AFFECTIONS OF THE EAR Examination of the External Ear. The ex ternal ear can be readily examined by inspec tion and manipulation without the aid of an instrument.
An ear speculum may be used to dilate the concha, and natural or artificial light may be reflected therein to facilitate the exploration of its depth.
Traumatic Lesions. The external ear, on account of its prominence and exposed situation, is subject to external injuries.
Contusions. Contusions of the concha vary in degree in different cases. There may be merely extravasation of blood into the sub cutaneous tissues, or a limmatoma may form beneath the perichondrium, or the cartilage may be fractured.
The symptoms are the usual ones for a con tusion, and the treatment is on general principles.
Open Wounds.Open wounds of the flap of the ear are usually lacerated, being generally caused by bites in dogs and by being torn by barbed wire or nails in the large animals. In horses they may be caused by bites of other horses.
Treatment.The treatment is as usual for open wounds, and comprises clipping of the hair from their edges, cleansing, disinfecting, and suturing them if possible. It is always desirable to immobilize the ears in the dog, to prevent shaking of them and interference with the healing process. This may be effected by a layer of cotton-wool applied over the wound and kept in position by a cap, securely fixed by strings intercrossed beneath the throat and tied over the poll and forehead, the flap of the ear being either turned down and compressed against the parotido-temporal region or turned backwards in contact with the occipital region. Excessive pressure must be avoided in long ears for fear of causing necrosis of their tips.
The dog has a great tendency to rub the affected ear on the ground or scratch it with a paw, so that the bandage or cap requires to be very securely fixed in this animal. A special cap of canvas or strong netting, kept in position by buckles and straps, may be used.
If the wound be not recent and in the form of a fissure through its border, it will be necessary to freshen its edges before suturing them, other wise healing by second intention will ensue, each border cicatrizing separately and leaving a permanent slit in the concha.
It may be necessary to tie the horse on the pillar-reins to prevent his rubbing the ear against the manger or side of the stall.
In the case of fracture of the base of the concha, displacement of the edges of the fracture may occur, causing more or less occlusion of the entrance to the auditory meatus. Treat ment of this condition is not necessary, and is not likely to have much effect.
When the injury is very severe necrosis may supervene, causing loss of a variable portion of the external ear.
hematoma.A haematoma or collection of extravasated blood and serum beneath the peri chondrium of the flap of the ear, usually on its inner aspect and rarely on the outer aspect, or in both situations, is a common condition in the dog.
Etiology. The lesion is due to the rupture of blood and lymphatic vessels, caused by in cessant shaking of the head and scratching the ear with a paw as the result of irritation of the interior of the concha, brought about, as a rule, by aural canker.
The affection is most common in long-eared dogs, but it occurs in all breeds, and is some times seen in the cat.
Symptoms. A fluctuating swelling appears in the flap of the ear, usually on its inner aspect, occupying the greater part of its surface from its tip to its base.
It is more or less inflammatory, showing a variable degree of abnormal heat and hyper sensitiveness. If infection gain entrance sup puration will ensue.
Treatment. The application of absorbent topics to promote absorption of the enlarge ment is of no avail.
It is necessary to incise the swelling on the middle line from its upper to its lower extremity, evacuate its contents, and treat the lining of the cavity with an irritant, like tincture of iodine, to bring about inflammation, granula tion, and cicatrization. After healing has taken place, the subsequent contraction of the scar tissue causes puckering and a variable amount of deformity. To keep the quantity of cica tricial tissue as small as possible and cause immediate and permanent union between the skin and the cartilage, thereby minimizing the deformity mentioned, the following procedure is generally effective: Having operated on the swelling as described, insert a series of interrupted sutures through the ear, across the edges of the wound, and tied on the outer surface of the flap. Immobilize the ear with a pad and bandage or cap. Heal ing of the opposed surfaces may occur by first intention. Frequently, however, the desired effect is not produced.
If this method be not adopted, or prove a failure, the wound must be kept open until the cavity fills with granulations from its periphery.
Otherwise the cutaneous wound will rapidly heal and the swelling will reform. After sutur ing, it is also necessary to examine the wound daily and squeeze out with a pledget of cotton wool any discharge that may accumulate beneath the skin on either side of the sutures. The consequent deformity is more marked or more noticeable in short ears.
Necrosis of the Conchal Cartilage.Necrosis of the concha is most common in the horse, and is the result of an open wound and infection of the cartilage.
Symptoms. The symptoms are those of a sinus, there being an inflammatory swelling with one or more orifices discharging a greyish, foetid, and sometimes blood-stained pus. The ear becomes deformed from contraction of the fibrous tissue replacing the destroyed cartilage.
Treatment. The treatment is on the usual principles for a sinus, comprising opening up of the passage, providing for drainage, the injection of antiseptic or irritant liquids, or mechanical removal of the necrotic cartilage with the knife or curette.
When the ear is extensively diseased it is necessary to amputate the concha as follows: cast the horse on the opposite side, have the head well extended, prepare the site of operation, inject a solution of cocaine hypodermically, make an incision encircling the concha about one inch from its base, dissect back the skin and the upper border of the parotid gland for a short distance, divide the auricular muscles in this situation, ligature the anterior auricular artery, sever the ligament uniting the cartilage to the auditory meatus, and remove the former. Apply a pad of gauze over the meatus to prevent the entrance of blood therein, and suture the skin in front of and behind the orifice.
Healing occurs in the course of a fortnight. The scutiform cartilage is seldom affected with necrosis. The condition is treated in the same way as that of the concha, the cartilage being easily dissected out and removed if necessary.
Ulceration of the Concha.This condition is most common in long-eared dogs, in which it is usually the result of a wound which is prevented from healing by the constant shaking of the ears, or by rubbing them on the ground or scratch ing them with a paw.
The ulcer is usually situated towards the border of the flap, but the inner aspect of the latter may become ulcerated when affected with canker or otorrhosa.
Treatment. —The first indication is to remove the cause of the condition by arresting the shak ing of the ears, or treating canker when it is present. The ears may be immobilized in the manner described in connection with wounds of the ear. If the ulcer be of long standing and too callous to granulate and cicatrize, it should be cauterized with silver nitrate, or stimulated by the application of a little biniodide of mercury ointment, rubbed into the skin in the vicinity and smeared over the ulcer. Otherwise thorough cleansing of the lesion and dressing it with iodoform powder prove sufficient with immobilization. The passage of a couple of setons through the ear in the vicinity of the ulcer is a method often used with success in obstinate cases.
Foreign Bodies and Parasites in the Ear. Foreign bodies seldom remain lodged in the ear, but occasionally inspissated wax or cerumen, or a pebble or a piece of wood, or a bit of grass is found there, causing irritation and inflammation if a long time in situ.
Parasites or insects such as flies, fleas, and mari may also gain entrance to the concha and act as irritants.
Symptoms. Attention is attracted to the ear by repeated shaking of the head and scratching of the ear with a paw. The patient may whine from the pain or irritation caused by the foreign matter or parasite.
Treatment. A strong jet of lukewarm water introduced by means of a good-sized syringe generally has the effect of dislodging and expel ling the offending object. A forceps or a blunt curette may also prove useful for removing it.
If inflammation is present treat accordingly. A piece of cotton-wool wrapped round a pen-handle and smeared with vaseline may be used for the re moval of parasites, which adhere to the ointment. Tumours. Tumours are found affecting the ears of all the domesticated animals. They comprise papillomata, polypoid fibromata, and sebaceous cysts.
Papillomata or warts are most common in cattle, in which they often appear in clusters. Sebaceous cysts are found inside the base of the ear in the horse. Fibromata and sarcomata also occur in this animal. Polypi, sessile or pedun culated, are most frequently seen in the dog, affecting the lower portion of the interior of the concha, where they are almost invariably due to chronic otorrhcea. There may be a discharge from the ear of a foetid liquid, sometimes blood stained.
When both ears are affected the patient is quite deaf.
Treatment. The treatment is excision of the tumours. Pedunculated growths can be readily cut off with scissors, while those with a large base may be dissected with a sharp, narrow bladed bistoury. The base of the tumour may be cauterized to destroy any trace of it that may remain.
Malignant neoplasms such as sarcoma and carcinoma require complete amputation of the concha or cartilage on which they are situated, and if the surrounding tissues are involved operation will be useless, as the tumours are then sure to recur even after complete excision and cauterization of their site with the hot iron.