- Email: [email protected]
Comparison of the Q-Tip Test and Voiding Cystourethrogram to Assess Urethral Hypermobility Among Women Enrolled in a Randomized Clinical Trial of Surgery for Stress Urinary Incontinence
Comparison of the Q-Tip Test and Voiding Cystourethrogram to Assess Urethral Hypermobility Among Women Enrolled in a Randomized Clinical Trial of Surgery for Stress Urinary Incontinence Lance P. Walsh, Philippe E. Zimmern,* Norma Pope and Shahrokh F. Shariat for the Urinary Incontinence Treatment Network From the Department of Urology, University of Texas at Southwestern Medical Center, Dallas, Texas
Purpose: We compared 2 measures of urethral hypermobility, the Q-tip test and voiding cystourethrogram, preoperatively in women recruited in 1 center participating in a multicenter randomized clinical trial comparing Burch colposuspension with autologous rectus fascia sling. Materials and Methods: Following institutional review board approval, women with stress urinary incontinence and pelvic organ prolapse stage 2 or less underwent a standardized standing voiding cystourethrogram and a Q-tip test at a 45 degree angle reclining position preoperatively. Urethral angle at rest and straining were measured with a radiological ruler (voiding cystourethrogram) or goniometer (Q-tip) by 2 different investigators blinded to each other findings. Results: In 43 patients the mean urethral angle at rest and UAS were 20 degrees ⫾ 12 and 51 degrees ⫾ 20, by voiding cystourethrogram compared to 16 degrees ⫾ 9 and 58 degrees ⫾ 10 by Q-tip test, respectively. The mean angle difference (urethral angle with straining minus urethral angle at rest) was greater for the Q-tip test (42 degrees ⫾ 9) than that for the voiding cystourethrogram test (32 degrees ⫾ 17; p ⬍0.05). Fewer patients (14% by Q-tip, 28% by voiding cystourethrogram) had urethral hypermobility using the definition of urethral angle at rest greater than 30, while almost all patients (91% by voiding cystourethrogram, 100% by Q-tip) had urethral hypermobility using the definition of urethral angle with straining greater than 30. However, using the definition of urethral angle with straining minus urethral angle at rest greater than 30, only 58% of patients had urethral hypermobility by voiding cystourethrogram compared to 98% by Q-tip. Conclusions: The voiding cystourethrogram and the Q-tip test measure urethral hypermobility differently. This may affect which patients are classified as having urethral hypermobility, and the choice of anti-incontinence surgery. Key Words: urethra; urinary incontinence, stress
sored network consisting of 9 centers that have enrolled 655 patients with stress or stress predominant urinary incontinence in a randomized trial comparing Burch colposuspension and autologous rectus fascia sling. This study is a single center initiated ancillary project aimed at comparing the Q-tip test values at rest and with straining to the radiological values of UAR and UAS in a subset of preoperative patients with known stress urinary incontinence enrolled in the UITN.
he appropriate technique used to measure UH and the definition of UH remain controversial. Several methods have been used to assess urethral hypermobility such as the Q-tip test and the VCUG. Some define UH as a Q-tip straining angle equal to or greater than 30 degrees. The UITN group arbitrarily selected a resting angle greater than 30 degrees or a maximum straining angle greater than 30 degrees. Others have defined UH as a change between rest and straining position. The presence of UH is important to some investigators and clinicians to decide on the optimal type of anti-incontinence surgery.1,2 Historically, a pubovaginal sling has been recommended for the treatment of intrinsic sphincter deficiency in a well supported urethra, whereas a colposuspension has been recommended for UH. This has recently been called into question since some women with stress incontinence secondary to UH may have some associated degree of sphincter deficiency. The UITN is a National Institutes of Health spon-
T
MATERIALS AND METHODS From May 2002 to June 2004 women with stress urinary incontinence were enrolled in an institutional review board approved Burch colposuspension vs autologous rectus fascia sling randomized controlled trial. They underwent preoperative standing VCUG and Q-tip tests. Exclusion criteria for a VCUG included patients with prior history of intravesical contrast allergy and patients with hip prosthesis or pelvic metal plate/screws. A complete VCUG consisted of 1) plain film; 2) a standing, lateral view of the bladder filled with 100 to 125 ml of contrast, with the catheter in place, under resting and then straining condition; 3) an anteroposterior view of the full bladder; 4) 1 standing lateral view of the full bladder, after catheter removal, under resting and then straining condition; 5) 1 or 2 standing, lateral views during voiding; and 6)
Submitted for publication September 16, 2005. Study received institutional review board approval. * Correspondence: Department of Urology, The University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9110 (telephone: 214-648-2888; FAX: 214-6488786; e-mail: [email protected]).
See Editorial on page 438.
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post-void plain film.3 The urethral axis was defined on the standing lateral view (number 2) by a line drawn along the length of the urethral catheter. This urethral axis intersected a vertical line drawn through the inferior border of the pubic symphysis and the resulting angle was measured from the vertical axis to the urethral axis using a standard radiological ruler calibrated at every 5-degree angle (see figure). According to the UITN protocol, the Q-tip test was performed with the subject reclined at a 45-degree angle. A sterile lubricated Q-tip was introduced in the urethra and withdrawn until resistance was met at the level of the urethrovesical junction.4 The angle of the Q-tip from the horizontal in degrees was measured using a goniometer at rest (UAR) and during straining (UAS). The Q-tip and VCUG measurements were performed at different times by 2 different investigators blinded to each others findings. Differences in urethral angles between Q-tip and VCUG analyzed as continuous variables were tested using the Wilcoxon test. Association in urethral angles between Q-tip and VCUG analyzed as categorical variable were tested using the Cohen’s kappa measure. Statistical significance in this study was set as p ⬍0.05. All reported p values are 2-sided. All analyses were performed with SPSS® version 11.5 for Windows. RESULTS Median patient age was 54 years (range 31 to 75, mean 53 ⫾ 11). The table shows the differences in urethral angles determined by the Q-tip and VCUG tests. The urethral angle at rest measured by the Q-tip test was significantly lower than that measured by the VCUG test. Conversely, the straining and the straining minus rest urethral angles were both significantly higher when measured by the Q-tip test than when measured by the VCUG test. We analyzed the data according to 3 commonly used definitions for UH: urethral rest angle over 30 degrees, urethral strain angle over 30 degrees, and urethral strain angle minus urethral rest angle over 30 degrees. The table shows the difference in the rate between patients diagnosed with UH using the 3 definitions for both the Q-tip and VCUG tests. The 3 definitions resulted in statistically different rates of patients potentially diagnosed with UH regardless of whether the Q-tip or VCUG test was used (all p values ⬍0.001). For both the Q-tip and VCUG tests, the rate of patients with UH was highest using the strain angle greater than 30 degrees definition, followed by the strain minus rest angle greater than 30 degrees definition, and was lowest using the strain angle greater than 30 degrees definition. When using the rest angle greater than 30 degrees definition, the rate of patients diagnosed with UH was significantly smaller with the Q-tip test than with the VCUG test. When using the strain angle greater than 30 degrees definition or the strain minus rest angle greater than 30 degrees definition, the rates of patients diagnosed with UH were significantly higher with the Q-tip test than with the VCUG test. DISCUSSION This limited study offers a unique head-to-head comparison between 2 modalities that measure UH. The VCUG was compared to the Q-tip test to document and measure the presence and severity of UH. Of the 3 definitions of UH, only
FIG. 1. A, true lateral view (complete superposition of femurs) during standing cystogram in resting position demonstrating urethral angle measurement. Urethral angle is angle between straight vertical line and dotted line representing urethral axis given by Foley catheter ending up with balloon (round circle) at urethrovesical junction. B, same patient in same position, but with straining. Urethral axis has increased from 30 degrees at rest to 50 degrees with straining indicating presence of urethral hypermobility. Level of bladder base is just below lower edge of pubic symphysis. Early cystocele confirms laxity of whole anterior vaginal wall.
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Q-TIP TEST AND VOIDING CYSTOURETHROGRAM TO ASSESS URETHRAL HYPERMOBILITY Differences of urethral angles measured by Q-tip and VCUG tests
Median rest angle (IQR) Median strain angle (IQR) Median difference of straining ⫹ rest angles (IQR) No. pts rest angle (% of procedure): 30 Degrees or less Greater than 30 degrees No. pts straining angle (% of procedure): 30 Degrees or less Greater than 30 degrees No. pts difference of straining ⫹ rest angles (% of procedure): 30 Degrees or less Greater than 30 degrees
Q-tip Test
VCUG
p Value
Continuous variables 15 (10) 60 (15) 40 (10) Categorical variables
20 (10) 50 (20) 30 (15)
0.050 (Wilcoxon test) 0.016 (Wilcoxon test) ⬍0.001 (Wilcoxon test)
37 (86) 6 (14)
31 (72) 12 (28)
0.193 (Cohen’s kappa measure test)
0 (0) 43 (100)
4 (9) 39 (91)
1.000 (Cohen’s kappa measure test)
1 (2) 42 (98)
18 (42) 25 (58)
0.233 (Cohen’s kappa measure test)
Data set was not found to be normally distributed using Kolmogorov-Smirnov statistics. Therefore, we chose to report the median and the IQR rather than the mean and standard deviation.
1 was met by both tests, namely UAS greater than 30 degrees. The change in position from rest to strain was amplified in supine position, possibly due to more pelvic relaxation and less postural tone. The differences in angle between the Q-tip test and VCUG were likely related to patient position instead of inherent differences between the 2 tests. Handa et al reported that the female urethra is more mobile in the supine than in the standing position.5 In that study the cotton swab test was performed in the standing and supine positions, and the urethral angle was measured in women with a variety of urogynecological complaints. The R, S and S-R values reported were 4, 43 and 41, and 17, 32 and 16 in the supine and standing positions, respectively. Of note, the S-R angles found by VCUG in the present study were very similar to the angles found in another study of women with SUI before undergoing an anterior vaginal wall suspension procedure.6 The Q-tip test was developed in 1971.7 During the course of preparing a patient for a bead chain cystourethrogram, the patient strained with a lubricated Q-tip in her urethra. A comparison of the results of the Q-tip and bead chain cystogram in over 40 patients revealed that R less than 10 degrees and S less than 20 were seen with good urethral support. A poorly supported urethra was subsequently defined as S greater than 30 degrees. Since then the Q-tip test has gained popularity in routine practice despite recognized shortcomings (see Appendix). Studies have shown that while the Q-tip test can measure UH, it does not help much with diagnosing SUI. Walters et al compared the results of the Q-tip test in subjectively continent women, women with SUI, and women with other types of urinary incontinence and voiding dysfunction.8 Significant differences in maximum stress Q-tip angle and urethral mobility were found between the continent controls and women with SUI. However, no differences were found between the 2 incontinent study groups. They concluded that the Q-tip test does not provide a specific urological diagnosis. While the Q-tip test can measure UH, it suffers from a lack of standardization which limits its usefulness. Studies have shown that bladder fullness, coexistent pelvic organ prolapse,8,9 upright patient position,5 and Q-tip malposition9 all affect the measured urethral angle. In the original article by Crystal and in all subsequent articles, factors such
as bladder fullness, coexistent organ prolapse, and Q-tip position are rarely reported. This lack of standardization brings into question the applicability of these studies findings to other patient populations. To mitigate the impact of these confounding factors, several authors have proposed a more standardized way to perform the Q-tip.9 It has been recommended to perform the Q-tip test with the bladder empty. Still, one relies on blind faith that the tip of the Q-tip is at the urethrovesical junction. These same factors undoubtedly influence the results of the VCUG test. However the urethral Foley catheter is soft and easy to introduce in the urethra, always gives a reliable measure of the urethral axis, and the test provides additional information on bladder volume and configuration, coexistent prolapse, and on the urethra during voiding. The patient can be studied in the standing position where leakage is most likely to occur.10 The VCUG has long been studied with the hope of establishing a relationship between urethral angle, bladder base position and continence. Stevens and Smith first described the technique of lateral bead-chain cystourethrography in 1937.11 Green characterized incontinence based on position of the bladder base and posterior urethrovesical angle.12 Loss of the posterior urethrovesical angle occurred in Type I incontinence, while Type II incontinence also included inferior displacement and rotation of the bladder base and urethra. Patients with type I incontinence benefited from simple anterior colporrhaphy 90%, whereas patients with Type II incontinence were successfully treated with anterior colporrhaphy only 50%, but had cure rates of 90% with retropubic suspension. Bergman expanded the Green criteria to include funneling of the bladder neck and the position of the urethrovesical junction and bladder base and found that none of these anatomic changes defined stress incontinence.13 Pelsing et al studied 159 women with leakage or voiding dysfunction as the chief complaint.14 They concluded that the VCUG has limited value because of detrusor instability producing urge incontinence and therefore false-positive stress incontinence. They reported the sensitivity and specificity of the VCUG in predicting SUI at 60% and 70%, respectively. In contrast, Showalter et al showed that the VCUG had good inter-rater reliability in measuring UAR, UAS and S-R using the same technique described in the
Q-TIP TEST AND VOIDING CYSTOURETHROGRAM TO ASSESS URETHRAL HYPERMOBILITY present article.6 Age matched values for UAR interpretation were also provided as well as data to show that, after surgical correction, UAR and UAS returned to age matched normal values, a finding suggestive that correcting anatomy may be a basic prerequisite for return to a normal function. Wall et al performed a logistic regression analysis of lateral bead-chain cystourethrograms.15 They showed that an important predictor of a successful surgical outcome was a large distance between the bladder neck and pubic symphysis at rest and increased mobility of the bladder neck before surgery. The importance of measuring UH stems from previous reports that have shown that patients who have SUI without UH have poor outcomes with Burch and should be treated by an alternative procedure such as a sling, artificial sphincter, or collagen injection.16 In Bergman’s study of 456 women with SUI, 15 had SUI and a negative Q-tip test (defined as a S-R less than 30). These patients subsequently underwent a retropubic surgery including revised Pereyra
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(6) or Burch (9). Of patients who underwent a Burch, 55% (5 of 9), and of those who underwent a Pereyra procedure 50% (3 of 6) had treatment failure. This failure rate was 5 times higher than that observed among women with SUI and a positive Q-tip who underwent the same procedure. Thus, not only defining UH is important, but defining the opposite, namely a fixed, nonmobile urethra may be an important determinant of the type of anti-incontinence repair. CONCLUSIONS In this limited study comparing UH measurements by Q-tip test and VCUG, we found that the number of patients with UH depends on the definition of UH chosen. The pros and cons of these 2 methods were reviewed, with an emphasis on standardization and relationship to incontinence. At present, there is no gold standard method to define UH. Thus patients’ clinical outcome after repair may help decide which test and which UH measurement carry the best predictive value.
APPENDIX Pros and cons of the Q-tip test and VCUG Q-TIP PROS
Inexpensive Widely available Easy to perform
CoNS
Inability to determine exact Q-tip position reduces accuracy Information limited to UH only Difficult to standardize
VCUG Favor leakage with standing position (gravity factor) Provide information on bladder/urethra and on voiding Films can be rereviewed for quality control Low level radiation exposure Rare: contrast dye allergy and infection risk Costs $150 to $200
7.
Abbreviations and Acronyms IQR SUI UAR UAS UH UITN VCUG
⫽ ⫽ ⫽ ⫽ ⫽ ⫽ ⫽
interquartile range stress urinary incontinence urethral angle at rest urethral angle with straining urethral hypermobility Urinary Incontinence Treatment Network voiding cystourethrogram
REFERENCES 1.
2.
3.
4.
5.
6.
Minassian, V. A., Drutz, H. P. and Al-Badr, A.: Urinary incontinence as a worldwide problem. Int J Gynaecol Obstet, 82: 327, 2003 DeLancey, J. O.: Structural support of the urethra as it relates to stress urinary incontinence: the hammock hypothesis. Am J Obstet Gynecol, 170: 1713, 1994 Zimmern, P.: The role of voiding cystourethrography in the evaluation of the female lower urinary tract. Prob Urol, 5: 23, 1991 Urinary Incontinence Treatment Network: Design of the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Urology, 66: 1213, 2005 Handa, V. L., Jensen, J. K. and Ostergard, D. R.: The effect of patient position on proximal urethral mobility. Obstet Gynecol, 86: 273, 1995 Showalter, P. R., Zimmern, P. E., Roehrborn, C. G. and Lemack, G. E.: Standing cystourethrogram: an outcome measure after anti-incontinence procedures and cystocele repair in women. Urology, 58: 33, 2001
8. 9.
10.
11. 12.
13.
14.
15.
16.
BOTH Good intra-rater reliability Good at measuring UH No available technique to standardize the straining effort Urethral catheterization with limited discomfort Poor at diagnosing incontinence
Crystle, C. D., Charme, L. S. and Copeland, W. E.: Q-tip test in stress urinary incontinence. Obstet Gynecol, 38: 313, 1971 Walters, M. D. and Diaz, K.: Q-tip test: a study of continent and incontinent women. Obstet Gynecol, 70: 208, 1987 Karram, M. M. and Bhatia, N. N.: The Q-tip test: standardization of the technique and its interpretation in women with urinary incontinence. Obstet Gynecol, 71: 807, 1988 Zimmern, P. and Lemack, G.: Voiding cystourethrography and magnetic resonance imaging of the lower urinary tract. New York: Marcel Dekker, Inc., chapt. 26, pp. 407– 421, 2001 Stevens, W. and Smith, S.: Roentgenological examination of the female urethra. J Urol, 37: 194, 1937 Green, T. H., Jr.: Development of a plan for the diagnosis and treatment of urinary stress incontinence. Am J Obstet Gynecol, 83: 632, 1962 Bergman, A., McKenzie, C., Ballard, C. A. and Richmond, J.: Role of cystourethrography in the preoperative evaluation of stress urinary incontinence in women. J Reprod Med, 33: 372, 1988 Pelsang, R. E. and Bonney, W. W.: Voiding cystourethrography in female stress incontinence. AJR Am J Roentgenol, 166: 561, 1996 Wall, L. L., Helms, M., Peattie, A. B., Pearce, M. and Stanton, S. L.: Bladder neck mobility and the outcome of surgery for genuine stress urinary incontinence. A logistic regression analysis of lateral bead-chain cystourethrograms. J Reprod Med, 39: 429, 1994 Bergman, A., Koonings, P. P. and Ballard, C. A.: Negative Q-tip test as a risk factor for failed incontinence surgery in women. J Reprod Med, 34: 193, 1989
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EDITORIAL COMMENT Increasing use of midurethral slings for all patients with SUI has cast doubt upon the usefulness of UH in the identification of types of SUI and in the selection of the antiincontinence procedure. Walsh et al report on an ancillary study from the UITN in which the University of Texas Southwestern investigators compared 2 measures of UH with the Q-tip test and a modified VCUG. Urethral angle at rest or straining was significantly different when measured by Q-tip test and VCUG. Furthermore, when variable definitions for UH were used, Q-tip and VCUG identified a different proportion of patients as having UH. The results of this well-done study may add to existing doubts about the usefulness of UH in the selection of the
anti-incontinence procedure. However, the only litmus test for determining the precise usefulness of UH will stem, it is hoped, from the final results of the UITN-Stress Incontinence Surgical Treatment Efficacy Results trial,1 which will assess the association between UH and the outcome of surgical treatment of SUI. Firouz Daneshgari Glickman Urological Institute The Cleveland Clinic Foundation Cleveland, Ohio 1.
Tennstedt, S. and Urinary Incontinence Treatment Network: Design of the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Urology, 66: 1213, 2005
Purpose: We compared 2 measures of urethral hypermobility, the Q-tip test and voiding cystourethrogram, preoperatively in women recruited in 1 center participating in a multicenter randomized clinical trial comparing Burch colposuspension with autologous rectus fascia sling. Materials and Methods: Following institutional review board approval, women with stress urinary incontinence and pelvic organ prolapse stage 2 or less underwent a standardized standing voiding cystourethrogram and a Q-tip test at a 45 degree angle reclining position preoperatively. Urethral angle at rest and straining were measured with a radiological ruler (voiding cystourethrogram) or goniometer (Q-tip) by 2 different investigators blinded to each other findings. Results: In 43 patients the mean urethral angle at rest and UAS were 20 degrees ⫾ 12 and 51 degrees ⫾ 20, by voiding cystourethrogram compared to 16 degrees ⫾ 9 and 58 degrees ⫾ 10 by Q-tip test, respectively. The mean angle difference (urethral angle with straining minus urethral angle at rest) was greater for the Q-tip test (42 degrees ⫾ 9) than that for the voiding cystourethrogram test (32 degrees ⫾ 17; p ⬍0.05). Fewer patients (14% by Q-tip, 28% by voiding cystourethrogram) had urethral hypermobility using the definition of urethral angle at rest greater than 30, while almost all patients (91% by voiding cystourethrogram, 100% by Q-tip) had urethral hypermobility using the definition of urethral angle with straining greater than 30. However, using the definition of urethral angle with straining minus urethral angle at rest greater than 30, only 58% of patients had urethral hypermobility by voiding cystourethrogram compared to 98% by Q-tip. Conclusions: The voiding cystourethrogram and the Q-tip test measure urethral hypermobility differently. This may affect which patients are classified as having urethral hypermobility, and the choice of anti-incontinence surgery. Key Words: urethra; urinary incontinence, stress
sored network consisting of 9 centers that have enrolled 655 patients with stress or stress predominant urinary incontinence in a randomized trial comparing Burch colposuspension and autologous rectus fascia sling. This study is a single center initiated ancillary project aimed at comparing the Q-tip test values at rest and with straining to the radiological values of UAR and UAS in a subset of preoperative patients with known stress urinary incontinence enrolled in the UITN.
he appropriate technique used to measure UH and the definition of UH remain controversial. Several methods have been used to assess urethral hypermobility such as the Q-tip test and the VCUG. Some define UH as a Q-tip straining angle equal to or greater than 30 degrees. The UITN group arbitrarily selected a resting angle greater than 30 degrees or a maximum straining angle greater than 30 degrees. Others have defined UH as a change between rest and straining position. The presence of UH is important to some investigators and clinicians to decide on the optimal type of anti-incontinence surgery.1,2 Historically, a pubovaginal sling has been recommended for the treatment of intrinsic sphincter deficiency in a well supported urethra, whereas a colposuspension has been recommended for UH. This has recently been called into question since some women with stress incontinence secondary to UH may have some associated degree of sphincter deficiency. The UITN is a National Institutes of Health spon-
T
MATERIALS AND METHODS From May 2002 to June 2004 women with stress urinary incontinence were enrolled in an institutional review board approved Burch colposuspension vs autologous rectus fascia sling randomized controlled trial. They underwent preoperative standing VCUG and Q-tip tests. Exclusion criteria for a VCUG included patients with prior history of intravesical contrast allergy and patients with hip prosthesis or pelvic metal plate/screws. A complete VCUG consisted of 1) plain film; 2) a standing, lateral view of the bladder filled with 100 to 125 ml of contrast, with the catheter in place, under resting and then straining condition; 3) an anteroposterior view of the full bladder; 4) 1 standing lateral view of the full bladder, after catheter removal, under resting and then straining condition; 5) 1 or 2 standing, lateral views during voiding; and 6)
Submitted for publication September 16, 2005. Study received institutional review board approval. * Correspondence: Department of Urology, The University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9110 (telephone: 214-648-2888; FAX: 214-6488786; e-mail: [email protected]).
See Editorial on page 438.
0022-5347/06/1762-0646/0 THE JOURNAL OF UROLOGY® Copyright © 2006 by AMERICAN UROLOGICAL ASSOCIATION
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Vol. 176, 646-650, August 2006 Printed in U.S.A. DOI:10.1016/j.juro.2006.03.091
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post-void plain film.3 The urethral axis was defined on the standing lateral view (number 2) by a line drawn along the length of the urethral catheter. This urethral axis intersected a vertical line drawn through the inferior border of the pubic symphysis and the resulting angle was measured from the vertical axis to the urethral axis using a standard radiological ruler calibrated at every 5-degree angle (see figure). According to the UITN protocol, the Q-tip test was performed with the subject reclined at a 45-degree angle. A sterile lubricated Q-tip was introduced in the urethra and withdrawn until resistance was met at the level of the urethrovesical junction.4 The angle of the Q-tip from the horizontal in degrees was measured using a goniometer at rest (UAR) and during straining (UAS). The Q-tip and VCUG measurements were performed at different times by 2 different investigators blinded to each others findings. Differences in urethral angles between Q-tip and VCUG analyzed as continuous variables were tested using the Wilcoxon test. Association in urethral angles between Q-tip and VCUG analyzed as categorical variable were tested using the Cohen’s kappa measure. Statistical significance in this study was set as p ⬍0.05. All reported p values are 2-sided. All analyses were performed with SPSS® version 11.5 for Windows. RESULTS Median patient age was 54 years (range 31 to 75, mean 53 ⫾ 11). The table shows the differences in urethral angles determined by the Q-tip and VCUG tests. The urethral angle at rest measured by the Q-tip test was significantly lower than that measured by the VCUG test. Conversely, the straining and the straining minus rest urethral angles were both significantly higher when measured by the Q-tip test than when measured by the VCUG test. We analyzed the data according to 3 commonly used definitions for UH: urethral rest angle over 30 degrees, urethral strain angle over 30 degrees, and urethral strain angle minus urethral rest angle over 30 degrees. The table shows the difference in the rate between patients diagnosed with UH using the 3 definitions for both the Q-tip and VCUG tests. The 3 definitions resulted in statistically different rates of patients potentially diagnosed with UH regardless of whether the Q-tip or VCUG test was used (all p values ⬍0.001). For both the Q-tip and VCUG tests, the rate of patients with UH was highest using the strain angle greater than 30 degrees definition, followed by the strain minus rest angle greater than 30 degrees definition, and was lowest using the strain angle greater than 30 degrees definition. When using the rest angle greater than 30 degrees definition, the rate of patients diagnosed with UH was significantly smaller with the Q-tip test than with the VCUG test. When using the strain angle greater than 30 degrees definition or the strain minus rest angle greater than 30 degrees definition, the rates of patients diagnosed with UH were significantly higher with the Q-tip test than with the VCUG test. DISCUSSION This limited study offers a unique head-to-head comparison between 2 modalities that measure UH. The VCUG was compared to the Q-tip test to document and measure the presence and severity of UH. Of the 3 definitions of UH, only
FIG. 1. A, true lateral view (complete superposition of femurs) during standing cystogram in resting position demonstrating urethral angle measurement. Urethral angle is angle between straight vertical line and dotted line representing urethral axis given by Foley catheter ending up with balloon (round circle) at urethrovesical junction. B, same patient in same position, but with straining. Urethral axis has increased from 30 degrees at rest to 50 degrees with straining indicating presence of urethral hypermobility. Level of bladder base is just below lower edge of pubic symphysis. Early cystocele confirms laxity of whole anterior vaginal wall.
648
Q-TIP TEST AND VOIDING CYSTOURETHROGRAM TO ASSESS URETHRAL HYPERMOBILITY Differences of urethral angles measured by Q-tip and VCUG tests
Median rest angle (IQR) Median strain angle (IQR) Median difference of straining ⫹ rest angles (IQR) No. pts rest angle (% of procedure): 30 Degrees or less Greater than 30 degrees No. pts straining angle (% of procedure): 30 Degrees or less Greater than 30 degrees No. pts difference of straining ⫹ rest angles (% of procedure): 30 Degrees or less Greater than 30 degrees
Q-tip Test
VCUG
p Value
Continuous variables 15 (10) 60 (15) 40 (10) Categorical variables
20 (10) 50 (20) 30 (15)
0.050 (Wilcoxon test) 0.016 (Wilcoxon test) ⬍0.001 (Wilcoxon test)
37 (86) 6 (14)
31 (72) 12 (28)
0.193 (Cohen’s kappa measure test)
0 (0) 43 (100)
4 (9) 39 (91)
1.000 (Cohen’s kappa measure test)
1 (2) 42 (98)
18 (42) 25 (58)
0.233 (Cohen’s kappa measure test)
Data set was not found to be normally distributed using Kolmogorov-Smirnov statistics. Therefore, we chose to report the median and the IQR rather than the mean and standard deviation.
1 was met by both tests, namely UAS greater than 30 degrees. The change in position from rest to strain was amplified in supine position, possibly due to more pelvic relaxation and less postural tone. The differences in angle between the Q-tip test and VCUG were likely related to patient position instead of inherent differences between the 2 tests. Handa et al reported that the female urethra is more mobile in the supine than in the standing position.5 In that study the cotton swab test was performed in the standing and supine positions, and the urethral angle was measured in women with a variety of urogynecological complaints. The R, S and S-R values reported were 4, 43 and 41, and 17, 32 and 16 in the supine and standing positions, respectively. Of note, the S-R angles found by VCUG in the present study were very similar to the angles found in another study of women with SUI before undergoing an anterior vaginal wall suspension procedure.6 The Q-tip test was developed in 1971.7 During the course of preparing a patient for a bead chain cystourethrogram, the patient strained with a lubricated Q-tip in her urethra. A comparison of the results of the Q-tip and bead chain cystogram in over 40 patients revealed that R less than 10 degrees and S less than 20 were seen with good urethral support. A poorly supported urethra was subsequently defined as S greater than 30 degrees. Since then the Q-tip test has gained popularity in routine practice despite recognized shortcomings (see Appendix). Studies have shown that while the Q-tip test can measure UH, it does not help much with diagnosing SUI. Walters et al compared the results of the Q-tip test in subjectively continent women, women with SUI, and women with other types of urinary incontinence and voiding dysfunction.8 Significant differences in maximum stress Q-tip angle and urethral mobility were found between the continent controls and women with SUI. However, no differences were found between the 2 incontinent study groups. They concluded that the Q-tip test does not provide a specific urological diagnosis. While the Q-tip test can measure UH, it suffers from a lack of standardization which limits its usefulness. Studies have shown that bladder fullness, coexistent pelvic organ prolapse,8,9 upright patient position,5 and Q-tip malposition9 all affect the measured urethral angle. In the original article by Crystal and in all subsequent articles, factors such
as bladder fullness, coexistent organ prolapse, and Q-tip position are rarely reported. This lack of standardization brings into question the applicability of these studies findings to other patient populations. To mitigate the impact of these confounding factors, several authors have proposed a more standardized way to perform the Q-tip.9 It has been recommended to perform the Q-tip test with the bladder empty. Still, one relies on blind faith that the tip of the Q-tip is at the urethrovesical junction. These same factors undoubtedly influence the results of the VCUG test. However the urethral Foley catheter is soft and easy to introduce in the urethra, always gives a reliable measure of the urethral axis, and the test provides additional information on bladder volume and configuration, coexistent prolapse, and on the urethra during voiding. The patient can be studied in the standing position where leakage is most likely to occur.10 The VCUG has long been studied with the hope of establishing a relationship between urethral angle, bladder base position and continence. Stevens and Smith first described the technique of lateral bead-chain cystourethrography in 1937.11 Green characterized incontinence based on position of the bladder base and posterior urethrovesical angle.12 Loss of the posterior urethrovesical angle occurred in Type I incontinence, while Type II incontinence also included inferior displacement and rotation of the bladder base and urethra. Patients with type I incontinence benefited from simple anterior colporrhaphy 90%, whereas patients with Type II incontinence were successfully treated with anterior colporrhaphy only 50%, but had cure rates of 90% with retropubic suspension. Bergman expanded the Green criteria to include funneling of the bladder neck and the position of the urethrovesical junction and bladder base and found that none of these anatomic changes defined stress incontinence.13 Pelsing et al studied 159 women with leakage or voiding dysfunction as the chief complaint.14 They concluded that the VCUG has limited value because of detrusor instability producing urge incontinence and therefore false-positive stress incontinence. They reported the sensitivity and specificity of the VCUG in predicting SUI at 60% and 70%, respectively. In contrast, Showalter et al showed that the VCUG had good inter-rater reliability in measuring UAR, UAS and S-R using the same technique described in the
Q-TIP TEST AND VOIDING CYSTOURETHROGRAM TO ASSESS URETHRAL HYPERMOBILITY present article.6 Age matched values for UAR interpretation were also provided as well as data to show that, after surgical correction, UAR and UAS returned to age matched normal values, a finding suggestive that correcting anatomy may be a basic prerequisite for return to a normal function. Wall et al performed a logistic regression analysis of lateral bead-chain cystourethrograms.15 They showed that an important predictor of a successful surgical outcome was a large distance between the bladder neck and pubic symphysis at rest and increased mobility of the bladder neck before surgery. The importance of measuring UH stems from previous reports that have shown that patients who have SUI without UH have poor outcomes with Burch and should be treated by an alternative procedure such as a sling, artificial sphincter, or collagen injection.16 In Bergman’s study of 456 women with SUI, 15 had SUI and a negative Q-tip test (defined as a S-R less than 30). These patients subsequently underwent a retropubic surgery including revised Pereyra
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(6) or Burch (9). Of patients who underwent a Burch, 55% (5 of 9), and of those who underwent a Pereyra procedure 50% (3 of 6) had treatment failure. This failure rate was 5 times higher than that observed among women with SUI and a positive Q-tip who underwent the same procedure. Thus, not only defining UH is important, but defining the opposite, namely a fixed, nonmobile urethra may be an important determinant of the type of anti-incontinence repair. CONCLUSIONS In this limited study comparing UH measurements by Q-tip test and VCUG, we found that the number of patients with UH depends on the definition of UH chosen. The pros and cons of these 2 methods were reviewed, with an emphasis on standardization and relationship to incontinence. At present, there is no gold standard method to define UH. Thus patients’ clinical outcome after repair may help decide which test and which UH measurement carry the best predictive value.
APPENDIX Pros and cons of the Q-tip test and VCUG Q-TIP PROS
Inexpensive Widely available Easy to perform
CoNS
Inability to determine exact Q-tip position reduces accuracy Information limited to UH only Difficult to standardize
VCUG Favor leakage with standing position (gravity factor) Provide information on bladder/urethra and on voiding Films can be rereviewed for quality control Low level radiation exposure Rare: contrast dye allergy and infection risk Costs $150 to $200
7.
Abbreviations and Acronyms IQR SUI UAR UAS UH UITN VCUG
⫽ ⫽ ⫽ ⫽ ⫽ ⫽ ⫽
interquartile range stress urinary incontinence urethral angle at rest urethral angle with straining urethral hypermobility Urinary Incontinence Treatment Network voiding cystourethrogram
REFERENCES 1.
2.
3.
4.
5.
6.
Minassian, V. A., Drutz, H. P. and Al-Badr, A.: Urinary incontinence as a worldwide problem. Int J Gynaecol Obstet, 82: 327, 2003 DeLancey, J. O.: Structural support of the urethra as it relates to stress urinary incontinence: the hammock hypothesis. Am J Obstet Gynecol, 170: 1713, 1994 Zimmern, P.: The role of voiding cystourethrography in the evaluation of the female lower urinary tract. Prob Urol, 5: 23, 1991 Urinary Incontinence Treatment Network: Design of the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Urology, 66: 1213, 2005 Handa, V. L., Jensen, J. K. and Ostergard, D. R.: The effect of patient position on proximal urethral mobility. Obstet Gynecol, 86: 273, 1995 Showalter, P. R., Zimmern, P. E., Roehrborn, C. G. and Lemack, G. E.: Standing cystourethrogram: an outcome measure after anti-incontinence procedures and cystocele repair in women. Urology, 58: 33, 2001
8. 9.
10.
11. 12.
13.
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15.
16.
BOTH Good intra-rater reliability Good at measuring UH No available technique to standardize the straining effort Urethral catheterization with limited discomfort Poor at diagnosing incontinence
Crystle, C. D., Charme, L. S. and Copeland, W. E.: Q-tip test in stress urinary incontinence. Obstet Gynecol, 38: 313, 1971 Walters, M. D. and Diaz, K.: Q-tip test: a study of continent and incontinent women. Obstet Gynecol, 70: 208, 1987 Karram, M. M. and Bhatia, N. N.: The Q-tip test: standardization of the technique and its interpretation in women with urinary incontinence. Obstet Gynecol, 71: 807, 1988 Zimmern, P. and Lemack, G.: Voiding cystourethrography and magnetic resonance imaging of the lower urinary tract. New York: Marcel Dekker, Inc., chapt. 26, pp. 407– 421, 2001 Stevens, W. and Smith, S.: Roentgenological examination of the female urethra. J Urol, 37: 194, 1937 Green, T. H., Jr.: Development of a plan for the diagnosis and treatment of urinary stress incontinence. Am J Obstet Gynecol, 83: 632, 1962 Bergman, A., McKenzie, C., Ballard, C. A. and Richmond, J.: Role of cystourethrography in the preoperative evaluation of stress urinary incontinence in women. J Reprod Med, 33: 372, 1988 Pelsang, R. E. and Bonney, W. W.: Voiding cystourethrography in female stress incontinence. AJR Am J Roentgenol, 166: 561, 1996 Wall, L. L., Helms, M., Peattie, A. B., Pearce, M. and Stanton, S. L.: Bladder neck mobility and the outcome of surgery for genuine stress urinary incontinence. A logistic regression analysis of lateral bead-chain cystourethrograms. J Reprod Med, 39: 429, 1994 Bergman, A., Koonings, P. P. and Ballard, C. A.: Negative Q-tip test as a risk factor for failed incontinence surgery in women. J Reprod Med, 34: 193, 1989
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Q-TIP TEST AND VOIDING CYSTOURETHROGRAM TO ASSESS URETHRAL HYPERMOBILITY
EDITORIAL COMMENT Increasing use of midurethral slings for all patients with SUI has cast doubt upon the usefulness of UH in the identification of types of SUI and in the selection of the antiincontinence procedure. Walsh et al report on an ancillary study from the UITN in which the University of Texas Southwestern investigators compared 2 measures of UH with the Q-tip test and a modified VCUG. Urethral angle at rest or straining was significantly different when measured by Q-tip test and VCUG. Furthermore, when variable definitions for UH were used, Q-tip and VCUG identified a different proportion of patients as having UH. The results of this well-done study may add to existing doubts about the usefulness of UH in the selection of the
anti-incontinence procedure. However, the only litmus test for determining the precise usefulness of UH will stem, it is hoped, from the final results of the UITN-Stress Incontinence Surgical Treatment Efficacy Results trial,1 which will assess the association between UH and the outcome of surgical treatment of SUI. Firouz Daneshgari Glickman Urological Institute The Cleveland Clinic Foundation Cleveland, Ohio 1.
Tennstedt, S. and Urinary Incontinence Treatment Network: Design of the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr). Urology, 66: 1213, 2005