Text book of veterinary medicine, Volume 3 (of 5)

by James Law

STRICTURE OF THE URETHRA.

This may be suspected when in spite of much straining the urine is habitually passed in a very fine stream, which has become finer and finer for a length of time, without complete arrest as in calculus. The introduction of a catheter will confirm the diagnosis and show the exact seat of the stricture.

It is determined by irritation caused by calculus, urethritis, ulcer, wounds, etc., which tend to the formation of a cicatrix encircling and narrowing the canal. One efficient cause is the injection of strong astringent or slight caustic solutions in the early stages of urethritis.

Treatment is by dilation, by bougies pointed and gradually thickening, or simply by an elastic staff which at first passes with some force and is replaced by a larger one as the urethra stretches under daily use.

Catheterization. In connection with diseases of the bladder and urethra the passing of the catheter is a most important operation which requires considerable skill on the part of the operator. A short statement of the method to be adopted for each of the domestic animals will therefore be in place.

Catheterization in the male Soliped. The catheter, a hollow, gum elastic tube, must be proportioned to the size of the animal, but for the average adult horse about 3½ feet in length and ⅓ inch in thickness. To give it the requisite solidity and resistance it is usually furnished with a stilet of whalebone or cane.

The operation is performed with the animal standing, in quiet animals without any restraint, but in the more sensitive or restive, with one fore foot held up; or with both hind feet in hobbles furnished with ropes passing between the fore limbs and tied over the neck in front of the withers; or finally with a twitch on the nose.

The rectum is emptied, and with the oiled or soapy hand the penis is found and slowly withdrawn from the sheath by steady traction. This is usually easy, though in certain cases, with a short penis and specially strong retractors, it will seriously tax the operator’s skill and address. In a specially obstinate case a hypodermic injection of morphine may be resorted to.

If the horse is down, as in paraplegia or hæmoglobinæmia, he may lie on his right side while the operator stoops over him from the loins; or his feet may be drawn together by hobbles, and the subject turned on his back, the operator placing himself as before on the left side.

The catheter must have been previously cleansed and disinfected outside and in. A mercuric chloride solution 1:2000, or boric acid 1:50 or permanganate of potash 1:50 may be employed. Then it must be smeared, preferably with vaseline but, in case of necessity, with sweet oil, glycerine, borated lard, or even castile soap.

The penis being withdrawn from the sheath, the catheter containing its stilet is introduced into the urethra and pushed on slowly and carefully until its point can be felt over the ischiatic arch. The stilet is now drawn out a few inches and the point of the catheter is bent forward over the ischium by the finger. The stilet is further drawn out and the catheter can easily be pressed on into the bladder. If any difficulty is experienced it may be guided by the hand introduced into the rectum.

In one extraordinary case, I found that the catheter entered a dilated seminal vesicle and failed to evacuate the bladder. This untoward occurrence must be rectified by the aid of the hand in the rectum. Usually the penetration of the bladder is signalized by the overcoming of resistance, and when the stilet is withdrawn the urine flows in a steady stream. If it fails to flow, a slight compression of the fundus of the bladder by the hand engaged in the rectum will start the stream.

The catheter should be withdrawn slowly and carefully.

Catheterization in the Bovine Male. Most veterinarians suppose that this is impossible, owing to the narrowness of the sheath interfering with the extraction of the penis, and the S shaped curve in the penis preventing the introduction of the catheter. Both obstacles can, however, be overcome in many cases. The bull may be tempted to protrude the penis by the presentation of a cow in heat, or in bull or ox the bulging anterior part of the organ may be protruded by careful manipulation through the sheath. Then the free extension of the penis can be made to efface the S shaped curve. The catheter must be small, not much over a line in caliber, and a metal stilet is employed. The animal may have to be placed under restraint, and the same antiseptic precautions are demanded as in the horse.

Catheterization in the Ram and Wether. These must be dealt with like the bull, the only additional difficulty being in the vermiform appendix. This is small and sinuous but the longitudinal opening on its lower surface is favorable to the introduction of the catheter.

Catheterization in the Dog. The fact that the urethra traverses the groove on the lower aspect of the bone of the penis, is held to prove an obstacle to the catheter, yet the introduction of the latter is in no sense difficult. Small or moderately sized dogs, may be held upright, the body resting on the rump and the pelvis inclined forward, which will favor the spontaneous protrusion of the penis. Or it may be pressed out by manipulation through the sheath. The catheter ⅔ ds. to 1 line in diameter may be 1¼ to 2 feet in length according to the size of the animal. It should be used aseptic.

Catheterization of the Mare. Nothing can be easier than this operation in the mare. The shortness and dilatability of the urethra, and the accessibility of its external orifice in the center of the floor of the vulva, 4 or 5 inches in front of the lower commissure, favors the introduction of the catheter. The latter may be a foot in length, perfectly straight and it may be constructed of silver or some other metal, which may be readily boiled and rendered aseptic. In the absence of a catheter the germ free nozzle of a rectal syringe may be used, or two fingers may be passed through the urethra and parted from each other so as to allow the exit of the urine.

Catheterization of the Cow and Heifer. The operation is often very difficult in the cow, by reason of the small size and undilatability of the urethra, and by the presence of two blind ducts (canals of Goërtner) above and to the two sides of the urethral opening. The thin rigid upper margin of the orifice projects down over it in a valvular manner so that the catheter will almost always find its way into one of the blind sacs. By introducing the tip of the index finger beneath the valvular fold and into the opening of the canal, the catheter may be directed beneath it and into the bladder. An apparatus consisting of a series of ribs of spring wire arranged in the form of a funnel and converging at one end to a point has been devised to insert into the urethral orifice, and guide the catheter which is passed through it.

Catheterization of the Bitch. The operation is rendered difficult by the narrowness of the passage, and the puckers and folds of the vaginal mucosa which serve to hide the urethral orifice. A small catheter like that used on the male is used or a short metallic catheter may be substituted. By directing this forward exactly in the median line of the floor of the vulva, with gentle pressure downward it may be made to enter the urethra. In case of special difficulty a bivalve speculum may be resorted to, to efface the mucous folds and reveal the orifice.