This paper reviews the background, development and clinical and urodynamic results of mid-urethral tapes (MUTs) from the first, which was the tension-free vaginal tape (TVT), to the development of the next generation of MUTs, the transobturator tapes. Many of the results of the clinical studies are not statistically significant because of small numbers and an inadequate length of follow up. Overall the MUTs are an important advance on the conventional and more invasive continence surgery, needing only a local or spinal anaesthetic with 24-h hospitalisation and a rapid recovery and return to work. The longest follow up studies indicate good continuation rates for continence, with minimal postoperative and follow up complications. Because of the potential for tape erosion, careful subjective and objective long-term follow up should be maintained.
The brilliant and innovative concept of the correction of urethral sphincter incompetence (USI) was described by Ulmsten et al. in 1996.1 The underlying theory was proposed by Petros and Ulmsten in 1990,2 leading to intense animal and clinical studies and resulting in the first commercial device, the TVT (Gynecare, Johnson and Johnson). Its basis is mid-urethral support, challenging the previous concept of bladder neck elevation, as the mode of correction of USI. It is likely that both mechanisms can work, although the latter is more likely to lead to voiding disorders.
The procedure is simple, safe, effective and speedy, and can be carried out under local anaesthetic with sedation, epidural or general anaesthetic. The tape does not have to be sutured in place and no catheter is required, unless there has been bladder penetration or other surgical procedures are involved. It can be a day-case or 24-h stay procedure. There are minor peri-operative complications, and the cure rate at 5 years is 85%,3 falling to 81% at 7 years.4
The currently available MUTs are shown in Table 1 and include the newer obturator tapes, which pass horizontally from one obturator fossa to the other.
The TVT was the first commercially available MUT and remains a market leader (Fig. 1). The tape is made of monofilament polypropylene with a pore size of 50 microns. It is placed by vaginal insertion only, and published papers confirm the ease of operability, minimal operative and postoperative complications and satisfactory long-term cure rate. Perhaps the best designed and thorough multi-centre surgical randomised controlled trial (RCT) was from Ward and Hilton,5,6 comparing the TVT and colposuspension (Table 2).
|TVT 175 ? 125||Colpo 169 ? 101|
|Neg pad||81% TVT 80% Colpo|
|BFLUTS||No leaks: 25% TVT, 20% Colpo|
|SF-36||Significantly lower scores for Colpo|
|Prolapse||Significant reduction in cystocele, more enterocele/cervical prolapse for Colpo|
|Void diff||More self-cath with Colpo|
|Prospective study 313 patients: FU mean 21.4 m|
|Urodynamics at 3 m. 50% combined prolapse|
|4% 2° surgery|
|5% bladder perforation|
|2.5% postop voiding difficulties|
|1.3% vaginal erosion|
|8.3% de novo urge incontinence|
|Cure USI: subjective 93.4%|
Yeni et al. (2003) studied the effect of TVT on sexual function in 32 sexually active women with urethral sphincter incompetence, and 24 controls.8 The index of female sexual function (IFSF) was used as a scoring notation. They found no change in the desire and arousal but orgasm, overall satisfaction and pain decreased. The incidence of coital incontinence fell from 28% to 6%.
In the UK NICE (National Institute of Clinical Excellence), the UK regulatory body, has stated in its guidance that ‘TVT may be used when conservative management has failed, and should take into account whether the family is complete’.9 Whilst this is a recommendation, it seems to ignore the wishes of some patients who might prefer an ‘instant’ cure rather than wait for pelvic floor exercises to work. Similarly some might feel that their incontinence is bad enough between pregnancies to warrant treatment at that stage knowing that, if the TVT is successful, they may have to undergo an elective Caesarian section subsequently to preserve the continence mechanism.
The disadvantages of the TVT include an awkward disposable handle – far better to have retained the original TVT with the re-usable handle – and, more importantly, the tape when pulled can narrow and shred at its edges.
In response to concern that the sharp needle insertion for the TVT is traumatic, TYCO developed its Intravaginal Sling (IVS) tunneller. The technique is similar to the TVT. The tunneller has a blunt tip (Fig. 2) and is disposable. The tape is made of knitted polypropylene polymer, designed to elicit minimal inflammatory response whilst encouraging fibrous tissue ingrowth. As yet there have been no RCTs, but mostly anecdotal reports. Ingeniously, the same inserter and tape may be used for vaginal vault prolapse as a posterior intravaginal sling.
Both TVT and IVS are inserted vaginally. Some clinicians feel that a ‘top–down’ insertion, from the supra-pubic region to the vagina, is safer and allows the operator greater control and less chance of bladder injury. In addition, a single cystoscopy is all that is required to exclude bladder injury. American Medical Systems (AMS) designed the tape known as ‘SPARC’, which could be passed from above. Two needles are used, and after both have been inserted the patient is cystoscoped and if there is no bladder injury the tape can then be attached at the vaginal site, withdrawn up to the supra-pubic area and then adjusted for tension. The needles are 3 mm in diameter and much smaller than those used for either TVT or IVS, and the tape has the advantage that it has a knotted resorbable tensioning suture running longitudinally through its length, which prevents the tape being over-stretched and leading to shredding. This is particularly useful if additional repositioning is required. However, the needles are quite thin and ‘whippy’, and are not as comfortable to direct compared with those of the TVT or IVS.
|104 women, mean FU 11.9 m, mean op time 30 min10|
|Objective cure 90%||Subjective cure 72%|
|Bladder injury 9%||de novo urge 10%|
|Voiding difficulty 11%|
|98 women, FU 12 m, mean op time 16 min11|
|Objective cure 80%||Subjective cure 83%|
|Bladder and urethral injury 10%||de novo urge 7%|
|Voiding difficulty 4%|
URETEX, manufactured by Bard, uses a unique PVC guide-wire to insert the tape, which can be carried out either from the vaginal aspect or the supra-pubic aspect, or using a mix of both routes. The tape is 12 mm wide, made of knitted polypropylene and covered with a PTFE placement sheath. The tape does not shred or curve under tension, and uses a 4-mm diameter needle for insertion. Giolitto et al.12 reviewed 249 women at follow up of 1 year and found that 94% were improved; there were two haematomas, 14 patients had a bladder perforation, 13 patients had a urinary tract infection, two patients had a urethral erosion and 36 patients had a temporary voiding difficulty. Clearly a longer and more objective follow up is required. A trans-obturator device has now been manufactured, using the same tape. Results are not yet available.
SAFYRE (Promedon) is a further device using a vaginal or supra-pubic route. The tape is pierced polypropylene mesh placed between two silicone columns made of multiple cone-shaped subunits, which anchor the tape in position without causing any local fibroblast interaction. The handle is re-usable, the needle diameter is 4.9 mm and the mesh width is 15 mm. A guide is used to deflect the bladder neck and urethra away from the needle as it is inserted. Because of lack of adhesion to the silicone columns the manufacturers claim that tape tension can be altered at any time after the initial surgery. Herrmann et al.13 studied 128 women of whom 55% had secondary surgery. At 9 months follow up 91% were cured, with a bladder perforation rate of 2.3%, voiding difficulties in 3.1% and transient urgency in 20%.
SABRE (Mentor) is a bio-absorbable polymer sling which is bio-compatible and broken down within the body. It is inserted through a vaginal incision, using a guide to direct the bladder neck away from the path of the needle. Herrmann et al.14 reviewed 20 women, followed up for 5 months, and found that 70% were cured. There were no complications. Again, the numbers are small, the follow up slim and more data are required.
In response to concerns that the retro-pubic passage of a needle carried with it the potential complication of bladder or urethral injury, Delorme described a trans-obturator tape that passed horizontally under the urethra and therefore was less likely to injure it (Fig. 3).15 The tape is made of heat-soldered monofilament nonwoven polypropylene with a pore size of 50 microns. It does not shred or curl when under tension, and is inserted by a single tunneller – a specially curved needle with a blunt tip and an eye for the tape to be passed through (Fig. 4). The patient is placed in the lithotomy position, in hyperflexion with thighs bent back on the abdomen at an angle of 120°. A similar incision in the vagina to that of other MUTs is used, situated over the middle third of the urethra, and at either side a tunnel is dissected up to the ischio-pubic ramus in the deep tissue layer between the vesico-vaginal fascia and the urethra. Next the lateral margin of the ischio-pubic ramus is identified and an incision is made on a horizontal line level with the clitoris. The tunneller is inserted across the obturator membrane and then turned horizontally to meet a finger inserted into the vaginal incision, which then guides the tunneller through and is able to keep this well away from the urethra or bladder, thus a cystoscopy is not needed afterwards. The tape is then inserted into the eye of the needle and withdrawn to the outside of the vulva. The procedure is repeated on the other side. The tape is adjusted to be tension-free behind the urethra, surplus tape is excised and the vaginal wounds closed. A catheter is not necessary, and the usual postoperative routine is observed. There is no risk to major vessels and the procedure is ideal for patients who have had previous retro-pubic surgery, particularly a sling, a Marshall Marchetti Krantz or a colposuspension. It is also ideal for any patient who has had any orthopaedic surgery to the symphysis pubis. Hampson-Evans noted that patients having a local anaesthetic and sedation required far less sedation for an Obtape compared with retro-pubic needle procedures (D. Hampson-Evans, personal communication, 2003).
The results of a 17-month follow up are shown in Table 5. Once the technique has been learnt, surgery lasted less than 15 min. Table 6 shows the results of a prospective randomised study comparing transverse obturator tape and TVT.16
|Prospective randomised study|
|102 patients FU 6.2 m|
|Complications more common with TVT|
|Bladder perforations (5) urethral injury (1)|
|Cure of USI, UI and frequency is similar|
|Retention, TVT (5) TOT (1)|
|TOT, no risk to bowel or major vessels|
American Medical Systems have developed their trans-obturator tape, called MONARC. It is made of monofilament polypropylene with a mid-line suture to allow further tensioning so that it does not shred. Jacquetin et al.17 reported 3 months' data on its use in 120 patients in a multi-centre international trial, with an intended 24-month follow-up. There was a significant reduction in postoperative pad weight and a significant improvement in patient QOL. 3.3% needed surgical revisions to release sling tension or remove slings, urinary infection occurred in 4.2% and urge incontinence occurred in just one patient. Recurrent incontinence was noted in two patients, and two patients had temporary urinary retention. Clearly these results, whilst promising, need to be reviewed at 2-year follow-up.
A new TOT procedure (TVT obturator, Gynecare) by de Leval to minimize urethral and bladder injury uses an ‘inside-out’ approach.18 A routine 1 cm vertical vaginal incision is made 1 cm proximal to the urethral meatus. Using scissors, lateral dissection under the vaginal mucosa proceeds to the ischio-pubic ramus; the obturator membrane is perforated and then a specially designed three-part introducer is inserted along the track, to emerge through the obturator foramen and then lateral to the labium majus. The tape (monofilament polypropylene, Gynecare) is passed through each helical introducer to the outside. de Leval's series describes 107 patients followed for just 1 month; 16% had had previous continence or prolapse surgery. There were no peri-operative complications but postoperatively one patient developed an erosion, three patients had urinary retention requiring a tape release procedure (no sectioning) and two patients had severe postoperative pain. There was no indication of the success of the operation. Clearly this technique needs a longer and a subjective and objective follow up; it is more complicated than its competitors, needing to use a left and a right introducer, with each introducer consisting of three parts. There is no substantive evidence that it is any safer than its TOT colleagues.