N.Gasbarro, M. Brusati, P. Lupo, A. Togliani

INTRODUCTION

The treatment of the female genuine stress incontinence (GSI) is one of the more controversial aspects of the gynecologic surgery. More than 200 surgical procedures have been developed (6, 14,24), but they can all be placed in three main groups: the operations with vaginal plication of the pubocervical fascia (Kelly plication), the needle suspensions of the vesical neck (Pereyra, modified Pereyra, Stamey, Raz, Gittes) and the retropubic suspensions (Marshall-Marchetti-Krantz, Burch).
The purpose of all these procedures is to elevate the bladder neck and to stabilize the proximal urethra according to Enhorning (11), whose theory states that the continence mechanism relies on the transmission of the intraabdominal pressure to the proximal urethra, as well as Beck’s theory (2) by which in the prevention of urinary leakage during times of increased abdomianal pressure it is crucial the urethral kinking. Recently, DeLancey (10) suggested the hammock hypothesis on the continence mechanism. According to the Author, the proximal urethra is supported by a hammock-like layer composed of the endopelvic fascia and the anterior vaginal wall.
During increases in abdominal pressure, the down-ward force compresses the urethra against the anterior vaginal wall, thereby closing the urethral lumen and preventing the loss of urine.
When the support system is damaged, an ipermobility of the vaginal wall follows and the urethra cannot be effectively compressed against it. According to this theory, the purpose of any surgical procedure should be the restoration of the “hammock” by means of the paravaginal defects repair or by a synthetic tape as in the Tension-free Vaginal Tape (TVT).

ANATOMY OF THE URETHRAL SUPPORT

According to DeLancey (8,9,10), who derived his description from the dissection of the pelvis of many female cadavers, the proximal tract of the urethra is supported by the anterior vaginal wall with the endopelvic fascia (pubocervical fascia) that in turn is fixed to the arcus tendineus fasciae pelvis and to the medial aspect of levator ani (SCHEME 1). The arcus tendineus fasciae pelvis is a thickening of the obturator and levator fasciae stretched from a ventral attachment at the pubic bones about 1 cm above the lower margin and 1 cm from the midline to the ischial spine.
The anterior vaginal wall with the pubocervical fascia is suspended through the pelvis by the arcus tendineus fasciae pelvis and both give support to the proximal urethra in an hammock-like fashion (SCHEME 2). During increases in abdominal pressure the urethra is compressed closed against the hammock and the loss of urine avoided. In order to retain the effectiveness of this closure mechanism, the integrity of the connections between the vagina, pubocervical fascia and arcus tendineus is of paramount importance, because only in this way the hammock is firm and the urethra can be efficiently compressed against it.
The DeLancey’s hypothesis also gives some explanation to the voluntary control of the voiding on the basis of the levator ani work. When these muscles relax the hammock is soft, the vesical neck descends and the urination can start. On the contrary, when the muscles contract the hammock is firmly taut, the urethra compressed and the urinary stream is stopped.

CLASSIFICATION AND SURGICAL APPROACH

By means of cystourethrography and /or perineal sonography in conjunction with the urodynamic studies (filling cystometry, urethral pressure profile, Valsalva leak point pressure) it is possible to classify the GSI as follows (Table I), (1, 5): Type 1 refers to urinary incontinence in the absence of urethral ipermobility (< 45o), Maximum Urethral Closure Pressure (MUCP) > 60 cm H2O and Valsalva Leak Point Pressure (VLPP) > 60 cm H2O; Type 2 results from severe urethral ipermobility, MUCP > 30 < 60 cm H2O and VLPP > 40 cmH2O; Type 3 refers to case with MUCP £ 30 cm H2O, VLPP £ 40 cm H2O (or £ 60 cm H2O in the case of coexisting urethral ipermobility) and funneling of the vesical neck at cystography and / or perineal sonography.
Type 3 is further divided into 3a, with urethral ipermobility, and 3b, without urethral ipermobility. Moreover, many cases of stress incontinence are of the mixed type: type 1-2, type 2-3, type 3-2. Briefly, it has been stated that two broad types of GSI can be encountered: the anatomic one (comprehensive of the type 1 and 2) related to the failure of the urethral supports and accounting for the 80-90 % of cases and the functional type (type 3 of the above mentioned classification) related to the dysfunction of the urethral sphincteric apparatus, accounting for the remainder (12, 13). On the basis of this dualistic view a surgical algorithm has been proposed with the indication for the bladder neck suspension in the case of anatomic incontinence and for the sling procedures or the periurethral injections in the case of functional incontinence. However, over the time this approach appeared too simple.
Rather than existing as an either -or dichotomy, patients fall along a continuum where both aspects interact to produce the clinical condition (24). For these reasons, the use is increasing of sling procedures as first-line treatment of GSI. In fact, the sling corrects the type 3 GSI as well as the thype 2, 1 and many Authors now suggest to doing a pubovaginal sling in all cases of GSI (4, 5, 18). However, as many as 30% of patients who underwent this operation complaints of difficult voiding that in some case requires the self-catheterization procedure (16, 26).
This serious complication can be accepted by patients who resort to sling after many failed surgical attempts, but it cannot be tolerated after the first surgical attempt for a moderate incontinence. In this setting, Petros and Ulmsten in the 90s proposed a new technique for the surgical treatment of GSI, the TVT (Tension-free Vaginal Tape) in which a prolene tape is placed under the middle urethra without tension (21, 23).
The free-tension urethrosuspension represents a new view in the treatment of stress incontinence, because it works only when it is necessary, under the stress, thereby restoring the hammock-like layer critical in the maintenance of the continence (10). Moreover, this operation requires a mininvasive technique and can be performed under local anaesthesia that permits the prompt evaluation of the continence by asking the patient to push. The preliminary results show a cure rate of 86-90% (15, 20, 22 25) and it made this operation well accepted by the worldwide surgeons. However, the technique is not free of risks and many serious complications have been reported as bladder perforations and large haematomas (15, 23, 25). In one case the external iliac vein was perforated (17). In order to avoid these risks, we developed a new method for the implantation of the tension-free tape that we describe in the subsequent pages.

TENSION - FREE URETHRAL SUSPENSION WITH PROLENE TAPE

The procedure is recommended for the treatment of type 2 GSI. The procedure can also be accomplished in the case of mixed GSI, type 2-3, provided that an adequate tension is applied to the tape, thus converting the operation in a sling procedure.

Tecnique
The procedure is carried out under epidural blockade. The patient is placed in the dorsolithotomy position and a Foley 18 CH is inserted in the bladder. Then, two small slitlike incisions about 1 cm in length are made at the level of the lateral vaginal sulci on each side (Photo 1).
When a cystocele is present, a longitudinal vaginal incision is performed on the midline and the cystocele is repaired former. With the index finger at a 45 angle the paraurethral space on each side is entered by releasing the attachment of the endopelvic fascia to the pubic rami (Photo 2) and by blunt dissection of the vaginal mucosa under the proximal urethra a shallow tunnel is developed for the passage of a prolene tape measuring 1.5 by 35 cm (Photo 4, 5).
At this point, two small suprapubic incisions 1 cm in transverse length are performed at the upper margin of the symphysis pubis (Photo 6) and the ligature carrier showed in Fig. 3 is driven through the paraurethral space with the index fingertip of the other hand to exit the vaginal incision, as in the Pereyra procedure (Photo 7, 8).
The extremity of the prolene tape is fixed to the needle (Photo 9, 10) that in turn is withdrawn suprapubically (Photo 11) and secured with a Kelly clamp to prevent its displacement (Foto 12).
Once this has been accomplished on both sides, the correct placement of the tape is assessed by placing the tips of a forceps under the tape and showing no tension (Photo 13).
Finally, the bladder is filled of 250 cc normal saline, the Foley is removed and the patient is asked to cough in order to ascertain the effectiveness of the procedure (Photo 14, 15).
Once the necessary adjustements have been completed, the tails in excess of the tape are trimmed and the vaginal and suprapubic incisions are closed. Study Group From May, 1, 1999 to August, 31, 2001, 35 patients with primary GSI underwent tensio-free urethral suspension with prolene tape at our Institution according to the technique previously described. All but two patients suffered from type 2 GSI. In these two patients a type 3 GSI was present and they required a tension to be applied to the prolene tape that made it a sling. In 19 patients this was the only surgical procedure performed, whereas in 12 it was incorporated into a vaginal hysterectomy, in 13 into an anterior colporrhaphy and in 11 into a colpoperineorrhaphy.
The operation could be performed without complications in all cases. The mean postoperative hospital stay was 2 days. With respect to postoperative complications there were 2 cases of low tract urinary infection, one case of urinary retention that disappeared by loosing the tape under local anaesthesia and one case of retropubic granuloma. The mean follow-up is of 13 months (range 0.5 - 27 months) and the success rate is of 92%

CONCLUSIONS

The general surgery trend as well as the urogynaecological one is toward a minimally invasive approach. In this perspective, the needle suspension procedures (Pereyra, modified Pereyra, Stamey, Raz, Gittes) give the advantage of a minimally invasive technique, but they resulted poor effective at long term follow-up with a 5-year cure rate of only 40% (3).
This is probably because the sutures pull through easily in patients with poor tissue. On the other hand, the retropubic suspensions of the vesical neck (Marshall-Marchetti-Krantz, Burch) are very effective with a 5-year cure rate of about 95%, but they imply a more aggressive approach (3, 7). To couple the effectiveness of the Burch with less surgical trauma, some methods of laparoscopic colposuspension have been developed in recent years.
However, data from a randomized controlled trial of laparotomic Burch versus laparoscopic one showed that the success rate of the latter is lower (95% vs 80%) (19). The TVT developed by Petros and Ulmsten represents the most important innovation in the surgical management of GSI because it descends from the idea that to correct the incontinence we must provide support to the urethra only when it is necessary, namely under stress.
However, the technique of implanting the tape under the urethra by means of two large sharp needles that are inserted in a blind manner from bottom to above in the paraurethral space determined an higher rate of injuries to bladder (5%) and vessels (15%) than expected for a miniinvasive procedure (15, 17, 23, 25).
The technique we developed uses a blunt needle that is driven through the paraurethral space from above to bottom covered by the index fingertip. In this manner we never observed vesical lesions or injuries to major vessels in spite of the same cure rate (92%). Moreover, our method is cheaper than TVT that requires an expensive disposable set. (trad.Interpres-Giussano)

N. Gasbarro, M. Brusati, P. Lupo, A. Togliani
Regione Piemonte ASL 7,
Chivasso Ospedale Civico -
Reparto di ostetricia e ginecologia