The last two decades have witnessed the launch of new surgical procedures, utilizing kits and synthetic materials, at a pace not formerly seen. Some launches have been preceded by thorough clinical documentation, others not. Any innovation, be it a theory or a treatment concept, is only fantasy until it has been tested and clinically documented.

Within the field of surgical management of female stress urinary incontinence the presentation of the mid-urethral theory (a part of the integral theory [1]) implied a paradigm shift of understanding of the mechanism of stress incontinence. The theory relied on discoveries and ideas presented between the 1950s and the 1980s by several clinicians, such as Axel Ingelman-Sundberg [2], Robert F. Zacharin [3, 4], and Ulf Ulmsten [5–7], just to mention a few. The theory was put into practice by a team led by Professor Ulf Ulmsten by developing a new minimally invasive, ambulatory, standardized surgical procedure to be named tension-free vaginal tape (TVT) at the time of its launch in Europe at the end of 1997 and in the USA at the end of 1998.

Several modifications of the procedure were tested before arriving at the final one, which included the use of a monofilament polypropylene tape with a mesh structure and a pore size of >75 μm.

Once the procedure was finalized the first prospective clinical trial was conducted at the Department of Obstetrics and Gynecology of the University Hospital of Uppsala, Sweden, of which Professor Ulmsten was the chairman. The trial included 75 primary cases of stress urinary incontinence that were followed for 24 months. The results, published in 1996, were very encouraging [8] and prompted further prospective clinical trials conducted in normal clinical settings. At this stage, it was decided to follow the same study protocol in all the trials to come.

The pre- and post-operative evaluations were to include urodynamic testing, a cough stress test, a 24-h pad-weighing test, a 2-day voiding diary, residual urine measurement, urine analysis, pelvic examination, and as a quality of life measure, a visual analog scale (VAS) on the bother caused by urinary symptoms. The criteria for cure and improvement were determined. To be regarded cured a patient should have a negative stress test, a negative pad test, be continent in post-operative urodynamics, and score less than 10 on the VAS, where 0 represents no urinary problems whatsoever and 100 unbearable urinary symptoms. Improvement required a negative stress test, a significant reduction of leakage on the 24-h pad test and a ≥70 % improvement of the individual VAS score. All other cases were regarded as failures.

A multicenter trial including six clinics in Finland and Sweden enrolled 130 primary cases of stress incontinence that were followed for a minimum of 12 months showed the same high rate of success as the initial trial. This study was published in 1998 [9], but the results had been available to the investigators at the beginning of the previous year. The results of trials with a follow-up of 4 years in women suffering from recurrent stress incontinence, intrinsic sphincter deficiency, and mixed urinary incontinence were published in 2001, once again with excellent cure rates [10–12]. As early as 2000, the 5-year follow-up results were available and published in June 2001 showing an overall cure rate of 85 % according to the above-mentioned criteria [13] Table 1. Two independent studies with a 3-year follow-up were published in 1999 [14, 15], revealing the same high success rates as the earlier studies. Today, we have the results after a 17-year follow-up period of the performance of the TVT procedure, which shows that no decline in cure rate has developed throughout the years and that no late onset problems occur with the polypropylene tape used in these by now rather elderly women [16].

Table 1 Number of patients, follow-up period, and cure rate of early clinical trials using the tension-free vaginal tape (TVT) procedure
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The most common complication of traditional incontinence operations has been persistent or recurrent stress incontinence, and for the most invasive procedures all the complications associated with major surgery. The minimal invasiveness of the TVT procedure and the idea of performing the operation under local anesthesia were aimed at reducing the risk of complications. Utilizing local anesthesia allowed an intra-operative cough stress test to be performed, the purpose of which was explicitly to avoid post-operative voiding problems. Training was thought to be the key to the success of performance of the operation, and the procedure was therefore carefully standardized to facilitate training.

An excellent opportunity to introduce the TVT procedure in Finland through a systematic training program, including all clinics in the country that performed incontinence surgery, arose, as one of the participants in the clinical development of the TVT operation was responsible for incontinence care in the largest university hospital in Finland. A representative of every hospital surgically treating stress incontinence was invited to the University Hospital in Helsinki to participate in a training program that included theoretical training (the importance of focusing on the mid-urethra and not the bladder neck), surgical training, and a follow-up program. Depending upon the earlier experience of the invited surgeons, each doctor had to attend 2–8 TVT operations, assist with 2–4 TVT operations, and finally perform 2–3 TVT operations under supervision. A certificate for performing the TVT operation alone was produced to those who successfully participated in the training. A deal with the provider of the TVT kit in Finland was made, which meant that only certified surgeons could obtain the TVT kits for clinical use.

The follow-up program included in the training called for registering any kind of intra- or post-operative complications and follow-up visits. This prospective program would thus include the learning curve of every single surgeon performing the TVT procedure. The results of this program were published in 2002. It included all 1,455 TVT procedures performed in the country by the end of 1999. Astonishingly low rates of complications were found, the rate of bladder injury, for instance, being only 3.8 % (Table 2) [19].

Table 2 Rate of complications in a nationwide registry of TVT procedures in Finland
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The TVT procedure, being the first minimally invasive surgical operation relying on the mid-urethra theory and utilizing a type 1 synthetic mesh as the tape material, was thoroughly studied and the results were documented before the procedure was offered for common clinical use. The results have furthermore been published in renowned peer-reviewed international journals, many of them well ahead of the launch of the procedure.

Recent history includes the launch and withdrawal of many modifications and copies of the TVT procedure, which shows that any variation of a procedure needs its own thorough clinical testing before it can be accepted for common use. The surprisingly high rates of complications such as bladder perforation and post-operative voiding problems seen in more recent reports compared with the rates seen in the initial ones from the Nordic countries emphasizes the need for proper training and adherence to the standardized performance of the operation in order to avoid complications and poorer performance. It is a waste of both public and private resources to launch poorly documented new treatment concepts and it is especially wrong for the women suffering from stress urinary incontinence to become the subjects of experimental efforts without ethical approval and written informed consent.