Lower urinary tract injuries after transobturator tape insertion by different routes: a large retrospective study

Authors

  • M Abdel-Fattah,

    Corresponding author
    1. Urogynaecology Unit, South Glasgow University Hospitals NHS Trust, Glasgow, UK
      M Abdel-Fattah, Urogynaecology Unit, South Glasgow University Hospitals NHS Trust, 1345 Govan road, Glasgow G51 4TF, UK. Email mohamed.abdelfattah@sgh.scot.nhs.uk
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  • I Ramsay,

    1. Urogynaecology Unit, South Glasgow University Hospitals NHS Trust, Glasgow, UK
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  • S Pringle

    1. Urogynaecology Unit, South Glasgow University Hospitals NHS Trust, Glasgow, UK
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M Abdel-Fattah, Urogynaecology Unit, South Glasgow University Hospitals NHS Trust, 1345 Govan road, Glasgow G51 4TF, UK. Email mohamed.abdelfattah@sgh.scot.nhs.uk

Abstract

Objectives  To identify the rate of, and risk factors for, lower urinary tract (LUT) injuries associated with the transobturator tension-free vaginal tape (TOT) procedure.

Design  Retrospective cohort study.

Setting  Tertiary referral urogynaecology centre.

Population  390 women who underwent transobturator suburethral tapes for management of urodynamic stress incontinence between July 2002 and January 2006.

Methods  Early cases were identified from theatre records and a case note review performed. From May 2005 (n= 94), data from an ongoing prospective audit were reviewed. Data for LUT injuries with TOT procedures were examined and routes of insertion were compared using Fischer’s exact test.

Main outcome measures  Rate of LUT injuries associated with the TOT procedures. Assessment of factors increasing risk of LUT injury, and comparison of the ‘outside-in’ and ‘inside–out’ techniques.

Results  241 women underwent TOT outside–in technique and 148 of them underwent inside–out technique. Four LUT injuries occurred (1%): two urethral injuries (0.5%) and two bladder injuries (0.5%). All LUT injuries occurred in the outside–in group, although this difference did not reach significance (P= 0.146). Bladder injuries occurred in women who underwent concomitant vaginal surgery, while urethral injuries occurred in women undergoing secondary procedures.

Conclusion  LUT injury is an uncommon complication of the TOT procedures, and in our hands only occurred with the outside–in technique. Intraoperative cystoscopy should be considered only in selected cases.

Introduction

The transobturator tension-free vaginal tape (TOT) is a relatively new procedure devised for the surgical treatment of urodynamic stress incontinence (USI). It consists of an entirely perineal insertion of a suburethral tape, placed at the midurethral level. It therefore keeps the principle of a minimally invasive procedure to reinforce the structures supporting the urethra, initially described in the tension-free vaginal tape procedure (TVT),1 while avoiding blind entry into the retropubic space and therefore theoretically minimises the risk of injury to the bladder, intestine, major vessels and nerves.

In 2001, Delorme2 described the transobturator tape using an ‘outside–in’ technique, in which the tape is inserted in a horizontal plane underneath the middle of the urethra between the two obturator foramina. The tape is tunnelled percutaneously around the inferior pubic ramus, and then guided by the surgeons’ finger into the suburethral vaginal incision. The authors presented a series of 150 women with stress urinary incontinence (without associated prolapse), and reported no case of lower urinary tract (LUT) injury and concluded that cystoscopy is not required, as the retropubic space is preserved intact.2 Delorme2 used Uratape® (Mentor- Porges, Le Plessis Robinson, France) mesh, a multifilament microporous mesh with pores <10 μm. However, this tape was associated with a high incidence of vaginal erosions and was later withdrawn from the market and replaced with the Obtape® (Mentor-Porges, Le Plessis Robinson, France), a nonelastic, laser cut, thermally bonded, monofilament polypropylene mesh, with pore size of 50 μm (macroporous). Since then different companies have produced various tapes: (Monarc®—American Medical Systems Inc., Minnetonka, MN, USA; Obtryx®—Boston Scientific, Natick, MA, USA; Uretex®—Bard; ARIS™—Mentor- Porges, Le Plessis Robinson, France) using the same outside–in TOT technique with minor modifications such as helical introducers and utilising different mesh materials in the tape.

The technique was later modified in 2003 by De Leval3 to allow the insertion of the transobturator tape with an ‘inside–out’ technique, using a ‘wing guide’ during the dissection of the paraurethral tunnel, for further protection of the LUT. De Leval3 used the same mesh used in TVT™ (Gynaecare, Jhonson & Jhonson, Berks, UK) (a monofilament macroporous, knitted, polypropylene mesh with pore size >75 μm) and presented a series of 107 women (including 33 women with associated prolapse), again without a case of LUT injury and concluded that cystoscopy is not required.3 This group re-emphasised that cystoscopy was not needed in their recent study on cadavers.4

Recently, there have been isolated case reports of LUT injury with the TOT procedure published.5–8 This study aims to identify the rate of, and risk factors for, LUT injuries associated with the transobturator approach for tension-free vaginal tapes and consequently the need of cystoscopy in this procedure. We also compare the incidence between the outside–in versus inside–out techniques. Clinical presentation, management and outcome of LUT injury cases are presented.

Patients and methods

This was a retrospective study of all women who had transobturator suburethral tension-free vaginal tapes for management of USI in a tertiary referral centre in the southwest of Scotland, over a 42-month period, July 2002 to January 2006. Subjects were identified from theatre records, and case notes were retrieved and reviewed. For the latter cases from May 2005 onwards (n= 94), we also reviewed the data from an ongoing prospective audit of these procedures. In our department, the transobturator approach has been the first choice approach for tension-free vaginal tapes since July 2003. This followed an internal audit in our unit that showed similar short-term cure rates to TVT™, but lower perioperative morbidity and a shorter learning curve. Two types of tapes have been used almost exclusively; Obtape® and TVT-O™, with the choice of tape being primarily decided by surgeon preference. In July 2005, we stopped using the Obtape® in favour of the new Porges-Mentor ARIS™ tape (a macroporous, knitted, monofilament polypropylene tape) due to high erosion rates associated with the Obtape®.9 Procedures were done as originally described.2,3 Raw data for LUT injuries with transobturator tapes, in general, are presented and both routes of insertion are compared using Fischer’s exact test (SISA 1989–1997, 2000).

Results

390 women underwent a transobturator tape procedure during the study period, of which 111 were associated with another surgical procedure (Table 1). One case note for a woman who underwent a TOT outside–in (as a sole procedure) could not be traced within the time frame of the study, leaving 389 women for analysis.

Table 1.  Types of procedures performed
ProcedureOutside–in, n= 241 (%)Inside–out, n= 148 (%)Total, n= 389 (%)
  • *

    Concomitant procedures were almost exclusively prolapse surgery, with a small number of women having an abdominal hysterectomy.

Sole163 (67.6)115 (77.7)278 (71.5)
Concomitant*78 (32.4)33 (22.3)111 (28.5)
Primary148 (61.4)124 (83.8)272 (70)
Secondary93 (38.6)24 (16.2)117 (30)

Table 1 shows the number of women who underwent each type of tape and whether or not this was performed as a sole procedure or along with a prolapse repair. 70% of the cases were done as primary continence surgery, compared with 30% secondary procedures following previous continence or prolapse surgery. Of the 241 women who underwent the outside–in technique, 192 (79.7%) had Obtape® inserted, 37 (15.4%) had ARIS® tape, four had Obtryx® transobturator tape and eight underwent Monarc® transobturator tape.

Four women (Table 2) in total were identified with LUT injury (1%): two women with urethral injury (0.5%) and two with bladder injury (0.5%). All the four women were in the outside–in group (1.7%), out of which three were associated with another procedure (anterior colporrhaphy n= 2, vaginal hysterectomy and anterior and posterior colporrhaphy n= 1).

Table 2.  Cases of lower urinary tract injuries: demography, diagnosis, management and outcome
 Case 1Case 2Case 3Case 4
  1. OAB, overactive bladder; DO, detrusor overactivity; UDS, urodynamics.

Age42684656
Parity3412
TechniqueOutside–inOutside–inOutside–inOutside–in
Type of tapeARIS–MentorObtape–MentorObtape–MentorObtape–Mentor
PrimaryNoNoYesYes
Previous surgeryAnterior Repair; Manchester Repair and TOT (Obtape)ColposuspensionNilNil
Sole procedureYesNoNoNo
Associated proceduresNilVaginal hysterectomy and anterior colporraphyAnterior colporraphyAnterior colporraphy
Type of injuryUrethral injuryUrethral injuryBladder injuryBladder injury
When injury occurredWith suburethral incisionWith suburethral incisionAt dissection for left paraurethral tunnelInsertion of right arm of tape
Surgeon experienceAt beginning of learning curveAt beginning of learning curveExperienced urogynaecologistExperienced urogynaecologist
When and how recognisedIntraoperatively by seeing the catheterIntraoperatively by seeing the catheterIntraoperativelyPostoperative haematuria
ManagementUrethra closed in two layersUrethra closed in two layersBladder closed in two layersCystoscopic resection of tape
Tape insertedYesYesYesYes
Other complicationsNoNoNoNo
Days of catheterisation101010None
OutcomeContinent at 3-month UDS: no USIIncontinent at 3-month UDS: mixed USI and DOUSI cured, OAB symptoms at 3-month follow upPersistent USI
Further ManagementNilConservative Management antimuscarinicAntimuscarinic treatmentTVT-O inserted 7 months later. Continent at 2-month follow up

Both women with urethral injury (Table 2) occurred in secondary procedures, where it was noted that the anterior vaginal wall was extremely thin and fibrosed. In one woman, this occurred following three previous vaginal procedures; (anterior repair, Manchester repair and failed TOT), while in the other woman the vaginal wall was fixed with difficult access due to a previous colposuspension. In both women, the injury occurred at time of suburethral incision and prior to the tape insertion. The urethral injury was closed in two layers, and the procedure completed with the tape inserted and adjusted tension free. A urethral catheter was left in situ for 10 days.

Both women with bladder injury occurred during primary continence procedures, but at the time of concomitant vaginal surgery. In one woman, the injury occurred at the time of left paraurethral tunnel creation and prior to tape insertion. The injury was diagnosed immediately, repaired in two layers, and the procedure completed with postoperative urethral catheterisation for 10 days. In the other women, the tape perforated the bladder at time of right arm of the tape insertion. This was not suspected surgically and was diagnosed with persistent postoperative haematuria and severe overactive bladder symptoms. Cystoscopic resection of the tape was performed 2 weeks postoperatively. This woman underwent TVT-O for persistent USI 7 months later and was subjectively dry on follow up a further 2 months later (Table 2).

Nine different consultants and their registrars, with varying degrees of experience performed the 389 procedures. The two cases of urethral injury occurred at the beginning of the learning curve of a senior registrar, while the two cases where bladder injury occurred were performed by experienced urogynaecologists.

When we compared the outside–in approach with the inside–out approach, all the injuries occurred in the outside–in group. This difference was not significant (P= 0.146). However, the numbers in both groups were smaller than those required to detect a difference with statistical significance. Considering that the rates of LUT injuries with these procedures are generally low, 284 women in each arm would be needed to detect 3% difference between both routes, with 80% power.

Discussion

The relatively safe insertion technique and the low perioperative morbidity described in the short to intermediate follow-up trials have led to the increasing popularity of the transobturator suburethral tapes in the treatment of USI10. The majority of the current literature supports insertion of a TOT, both outside–in and inside–out techniques, without the need of cystoscopy. Dargent et al.11 and Spinosa and Dubuis12 reported on 71 and 117 cases of TOT respectively, using the outside–in technique. They performed cystoscopy in all cases, and there were no cases of LUT injuries. Recently, Deval et al.13 confirmed the same findings in their prospective series of 129 women.

Comparing TOT outside–in with TVT™, all the studies have shown significantly lower rates of bladder injuries in the TOT groups. de Tayrac et al.14 in a randomised trial, showed no bladder perforations in the TOT group compared with 10% in the TVT™ group. Mellier et al.15 reported exactly the same figures, although in their series they had one case of urethral injury in the TOT group (1%). Fischer et al.16 have also shown lower rates of bladder perforations: 0.5 versus 4.5% in TOT and TVT™, respectively. More recently, David-Montefiore et al.,17 who performed routine cystoscopy in all the cases, reported a significantly higher rate of bladder injury in the TVT™ group compared with the TOT group (4/42 versus 0/46). There are no studies reported that compare the inside–out technique with the TVT™.

Case reports of bladder injury after TOT procedures have been reported.5–8 Roumeguere et al.18 have reported three urethral (2.5%) and one bladder (0.8%) injury in their series of 120 women who underwent a TOT outside–in procedure, including ten cases performed with an associated vaginal repair procedure. They mentioned that all injuries occurred at the beginning of the surgeons’ learning curve. However, there were no details mentioned as regards when the injury occurred, or of other risk factors such as concomitant surgery or previous vaginal surgery.

In this study, the largest independent series reported to date, we observed LUT injuries in 1% of cases, equally divided between bladder (0.5%) and urethral injuries (0.5%). The two cases of urethral injury that occurred during the time of suburethral incision are believed to be directly related to the thin and fibrous nature of the vaginal wall due to repeated vaginal surgery in one case and to the fixation and lack of vaginal wall mobility following colposuspension in the other.

Both cases of bladder injury in this study occurred in women undergoing primary continence surgery and were directly related to the transobturator surgical approach. One case occurred during creation of the lateral dissection towards the left obturator area. This case was associated with marked cystocele secondary to a lateral defect, which could have led to a defect in the fixation of the endopelvic fascia at the level of the arcus tendineus, leaving room for the bladder base to sink into the paravaginal space and therefore exposed to injury. However, cystocele was present in 40 women in this series, with only one case of bladder injury. In the other case, the bladder injury occurred during insertion of the right arm of the TOT. This was only diagnosed 2 weeks postoperatively with urgent cystoscopy, due to persistent haematuria and marked de novo urgency. Extra vigilance should be given to cases where postoperative haematuria occurs, even if it is mild.

Concomitant procedures and previous vaginal surgery appear to be risk factors for LUT injuries with TOT and therefore extra care should be taken during the incision and dissection. We found the presence of a size 16 Foley catheter during dissection of valuable help in immediate diagnosis of both cases of urethral injury. Our practice is to insert the TOT prior to any concomitant surgery, however, the adjustment of the tape is done at the end of all procedures to avoid any effect that the change in the vaginal axis may have on the tension of the tape. It is not clear whether the increased risk of bladder injury is due to the concomitant procedure or indeed due to the associated prolapse.

It could be that the learning curve experience with TOT contributed to the women with urethral injury, but the injuries occurred at the time of the suburethral incision rather than at the tape insertion, and the surgeon was quite experienced with suburethral tapes in general; therefore, it is unlikely to be an experience issue. Moreover, the cases of bladder injury occurred with two experienced urogynaecologists. The two urethral injuries and one bladder injury were detected immediately during the procedure and managed with repair, and the TOT procedure was completed. Only one woman (bladder injury) went unrecognised and would have been diagnosed using perioperative cystoscopy had the significance of mild postoperative haematuria been realised.

It could be debated whether inserting a suburethral tape following the repair of a urethral injury is wise, given the theoretical increase in risk of a fistula or urethral erosion. We feel, however, that if a sound two-layer urethral repair is achieved, the insertion of an entirely tension-free transobturator tape should not increase the above risks; therefore, the procedures in this series were completed, and the tapes were inserted. Neither case was complicated by urethral erosion or fistulae. In the woman with a bladder injury, it was believed that insertion of the tape would not compromise the healing of the bladder repair.

In this series of 389 women, routine intraoperative cystoscopy would have detected only one woman with undiagnosed bladder injury. In our opinion, intraoperative cystoscopy should be considered in women who have concomitant vaginal surgery for prolapse, previous repeated vaginal surgery or where the TOT procedure is considered difficult. Furthermore, surgeons inexperienced with this approach might wish to consider cystoscopy routinely. In the immediate postoperative period, cystoscopy might be a wise precaution in women with haematuria to rule out any occult bladder or urethral injury. Likewise, if severe and worsening bladder symptoms develop, cystoscopy to exclude the presence of tape in the bladder should be considered.

Conclusion

LUT injury is an uncommon complication of the transobturator tape, which in our hands occurred only with the outside–in procedure. Intraoperative cystoscopy should be only considered in selected women. Postoperative problems such as haematuria should raise the suspicion of LUT injury and warrant immediate cystoscopy.

Ancillary