The latter variety of uretero-vaginal fistulm, which occur in that por tion of the bladder corresponding to the trigomon, and are always found in connection with a partial destruction of the vesical wall, should be designated as the lower variety; for they differ both therapeutically aud. prognostically from the kind described before as occurring in the fundus vagina, which may be called the upper variety. Simon found such a oue on the left side, Ith of an inch from the os and 21th inches from the external urethral orifice. The fistula was -flu X 1th inch in size, and the left ureter, which could be reached with the sound, was destroyed for its lower 1th inch.
The position of vesico-utero-vaginal fistul& (see Fig. 53, a and b) is de scribed by the name. They occupy the vault of the vagina, are round, or quadrangular, and not large as a rule. The deeper ones, where the anterior lip of the cervix is destroyed, arc not much larger, since the pos terior lip is often also involved. As a rule, both :ire median, since with a contracted pelvis the chief pressure is upon the middle of the anterior pelvic wall.
The utero-vesical fistulre are situated Ito of an inch from the external cervical lip, either in the median line, or to one side. They are usually as large as a pea or bean. Only in mre cases are they found combined with deep utero-vesico.vaginal fistula3, being divided off from it by a thin, narrow bridge of tissue. The uretero-uterine fistula3 are very rare, and are usually so small as to be hardly visible to the naked eye. The former are placed more in the middle of the anterior wall, while the latter are placed at the sides, and somewhat forwards. The three cases observed respectively by B6rard, Puech, and Freund did not any of them come under post-mortem observation.
The vesico-intestinal fistuke are situated its follows: the vesico-rectal, the vesicointestinal, and the vesico-ventricular are of course situated on the sides, posterior wall, or vertex of the bladder. Long fistulous tmcts may arise. A coil of the small intestine may adhere to the bladder, and perforation occur at the point of adhesion; or an inflammation of the pelvic cellular tissue may perforate both bladder and rectum.
Finally, the urinary fistulre of the anterior alxlominal wall, the external urinary fistultv, form longer or shorter channels or slits, as we have seen when considering version of the bladder.
The edges of the fistulre are at first ustiallv swollen, uneven, infiltrated, tender, and bleed easily when touched. Gradually necrotic portions are cast off, secretion diminishes, the margins become firmer, and the vaginal pavement epithelium grows over the edges of the wound. A connective tissue proliferation now takes place between the bladder and the vaginal wall, and the edges of the fistula become thinner, indurated and tense. Thus Freund proved in a carefully observed case, that the bladder was adherent to the vaginal wall for a concentric ring 2 to 3 lines in width. Microscopically, we see abundant connective-tissue proliferation between the adherent portions of the two organs; the muscular layer and the mucous membrane become thinner 88 you advance nearer to the edges of the fistula, the papilhe are less marked, until at 31wth inch from the edge of the orifice, the entire thickness consists of a hard, cartilaginous like and poorly vascularized connective tissue, in which we can still recog nize some remains of the degenerated mucous membrane. Of course the extent to which these processes advance depends largely upon the cause of the fistula. If there has been but little contusion, or perhaps only a simple cut, the vitality of the margins is better, the lips of the wound are thicker, the granulations are more vigorous, the scar is smaller, and the neighboring tissues are less implicated. I might refer to cases that I hare myself seen, where the fistula was caused by a forceps blade, and where months later the edges were as described; or I might mention Bouqu6's case (1. c. 1875, p. 124-125), of which he says: " les bourgeons charnus sent tellement volumineux, qu'ils arrivent au contact en faisant pont au dessus de la troae anormale, etc." On the other hand, there seem to be some special causes which tend to cause the thinning of the edges of the fistula above described. Thus tension of the edges caused by contracting cicatricial tissue, and especially fixation of the edges of the fistula to one or other of the bones of the an terior pelvic wall, appear likely to do so. And if, as sometimes occurs, inflammatory processes in neighboring organs cause tension of different parts of the border in different directions, it is easily understood how thinning from tension may occur.