If the sinus has already been exposed before the accident occurs, the surgeon promptly arrests the hæmorrhage by placing the forefinger of his left hand directly over the wound in its wall and exerts sufficient pressure to completely obliterate the sinus at this point. With his finger kept in this position, the wound cavity is carefully dried, and, if there be sufficient room, a piece of sterilized gauze is then packed between the bone and the outer wall of the sinus, both above and below the site of the injury. If there be not enough room to do this, then the surgeon with his right hand, or the assistant, should punch away more bone by means of bone forceps. After the lumen of the sinus has been obliterated above and below the injured area, the finger may be removed. If the packing has been successful, there will be no bleeding; if there be still slight bleeding, it can be controlled by further pressure. If possible, this method should always be carried out, as it practically excludes any chance of after-infection of the sinus.
If the injury takes place before the sinus has been sufficiently exposed to permit of direct pressure with the finger, then the only thing to do is to press in a small strip of gauze and plug the opening. As to what should be done next is a matter of opinion. Some surgeons are content to leave the gauze in situ. The author prefers to expose the sinus further, as in the former case, and to make certain that it is obliterated above and below the injured area. No doubt, if the injury be slight, the pressure of the strip of gauze covering the puncture will be sufficient to control the hæmorrhage, and the patency of the sinus may be maintained on healing. At the same time infection of the sinus has been known to take place, although the symptoms of this may not occur for ten days or two weeks after the operation.
If the sinus projects far forwards the gauze plugs may so inconvenience the operator as to prevent him completing the operation, which therefore may have to be delayed for at least a week. If, however, the sinus be injured at an early stage of the operation and the symptoms for which it is being performed are urgent, then, in spite of all difficulties, the antrum, at any rate, must be opened to permit of drainage, the operation being completed at a later date.
Injury to the facial nerve. The nerve may be injured in any part of its course within the tympanic cavity, or in its vertical course through the stylo-mastoid canal. To avoid this injury, curetting of the tympanic cavity should always be performed gently, and care should be taken not to chisel too low down,—the usual fault of the inexperienced.
Twitching of the face means that the nerve has been touched. If the patient be under deep anæsthesia, it is difficult to say whether the nerve has been injured or divided. In a case of doubt, it is wiser to discontinue the anæsthetic until the conjunctival reflex returns, when it can easily be demonstrated whether the facial nerve is affected or not.
If the injury be the result of curetting, it is wiser to do nothing. Recovery almost invariably takes place, owing to the fact that the paralysis has been caused by slight injury of the nerve. If, however, the nerve has been chiselled through, and the injury has occurred in its lower portion, it should be freely exposed over this area. The severed ends of the nerve should then be approximated and left in situ. In this case permanent paralysis is possible.
The after-treatment consists in avoidance of pressure in packing, the giving of strychnine internally, and faradism or galvanism to keep up the tone of the facial nerve and the muscles it supplies. Careful testing of the electrical reaction will show whether nerve regeneration is taking place or not. If the paralysis has existed for six months, and if in addition there be a definite reaction of degeneration, then the question of anastomosing the peripheral portion of the facial nerve to the spinal accessory, or what is more advisable, to the hypoglossal nerve, may be considered (see Vol. I, p. 452).
Injury to the labyrinth. Of the semicircular canals the external is the more liable to injury. The cochlea may also be injured from violent curetting of the promontory, or infected from dislodgment of the stapes; or it may even happen that a careless operator may inadvertently chisel through the promontory itself. In consequence of these accidents, vertigo, vomiting, and nystagmus may persist for several days, but as a rule they gradually diminish and disappear.
The treatment is expectant. As a result of pyogenic infection, suppuration of the labyrinth may occur. Even if this does not take place, complete deafness may result.
Injury to the dura mater. The subsequent danger is meningitis, fortunately a rare occurrence. The immediate treatment is to irrigate the part with weak biniodide of mercury solution, and then to remove more bone over the site of the injury. The intracranial pressure will keep the dura mater in close contact with the bone, so that if subsequent infection occurs there will be free drainage. The site of injury should be carefully isolated from the general mastoid wound cavity by covering it with sterilized gauze. If signs of meningeal irritation occur, the wound should be inspected, and if there be any evidence of localized meningitis, it should at once be surgically treated.