The denudation should be extended some distance beyond each angle of the fistula, in order to secure perfect apposition in these positions. The length and shape of the needle used for closing the opening varies with the fancy of the operator. As a rule, a small needle, straight or curved at the point, is most convenient (Fig. 182). [Illustration: FIG. 182.--Fistula-needles.] The needle should be introduced about an eighth of an inch from the edge of the vaginal mucous membrane, and should be made to emerge at the edge of the mucous membrane of the bladder. It should be reintroduced and emerge in the reverse order on the opposite side (Fig. 183). The sutures should be placed about a quarter of an inch apart. After the sutures have been introduced, and before they have been shotted or tied, the bladder should be thoroughly washed out with a warm boric-acid solution. The operator should make sure that no blood-clot is left in the bladder. After the sutures have been shotted a light gauze tampon may be placed in the vagina. A permanent soft-rubber catheter may be introduced through the urethra, or the urine may be drawn every three or four hours after the operation. If care is given to the cleanliness of the catheter, it is perhaps best to retain it in the bladder for three or four days, after which the urine may be drawn every four hours. The catheter should be removed twice in twenty-four hours for purposes of cleansing. The eye of the catheter frequently becomes obstructed by blood-clot. It should not be forgotten that the bladder is often much contracted in old cases of vesico-vaginal fistula, and as the capacity is diminished more frequent catheterization than usual is necessary. Boric or benzoic acid should be continued during the convalescence. The gauze tampon should be removed on the second day. The bowels should be moved on the second or third day. The sutures may remain for two weeks. The woman may sit up at the end of two weeks. [Illustration: FIG. 183.--Vesico-vaginal fistula with the sutures introduced.] The operation described here--more or less modified in order to meet the requirements of different cases--will result in cure in the great majority of instances. Often much depends upon the ingenuity and the mechanical skill of the operator. Sometimes two or three operations are necessary before the opening can be completely closed, the operator closing part at each sitting. In the case of a small fistulous opening it may be necessary to enlarge it by free incision before the denudation and the introduction of the sutures can be properly accomplished.