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Obstetrics & Gynecology 2004;104:1270-1274
© 2004 by The American College of Obstetricians and Gynecologists
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ORIGINAL RESEARCH

Lateral Excision of Tension-Free Vaginal Tape for the Treatment of Iatrogenic Urethral Obstruction

Cheng-Yu Long, MD*, Tsia-Shu Lo, MD{dagger}, Cheng-Min Liu, MD*, Shih-Cheng Hsu, MD*, Yu Chang, MD* and Eing-Mei Tsai, MD, PhD*

From the *Department of Obstetrics and Gynecology, Kaohsiung Municipal Hsiao Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; and {dagger}Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Chang Gung University, Tao-Ysuan Hsien, Taiwan

Address reprint requests to: Dr. Eing-Mei Tsai, Department of Obstetrics and Gynecology, Kaohsiung Municipal Hsiao Kang Hospital, 482 Shan-Ming Road, Hsiao-Kang Dist. 812, Kaohsiung, Taiwan; e-mail: K83263{at}kmhk.kmu.edu.tw.


   ABSTRACT
TOP
ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
OBJECTIVE: To report our experience on lateral excision of tape in women with iatrogenic urethral obstruction after the tension-free vaginal tape (TVT) procedure.

METHODS: Seven women had iatrogenic urethral obstruction based on their clinical and urodynamic findings. All underwent lateral excision of the tape using the vaginal approach. Lower urinary tract symptoms, postvoid residual volume and urodynamic data were evaluated before and after excision.

RESULTS: Before excision, all subjects had either irritative symptoms or increased postvoid residual volume (more than 100 mL), and 6 (85.7%) voided with strain. The mean time from initial surgery to tape excision was 28 days (range 4 to 108), with an average follow-up of 32 months (range 24–39). After the excision, voiding dysfunction was resolved in 6 of 7 patients. The remaining patient had significant improvement with only occasional symptoms of irritation. Two (28.6%) women reported recurrent stress incontinence and 1 (14.3%) required surgical treatment. The intervals for the 2 recurrent patients from TVT to excision were 4 days. The intervals for the 5 continent women were 15 to 108 days.

CONCLUSION: Urethral obstruction after TVT is a relatively uncommon condition. It can be effectively treated with transvaginal lateral excision of the tape. Recurrent stress incontinence seems to be less likely to occur when the takedown procedure occurs beyond 14 days after the initial TVT operation.

LEVEL OF EVIDENCE: III

More than 150 different procedures have been described in the literature for the treatment of female stress urinary incontinence. Among them, Burch retropubic urethropexy and pubovaginal sling are the most popular operations because of their excellent results.1,2 In 1995, Petros and Ulmsten3 introduced a new, minimally invasive surgery for treating female stress incontinence, namely the tension-free vaginal tape (TVT) procedure. Based on the integral theory, continence can be achieved by placing a vaginal tape underneath the mid-urethra without tension to reinforce the weakened pubourethral ligament.3,4 In theory, TVT achieves dynamic compression of the urethra at stress and is not likely to obstruct urine flow during micturition. However, cases of iatrogenic urethral obstruction have been reported.5–9

Iatrogenic obstruction can be treated with full urethrolysis,5–7 a limited suprameatal approach,10 or a simple method of transvaginal excision of the vaginal tape.11–13 Herein, we report the effectiveness of transvaginal lateral excision of tape in 7 patients for correcting voiding dysfunction and urethral obstruction after the TVT (Gynecare TVT, Ethicon, Inc., Piscataway, NJ) procedures.


   MATERIALS AND METHODS
TOP
ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Between June 2000 and November 2003, 71 women underwent TVT procedures at our hospital for stress urinary incontinence or mixed incontinence associated with or without gynecologic disease. All of them were evaluated with pre- and postoperative urinalyses, detailed histories, pelvic examinations, cotton-tipped swab tests, 1-hour pad tests, and multichannel urodynamic testings.

Urodynamic studies included uroflowmetry, filling and voiding cystometry, and urethral pressure profilometry. Noninstrumented uroflowmetry was used to record maximum flow rate and postvoid residual volume after catheterization. Filling cystometry was carried out with 8 French microtip transducer pressure catheters with a dual-sensor catheter placed in the bladder and a single-sensor catheter placed 15 cm into the rectum. Sterile water was infused at a rate of 60 mL/min by an infusion pump. Maximum cystometric capacity was the volume at which the patient felt she could no longer delay micturition. At capacity, patients were asked to void and pressure flow voiding studies were performed.

The diagnosis of urethral obstruction after the TVT procedure was mainly based on urodynamic evidence. Bladder outlet obstruction was defined as detrusor pressure at peak flow greater than 20 cm H2O during pressure flow study with maximal flow rate of less than 12 mL/s in noninstrumented uroflowmetry.14 Patients with low-pressure, low-flow urodynamics (detrusor pressure at peak flow less than 20 cm H2O, maximum flow rate less than 12 mL/s), new onset or worsened symptoms (frequency, urgency, and the need to strain to void), and postvoid residual volume more than 100 mL were deemed equivocal for obstruction but were also enrolled in the study. All participants were first managed with conservative treatment, including medications, intermittent catheterization, and urethral dilation. If these management steps proved ineffective, patients were offered the option of transvaginal tape excision. The tape excision procedures were performed on an outpatient basis between October 2000 and January 2002.

Patients were placed in the lithotomy position. Under local anesthesia, a vertical vaginal incision was made approximately 1.5 cm below the urethral meatus. After careful dissection of the vaginal wall, a cystoscope was inserted and pushed downward to help to locate the TVT tape. Once the tape had been exposed, it was simply transected 1–2 cm right to the urethra and left in place (Fig. 1). The tape usually did not move off the periurethral fascia, forming a "J " shape sling in situ. No additional effort was made to free the tape elsewhere. The vaginal wall was closed and the patient was discharged the same day without catheterization.



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  		Fig. 1. Diagram of the incision procedure. C, cystoscope; T, tension-free vaginal tape; U, urethra; W, vaginal wound; I, incision.

Long. Lateral Tape Excision for Urethral Obstruction. Obstet Gynecol 2004.

 

Before excision, all subjects were requested to sign an informed consent approved by the Institutional Review Board of the Kaohsiung Medical University. After excision, follow-up was scheduled at 1, 2, 3, 6, 9, and 12 months. After 1 year, subjects were interviewed by telephone every 6 months. Urodynamic testings and cotton-tipped swab tests were evaluated at 3 months after the excision. Urethral hypermobility was defined as cotton-tipped swab straining angle more than 30 degrees.15 Results were assessed based on the improvement of obstructive (the need to strain to void) and irritative (frequency or urgency) symptoms, postvoid residual volume, and urodynamic findings.


   RESULTS
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
After the TVT procedure, 7 (9.9%) women were diagnosed as iatrogenic urethral obstruction based on their clinical and urodynamic findings (Table 1), occurring in the third, sixth, seventh, ninth, 14th, 23rd, and 36th cases. Their clinical background is shown in Table 2 and surgical results are detailed in Tables 3 and 4. All subjects had urodynamically proven genuine stress incontinence preoperatively without concomitant surgery and reported normal voiding before their TVT procedures. Four patients had new onset of frequency or urgency, and 3 had pre-TVT irritative symptoms that worsened postoperatively. Six women reported straining to void, and 2 had recurrent urinary tract infections after the TVT procedures. The postvoid residual volume was 100 mL or greater in 7 patients. All had a urodynamic study; urethral obstruction (maximum flow rate less than 12 mL/s, detrusor pressure at peak flow more than 20 cm H2O) was observed in 6 patients. One patient had low-pressure low-flow voiding dynamics (maximum flow rate was 5 mL/s and detrusor pressure at peak flow was 12 cm H2O), and was deemed equivocal for obstruction. After the TVT operation, the mean maximum flow rate decreased from 21 mL/s to 9 mL/s, and the mean detrusor pressure at peak flow increased from 22 cm H2O to 37 cm H2O. Other characteristics revealed no apparent changes from pre- to post-TVT values. Of 4 patients with new onset of frequency or urgency symptoms, post-TVT urodynamics showed 2 had de novo detrusor overactivity. The number of women exhibiting urethral hypermobility decreased from 6 to 5 after the TVT procedures.


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  		Table 1. Clinical and Urodynamic Findings After the Tension-Free Vaginal Tape Procedures (N = 71).

 

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  		Table 2. Clinical Background

 

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  		Table 3. Surgical Results by Symptomatology

 


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  		Table 4. Urodynamic Surgical Results

 
The lateral sling excision was performed without complication in all patients. The mean operation time was 16 minutes (range 10 to 28). After an average of 32 months of follow-up, 6 patients reported no irritative symptoms (4 with new onset and 2 with worsened symptoms after TVT operation). One felt significant improvement from the pre-TVT baseline but had occasional episodes of urinary frequency and urgency. None of the 7 patients reported straining to void or urinary tract infection after excision. After incision, postvoid residual volumes less than 100 mL were found in 5 patients. Two patients refused catheterization and urodynamics due to the absence of urinary symptoms. Postexcision urodynamics revealed the maximum flow rate of 12 mL/s or greater in all 5 women. The mean value of detrusor pressure at peak flow decreased from 37 cm H2O to 25 cm H2O. Other characteristics still showed no apparent change, and detrusor overactivity was absent after the excision procedure. In addition, the number of women exhibiting urethral hypermobility (n = 5) remained unchanged after urethrolysis.

The mean time from TVT operation to takedown of the tape was 28 days (range 4 to 108). Five patients (71.4%) remained continent after the excision procedure. One (14.3%) had mild stress incontinence requiring no treatment and was considered improved compared with pre-TVT baseline. The remaining 1 (14.3%) reported complete recurrence of stress incontinence equal to the initial condition 11 months after takedown, and did not desire additional surgical intervention. Five continent women underwent sling excision 15 to 108 days after the TVT procedure, and the corresponding figures for the 2 recurrent women were identical: 4 days.


   DISCUSSION
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Based on integral theory, dorsal compression of the urethra should not occur during the TVT procedure.3–4 It is, however, difficult to determine the ideal distance between the tape and urethra for a new TVT performer. Some authors have suggested inserting a Kelly clamp between urethra and tape to prevent voiding dysfunction.8 In our study, iatrogenic obstruction occurred in 5 (71.4%) of the first 15 cases; another 2 obstructions occurred in the 23rd and 36th cases, indicating the existence of a learning curve for the procedure. This also accounted for the higher rate of urethral obstruction (9.9%) in our study.

The optimal assessment of the patients with iatrogenic obstruction remains unclear. Several studies have found that urodynamic parameters alone do not predict the outcome of urethrolysis, and 10% to 64% of patients in retention could not show a detrusor contraction during pressure flow studies.5,16 In the present study, we defined urethral obstruction on the basis of urodynamic criteria of Groutz et al (detrusor pressure at peak flow more than 20 cm H2O and maximum flow rate less than 12 mL/s).14 As a result, 1 patient (14.3%) without a detrusor contraction was deemed equivocal for obstruction, yet she responded well to the excision. This implies high-pressure low-flow voiding urodynamics do prove the obstruction, but they are not a consistent finding. We believe videourodynamic testing is more appropriate in this entity due to the direct image of the bladder outlet.17 In addition, cotton-tipped swab tests seem to be unreliable in predicting the results of tape incision due to the limited effect of the TVT on urethral mobility.18

As with other anti-incontinence surgery, TVT may bear the low risk of postoperative voiding dysfunction. The majority of scenarios can be successfully managed by conservative methods, including medications, intermittent catheterization, timed toileting, pelvic muscle exercises, or Hegar dilation.19 Once symptomatic urethral obstruction is confirmed, release of the TVT tape is necessary. Similarly, all of the 7 women with iatrogenic obstruction required surgical release of the TVT tape in our study. Most investigators preferred transvaginal urethrolysis rather than retropubic or suprameatal approaches, because the procedure is simpler and easier.5–7,10–13 In a patient undergoing retropubic urethropexy, perforation of the endopelvic fascia may be required to free the urethra on all sides, because the scarred area is between the pubis and urethra. In a TVT procedure, however, full urethrolysis seems to be unnecessary due to the obstructive mechanism of dorsal compression.

Other authors have suggested inserting a clamp to spread the plane between the tape and urethra before midline incision, and one urethral laceration occurred in their study.20 In our experience, lateral tape excision can be performed smoothly without wide dissection, which minimizes blood loss. As a result, the tape was slightly retracted but not mobilized off the periurethral fascia, leaving a holding effect of a "J" shape tape without disturbance of lateral support. A lateral excision might be particularly beneficial to avoid urethral injury in cases whose tape can be identified.

Mclennan and Bent21 performed a transvaginal sling incision and interposition of new biologic material in 4 women with urinary retention. The success rate was 100%, but stress incontinence recurred in 25% of cases. Amundsen et al22 reported good results in 8 patients who underwent midline sling incision without further dissection. Recently, Kusuda reported successful resolution of obstructive symptoms in 5 women undergoing lateral sling incision.12 Similarly, Defreitas et al23 had a success rate of 94% in 16 women with lateral incision, but a 34% rate of stress incontinence recurred. Our success rate of 100% and recurrent stress incontinence rate of 28.6% are similar to these studies.

Goldman suggested that postincision residual irritative symptoms are related to a longer interval between initial surgery and takedown.20 In addition, some investigators found that autologous rectus fascia slings might not be identified due to dense fibrosis in 9 of 12 patients.22 We did not encounter these conditions in our study, and cutting procedures invariably presented no difficulty. This may be due to the use of different tape material as well as the shorter interval to excision (average 28 days, range 4 to 108 days) in our study. Our success rate of 100% compares favorably with other reports. Only 1 patient had mild residual irritative symptoms after takedown of the tape, but she improved above pre-TVT baseline. Another interesting finding was that stress incontinence recurred in 2 patients (28.6%) with the shortest interval of 4 days to excision. The excision procedures were performed because of patients’ strong request. The other 5 patients with intervals longer than 14 days (range 15 to 108) remained continent during an average of 32 months of follow-up.

The results of our study suggest that urethral obstruction after TVT is a relatively uncommon condition, and can be effectively treated with transvaginal lateral excision of tape. In most cases, the lateral excision procedure does not compromise overall improvement of stress incontinence, and its results are comparable to those of midline excision. However, an interval of longer than 14 days between initial surgery and takedown is suggested. It is unclear whether postexcision continent women will remain free of stress incontinence in the long term. Further prospective studies and longer follow-up will be helpful to assess how long the continent results will be sustained.


   Footnotes
 
Received April 9, 2004. Received in revised form July 25, 2004. Accepted August 5, 2004.

doi:10.1097/01.AOG.0000146282.51404.93


   REFERENCES
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
1. Nilsson CG, Kuuva N, Falconer C, Rezapour M, Ulmsten U. Long-term results of the tension-free vaginal tape (TVT) procedure for surgical treatment of female stress urinary incontinence. Int Urogynecol J Pelvic Floor Dysfunct 2001;12(suppl):5–8.

2. Alcalay M, Monga A, Stanton SL. Burch colposuspension: a 10–20 year follow-up. Br J Obstet Gynaecol 1995;102:740–5.[Medline]

3. Petros P, Ulmsten U. Intravaginal slingplasty: an ambulatory surgical procedure for treatment of female urinary incontinence. Scand J Urol Nephrol 1995;29:75–82.[Medline]

4. Petros P, Ulmsten U. An integral theory and its method for the diagnosis and management of female urinary incontinence. Scand J Urol Nephrol Suppl 1993;153:1–93.[Medline]

5. Nitti VW, Raz S. Obstruction following anti-incontinence procedures: diagnosis and treatment with transvaginal urethrolysis. J Urol 1994;152:93–8.[Medline]

6. Foster HE, McGuire EJ. Management of urethral obstruction with transvaginal urethrolysis. J Urol 1993;150:1448–51.[Medline]

7. Cross CA, Cespedes RD, English SF, McGuire EJ. Transvaginal urethrolysis for urethral obstruction after anti-incontinence surgery. J Urol 1998;159:1199–201.[Medline]

8. Wang KH, Neimark M, Davila GW. Voiding dysfunction following TVT procedure. Int Urogynecol J Pelvic Floor Dysfunct 2002;13:353–7.[Medline]

9. Rardin CR, Rosenblatt PL, Kohli N, Miklos JR, Heit M, Lucente VR. Release of tension-free vaginal tape for the treatment of refractory postoperative voiding dysfunction. Obstet Gynecol 2002;100:898–902.[Abstract/Free Full Text]

10. Petrou SP, Brown JA, Blaivas JG. Suprameatal transvaginal urethrolysis. J Urol 1999;161:1268–71.[Medline]

11. Ghoniem GM, Elgmasy AN. Simplified surgical approach to bladder outlet obstruction following pubovaginal sling. J Urol 1995;154:181–3.[Medline]

12. Kusada L. Simple release of pubovaginal sling. Urology 2001;57:358–9.[Medline]

13. Nitti VW, Carlson KV, Blaivas JG, Dmochowski RR. Early results of pubovaginal sling lysis by midline sling incision. Urology 2002;59:47–52.[Medline]

14. Groutz A, Blaivas JG, Chaikin DC. Bladder outlet obstruction in women: definition and characteristics. Neurourol Urodyn 2001;19:213–20.

15. Blaivas JG, Groutz A. Urinary incontinence: pathophysiology, evaluation, and management overview. In: Walsh PC, Retik AB, Vaughan ED, Wein AJ, editors. Campbell’s urology. 8th ed. Philadelphia (PA): Saunders; 2002. p. 1038.

16. Carr LK, Webster GD. Voiding dysfunction following incontinence surgery: diagnosis and treatment with retropubic and transvaginal urethrolysis. J Urol 1997;157:821–3.[Medline]

17. Nitti VW, Tu LM, Gitlin J. Diagnosing bladder outlet obstruction in women. J Urol 1999;161:1535–40.[Medline]

18. Klutke JJ, Carlin BI, Klutke CG. The tension-free vaginal tape procedure: correction of stress incontinence with minimal alteration in proximal urethral mobility. Urology 2000;55:512–4.[Medline]

19. Lo TS, Wang AC, Horng SG, Liang CC, Soong YK. Ultrasonographic and urodynamic evaluation after tension free vagina tape procedure (TVT). Acta Obstet Gynecol Scand 2001;80:65–70.[Medline]

20. Goldman HB. Simple sling incision for the treatment of iatrogenic urethral obstruction. Urology 2003;62:714–8.[Medline]

21. McLennan MT, Bent AE. Sling incision with associated vaginal wall interposition for obstructed voiding secondary to suburethral sling procedure. Int Urogynecol J Pelvic Floor Dysfunct 1997;8:168–72.[Medline]

22. Amundsen CL, Guralnick ML, Webster GD. Variations in strategy for the treatment of urethral obstruction after a pubovaginal sling procedure. J Urol 2000;164:434–7.[Medline]

23. Defreitas G, Herschorn S. Unilateral pubovaginal sling release: a minimally invasive transvaginal approach. J Urol 2000;163(suppl):74.




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 Obstet GynecolHome page
C. Y. Long and E. M. Tsai
Lateral Excision of Tension-Free Vaginal Tape for the Treatment of Iatrogenic Urethral Obstruction
Obstet. Gynecol., June 1, 2005; 105(6): 1491 - 1492.
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 Obstet GynecolHome page
H. Phillip and P. Tooz-Hobson
Lateral Excision of Tension-Free Vaginal Tape for the Treatment of Iatrogenic Urethral Obstruction
Obstet. Gynecol., June 1, 2005; 105(6): 1490 - 1491.
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