_Wound of the lateral sinus._ This is a serious matter for two reasons: firstly, it may prevent completion of the operation; and secondly, it may lead to infection of the sinus.

If the sinus has already been exposed before the accident occurs, the surgeon promptly arrests the haemorrhage 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 a.s.sistant, 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 haemorrhage, 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 ca.n.a.l. 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 anaesthesia, it is difficult to say whether the nerve has been injured or divided. In a case of doubt, it is wiser to discontinue the anaesthetic 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 ca.n.a.ls 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.

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 ma.s.ses 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 part.i.tion 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 ca.n.a.l, 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.

CHAPTER VII

OPERATIONS UPON THE LABYRINTH

GENERAL CONSIDERATIONS

Labyrinthine suppuration usually occurs in the course of a chronic middle-ear suppuration; more rarely, as the result of tuberculous disease of the temporal bone, or in consequence of an acute middle-ear suppuration. In the latter case, however, it is a matter of experience that, although symptoms of labyrinthine suppuration may be present, they almost invariably subside as a result of drainage of the middle ear and mastoid. This is an important point which should be remembered, as otherwise the labyrinth may be explored unnecessarily at a considerable risk to the patient's life.

The most frequent paths of extension of the pyogenic infection from the middle ear to the internal ear are through the external semicircular ca.n.a.l, the promontory, and the fenestra ovalis, the result of cholesteatomatous erosion, caries, or necrosis. Hinsburg, in 198 cases of labyrinthine suppuration, traced the infection in 61 cases. In 27 cases the infection had entered through the external semicircular ca.n.a.l, in 17 through the fenestra ovalis, in 7 through a fistula of the promontory, in 5 through the fenestra rotunda and ovalis, and in 5 through a fistula in the posterior or superior semicircular ca.n.a.l (_Archives of Otology_, 1902, vol. x.x.xi, p. 116).

Although operations on the labyrinth are practically limited to suppurative disease, yet under certain conditions they are justifiable when no suppuration is present.

These operations may consist in partial or complete opening of the semicircular ca.n.a.ls, or of the vestibule, or in removal of the cochlea, or complete extirpation of the labyrinth.

INDICATIONS FOR OPERATION

(i) =In non-suppurative labyrinthitis.=

(_a_) _To relieve vertigo._ This operation is only justifiable if the condition cannot be cured by other methods, and is so distressing as to render the patient's life unendurable.

In such cases it is first essential to make certain that the attacks of vertigo originate from some lesion within the semicircular ca.n.a.ls. For this reason the other forms of vertigo must be excluded, and, in addition, there should be evidence of definite involvement of the labyrinth, such as falling over of the patient to the affected side, internal-ear deafness, or post-suppurative changes within the middle ear, suggestive that the internal ear has also become affected. It must, however, be remembered that it is possible, though extremely rare, for a lesion, limited to the semicircular ca.n.a.ls, to produce marked vertigo without any deafness being present, in which case the operation will be limited to extirpation of the semicircular ca.n.a.ls.

(_b_) _To relieve tinnitus._ If the tinnitus be unbearable and all other measures have failed to cure it, the question of extirpation of the cochlea, in order to destroy the nerve-terminals, may be discussed. This operation, so far, has not been completely successful, and therefore it cannot be recommended.

In this connexion it may be mentioned that, instead of attacking the cochlea, it has been proposed to divide the auditory nerve before it enters the internal meatus. Charles Ballance has recently described such a case.

The difficulty of this latter operation and the very slight chance of cure which it offers, owing to the tinnitus probably being central, are sufficient to raise the question as to whether such an operation is really justifiable.

(ii) =In suppurative labyrinthitis.= The object of the operation is to remove the infective focus and, by permitting drainage, to prevent further complications, such as meningitis or intracranial suppuration.

Before deciding the question of operation every means available should be used to determine: (1) whether the symptoms are merely the result of disturbance of the labyrinthine function in consequence of suppuration still limited to the tympanic and mastoid cavities; (2) whether the labyrinthine lesion is localized or general; (3) whether the labyrinthine suppuration is a.s.sociated with some intracranial complication, more especially meningitis or cerebellar abscess.

Suggestive of labyrinthine suppuration are vertigo, vomiting, spontaneous nystagmus, and disturbances of the equilibrium. In the more acute cases there may be loud tinnitus, pyrexia, rapid onset of deafness (with inability to hear high tuning-forks and loss of bone conduction), facial paralysis, and deep-seated pain.

In addition much information may be gained by determining the character of the _spontaneous nystagmus_, if present, or whether nystagmus can be elicited by _Barany's caloric tests_.

(_a_) If the ear be normal, there is no spontaneous nystagmus.

If, however, the ear be syringed with water above or below the body temperature, a rotatory nystagmus will be obtained if the patient's head is kept in the erect position, or a horizontal nystagmus if the patient is lying in the horizontal position with the face upwards.

Syringing with hot water causes a nystagmus directed _towards_ the ear syringed; syringing with cold water, _away from_ the ear.

(_b_) If there be a localized labyrinthine lesion, and the function of the labyrinth is still maintained, the same results will be obtained on syringing. Care, however, must be taken that the syringing is not forcible, otherwise the caloric tests will be unreliable, as in these cases nystagmus may be produced on even slight increase of pressure within the external auditory ca.n.a.l, and with this there may be a sensation of giddiness and nausea.

Spontaneous nystagmus, however, will probably be present, and will be directed towards the affected side. This spontaneous nystagmus is greatly modified by the caloric tests, being strongly exaggerated on syringing with hot water, and weakened or arrested on syringing with cold water.

(_c_) If the function of the labyrinth be destroyed, as in suppurative labyrinthitis, nystagmus will not be produced as a result of the caloric tests, but the spontaneous nystagmus, if present, will be directed towards the opposite, the normal side.

These various tests must be taken in combination with the symptoms, and frequently are of extreme value in deciding whether operation is indicated or not.