RESULTS OF THE OPERATION
With regard to life. If, at the time of the operation, the disease be limited to the mastoid cavity, there should be no immediate danger to life.
With regard to recovery. (i) The operation is successful. Roughly speaking this occurs in at least 80% of the cases, complete healing taking place within eight to twelve weeks. If skin-grafting has been successfully performed the duration of healing may be considerably shorter. If the bone disease has been eradicated with complete healing of the cavity, the possibility of intracranial complications in the future can be excluded. On this account the patient may be considered as a healthy individual from an insurance point of view.
(ii) The after-treatment may be prolonged. The chief causes of delay in healing and continuance of the suppuration are sepsis and caries of some part of the bony wall, usually the promontory or floor of the tympanic cavity, or around the orifice of the Eustachian tube. In the former case the use of ear-baths of hydrogen peroxide or of rectified spirit, or frequent syringing of the cavity with a weak biniodide of mercury solution, and afterwards drying it and protecting it with gauze, may be sufficient to effect a cure. In the latter case the local condition must be treated.
Another condition delaying cure is reinfection from the throat through a patent Eustachian tube. In this case, although the mastoid cavity becomes lined with epithelium, mucous membrane may still cover not only the region around the Eustachian orifice, but the main portion of the tympanic cavity. The chief object in these cases is to close the orifice of the Eustachian tube. Sometimes this can be done by curetting under cocaine; in other cases by actual cauterization. After closure has been obtained, the cavity should be dried and gently packed with gauze impregnated with boric acid or aristol powder.
Again, cholesteatomatous formation may be the immediate cause of relapses. In these cases it is very difficult to remove all the diseased tissue. Even although the patient may apparently be cured, yet, unless kept under close observation, recurrence of cholesteatomatous masses take place, and frequently cause further caries of the underlying bone.
Finally, delay in healing may be due to careless after-treatment: if the cavity has not been properly packed, granulations spring up in the region of the aditus and gradually form a partition between the mastoid and tympanic cavities. If this takes place, further disease of the bone may occur owing to the retention of the secretion.
(iii) Symptoms may occur pointing to some intracranial complication, and further operation may become necessary.
With regard to hearing. The hearing power depends not only on the condition before operation, but also on the result of the after-treatment. The average hearing power after the removal of the malleus and incus is about 12 feet off for ordinary conversation. The same result should be obtained after the complete mastoid operation, provided there be no internal-ear deafness and provided the stapes be not already ankylosed within the fenestra ovalis. If the patient before operation hears conversation at a greater distance than 12 feet he should be told that the hearing power may be reduced to this amount. If, however, there be considerable deafness, due to polypi or granulations blocking up the tympanic cavity and auditory canal, the hearing power may be improved by the operation. The ultimate hearing depends on the condition of the stapes within the fenestra ovalis: if it remains freely movable, the hearing power may be extremely good. The great object, therefore, of the after-treatment is to prevent the inner wall of the tympanic cavity becoming covered with granulations which may become organized later into a fibrous pad covering the inner wall of the tympanic cavity, and thus prevent movement of the stapes and, in consequence, marked deafness. The prevalent idea that the hearing power is destroyed irrevocably, as a result of the complete operation, is quite wrong: equally so is the harmful statement that, as a result of this operation, complete restoration of the hearing can be obtained.