1. Purulent inflammation in the mastoid process appearing in the course of suppuration of the middle ear when persistent severe pain in the bone cannot be subdued by the application of the ice-bag, leeches, or by Wilds' incision. (Schwartz).
2. Painful inflammation in the mastoid process occurring in acute and chronic suppuration of the middle ear, in consequence of growths filling up the external meatus or the tympanic cavity. When attempts to remove the obstacle to the free escape of pus have failed, the operation is imperative. (Grüning). The operation is indicated even though the soft parts over the mastoid are not swollen or infiltrated. (Politzer).
3. When the posterior superior wall of the meatus is bulging, and when after incision the abscess is not emptied and the symptoms of retention of pus continue. (Toynbee, Duplay).
4. Persistent pain and tenderness in the mastoid process lasting for days or weeks, in which there is probably an osseous abscess not communicating with the tympanic cavity. (Politzer).
5. In every suppuration of the middle ear combined with inflammation of the mastoid process in which fever, vertigo and headache are developed during the course of the affection, which may indicate a dangerous complication. In such cases the indication for the operation is vital. (Politzer, Roosa, Buck.)
As to the time when the operation should be performed, writers do not agree. While one proposes that the operation should be done as soon as there are symptoms of inflammation of the mastoid process, another defers it till the dangerous symptoms (fever, headache, vertigo, etc.,) set in. The latter proposal must not be followed, as in many cases it would be too late; on the other hand, many cases will recover without an operation. As far as it can be formulated, I would say that in a given case of acute purulent inflammation of the mastoid process I would first apply leeches, poultices, cathartics, antiflogistics. If the inflammation is not promptly subdued, I would make a Wilds' incision, including the periosteum, if the bone is found softened; or if a fistulous opening is found, this should be enlarged at once. If the bone is found healthy and not roughened, if there is no fever, vertigo, headache, etc., I would wait a few days; if the symptoms, pain, tenderness, etc., do not subside, I would then perforate the mastoid process.
For the performance of the operation trepans were formerly used, which were replaced by drills which are still used by Buck, Jacobi, Lucae and others, but by most operators they have been set aside, owing to their uncertain and dangerous advance in the deep parts, and on account of their soiling the wound with splinters. The most rational and safe method is by means of the chisel, as recommended by Schwartz, and is performed as follows: The patient being anæsthetized, a perpendicular incision beginning a little above the linea temporalis, extending an inch and a half in length immediately behind the attachment of the auricle. Formerly I employed a straight incision, but recently have followed the suggestion of Politzer, and from the superior end of the perpendicular incision a second one is made backward at right angles, thus forming a flap, which I have found to simplify the operation very much, as it affords a better view of the locality and extent of any pathological changes which may have taken place, and gives more room for operative procedures, and the periosteum can readily be removed to any desired extent. The linea temporalis and the more or less strongly developed protuberance on the posterior superior orifice of the osseous meatus, so strongly urged by authors, are very nice guides theoretically or to point out on an exceptional skull in the class room, but practically are seldom well enough developed to be of any use to the operator. The best guide to go by is to take the superior wall of the meatus as the upper boundary, and the angle formed by the plane of the mastoid with the posterior wall of the external meatus for the anterior boundary when opening the mastoid. This is best determined by pressing the finger into the meatus. Often in children, and when the bone is diseased in adults, the cortical plate of bone can be removed with the hand chisel, and we come at once upon the pus cavity, or diplœ, or cholesteatomatous epidermic masses, or a sequestrum of dead bone, or bleeding granulation tissue, or whatever the case may present. Sometimes the external plate is very thick and we have to chisel our way carefully for almost half an inch before reaching the diplœ, or may find the entire mastoid process sclerossed. No absolute rule can be given as to the depth it is safe to penetrate. Schwartz says "never to go deeper than 25 mm." Buck says "it is better to place the extreme limit at 20 mm," about three-fourths of an inch.
Although I do not consider the operation a particularly dangerous one, especially with the chisel where we can watch each step of the operation; and even though we opened into the lateral sinus or the duramater, the injury would not be necessarily fatal. Yet I would not advise any one to attempt it (unless the indications are imperative) who has not performed the operation on the dead subject. Politzer says "no one should operate on the living before having performed the operation at least forty or fifty times on the dead." I cannot close this article better than in the words of Dr. St. John Roosa, to whose admirable work I am indebted for a large portion of this article.
"Yet, hesitation, when the way is plain, or when the chances are largely on the side of the necessity of the removal of pus, cannot be too sternly condemned. No drug has yet been discovered which can be substituted for the scalpel or trephine when pus has actually formed in the mastoid cells. I wish, however, to repeat what I have said before on the subject of surgical operations. I am in full accord with the great English surgeon, Sir James Paget, who, in his admirable lectures, expresses many times his hesitation to perform any surgical operation, however trivial, that is not absolutely required. We have no right, I think, to perform operations to clear up doubtful diagnosis. If in case the operation proves to have been unnecessary, the patient will be decidedly the worse for it. If we put ourselves in the place of our patients, what we may regard as a trifling thing—"a mere cut"—will not be so esteemed. A mere cut, when unnecessary, may have the most serious consequences, and all the history and symptoms should be carefully weighed before even that is undertaken. Such care will never prevent prompt, rapid and thorough surgical interference when demanded.
In teaching medical students, I have always found them, when fully awakened to the dangers of neglecting certain diseases, to be more apt to do too much than too little, especially with the knife and active drugs. It is possible, also, that the crying ignorance and neglect of the previous decades in regard to the treatment of aural disease has had a tendency to cause us, who see many of the afflictions of the ear, to lean toward the side of surgical operations upon the drum, head and mastoid. This is a leaning no less dangerous to the cure of some cases than was the steering toward Scylla or Charybdis to the safe navigation of ancient mariners."