-tip angles with prolapse reduction and bladder fullness.
The demonstrated differences had a clinical impact in surgical procedure choice in 15% of the subjects: those who had a Q-tip angle of more than 30° without the prolapse reduced and less than 30° with the prolapse reduced. Because preoperative bladder neck mobility assessment is an important factor in delineating a successful treatment plan, 1–3 our preoperative counseling was affected in these patients. In addition, for patients with intrinsic sphincter deficiency, we recommend urethral bulking when there is no hypermobility and a suburethral sling in the presence of hypermobility.
These data demonstrate significant differences in bladder neck mobility assessment based on prolapse reduction and bladder fullness in patients with severe vaginal prolapse. It exemplifies the need for standardization of the Q-tip measurement technique, as well as for further studies that will demonstrate the degree of clinical significance of these findings. Until then, we recommend using the measured Q-tip angle without the prolapse reduced and with the bladder empty in making surgical treatment recommendations.
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