THE HORSE MOLARS CONTROL. Cast and the patient.
Site of Operation. The site of operation is the level of the free extremity of the fang of the tooth to be removed.
Instruments. The special instruments re quired for the operation are a trephine, a sharp chisel, a punch, and a mallet.
Operation. Having accurately located and prepared the site, remove a disc-shaped piece of skin about one inch in diameter. If there are vessels or nerves in the way push them aside, cut through or push aside muscular tissue if present, and expose the bone. Trephine the latter over the centre of the dental fang. To make sure of trephining in the right place, insert the mouth speculum and pass a sharp-pointed, long-bladed bistoury through the cheek close to the alveolar border at the level of and parallel to the long axis of the affected tooth to serve as a guide. Operate on a line coin ciding with the direction of the bistoury. A trocar might be used instead of the knife for this purpose.
Having exposed the extremity of the fang, enlarge the trephine opening by means of the chisel and mallet, taking care to direct the edge of the instrument towards the affected tooth to avoid wounding the neighbouring alveolus. When the fang has been uncovered in its entire width and for about half of its length, apply the punch at its free extremity and, holding it parallel to the long axis of the root of the tooth, strike it smartly and repeatedly, but not too forcibly, with the mallet so as to repel the tooth into the mouth, whence it must be instantly removed to prevent its being swallowed or falling into the larynx. Take care not to allow the punch to become displaced so as to pene trate between the tooth and the alveolar wall, causing fracture of the latter and exposure and infection of the adjoining alveolus.
Williams, of New York, recommends removal of the entire outer wall of the alveolus, which makes repulsion easier and prevents the for mation of a fistula afterwards. He also advises fracturing the fang transversely and longitudin ally by means of a heavy chisel and mallet, and removing it piecemeal in eases where repulsion of the intact tooth is very difficult. Greater care has to he exercised in repelling the inferior molars owing to the thinness of the lower jaw rendering it more liable to fracture. The punch in this ease must be struck cautiously and lightly. Operation on the superior molars, with the exception of the first two, involves opening of the maxillary sinus.
After removal of the tooth, wash out the alveolus with a non-irritant, antiseptic lotion, and if the whole of the outer alveolar wall has not been removed plug the passage with anti septic gauze. Renew the dressing daily until healing is almost accomplished.
Occasionally, especially when two contiguous teeth have been repelled, a fistula into the sinus persists and food material accumulates in the latter. The remedy for this condition is to open, evacuate, and wash out the sinus and fill the passage with gutta-percha. Soften the gutta-percha by immersion in hot water, and, with the fingers of one hand in the sinus and those of the other in the mouth, pack it in the passage, spreading it out slightly above and below to prevent it falling out. If the com munication is with the nasal passage the same procedure is adopted. Several cases of success ful treatment in this way have been recorded, including one by the author.
The gutta-percha may remain in position for years.
Dentition Fever. Dental affections which impair mastication are responsible for con stitutional disturbance, which is more or less pronounced according to the degree of interfer ence with this important function.
The term"dentition fever"has been applied to the train of symptoms which sometimes appears during the eruption of the permanent teeth in the horse, due, apparently, to a variable degree of inflammation or tenderness of the gums caused by the irritation of the partially separated temporary teeth and the pressure of the developing permanent teeth.
It is usually between the ages of three and a half and four years that the condition is most frequently observed, this being the period during which the greatest number of teeth are being erupted, the following making their appearance about this time: the lateral incisors, the third and sixth permanent molars, and the canine teeth when present.
Symptoms. The usual symptoms of mastica tory trouble are observed, quidding, salivation, etc., and in addition those of indigestion and unthriftiness. Examination of the fasces in this as in other affections of dental origin shows that the food has been imperfectly chewed, that a large proportion of the grains of corn are passed intact. The animal is often affected with a cough, and the skin may be affected with papules, while the coat is dry and staring. The subject is comparatively weak and easily sweated if put to work.
Treatment. Examine the mouth and remove partially separated teeth. Give food that is easily masticated; a good allowance of bran mashes and steamed crushed oats or boiled barley. Prescribe some alkaline medicine to be given in the drinking-water, and an astringent mouth-wash to allay any inflammation that may exist.
Affections of the Eustachian Tubes. Wounds. —Wounds of the Eustachian tubes are rare except in conjunction with fracture of the base of the cranium, when they are of no practical importance, on account of the fatal nature of the latter.
Pathological conditions of neighbouring struc tures may involve the ducts. Their mucous lining being continuous with that of the pharynx and middle ear, inflammatory conditions affect ing these organs are usually propagated to it. Foreign Bodies in the Tubes.Cases of par ticles of hay and grass and alimentary matter being lodged in the conduits have been recorded. Obstruction of the Tubes. The Eustachian tubes may become more or less obliterated as the result of inflammatory thickening, causing, a variable degree of deafness owing to -intef ference with the equilibrium of air pressure on both sides of the tympanum, the consequence being that the bones of the ear, pressed upon by the tympanic membrane which is displaced inwards, cause compression of the liquid in the labyrinth through the foramen ovale disturbing its function, and sometimes causing brain symp toms by irritation of the numerous nervous ramifications of the labyrinth communicating with the brain.
Positive diagnosis of the foregoing conditions is extremely difficult, and even if they are recognized little can be done for them except, where possible, to treat affections in their vicinity with which they may be associated.
Catarrh of and Collection. of Pus in the Guttural Pouches. Etiology. The cause of catarrhal inflammation of one or both guttural pouches may be: (1) Acute pharyngitis, the in flammation spreading from the pharynx through the Eustachian tubes. In this way it may be a complication of strangles. (2) Inflammation in the vicinity, being propagated to the pouch by contiguity through the agency of bacteria, as may happen in a case of parotitis, or sub parotid or post-pharyngeal abscess. (3) Food material gaining entrance to the pouch from the pharynx—a rare occurrence.
The inflammation assumes a chronic course and the exudate accumulates for want of a dependent orifice, the only means of escape being the Eustachian tube, whose upper opening is not at the lowest part of the cavity and con sequently only acts as an outlet when the head is lowered or the walls of the pouch are com pressed, as in the act of swallowing or mastication. There is therefore always a certain quantity of fluid present causing irritation and perpetuating the lesion. Much of the solid portion of the contents becomes inspissated and formed into chestnut-like bodies called chondroids, of which a large number may be present.
Symptoms. The symptoms of pus in the guttural pouches are: (1) An intermittent nasal discharge, which may be uni- or bilateral. Although only one pouch may be affected, the discharge may be from both nostrils. It appears during feeding; when the head is lowered; during exercise; and sometimes when the pouch is compressed externally. It is inodorous as a rule, muco-purulent in character, contains yellowish-white flocculi of variable size, and does not adhere to or become inspissated on the nostrils. In rare cases it is blood-stained. due to ulceration of the lining of the cavity.
Glands. The glands become enlarged, as in the case of empyema of the sinus, and are not adherent to the jaw.
(3) Swelling in the parotid region, only notice able when the pouch is much distended. It may be abnormally hot and slightly painful.
(4) Interference with swallowing and respira tion, observed when the pouch becomes greatly distended owing to stenosis or partial obstruc tion of the Eustachian duct, allowing the escape of a much smaller quantity of the contents than usual. The patient has difficulty in swallowing, makes a respiratory noise, and shows more or less dyspncea during exercise due to the swelling encroaching on the pharynx and larynx.
(5) Rupture of the pouch, which rarely occurs, due to its excessive distension and repeated efforts of swallowing and snorting.
(6) Holding the head towards the sound side when the horse is being ridden, observed in some cases.
(7) A rattling noise in the pouch during exercise, sometimes perceived and due to agitation of the contents.
Diagnosis is based on: (1) the intermittency of the discharge; (2) its consistency and non offensive nature; (3) the local swelling; (4) enlargement of the submaxillary glands; (5) the absence of characteristics of other condi tions which cause a nasal discharge.
When in doubt Gunther's catheter may be passed through the inferior meatus of the nasal chamber and through the Eustachian tube into the pouch, whence fluid, if present, will escape through the catheter. The instrument is com posed of metal and is slightly curved at its distal extremity. The pharyngeal entrance to the Eustachian tube is at the same level as the temporal canthus of the eye, and the distance from this point to the nostril is measured on the instrument and marked by a runner for the purpose. The catheter is introduced into the nose, and when it has entered as far as the point indicated by the marker the level of the Eusta chian opening is reached, and the proximal end of the instrument must then be held close to the septum nasi so as to direct the other end outwards and enable it to enter the orifice, which is on the outer wall of the pharynx. To facilitate the passage of the instrument and to diminish the resistance of the horse, it should be immersed in warm water and smeared with vaseline before using it.
It requires considerable practice to acquire the necessary skill to make the instrument enter the Eustachian tube.
Prognosis. There is no chance of spontaneous cure, but when the pus becomes inspissated and the quantity of liquid becomes diminished the functional disturbance is relieved. Death rarely supervenes from hemorrhage due to ulceration of the mucous membrane and the opening of an artery, or to gangrenous pneumonia caused by alimentary matter gaining entrance to the lungs.
Treatment. The treatment comprises: (1) Antiseptic inhalations, which may be of some use in a recent case in allaying inflammation of the mucous membrane, but once pus has accumulated in the pouch they have no bene ficial effect.
(2) The passage of Gunther's catheter to evacuate the fluid contents and to enable the cavity to be irrigated with an antiseptic or astringent lotion introduced through the cath eter by means of a syringe. As it does not effect removal' of the solid bodies or chondroids, this method of treatment is only palliative in its results and requires frequent repetition owing to the fluid being re-formed by the irritation caused by the solid matter remaining.
(3) Operating for the purpose of removing the liquid and solid contents through an opening in the external wall of the pouch. Before attempt ing to operate, and in order to understand the description of the operations performed, an accurate knowledge of the anatomy of the parotid and pharyngeal regions is essential, and to acquire it a work on anatomy should be con sulted and the regions should be carefully dis sected in the dead subject. There are several important vessels and nerves near the sites of operation, and if an intimate knowledge of their situations is not possessed by the operator he cannot proceed with confidence.
Methods of Operation. The principal methods of operation are as follows: (1) Hyovertebrot omy; (2) Dieterich's method; (3) Viborg's method; (4) Puncture of the pouch through the parotid gland.