A new tension-adjustment technique for sling operation: an animal model

To investigate the effectiveness of a new tension-adjustment technique for postoperative voiding difficulties encountered after sling operations.

To test our new method, urethral obstruction was developed in 5 female dogs by modifying the sling operation by exerting more tension on a specially prepared polypropylene strip in which a gap had been developed. After filling the bladder with isotonic solution, detrusor contractions were induced by pelvic nerve stimulations, and urodynamic studies were performed to document the urethral obstruction. In each case Foley catheters were inserted into the bladder and left in place until the time of tension adjustment. Tension adjustment was performed in the 1st, 2nd, 3rd, 4th and 5th weeks postoperatively for dogs 1, 2, 3, 4, and 5, respectively.

On the day of tension adjustment, after filling the bladder with isotonic solution and removing the Foley catheter, none of the dogs, except dog 3, was able to produce a free flow of urine either spontaneously or provoked by detrusor contractions. The release of the prolene sutures was readily achieved in all cases except dog 5. In this case, sling takedown was achieved after surgical exploration in which the sling location was confirmed by following the prolene sutures and Hegar's dilator. After identifying the sling, the gap was opened by cutting the prolene sutures, instead of a sling incision. Release of the prolene sutures resulted in a distinct drop in the urethra with decreased resistance of Hegar's dilator. The improvement in voiding was confirmed by postoperative urodynamic studies and was immediate in all cases.

Our new technique for postoperative voiding difficulties encountered after sling operation is simple, effective and avoids re-operation in the early postoperative period.