CONGENITAL AND ACQUIRED MALFORMATIONS OF THE URETERS.
As the integrity of the kidneys is to a large extent dependent on the condition of the ducts by which the urine is conveyed to the bladder, it will be proper to consider other sources of interruption in addition to the stoppages that are occasioned in these tubes by calculi and strictures in the ordinary acceptation of the term. Hav ing referred to this subject already in connection with the conditions just named as well as with hydronephrosis, my remarks will now be confined to certain congenital and acquired malformations of the ure ters. It is necessary that the surgeon should have some knowledge of these deviations, otherwise in the case of an exploration he might find himself considerably embarrassed.
It will hardly be requisite to indicate all the congenital varieties that have been met with, after what has been said in my description of the malformations of the kidney. If a person is born with only one kidney it stands to reason that this will probably be represented by a single duct. On the other hand instances are recorded where one kidney has had two or even more ureters, which, as a rule, have coalesced into one tube before entering the bladder. Sir William Roberts gives an instance where the ureters crossed on their way to the bladder. In what are called horseshoe kidneys, where the two organs are united by a transverse bar, either at their base or at their apex, there are usually two ureters. which descend in front of the con necting link. According to Dr. Wilks there are exceptions to this, the ducts descending occasionally behind the bridge. Sir Henry Thompson" saw a kidney with two ducts which united into a single ureter about an inch below their necks. Mr. J. Wood," on the other hand, has described an instance where the union did not take place until about an inch from the bladder.
Reference has already been made to the great dilatation the ure ters sometimes undergo. These tubes have been found to resemble in size a portion of the small intestine. When produced by distal causes, as for instance prostatic obstruction or urethral stricture, by containing urine and undergoing inflammation they add materially to the gravity of the case. Where the obstruction in front of the bladder is so great as to induce this and to threaten, by its persis tence and resistance to all ordinary treatment, extension of the in flammation to the kidneys and their dilatation and eventual disin tegration, the surgeon is justified in entertaining measures which will permit of a free and incontinent escape of urine from the bladder.
The adoption of some form of bladder drainage under these Circum stances is often to be recommended. The technique of this proceed ing, which is one that does not entail additional risk so far as the operation is concerned, is fully described in my article on diseases of the bladder. That the consequences of obstruction in front are extend ing to the ureters and are commencing to influence the kidneys may be inferred by various circumstances which gradually develop in connection with some of the worst forms of prostatic and urethral obstruction. More especially are they to be observed in association with that variety of dense and contractile strictures which results from wounds and laceration of the male urethra.
The mode in which dilatation of one or both ureters is usually brought about is through the expulsive pressure of a normally dis posed or an hypertrophied bladder upon its contents, much in the same way that pressure with the hand on a rubber ball syringe, un protected by valves, has a tendency to drive its contents into both the afferent and the efferent tubes with which it is connected. In this way in a case of urethral stricture dilatation of the ureters as well as of the urethra on the proximal side of the obstruction is gradually brought about.
There are, however, examples where the process is somewhat different; excluding cases where the ureters are dilated by what de scends, as, for instance, the frequent passage of renal calculi, of pus, and of other fluid and semi-solid contents of the kidneys in the course of disease, there are others which do not admit of explanation in these ways. Specimens are occasionally met with in young persons where the ureters are enormously dilated and yet no mechanical ex planation of this can be found in the bladder or its contents, or in any portion of the urethra, prostatic hypertrophy being, of course, out of the question. In a case reported and commented on by Dr. Dawson Williams " in a boy five and a half years of age, no other conclusion could be arrived at than that the dilatation of both ureters and kidneys was probably of congenital origin, an assumption which Mr. Targett has also offered in explanation of some forms of sacculation of the bladder. That frequent spasm of the bladder is sometimes a cause of dilatation above I can have no doubt. I have seen this on several occasions in both sexes in cases of tubercu lar ulceration limited to the bladder, where the latter, though of small capacity, was kept in an almost constant state of contraction.