Transobturator “outside – in” procedures
This concept was first described in 2001, and represented a completely different approach for placement of the tension – free mid – urethral tape. Initially a welded semi – rigid tape of non – woven monofilament polypropylene was used, with 5% elasticity and 70% porosity (Obtape TOT device). This tape is now obsolete. Women are placed in the Lithotomy position, and the 10mm tape passes sub – urethrally through the obturator fossa to exit the skin through a small incision on the medial aspect of the inner thigh. The introducer passes from the obturator fossa medially inwards towards the vagina, hence the “outside – in” appellation.
The manufacturers (Mentor – Porges) have since introduced the ArisR type 1 light weight superior mesh, being woven in such a manner as to have low elasticity. Since 2002 more than 25, 000 TOT procedures have been performed, giving a reported success rate of 80% - 90%, improvement in continence of 7% – 9%, and a failure rate of up to 7%. Complications include bladder injuries in 0.7% of cases, and a 3% – 5% incidence of voiding dysfunction.
Post – operative retention occurs in around 0.5% of cases, with other complications including thigh pain, haematomas, vaginal and urethral erosions. The overall Obtape complication rate is around 3.6%. These results have been carefully collated by a French Multicenter Registry with ObtapeR surveillance, comprising 9 centres and including data from some 730 women.
In a recent study of 117 women, the ObtapeR afforded a 92% cure (defined as complete or partial satisfaction), with a 5% complication rate. Tape erosions over the 22 month follow – up period, occurred in 3 cases.
Another popular “outside – in” device is the MonarcR tape, and one – year data shows similar results. The objective cure rate is 82%, with adverse events including mesh erosions, urinary retention and urinary tract infections.
Data are very difficult to interpret and care must be taken when comparing studies. Since no “head to head” prospective randomized comparative trials of methods have been presented, it is impossible at this point to claim superiority or safety of one product over another.
Transobturator “inside – out” procedures
The Transobturator “inside – out” approach was first mooted by de Leval in 2003. The device is introduced through a 10mm suburethral vaginal skin incision, and passed laterally through the obturator fossa to the medial thigh area, and hence the “inside - out” moniker. This novel approach was developed after extensive cadaveric dissection and one year data suggest a 91% cure rate, with 5% of cases showing improvement. Post operative complications include voiding dysfunction in 5% of women, with a 12% incidence of transient inner thigh pain and a few cases of vaginal healing defects. In a 2004 prospective series, Waltregny found a cure rate of 94% with no reported complications. Procedures typically take around 20 minutes to perform, and may be done as day case procedures if the patient prefers. Although general or regional anaesthesia is the norm, they may be done under local anaesthetic. Intra – operative cystoscopy is not generally required.
It is difficult to draw conclusions from these data, and clinical trials will show comparative success rates and the incidence of perioperative complications.
It has become common to measure the “passing distance” of the different devices to vital anatomical structures in preserved or fresh cadaver specimens, but once again this does not necessarily translate to clinical safety or otherwise.