That which is essentially a foreign body may be produced by an accumulation of cerumen in wax-like form within the auditory canal. Neglectful patients sometimes allow this to accumulate until it constitutes not only a source of irritation but an obstacle to hearing. Its removal is not ordinarily accompanied by difficulty, but requires patience and often considerable effort, not only with instruments, but with irrigation, especially with an alkaline solution, by which the waxy substance is softened.
A phenomenon noted in many of these cases, where instrumentation has to be practised within the vicinity of the middle ear, is coughing or sneezing, sometimes to a degree which interferes with the work to be done. This is a reflex to be explained through connection with the pneumogastric nerve.
THE EXTERNAL AUDITORY CANAL.
In the fibrocartilaginous as well as in the more richly cellular portions of this passage-way small phlegmonous processes frequently occur. They give rise to an amount of suffering, and even of sympathetic reaction, disproportionate to the extent of the difficulty. They are called furuncles, or boils, sometimes occurring singly, often in groups. A commencing process of this kind may be cut short by the use of an ointment of 1 to 2 per cent. yellow sulphate of mercury, but after the furuncle is well developed it is best treated by free incision, which can be made with the freezing spray, and without much pain to the patient.
More extensive phlegmonous destruction, assuming even carbuncular form, is occasionally met with in this region. There will be more or less necrosis of tissue in such cases, which will require removal, usually with the sharp spoon. These cases are not without their danger, since the veins connect so freely with the interior of the cranium.
Hyperostosis and exostosis produce either a narrowing of the auditory canal or its complete obstruction, and sometimes even the formation of an osseous tumor of considerable size. A thickening and even new formation of bone may be the result of the chronic irritative processes which frequently occur in the middle ear, but many of these conditions occur in the newborn, in whom they are to be regarded as congenital excesses and in whom they frequently cause permanent impairment or loss of hearing. Some of the osteomas in this region are of bone-like hardness, their density being sufficient to dull or even to break the finest tempered steel instruments.
A small exostosis may be removed with the ordinary instruments of the surgeon or the dental engine, but the larger and more dense growths offer formidable difficulties for the operator and uncertain results for the patient. When growths of this kind attain considerable size they should not be attacked through the natural passages, but the auricle should be separated and pushed forward and the auditory canal opened.
THE MIDDLE EAR.
The middle ear has for its external boundary the membrana tympani, which, for clinical purposes, constitutes a limit beyond which the general surgeon should not trespass, the structures within being those within the field of the aural surgeon. Nevertheless the student of surgery should realize that the membrane of the drum may be ruptured in consequence of a blow upon the external ear, or perhaps by the sudden condensation of air produced by explosions, etc. It may, moreover, be lacerated in consequence of various injuries to the head, basal fractures, etc., even those involving the opposite side of the head; it may also be injured by foreign bodies, introduced usually from without and through the canal. While this membrane has normally an opening by which air pressure is equalized on either side, this seems to play but a small part in the liability to or exemption from injury such as just described. The membrane has its own blood supply, which can become congested to a degree permitting considerable escape of blood after laceration. It does not follow that bleeding from the ear is necessarily an indication of basal fracture, after injuries of the head, unless the hemorrhage is continuous and considerable, in which case it may be stated that the injury must be deeper and more extensive than one of the membrane alone. If, however, cerebrospinal fluid can be detected as escaping with and diluting the blood, or escaping independently, then the diagnosis of basal fracture may be regarded as certain.
After such injuries as lead to hemorrhages from the ear the external auditory canal, should be irrigated and protected against infection by light tamponing, etc.