Introital ultrasound of the lower genital tract ... - Wiley Online Library

Ultrasound Obstet Gynecol 2004; 23: 277–283 Published online 17 February 2004 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.982

Introital ultrasound of the lower genital tract before and after colposuspension: a 4-year objective follow-up V. VIERECK*, H.-U. PAUER*, W. BADER†, M. OPPERMANN*, R. HILGERS‡, A. GAURUDER-BURMESTER§, R. LANGE¶, G. EMONS*, R. HACKENBERG** and T. KRAUß* Departments of *Gynecology and Obstetrics and ‡Medical Statistics, Georg-August-University Goettingen, Goettingen, †Department of Gynecology and Obstetrics, University Witten/Herdecke, Witten, §Department of Gynecology and Obstetrics, Charit´e Medical School, Humboldt University, Berlin, ¶Office and German Red Cross Hospital, Alzey and **Department of Gynecology and Obstetrics, Philipps-University, Marburg, Germany

K E Y W O R D S: bladder neck; colposuspension; introital ultrasound; stress urinary incontinence

ABSTRACT Objective To assess the topography of the bladder neck by introital ultrasound before and after open colposuspension. Methods Three hundred and ten women with urodynamically proven stress urinary incontinence were included in this long-term study to investigate the position and function of the bladder neck at rest and during straining. Height (H), distance (D), and urethrovesical angle of the bladder neck (β) were measured by means of preoperative and postoperative introital ultrasound. Women were followed up; 152 of them (49%) completed 48 months of follow-up. Results At the 6-month follow-up examination, 90.0% of the women were continent (279/310), 3.5% (11/310) showed voiding difficulties, 3.5% (11/310) had urgency, and 1.6% (5/310) had developed de novo urge incontinence. At the 48-month follow-up, 76.8% of the patients were still continent. All postoperative measurements yielded significantly lower values for angle β at rest and during straining compared with the preoperative results (P < 0.0001). The median linear movement of the bladder neck during straining decreased from 18.0 mm before surgery to 6.4 mm at the 48-month follow-up (P < 0.0001). The median level of ventrocranial elevation of the vesicourethral junction was 14.3 mm immediately after surgery, 9.9 mm after 6 months and 6.6 mm after 48 months. The degree of surgical bladder-neck elevation was associated with postoperative urgency/de novo urge incontinence (P < 0.0001) and voiding difficulty (P < 0.0001).

Conclusions The colposuspension procedure reduces angle β at rest and during straining, restricts linear movement with straining, and elevates the bladder neck. Perioperative introital ultrasound improves understanding of this surgical procedure and might help to prevent postoperative complications. Copyright  2004 ISUOG. Published by John Wiley & Sons, Ltd.

INTRODUCTION All incontinence surgery aims at rectifying involuntary loss of urine while avoiding such complications as micturition disorders and the formation of rectoceles and enteroceles. Of all operative approaches, the open Burch colposuspension procedure continues to be considered the gold standard1 . The operation improves pressure transmission and thus ensures continence in the presence of increased intra-abdominal pressure2 . Publications in the literature report 5–10-year cure rates of over 80% for primary interventions and of 60–70% for repeat surgery3,4 . None of the parameters determined by urogynecological diagnostic assessment allows for reliably predicting the postoperative course. The effect of colposuspension on the level of elevation and mobility of the bladder neck, on the other hand, can be determined objectively. These parameters can be determined in a reproducible and technically simple manner by means of urogynecological ultrasound5 – 16 . The aim of the present study was to compare the position and movement of the bladder neck as determined by introital ultrasound before and immediately after surgery, as well as 6, 12, 24, 36, and 48 months after colposuspension, in order to determine the morphological

¨ Gynakologie ¨ ¨ Gottingen, ¨ Correspondence to: Dr V. Viereck, Klinik fur und Geburtshilfe, Georg-August-Universitat Robert-Koch-Straße 40, D-37075 Goettingen, Germany (e-mail: viereck@med.uni-goettingen.de) Accepted: 15 October 2003

Copyright  2004 ISUOG. Published by John Wiley & Sons, Ltd.

ORIGINAL PAPER

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outcome of incontinence surgery and changes over time. In addition to the description of the macroanatomy, we assessed the possible relationship between the degree of bladder-neck elevation, cure rate and postoperative complications in patients undergoing colposuspension. If an association exists, the degree of bladder-neck elevation and anatomical changes of the bladder-neck position over time relative to the surgical outcome might provide insight into the contribution of the bladder-neck position to the continence mechanism. Some authors still attribute surgical success to a high position of the bladder neck. Based on the results, intraoperative introital ultrasound might then in the future help to avoid postoperative complications resulting from overcorrection (such as voiding dysfunction and de novo urge incontinence) without compromising the surgical outcome.

METHODS The women recruited for this study underwent surgery for urodynamically proven primary genuine stress incontinence (GSI) in the period September 1992 to December 200117 . A total of 310 women of a total of 318 consecutive patients completed postoperative follow-up at 6 months and was included in the analysis. Eight patients were excluded from the investigation because they were lost to postoperative follow-up at 6 months. On clinical and urodynamic examination at discharge all patients except one (mild voiding dysfunction) were continent and did not complain of postoperative complications. The patients were recruited from the university hospitals in Marburg/Goettingen (n = 93) and Witten (n = 46) as well as from the German Red Cross Hospital in Alzey (n = 171). The surgical technique used in all cases was open colposuspension1 . Modifications of this technique involved primarily the exposure of the paraurethral tissue and anterior bladder wall, lateral tangential placement of non-absorbable sutures (Ethibond No. 1 sutures), and the loose approximation of the vaginal fascia to Cooper’s ligament. One hundred and fifty-two of the 310 patients underwent follow-up for a total of 48 months. Twentyseven women had a history of previous anterior repair. Women with mixed urinary incontinence or third-degree genital prolapse were excluded. Since all study patients underwent the usual clinical and urodynamic investigations (comprising cystometry, urethral pressure profilometry, and uroflow studies) and introital ultrasound of the bladder neck before surgery, the study was exempted from ethics committee approval by the Institutional Review Board of the University of Goettingen, Germany. Clinical assessment of voiding dysfunction included history and general, neurological and pelvic examinations. Ultrasound examination for residual urine and upper urinary tract dilatation was performed. All women had a suprapubic catheter inserted. The catheter was clamped after 5 days and managed by a standard regimen. The catheter was removed when postoperative void residuals were repeatedly below 50 mL urine (median, 8 days; range, 5–14 days). The


outcome of the operation was assessed objectively by coughing test with the women in the supine position and standing, clinical examination, and ultrasound (introitus and residual urine) 5–14 days after surgery (following removal of the catheter) and at followup after an average (± 1.5 months) of 6, 12, 24, 36 and 48 months. Urodynamic measurement was repeated 6 months postoperatively or in the case of recurrence. All participating centers performed introital ultrasound under standardized conditions using a Siemens Sonoline Adara (Siemens AG, Erlangen, Germany) ultrasound machine with pressure-free probe application (6-MHz vaginal probe)6,7,9,12,13 . The patients were examined in the recumbent position for cystometry after filling of the bladder with warm saline to a volume of approximately 300 mL. Postoperative measurement was performed at a filling volume of 200–300 mL as determined by ultrasound. Published reports on introital ultrasound suggest that a significant effect on height (H) will only be seen at a bladder filling volume of less than 200 mL9,12 . Measurements were performed at rest and during straining12,13,18 . Anatomical findings of the lower urogenital tract were analyzed using a coordinate system in which the internal urethral meatus on the ultrasound scan was defined by means of a horizontal reference line through the inferior symphyseal bony point (line through inferior border of symphysis pubis according to the radiographic definition) and a second line running perpendicular to this reference line (Figure 1). H and distance (D) were measured in millimeters and documented on photographs during the different functional states. In addition, the urethrovesical angle of the bladder neck (β) and funneling of the proximal urethra were analyzed10 – 12 . Bladder-neck elevation after surgical colposuspension was determined by vector equation as the linear distance between the preoperative Postoperative B B

S

H D

L

Preoperative

Figure 1 Schematic diagram of bladder-neck position before (broken line) and after (solid line) colposuspension with the parameters H and D, indicating the postoperative elevation of the bladder neck as reflected by the increased distance of H from the horizontal line through the inferior border of the symphysis pubis. The newly introduced parameter H expresses the difference between postoperative H and preoperative H. The arrow symbolizes the ventrocranial linear movement resulting from bladder-neck elevation. B, bladder; L, horizontal line drawn through the inferior border of the symphysis pubis; S, symphysis pubis.

Ultrasound Obstet Gynecol 2004; 23: 277–283.

Preoperative and postoperative determination of bladder-neck position and postoperative positions of the bladder neck (linear ventrocranial elevation, Figure 1). An analogous method was used to determine bladder-neck displacement during straining (linear dorsocaudal movement with straining). A negative value was assigned when H during straining was below the inferior symphyseal line. Sonography was performed by four examiners in three hospitals. Image evaluation and analysis was done by one reader. Inter-rater variability, established in earlier studies, was ± 3 mm13 . All definitions used are in accordance with the guidelines of the International Continence Society19 and with the recommendations for performing sonography of the lower urinary tract as part of urogynecological functional assessment issued by the German Urogynecology Working Group12 . Voiding dysfunction was defined as symptoms of stranguria and a postmicturation residual volume of > 50 mL at discharge (median, 40 mL; range, 0–220 mL). Statistical analysis was performed using STATISTICA (version 6.1.144, English, StatSoft Inc., Tulsa, OK, USA (2003)). Descriptive statistics were computed for demographic and anamnestic patient data. The results are presented as median and range. Intraindividual changes over time were analyzed using the sign test. Dichotomic data were assessed by means of McNemar’s test. Cure was objectively determined by negative supine and standing cough test. Subjective cure in terms of continence was evaluated using the patient’s history and a detailed urinary incontinence questionnaire. The time until recurrence was defined as the time until incontinence occurred or recurred (recurrence-free interval). Patients who did not become continent after surgery were assigned 0 as the time of recurrence. The corresponding Kaplan–Meier estimators were calculated and yielded the respective rates at the selected follow-up times. Groups were compared using the Gehan–Wilcoxon test. This test was also used to analyze the times until the first occurrence of voiding difficulties, urge symptoms, and de novo urge incontinence. Statistical significance was assumed at P < 0.05.

RESULTS The patients’ median age at the time of surgery was 55 (range, 26–85 years). Median height and weight were

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165 (range, 146–184) cm and 70 (range, 50–115) kg, respectively. The median parity was 2 (range, 0–8). The mean length of follow-up was 35.1 months, the median was 36 months and the range was 6–48 months. The median H at rest in the patients with GSI was 13 mm before surgery, 21 mm immediately after surgery, 18 mm at the 6-month follow-up and 14 mm at the 48-month follow-up (Table 1). Descent of the bladder neck during straining led to positions below the inferior border of the symphysis pubis in some patients before surgery, resulting in a median H of −3 mm. Median H with straining was 17 mm immediately after surgery, 14 mm at the 6-month follow-up and 10 mm at the 48-month follow-up (P < 0.0001) (Table 1). The colposuspension operation resulted in a median bladderneck elevation (linear ventrocranial elevation) of 14.3 mm immediately after surgery, 9.9 mm at the 6-month follow-up (P < 0.0001) and 6.6 mm at the 48-month follow-up (P < 0.0001) (Table 2). Linear dorsocaudal movement of the bladder neck during straining decreased from 18.0 mm preoperatively to 6.4 mm immediately after the procedure, 5.8 mm at the 6-month followup (P < 0.0001) and 6.4 mm at the 48-month followup (Table 3). Angle β measured at rest decreased from 115◦ (range, 65–180◦ ) preoperatively to 86◦ (range, 60–125◦ ) immediately after surgery (P < 0.0001). The corresponding values during straining decreased from 152◦ (range, 78–184◦ ) to 95◦ (range, 65–139◦ ) Table 2 Linear ventrocranial elevation relative to preoperative findings, immediately after surgery, and at 6–48-month follow-up

n

Elevation (mm, median (range))

310 310 294 268 196 152

14.3 (2–39) 9.9 (2–30)*** 8.6 (1–31)*** 7.6 (1–29)*** 7.0 (0–25)*** 6.6 (1–27)***

Time of measurement Postoperative Immediately 6 months 12 months 24 months 36 months 48 months Sign test: ***P < 0.0001.

Table 1 Height (H) and distance (D) of the bladder neck at rest and during straining measured by introital ultrasound before colposuspension, immediately after surgery, and at 6–48-month follow-up Resting measurement (mm, median (range)) Time of measurement Preoperative Postoperative Immediately 6 months 12 months 24 months 36 months 48 months

N

H

Straining measurement (mm, median (range)) D

H

D

310

13 (0 to 28)

18 (6 to 42)

−3 (−36 to 24)

24 (9 to 45)

310 310 294 268 196 152

21 (8 to 38)*** 18 (2 to 31)*** 16 (−2 to 29)*** 15 (−3 to 28)** 14 (−6 to 26)* 14 (−8 to 25)

6 (−6 to 22)*** 9 (−3 to 29)*** 9 (−1 to 29)*** 10 (3 to 28)*** 10 (2 to 25)*** 11 (−2 to 22)***

17 (−8 to 36)*** 14 (−13 to 31)*** 12 (−14 to 25)*** 11 (−15 to 25)*** 10 (−16 to 23)*** 10 (−9 to 21)***

9 (−2 to 32)*** 11 (2 to 40)*** 13 (3 to 42)*** 14 (4 to 35)*** 14 (2 to 36)*** 15 (7 to 39)***

Measurement of H and D is shown in Figure 1. Sign test: *P < 0.05, **P < 0.001, ***P < 0.0001.



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280 Table 3 Linear dorsocaudal movement with straining before colposuspension, immediately after surgery, and at 6–48-month follow-up

n

Preoperative Postoperative Immediately 6 months 12 months 24 months 36 months 48 months

310 310 310 294 268 196 152

Movement (mm, median (range)) 18.0 (2–49) 6.4 (1–27)*** 5.8 (0–33)*** 5.8 (0–28)*** 6.3 (1–19)*** 6.1 (1–21)*** 6.4 (2–23)***

Sign test: ***P < 0.0001. Table 4 Numbers showing funneling before colposuspension, immediately after surgery, and at 6–48-month follow-up n


310 310 310 294 268 196 152

Funneling (n (%)) 171 (55.2) 34 (11.0)*** 38 (12.3)*** 29 (9.9)*** 22 (8.3)*** 13 (6.8)*** 8 (5.3)***

Quantile (%)

Time of measurement

incontinence distinguished by the Ingelmann-Sundberg scale: Grade I GSI (n = 61), Grade II GSI (n = 114), and Grade III GSI (n = 135). No grade-related differences were identified for preoperative H (at rest and during straining) and the level of bladder-neck elevation. Comparison of the patient data according to previous anterior repair (n = 27, Figure 2) and to the centers participating in the study yielded no significant differences. The colposuspension was associated with an objective cure rate of 94.5% of the patients (293/310) immediately after surgery (Figure 3). Improvement was seen in 3.9% (12/310) of the cases. The incidence of surgical failures was 1.6% (5/310). The cure rate at the 6-month follow-up was 90.0%. The overall rate of voiding difficulties was 26.8% (83/310) directly after surgery as opposed to 3.5% (11/310) at the 6-month follow-up (Figure 4). Only two patients had persistent voiding difficulties after 12 months but these had resolved by 2 years. The Kaplan–Meier

McNemar test: ***P < 0.0001.

n


310 310 310 294 268 196 152

Hypermobility (n (%)) 208 (67.1) 17 (5.5)*** 15 (4.8)*** 18 (6.2)*** 7 (2.7)*** 2 (1.0)*** 3 (2.0)***

McNemar test: ***P < 0.0001.

(P < 0.0001). Funneling of the bladder neck was visualized in 171 of the 310 (55.2%) stress-incontinent women before intervention. Surgery significantly reduced funneling to 12.3% (38/310) after 6 months (P < 0.0001) (Table 4). Hypermobility of the bladder neck (defined as dorsocaudal linear movement > 15 mm during straining) was present in 67.1% (208/310) of the patients before surgery. Colposuspension significantly reduced the incidence of hypermobility to 4.8% (15/310) of the patients at the 6-month follow-up (P < 0.0001) (Table 5). The parameters determined by introital ultrasound were subsequently analyzed in relation to the three grades of


0

5

10

15

20

25

30

35

40

Elevation (mm)

Figure 2 Empirical distribution function of postoperative bladder-neck elevation in relation to previous anterior repair (n = 27). There was no significant difference between patients with (dashed line) and those without (dotted line) previous anterior repair (Wilcoxon–Mann–Whitney test, P = 0.2070). The solid line represents the two groups combined. 1.0 Proportion recurrence-free

Table 5 Numbers showing hypermobility (linear dorsocaudal movement of bladder neck with straining > 15 mm) before colposuspension, immediately after surgery, and at 6–48-month follow-up

100 90 80 70 60 50 40 30 20 10 0

0.9 0.8 0.7 0.6 0.5 0.4 0

6

12

18 24 30 Time (months)

36

42

48

Figure 3 Proportion of recurrence-free women with time after colposuspension comparing patients with vertical bladder-neck height correction H (resting Hpostop – resting Hpreop ) between 1 and 10 mm (solid line, n = 195) and H exceeding 10 mm (dashed line, n = 115). The two groups did not differ significantly in terms of absence of recurrence (P = 0.1430, Gehan–Wilcoxon test). The overall recurrence rate is shown for comparison (dotted line).


Proportion voiding difficulty-free

Preoperative and postoperative determination of bladder-neck position 1.00 0.90 0.80 0.70 0.60 0.50 0

6

12

18 24 30 Time (months)

36

42

48

Proportion urgency-/urge incontinence-free

Figure 4 Proportion of voiding difficulty-free women with time after colposuspension comparing patients with vertical bladder-neck height correction H (resting Hpostop – resting Hpreop ) between 1 and 10 mm (solid line, n = 195) and H exceeding 10 mm (dashed line, n = 115). The two groups differed significantly in terms of absence of voiding difficulties (P < 0.0001, Gehan–Wilcoxon test). The overall rate of voiding difficulties is shown for comparison (dotted line).

1.00 0.95 0.90 0.85

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continent at the 48-month follow-up (Figure 3). There was complete agreement between objective and subjective results regarding the incontinence-free period in 285 of the 310 patients (91.9%). In addition, the results showed that bladder-neck elevation based on the patient’s individual preoperative resting H was associated with significantly fewer complications such as urgency, de novo urge incontinence, or voiding disorder (Gehan–Wilcoxon test; P < 0.0001) when the vertical height correction H (resting Hpostop – resting Hpreop ) was 1 to 10 mm. In contrast, the patients with a height correction > 10 mm (n = 115) had an incidence of new occurrence of urgency or de novo urge incontinence at the 6-month follow-up of 27.0% (vs. 6.2% for H = 1 to 10 mm) (Kaplan–Meier estimator; Gehan–Wilcoxon test; P < 0.0001) (Figure 5). Six of the seven patients with de novo urge incontinence were in the group with H > 10 mm. The rate of voiding difficulties occurring immediately after surgery was 40.0% for H > 10 mm vs. 18.5% for H = 1 to 10 mm (Kaplan–Meier estimator; P < 0.0001) (Figure 4). This complaint was transient, of short duration, and occurred predominantly immediately after surgery. The two groups did not differ significantly in terms of the recurrence-free interval (Gehan–Wilcoxon test; P = 0.1430). The proportion of patients free from recurrence at the 48-month follow-up was 78.4% for H = 1 to 10 mm vs. 74.1% for H > 10 mm (Kaplan–Meier estimator; Figure 3).

0.80

DISCUSSION

0.75 0.70 0.65 0

6

12

18

24

30

36

42

48

Time (months)

Figure 5 Proportion of urgency-free and de novo urge incontinence-free women with time after colposuspension comparing patients with vertical bladder-neck height correction H (resting Hpostop – resting Hpreop ) between 1 and 10 mm (solid line, n = 195) and H exceeding 10 mm (dashed line, n = 115). The two groups differed significantly in terms of absence of these complications (P < 0.0001, Gehan–Wilcoxon test). The rate of these complications was 6.7% vs. 29.1% at the 48-month follow-up. The overall rate of these complications is shown for comparison (dotted line).

estimator showed that no new voiding difficulties occurred after 12 months. Immediately postoperatively, the incidence of urgency was 10.6% (33/310) and that of de novo urge incontinence was 2.3% (7/310). The incidence of urgency was 3.5% (11/310) at the 6-month follow-up and 1.7% (5/310) at the 12-month follow-up. At 6 months 1.6% (5/310) of the patients were suffering from symptoms of de novo urge incontinence, and 1.0% (3/294) at the 12month follow-up. No additional occurrences of urgency or de novo urge incontinence were observed after 24 months (Figure 5). A total of 76.8% of the patients were still


Quantitative determinations by urogenital ultrasound such as measurement of the vertical height of the bladder neck relative to the inferior border of the symphysis pubis or of the posterior urethrovesical angle are primarily of scientific interest, since, for instance, the correlation between changes in this angle and a patient’s complaint is poor in most cases. In our study stress-incontinent women showed a more pronounced decrease in H with straining compared with data reported in the literature8,9,12,20 . Our preoperative results confirm the observation that bladder-neck topography is altered in stress-incontinent women. These patients have a significantly lower bladder neck at rest than do continent women9,20 . Consistent with a loss of anchorage, the bladder neck in these patients descends below the level of the inferior border of the symphysis pubis on straining, resulting in a median difference of height Hrest – height 20 ¨ , Hstraining of 16 mm. However, unlike Stein and Kunzel we did not find the preoperative extent of bladder-neck descent during straining to correlate with the severity of incontinence. Introital ultrasound allows for excellent assessment of the bladder-neck region5 – 16,18,20,21 . Determination of the vertical distance from the bladder outlet to the line through the inferior border of the symphysis pubis in our patient population nearly always showed a significantly higher bladder-neck position immediately after surgery and up to 48 months postoperatively, both


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at rest and during straining (Table 1). Measurement of the horizontal D showed ventral displacement of the bladder neck that persisted with straining (Table 1). Ventrocranial displacement of the internal urethral meatus by colposuspension produced an elevation of 14 (range, 2–39) mm immediately after surgery and resulted in a significant reduction of the urethrovesical angle β. Atherton and Stanton14 , using transperineal ultrasound 3–4 weeks after colposuspension, found a bladder-neck elevation of 18 mm. Funneling of the proximal urethra during straining is a typical finding in stress urinary incontinence and may also induce relevant diurnal urgency in patients in whom other causes have been excluded. Colposuspension results in a permanent and significant reduction of funneling (Table 4). The ventrocranial displacement of the bladder neck following incontinence surgery is easily demonstrated by comparing H before and after surgery (Table 1). In our patient population, H values at the 48-month follow-up were still greater than they were before colposuspension. The extent of elevation in most patients is higher immediately after surgery than it is after 6 months (Table 2). However, these higher values must be interpreted with caution since they are most probably due to the presence during the early postoperative period of periurethral inflammation, edema or hematoma. The stabilization of the urethrovesical junction by colposuspension was most apparent on ultrasound during straining. The extent of linear movement of the bladder neck in the dorsocaudal direction was only 6.4 mm at the 48-month follow-up, which was significantly below the postoperative value (Table 3). The 5-year continence rate reported in the literature ranges from 52 to 78%4,22 – 24 and Alcalay et al.3 reported a continence rate of 78% (n = 109) after an average of 5 years. The continence rate at the 4-year follow-up was 76.8% in our study population. Funneling was present in only 12.3% of our patients 6 months postoperatively. Dietz and Wilson4 , on the other hand, noted funneling in 11% (9/83) of their patients after follow-up for 2–12 years. In addition, they diagnosed newly occurring hypermobility of the bladder neck during straining (> 15 mm vertical bladderneck descent at ultrasound) in 12% (10/83) of their patients at an average follow-up of 6.1 years. However, the authors present no data on the first 2 years. In our patient population, hypermobility, defined as > 15 mm dorsocaudal linear movement on ultrasound, was present in 67.1% (208/310) of the women before surgery as opposed to only 4.8% (15/310) 6 months postoperatively. It is generally difficult to predict the risk of recurrence and possible complications in the long-term follow-up of patients having undergone surgical management of incontinence. Proper diagnostic assessment is required in patients with inconclusive postoperative voiding difficulties. The results of this study suggest that introital ultrasound is a suitable modality for rapid diagnostic clarification in such cases. Ultrasound is easy to perform and rapidly provides a diagnosis of overcorrection


following suspension procedures (e.g. rigid bladder-neck fixation near the symphysis pubis). Elevation of the bladder neck by colposuspension is associated with a risk of voiding dysfunction, which has a mean frequency of 12.5% (range, 3–32%)3,4,22 – 25 , and the occurrence of urgency or de novo bladder instability is reported to range between 5 and 41%3,4,14,22 – 25 . This wide range is due to different definitions of symptoms and patient populations (primary/repeat interventions)3,22 – 25 , which also accounts for the fact that reliable data on the frequency of postoperative complications are still lacking23 . Lateral and moderate elevation of the vaginal wall (loose approximation of threads, so-called ‘suture bow-stringing’) was found to reduce the longterm incidence of newly occurring urge incontinence to less than 3%15,23,24 . The results of our study suggest that H = 1 to 10 mm, when compared with H > 10 mm, is associated with a markedly lower incidence of postoperative complications such as urgency or de novo urge incontinence (at 6 months: 27.0% vs. 6.2%) and of transient, short-term voiding difficulties (6 months: 42.6% vs. 20.0%) while the cure rate remains the same (Figures 3–5). However, so far no intervention trial randomizing patients to two different colposuspension techniques exists. The results of our study thus support the ‘hammock hypothesis’ proposed by DeLancey26 . This theory assumes that stabilization of the suburethral supportive layers consisting of the anterior vaginal wall and the endopelvic fascia improves pressure transmission and thus ensures compression of the urethra against these layers during coughing. According to his theory, the height of the intra-abdominal position of the bladder neck does not necessarily play a role. On the other hand, Enhorning2,27 postulates that elevation of the bladder neck is a major component of the continence mechanism. He assumes that continence during coughing is brought about by intra-abdominal pressure transmission to the urethra through re-elevation of the bladder neck into the visceral area. However, excessive elevation of the bladder neck and urethral compression may easily give rise to the aforementioned complications24 . Our study suggests that the creation of a stable suburethral base might be one essential effect of colposuspension. Clearly, our study does not allow exclusion of an important role for tissue quality or other intraoperative aspects besides bladderneck elevation.

CONCLUSIONS Our findings obtained by introital ultrasound have demonstrated that the colposuspension procedure stabilizes the bladder neck by reducing its angle β at rest and during straining as well as its linear dorsocaudal movement during straining. Our results furthermore support the hypothesis that strong suburethral stabilization with only moderate elevation of the bladder neck by colposuspension is sufficient for preservation of the continence mechanism26 – 29 . H is a suitable sonomorphological


Preoperative and postoperative determination of bladder-neck position parameter that is easy to determine and allows for the preoperative diagnosis of lost anchorage of the bladderneck region in patients with stress urinary incontinence, along with the postoperative assessment of the outcome of surgery, the risk of recurrence and the rate of complications. Introital ultrasound is easy to perform and enables simple perioperative determination of H in a routine gynecological setting. Based on the generated hypotheses intraoperative introital ultrasound might be used for monitoring the proper placement of sutures and thus it may contribute to standardization of the operative technique and reduction of the postoperative complications associated with colposuspension. However, the question as to how much bladder-neck elevation is required to reduce complications and achieve continence cannot be answered by this study. The potential for standardizing the operative technique is currently being investigated in an ongoing, prospective long-term trial.

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