CHAPTER III

OPERATIONS UPON THE TYMPANIC MEMBRANE AND WITHIN THE TYMPANIC CAVITY

SURGICAL ANATOMY OF THE TYMPANUM

=The tympanic membrane.= The chief points to notice when operating on the tympanic membrane are its inclination and its relation to the inner wall of the tympanic cavity.

The normal membrane is inclined obliquely downwards and forwards so that it forms an obtuse angle of 140 degrees with the roof and an acute angle of 27 degrees with the floor of the external meatus. In infants the inclination is even greater.

Its relation to the tympanic cavity varies in its different parts. It lies nearest to the inner wall in the region of the umbo, being only 2 millimetres distant from the promontory, and is furthest from it in the posterior quadrant.

Running backwards, just below the posterior fold, is the chorda tympani nerve, which may be cut through in the act of paracentesis and in division of the posterior fold.

=The tympanic cavity.= For the purpose of description the portion of the tympanic cavity above the level of the tympanic membrane is known as the _attic_ or _epitympanic cavity_; whilst the part below its level is called the _cellar_ or _hypotympanic cavity_ (Fig. 186).

The =attic= contains the head of the malleus and the body and short process of the incus, and communicates posteriorly with the antrum by a variable sized opening--the aditus. Its roof, the tegmen tympani, a plate of bone frequently of extreme thinness, separates the cavity of the middle ear from the middle fossa of the cranium. The facial canal extends backwards along the inner and upper border of the tympanic cavity, passing above the vestibule and the fenestra ovalis to curve downwards posteriorly beneath the external semicircular canal, which at this point forms the inner and inferior boundary of the aditus.

The =ossicles= form a movable chain fixed at three points: namely, the attachment of the handle of the malleus to the tympanic membrane; the posterior ligament of the incus, a feeble structure, binding its short process to the entrance of the antrum; and the strong annular ligament connecting the footplate of the stapes to the margins of the fenestra ovalis.

In addition, the anterior, external, and superior ligaments of the malleus also tend to keep it in position and limit its movements.

The tensor tympani muscle, extending from the processus cochleariformis, crosses the tympanic cavity to be inserted into the inner margin of the neck of the malleus; and the stapedius muscle emerging from the apex of the eminentia pyramidalis is inserted into the head of the stapes.

These ligaments and muscles partially divide the cavity into smaller compartments, such as the outer attic and Prussak’s space, so that in some cases inflammation may be limited to only a part of the tympanic cavity; a fact to be remembered in considering the question of operative procedures.

OPERATIONS UPON THE TYMPANIC MEMBRANE

PARACENTESIS

=Indications.= The chief object of paracentesis (myringotomy or simple incision) is to permit of escape of fluid from the tympanic cavity.

(i) _In acute inflammation of the middle ear_, if the acute symptoms continue in spite of palliative treatment, and the following conditions are present:--(_a_) An increasing congestion and bulging of the tympanic membrane, especially if accompanied by earache and pyrexia. (_b_) The obvious presence of pus within the tympanic cavity, shown by a circumscribed, angry red or yellow protuberance on the tympanic membrane. (_c_) Accompanying cerebral symptoms, such as drowsiness, vomiting, vertigo, and convulsions. (_d_) Tenderness over the mastoid process. (_e_) Paroxysms of pain acute enough to prevent sleep.

Paracentesis should be done early in infants and in specific fevers. In the former case even a slight middle-ear inflammation may give rise to all the cardinal symptoms of meningitis, which frequently subside rapidly as the result of simple paracentesis; in the latter, there may be rapid destruction of the drum, which a timely incision may possibly prevent.

(ii) _In middle-ear catarrh with exudation._ Paracentesis is justifiable in order to remove the secretion, if the hearing does not improve after a month’s treatment, owing to the existence of exudation within the tympanic cavity.

(iii) _As a preliminary to intratympanic operations._

=Operation.= The auricle and surrounding parts are surgically cleansed (see p. 309), the preliminary toilet, if possible, being carried out at least half an hour before the operation is performed.

Although apparently a trivial matter, it is of the utmost importance to render the auditory canal as aseptic as possible in order to prevent secondary infection of the tympanic cavity from without.

It is wiser to give a general anæsthetic, such as gas and oxygen, as the pain of the operation may be intense. If this is refused, local anæsthesia by Gray’s solution (see p. 310) or by a subcutaneous injection of cocaine and adrenalin may be employed. In infants an anæsthetic is not necessary.

The patient may be sitting up or lying down. If a general anæsthetic has not been given, the patient’s head must be held firmly by an assistant in order to prevent sudden movement. The surgeon works by reflected light in order to obtain a clear view of the tympanic membrane.

The point of election for the incision is through the posterior part of the membrane, excepting when it is obvious from the bulging and appearance of the membrane that the incision must be made in the anterior inferior quadrant.

The incision is made by means of a paracentesis knife, which is shaped like a tiny bistoury set at an angle to its handle (Fig. 187). The double-edged spear-shaped knife is now seldom used, as with it there is a tendency to puncture rather than to incise the membrane.

The tympanic membrane is pierced by the paracentesis knife at its inferior posterior margin. With a quick movement the drum is incised freely, the incision being carried in an upward direction midway between the malleus and the circumference of the membrane posteriorly, until it reaches Shrapnell’s membrane (Fig. 188). In making this incision the inclination of the membrane must not be forgotten. Owing to its lower margin being more deeply placed than the upper, there is a tendency for those who have not had much practice in doing a paracentesis to begin their incision too high up, as they fail to realize the greater depth of the canal at this point. The soft tissues of the upper posterior wall of the external meatus close to the membrane, if much congested, may be incised also in the act of withdrawing the knife. In doing this the chorda tympani nerve may perhaps also be cut, resulting in loss of taste on the affected side for a time; this is a matter of no importance. As a result of this free incision, drainage is given to the contents of the tympanic cavity, attic, and antrum.

In order to prevent rapid closure of the perforation and to give better drainage, some authorities advise making a flap-shaped incision. To do this, the membrane is incised upwards, nearly to its upper border; the knife is then carried backwards and downwards before it is withdrawn from the wound.

Occasionally the acute inflammation is limited to the attic, Shrapnell’s membrane appearing deeply congested and bulging outwards so as to cover the processus brevis, whilst the rest of the membrane may be only slightly injected. In such cases it is sufficient to incise the bulging area, beginning the incision just above the region of the processus brevis and carrying it horizontally backwards to its posterior extremity (Fig. 189).

=After-treatment.= In acute middle-ear inflammation, after the first rush of blood and discharge has been mopped away, a small drain of sterilized gauze should be inserted into the auditory canal and the ear protected with a pad of sterilized gauze. The dressing and gauze drain should be changed as often as may be necessary, depending on the amount of discharge. The ear should not be syringed out unless the discharge becomes very profuse and thick.

In acute middle-ear catarrh with exudation, a Siegle’s speculum (Fig. 194) should be inserted into the meatus after free incision of the membrane, and as much fluid as possible extracted by suction. In addition, gentle inflation by means of Politzer’s method will help to expel from the middle ear the fluid, which should then be mopped out of the external meatus. This should be repeated daily.

=Difficulties and dangers.= The usual fault is to mistake the congested posterior wall of the external meatus for the membrane.

If the patient is not under an anæsthetic, the incision may be made too timidly, the membrane being only scratched. The pain thus inflicted will cause the patient to jerk away the head and probably prevent the membrane from being incised freely. The incision, therefore, must be made in a bold and rapid manner. It is better to make the incision too free than too small.

Care must be taken not to plunge in the knife too deeply for fear of wounding the mucous membrane of the inner wall of the tympanic cavity. This may result in adhesions between it and the membrane.

Further, cases have been recorded in which a too violent incision has injured or dislodged the ossicles, or in which severe hæmorrhage has occurred, presumably from puncturing the bulb of the jugular vein, which was projecting abnormally through the floor of the tympanic cavity.

The two chief causes of failure are insufficient drainage from too small an incision, which may necessitate a further operation, and secondary infection from without.

=Results.= In the majority of cases, provided free drainage is established, the discharge ceases and healing of the membrane takes place from within a day or two to four weeks, depending on the character of the case. If the symptoms continue it may become necessary to perform the mastoid operation (see p. 373).

ARTIFICIAL PERFORATION OF THE TYMPANIC MEMBRANE

The object of the operation is to equalize the pressure within the tympanic cavity and external meatus so as to enable vibrations of sound to be transmitted more readily by the membrane and chain of ossicles to the inner ear.

=Indications.= (i) In the case of an extremely calcified membrane which apparently cannot vibrate.

(ii) To relieve tinnitus or vertigo which appears to be due to an alteration of tension within the tympanic cavity, the result of an impermeable stricture of the Eustachian tube.

(iii) As a means of diagnosis. If the hearing be improved or the subjective symptoms relieved as a result of the artificial opening, then, if the perforation closes (as it probably will do), the surgeon is in a position to suggest some more radical measure, such as ossiculectomy (see p. 351).

=Operation.= Two methods are employed: (i) The knife; (ii) The galvano-cautery. The perforation should be made in the postero-inferior quadrant.

In favour of the galvano-cautery is the fact that the perforation does not tend to close so rapidly. On the other hand, considerable damage may be done unless it is applied with extreme care. For this reason it is wiser to operate under a general anæsthetic, such as gas and oxygen.

If the _paracentesis knife_ be used it is not sufficient to make a simple incision; a small triangular flap must be excised. The operation should be performed under good illumination. The paracentesis knife is inserted boldly through the membrane a little behind and above the umbo. The membrane is incised in an upward and slightly backward direction towards its margin; then downwards parallel to its posterior border; then horizontally forward, meeting the original point of the incision. The excised portion of the membrane is removed by seizing it with a fine pair of crocodile forceps, or by means of a fine snare, if it has not been completely detached.

The _galvano-cautery_ is applied cold; when it is in contact with the drum, the circuit is closed so that the point of the cautery becomes red-hot. After the membrane has been burnt through it is withdrawn rapidly so as not to scorch the surrounding tissues. In using the cautery care must be taken to push it only just through the membrane for fear of injuring the inner wall of the tympanic cavity.

=After-treatment.= The after-treatment consists in protecting the ear by a strip of gauze, which is changed as often as may be necessary.

DIVISION OF THE ANTERIOR LIGAMENT

=Indication.= It is advised by Politzer in those cases of marked retraction of the drum in which inflation causes an immediate improvement in hearing, which, however, only lasts a short time. In several cases Politzer found the cause of this to be due to tension of the anterior ligament causing retraction of the malleus.

=Operation.= The anterior fold is divided with the paracentesis knife just in front of the processus brevis of the malleus. The knife is then introduced 2 millimetres inwards through the incision and made to cut in an upward direction as far as Shrapnell’s membrane (Fig. 190, C). This should divide the ligament.

If the operation be successful, improvement in hearing and also diminution of the subjective noises should take place.

DIVISION OF THE POSTERIOR FOLD

=Indication.= The same as for the anterior ligament. Owing to the increased tension of the upper posterior quadrant of the tympanic membrane, it is assumed that the movements of the malleus are diminished, and with this the hearing power. Seeing, however, that the prominence of the posterior fold is due to the projection outwards of the processus brevis as a result of the handle of the malleus having become indrawn with the membrane, it is difficult to understand how its division can possibly be a means of restoring the retracted membrane to its normal condition.

On the few occasions on which I have performed this operation, no improvement has followed. Others, however, maintain that it may do good in certain cases. This, perhaps, may be possible if it is combined with other intratympanic operations, such as division of the anterior ligament or of the tensor tympani muscle.

=Operation.= The paracentesis knife is inserted through the most prominent part of the fold and is made to cut through it from above downwards (Fig. 190, B). If this is successful, gaping of the cut edges takes place and the membrane assumes a less retracted position, and increased hearing and diminution of the subjective symptoms should occur on inflation and rarefying of air within the external ear.

INTRATYMPANIC OPERATIONS

=General considerations with regard to intratympanic operations and their results.= The chief difficulty, from a clinical point of view, is to determine beforehand the exact pathological changes which already exist within the tympanic cavity. For this reason the indications given with regard to operation are of necessity somewhat empirical. For example, retraction of the tympanic membrane may be due to closure of the Eustachian tube; to adhesions between it and the promontory; to contraction of the tensor tympani, of the anterior ligament, or of the posterior fold. An operation to remove only _one_ of these causes may, therefore, be insufficient; the difficulty is to know what to do. Even if further operations are performed, the result may be negative owing to adhesions having taken place already between the ossicles themselves, or from binding down of the incudo-stapedial joint or of the stapes to the inner wall of the tympanic cavity. And apart from this, even if temporary benefit is obtained, the final result may be worse than that which existed before operation owing to the natural tendency for adhesions to re-form.

The prognosis is better in the case of post-suppurative conditions than in the non-suppurative ones.

Improvement by operation may be hoped for if a temporary increase in the hearing power, with diminution of the subjective symptoms, is obtained as a result of inflation; especially in those cases in which the malleus is only locally adherent to the promontory.

Generally speaking, however, these operations are not recommended, owing to the impossibility of being able to give a good prognosis, and therefore they can only be considered as experimental.

_These operations are contra-indicated_--(1) If there be internal-ear deafness.

(2) If the stapes (as shown by tuning-fork tests and Gellé’s test) be ankylosed within the fenestra ovalis, especially in the case of otosclerosis.

(3) If the membrane be completely adherent to the inner wall at its upper posterior quadrant, especially if this is of long standing, as the stapes will almost certainly also be fixed by adhesions.

DIVISION OF INTRATYMPANIC ADHESIONS

The position and extent of the intratympanic adhesions vary exceedingly, and may be the result either of middle-ear catarrh or suppuration. The following conditions may be found:--

(i) Adhesion of the handle of the malleus to the promontory, the rest of the tympanic membrane being movable.

(ii) Adhesions between other parts of the tympanic membrane and the inner wall of the tympanic cavity, either by bridles or bands of fibrous tissue, or by the membrane itself being adherent over a large area.

(iii) Adhesion of the edge of a perforation to the inner wall.

(iv) Adhesions surrounding the articulation between the incus and stapes, and the stapes itself.

=Indications.= Operation is justifiable in the case of adhesion of the malleus to the promontory if the rest of the membrane is freely movable; if the membrane bulges outwards and there is temporary improvement in hearing on inflation; and if examination shows that the labyrinth is intact. This operation is all the more indicated if there is marked deafness on both sides: it should then be attempted on the worse side. If, however, the intratympanic adhesions are extensive, it is very doubtful whether an attempt to separate the free part of the membrane from the part adherent to the inner wall is worthy of consideration.

It must also be remembered that adhesions in the region of the stapes cannot be seen, unless a large perforation of the membrane already exists. Operation is then only justifiable as a last resource if there is extreme deafness accompanied by distressing subjective symptoms.

=Operation.= Unless the patient is very sensitive or nervous, local anæsthesia is sufficient. It is more convenient for the patient to be sitting up in a chair than to be in the recumbent position. The surgeon works by reflected light. Before the operation is begun, the ear must be surgically cleansed and carefully dried.

(i) _Adhesion of the handle of the malleus to the promontory._ With a paracentesis knife the membrane is incised round the handle of the malleus (Fig. 191). A small sickle-shaped knife, fixed at right angles to its shaft, is then inserted through the incision (in front of or behind the malleus as may be most convenient to the operator) and is made to cut through the adhesions between the malleus and the promontory (Fig. 192). In order to make sure that this has been accomplished, a small ring-knife, such as is used in the operation of ossiculectomy, is passed round the tip of the malleus, between it and the inner wall of the promontory, and slight traction is then exerted in order to pull the handle of the malleus outwards from the inner wall.

Provided asepsis has been maintained, this small operation seldom gives rise to any inflammatory reaction. The after-treatment consists in inserting a strip of gauze into the auditory canal; if it becomes moist with secretion, it should be changed.

Many methods have been devised to prevent recurrence of adhesions, but few are successful. Amongst these are daily inflation of the ear by means of Politzer’s method or the catheter; the injection of oil into the middle ear; and the insertion of small pieces of celluloid between the malleus and inner wall of the promontory according to the method of Gomperz. Another method is to _resect the handle of the malleus_ (Fig. 195). After being freed from the promontory as above described, the manubrium is cut through with a pair of fine scissors (Fig. 174) just below the processus brevis, and the lower fragment is removed by means of Sexton’s forceps (Fig. 193).

(ii) _Adhesion between the membrane and the inner wall of the tympanic cavity._ Siegle’s speculum should be used to determine the position and extent of the adhesions (Fig. 194).

There are two methods of operation:--

(_a_) In the case of bands forming a bridle between the tympanic membrane and inner wall, an attempt may be made to cut through them. This is done by incising the membrane with a paracentesis knife in front of or behind the adherent portion, and then inserting through this incision the sickle-shaped knife. By rotating it upwards or downwards, as the case may be, the bands forming the adhesions are cut through. If this has been successfully performed, and if the retraction of the membrane was solely due to these bands, the tympanic membrane will be found to be freely movable on diminishing the pressure of air within the external meatus by means of Siegle’s speculum.

(_b_) If the adhesions be extensive, the only method affording a chance of success is to separate the free portion of the tympanic membrane from the part adherent to the inner wall, leaving the latter _in situ_. To do this the membrane is incised with a paracentesis knife just beyond the margin of the adherent portion, the incision being carried right round the affected part. A tiny spatula, bent at right angles to its shaft, is then inserted through the incision and passed round beneath the movable portion of the membrane so as to free it completely (Fig. 192).

(iii) _Adhesion of the edge of a perforation to the inner wall._ If the middle-ear suppuration has only recently ceased, it may be sufficient to divide the adhesion with a small knife curved on the flat and afterwards force the tympanic membrane outwards by means of inflation through the Eustachian tube, and by rarefaction of the air within the external meatus. In the majority of cases, however, it is necessary to excise the adhesion, especially in the more chronic conditions. This is done by cutting through the movable part of the membrane just beyond the adherent portion (_vide supra_).

(iv) _Adhesions surrounding the articulation between the incus and stapes, and the stapes itself._ These adhesions can only be observed if a large perforation involves the upper posterior quadrant. Even then it may be anatomically impossible to see the stapes. The operation should only be performed if definite bands of adhesions can be seen. Sometimes, although rarely, it happens that such adhesions are present. If the incudo-stapedial joint be fixed to the inner wall of the tympanic cavity, the adhesions are separated from it by passing the knife between the joint and the inner wall. In order to cut through adhesions surrounding the base of the stapes, a small horizontal incision should be made along its upper margin, and also along the lower, if this is in view. This operation, however, is seldom of any value.

TENOTOMY OF THE TENSOR TYMPANI

=Indication.= The chief indication for this operation is marked retraction of the tympanic membrane, in a case of middle-ear deafness, in which there are no adhesions between the membrane and the inner wall of the middle ear, and in which it is assumed that the retraction is due to shortening of the tensor tympani muscle.

=Operation.= The first step of the operation is to incise the tympanic membrane with a paracentesis knife in a vertical direction just behind the margin of the malleus. At the same time the posterior fold can be cut through, if required, by continuing the incision upwards. Through the incision thus made Schwartze’s tenotomy knife (a very fine blunt-pointed instrument curved on the flat (Fig. 196)) is inserted, its point being directed upwards. The knife is pushed upwards until its shaft is on a level with the processus brevis. The handle is then rotated in a forward direction so that the sharp edge of the knife, which is kept close to the posterior border of the neck of the malleus, makes a circular movement forwards and downwards and thus cuts through the tendon of the muscle. If the knife has been too deeply inserted, the attempt to rotate the shaft forwards will be resisted by the projecting processus cochleariformis. To overcome this difficulty the shaft of the instrument is rotated backwards so as to raise the point of the tenotomy knife and thus free it; the instrument is then withdrawn slightly and the shaft again rotated forwards. The division of the tendon can be distinctly felt, and may be accompanied by a slight crackling noise; after this has been effected, the knife is rotated backwards and withdrawn through the incision in the tympanic membrane.

=After-treatment.= There is usually a slight effusion of blood within the tympanic cavity, but no special treatment is required beyond keeping the ear aseptic. Absorption takes place rapidly.

The _result_ of the operation is disappointing. There is seldom any improvement with regard to hearing; a few cases, however, have been reported in which the attacks of vertigo have diminished in intensity.

TENOTOMY OF THE STAPEDIUS

=Indications.= They are limited.

(i) As the result of middle-ear suppuration the malleus and incus may become exfoliated. The theory has been advanced that the unopposed action of the stapedius muscle prevents free movement of the stapes in these cases, and for this reason tenotomy of its tendon is advocated.

This operation, however, should only be performed provided that the edge of the membrane is not adherent to the inner wall of the tympanic cavity, and there is no internal-ear deafness.

(ii) The operation is also performed as a preliminary measure to removal of the stapes (see p. 361).

=Operation.= The operation is simple, as the head of the stapes and the tendon of the stapedius muscle are usually within view in consequence of the destruction of the tympanic membrane. The ear is cleansed and dried, and the part rendered insensitive by the previous application of a pledget of cotton-wool soaked in cocaine solution. The tiny tendon is severed with a snick of the paracentesis knife, cutting through it from above downwards under good illumination.

=Results.= These vary; usually there is no improvement, but sometimes marked increase of hearing occurs. As the operation can do no harm and can be done without any inconvenience to the patient, it may be attempted subject to the restrictions given above.

REMOVAL OF GRANULATIONS FROM THE TYMPANIC CAVITY

=Indications.= Granulations should always be removed if conservative treatment fails.

=Operations.= (_a_) _Cauterizing_; (_b_) _Curetting._ The former method is employed when the granulations are very small and localized; the latter when they are multiple and larger.

=Cauterization.= The tympanic cavity is cleansed and rendered anæsthetic (see p. 310). The auditory canal and tympanic cavity are then carefully dried. This is of importance in order to prevent scalding of the surrounding tissues during the act of cauterization. The ordinary electric cautery is used; only a weak current is necessary as the point of the cautery, of necessity, is very small. Under good illumination, the cautery is inserted cold along the auditory canal until it just touches the granulation. The circuit is then closed, and on the point of the cautery becoming white-hot, it is pressed against the granulation and then rapidly withdrawn from the ear. The current should not be shut off until the cautery is withdrawn, otherwise it will adhere, on cooling, to the tissues with which it is in contact, and on withdrawal will cause bleeding.

Instead of the electric cautery, the granulations may be touched with a bead of chromic acid fused on to a probe, or with a saturated solution of trichloracetic acid. The galvano-cautery has the greatest effect. Chromic acid has the disadvantage that unless it is very accurately applied it tends to affect a larger area than was possibly intended. Trichloracetic acid, although more localized in effect, is not so potent.

_After-treatment_ consists in blowing in a slight amount of boric acid powder and keeping the ear dry.

=Curetting.= This is performed by means of small ring-knives (Fig. 178) or sharp spoons. They vary in size, and are either straight or bent in different directions to the shaft of the instrument. The instrument selected depends on the position and size of the granulation.

To minimize the hæmorrhage, adrenalin may be added to the cocaine solution. The curette is made to encircle the granulation and cuts through its attachment with a firm movement, limited to the area of the granulation. Curetting should not be done in a haphazard fashion, but deliberately under good illumination. If bleeding occurs it must be arrested before further curetting takes place.

_After-treatment._ The ear is syringed out to remove any fragments of granulation tissue or blood-clot. It is then dried and a strip of sterilized gauze inserted. After twenty-four hours this is removed and drops of rectified spirits, if necessary containing ten grains of boric acid or a drachm of the perchloride of mercury lotion to the ounce, may be instilled into the ear three or four times a day.

=Dangers.= With due care none should occur. The following mishaps, however, have occurred from too violent curetting: (1) Injury or displacement of the ossicles; (2) internal-ear suppuration from dislodging of the stapes or injury to the promontory; (3) facial paralysis; (4) meningitis from injury to the tegmen tympani; (5) acute inflammation of the mastoid process.

=Results.= Provided that the granulations are localized and due to inflammation of the mucous membrane, a good result may be anticipated. If, however, there be underlying bone disease of the tympanic walls, or if the mastoid process be already affected, recurrences are usual, and further operative treatment may become necessary.

OPERATIONS UPON THE OSSICLES

DIRECT MOBILIZATION OF THE OSSICLES

The object of the operation is to improve the hearing by breaking down the fibrous adhesions with the tympanic cavity, which diminish the mobility of the ossicles.

=Direct massage of the malleus.= =Indications.= (i) As a therapeutic measure. If the malleus be adherent to the promontory and there is no improvement on inflation, but perhaps slight improvement as a result of pneumatic massage.

(ii) As a means of diagnosis. If temporary improvement takes place it may be assumed that the stapes is not absolutely fixed, and that the deafness is partly due to adhesions preventing movements of the ossicles, a condition which may point to the advisability of performing ossiculectomy in suitable cases.

=Operation.= The ear is rendered insensitive by means of cocaine or Gray’s solution (see p. 310).

The manipulation is carried out with a Lucae’s probe (Fig. 197). Within its handle is a spring to render its movements resilient; and at its tip is a cuplike depression to embrace the point of the processus brevis of the malleus. The tip of the probe may be covered by a fine layer of cotton-wool or india-rubber.

The probe is inserted, under good illumination, into the auditory meatus and is applied to the processus brevis of the malleus. The vibrations are given by the rapid movements of the hand from the wrist, the arm being kept fixed. This procedure, which may be painful, should not last longer than one minute. Frequently there is considerable reaction, shown by congestion about the processus brevis and Shrapnell’s membrane. It is therefore wiser not to repeat the procedure at shorter intervals than one week.

=Results.= It is difficult to foretell what the result will be, as it is chiefly dependent on the extent of the adhesions already existing within the tympanic cavity and on the mobility of the stapes within the fenestra ovalis. If the latter is already fixed, then improvement is impossible. If, however, the adhesions are limited, a better result may be obtained by this method than by pneumo-massage and inflation. The surgeon must be guided by the extent and duration of the improvement as to how long to continue the treatment. Unfortunately, relapses are not uncommon, though temporary benefit may be obtained.

=Massage of the stapes.= This is only done as a last resource in the hope of obtaining some improvement in hearing.

=Indications.= (i) In cases in which mobilization of the malleus has caused no improvement, and it is hoped, from the history of the case, that this is due to fibrous adhesions fixing the stapes within the fenestra ovalis. This condition must be carefully distinguished from otosclerosis or bony ankylosis of the stapes, in which latter conditions any such procedure is absolutely contra-indicated.

(ii) Direct mobilization may be undertaken as a preliminary step previous to removal of the stapes itself. If the stapes is movable and slight improvement occurs, then its removal may be justifiable under certain conditions. If, however, the stapes is fixed and no improvement occurs, then its removal will be attended with such difficulty as to almost negative this being attempted.

=Operation.= If a perforation of the upper posterior quadrant be present, a small pledget of cotton-wool soaked in a 20% solution of cocaine is brought into contact with the inner wall of the tympanic cavity. After a few minutes Lucae’s probe is placed in position against the head of the stapes and the vibratory movements are carried out. If no perforation of the drum exists, then it is first necessary to excise a flap in the upper posterior quadrant of the membrane.

=Difficulties.= The chief difficulty is anatomical. Projection forward of the upper posterior part of the tympanic ring or a deeply placed niche of the fenestra ovalis may prevent a view of the stapes.

If the membrane has to be incised, the slight amount of bleeding may also prevent a good view being obtained.

There is no actual danger in the operation, but if the stapes is fixed or if much force is used, it is by no means difficult to fracture the crura of the stapes.

REMOVAL OF THE OSSICLES

Except under the most rare conditions only the malleus and incus are removed; the stapes, if possible, being left undisturbed.

These operations will therefore be considered separately.

=Removal of the malleus and incus.= This operation was first proposed by Schwartze in 1873, and later by Kessel, Ludewig, Sexton, and Zeroni.

=Indications.= The indications for operation may be considered with regard to (1) chronic middle-ear suppuration and (2) non-suppurative middle-ear disease, whether the result of a previous middle-ear suppuration or of a chronic middle-ear catarrh.

In chronic middle-ear suppuration, the chief object of the operation is to ensure drainage and if possible to remove the cause of the suppuration; in non-suppurative conditions, to improve the hearing.

It may here be mentioned that the position of the perforation in the attic region is frequently of importance when considering the question of treatment. If situated in front of the malleus, the disease is probably limited to the outer attic region and malleus; if just behind the malleus, then probably both the malleus and incus are affected; but if the perforation extends farther back, involving the upper posterior quadrant of the drum, especially its bony margin, it suggests disease not only of the ossicles together with the walls of the aditus and antrum, but perhaps also of the mastoid process (Fig. 198).

(i) _In chronic middle-ear suppuration._ Before operation is considered, it is presumed that conservative measures, such as syringing, instillation of astringent and antiseptic drops, and washing out of the attic by means of Hartmann’s canula with various solutions, have been given a thorough trial and failed.

(_a_) If the suppuration be limited to the attic region (although the main portion of the tympanic membrane is intact), provided there is marked deafness and there are symptoms of lack of free drainage indicated by recurrent attacks of headache, a feeling of heaviness or giddiness, or pain radiating up the head on the affected side.

(_b_) If there be caries of the malleus and incus, and the outer attic wall, with recurrence of granulations after repeated removal, especially if accompanied by cholesteatomatous formation, provided there is no evidence of disease of the mastoid process itself.

(_c_) Although the general symptoms and the condition found on examination justify the complete mastoid operation, yet if the patient refuses to have this operation performed, the simpler operation of ossiculectomy may be undertaken if desired. This will permit of free drainage and diminish the risk of future intracranial complications. It should, however, be clearly explained to the patient that no guarantee can be given with regard to effecting a permanent cure as a result of this operation.

(ii) _In non-suppurative conditions._

(_a_) If there be marked middle-ear deafness, the result of adhesions, and the malleus is fixed to the promontory. Operation is justifiable if it is found that after each inflation of the middle ear, improvement of hearing is obtained which, however, is not permanent but only temporary.

(_b_) If, as the result of artificial perforation, made under the conditions already laid down, improvement takes place temporarily, but a relapse occurs from closure of the perforation (see p. 340).

(_c_) If tinnitus and attacks of vertigo, due to marked retraction of the membrane, are temporarily relieved by inflation. In this case operation should only be carried out as a last resource after all other measures have failed to cure and if the symptoms are very severe and distressing.

(_d_) If there be marked middle-ear deafness with extensive adhesions on both sides and evidence points to the stapes being freely movable. The operation is justifiable, as an experiment, on the worse side.

=Operation.= The only operation to be considered is the intrameatal one. Stacke originally suggested a post-auricular incision, and reflecting the auricle forward, and, after removing the ossicle, to remove also the outer attic-wall by means of the chisel. This method, however, has now been given up as being too radical, but will be mentioned later on in connexion with the mastoid operation (see p. 397).

Unless contra-indicated, a general anæsthetic should be given, as it is not always possible to foretell whether the operation will be difficult or easy. In addition it may be necessary to curette out granulations and also to remove the outer wall of the attic. Unless the patient is very insensitive, this is almost impossible under local anæsthesia (see p. 311).

Before the anæsthetic is given, the ear should be filled with a 5% solution of cocaine containing a 1 in 2,000 solution of adrenalin chloride in order to diminish the bleeding during the operation.

The field of operation is isolated from the surrounding parts by covering the head with a sterilized towel having an opening cut in it just sufficient to expose the auricle and meatus.

The following are the steps of the operation: (1) freeing the malleus from its attachments to the tympanic membrane, and from the inner wall of the middle ear, if adherent to it; (2) cutting through the tendon of the tensor tympani muscle; (3) removal of the malleus; (4) removal of the incus; (5) removal of the outer wall of the attic; (6) curetting out of granulations, if present. The method of operation varies slightly according to the condition found.

=Removal of the malleus.= In post-suppurative and non-suppurative conditions the chief cause of failure is the recurrence of adhesions, so for this reason it is wisest to remove the membrane as completely as possible.

With a paracentesis knife, the membrane is incised below and behind the malleus. The incision is then carried upwards along its posterior border to the posterior fold, then round the complete margin of the tympanic membrane and along the anterior fold and border of the malleus, so as to meet the original point of the incision. The knife is then reinserted just in front of the processus brevis and cuts through the anterior ligament in an upward direction; in a similar fashion the posterior fold is also cut through (Fig. 190).

The next step is tenotomy of the tensor tympani muscle (see p. 345).

The malleus thus freed can easily be removed by seizing its handle with a pair of Sexton’s (Fig. 193) or crocodile forceps (Fig. 179). In removing the malleus it is necessary to remember that its head is situated within the attic and therefore cannot be pulled out directly, but must first be drawn downwards until it is seen within the tympanic cavity. If this precaution be not taken, the neck of the malleus may be broken, leaving the head behind. If this takes place its extraction may be a matter of difficulty.

Instead of using Sexton’s forceps, the malleus may be removed by means of Wilde’s snare. This is the method advocated by Schwartze. After cutting through the tensor tympani muscle, the loop of the snare is threaded over the head of the malleus and guided upwards until it embraces its neck. The loop is then drawn tight so as to hold the malleus firmly in its grasp. The ossicle is extracted by first pulling it downwards (Fig. 199), so as to dislodge it from the attic, and then outwards (Fig. 200).

Another method of extracting the malleus, and in my opinion the one to be preferred, is by Delstanche’s ring-knife (Fig. 201). This instrument differs from the ordinary ring-knife in that the upper border of its anterior part is especially sharpened so as to form a fine cutting surface. After the malleus has been freed from the membrane by means of the paracentesis knife, Delstanche’s ring-knife is made to encircle its handle. It is then pushed gradually upwards, keeping as close to the posterior border of the malleus as possible, until it cuts through the attachment of the tensor tympani. In doing this the instrument will embrace the neck of the malleus (Fig. 202). This permits of sufficient leverage to extract the malleus by gentle traction in a downward and outward direction without danger of fracturing its shaft. If much resistance be felt, probably the tensor tympani muscle has not been cut through, and another attempt should be made to do this before trying further extraction. The advantage of this instrument is, that once the knife has encircled the malleus it should be possible not only to cut through the tensor tympani, but to extract the bone itself without the use of any other instrument. If Schwartze’s tenotomy knife be used, two tenotomy knives are required, one for the right and one for the left ear. Delstanche’s ring-knife is equally good for either ear.

=Extraction of the incus.= Although it is frequently stated that extraction of the incus is more difficult than that of the malleus, in reality it is the easier part of the operation as, unlike the malleus, it has no firm attachments.

After removal of the malleus all hæmorrhage must be arrested and a view obtained of the inner wall of the tympanic cavity. If it be possible to see the long process of the incus and its articulation with the head of the stapes, the articulation should be cut through with a small sickle-shaped knife. The knife is inserted just in front of the long process of the incus and, keeping close to it posteriorly, is made to cut downwards and backwards, thus separating its connexion with the stapes. Frequently the long process cannot be seen, or it may indeed have already disappeared as a result of caries. Theoretically this delicate manœuvre is performed in order to prevent injury or dislodgment of the stapes during the act of removal of the incus. From a practical point of view, however, it does not appear to make any difference whether the incudo-stapedial articulation is cut through or not.

A variety of instruments have been described for the purpose of removal of the incus. Ludewig’s incus hook (named after Ludewig, who was one of the first to draw attention to this operation) is still recommended by many as being the best. It consists of a solid curved hook, having a length of 5 millimetres and a width of 2 millimetres, bent at right angles to its shaft (Fig. 203). A pair of these are necessary, one for each ear; also several sets of different sizes may be required owing to the variation in depth, height, and roof of the attic region. I, however, prefer Zeroni’s (Fig. 204). This hook, instead of being solid, consists of a steel eyelet having a backward curve similar to that of Ludewig’s.

The technique is the same whichever pattern is employed. The instrument is inserted in such a fashion that the hook is directed upwards, having its concavity backwards. It is passed into the attic at the point previously occupied by the head of the malleus. The shaft of the instrument is then rotated backwards so that the hook passes over the body of the incus (Fig. 205). As the rotatory action is continued downwards and finally forwards, the incus is dislodged from its position and forced into the tympanic cavity. It can now be seized by a pair of Sexton’s or crocodile forceps and removed. If it falls into the floor of the tympanum, it can usually be dislodged by syringing, or else by means of a small hook passed in circular fashion along the floor of the cavity.

=Removal of the outer wall of the attic.= In the majority of cases of chronic middle-ear suppuration, it is advisable to remove the outer wall of the attic in addition to performing the simple operation of ossiculectomy. If granulations be present they should first be removed, in order to give a clear view of the inner wall of the tympanic cavity, which can usually be obtained, owing to the fact that a large perforation of the membrane is probably present. The malleus and incus are then removed.

To remove the outer wall of the attic a small but strong pair of punch-forceps is required (Fig. 206). The instrument is directed along the roof of the auditory canal, its cutting edge held upwards and the blades kept slightly open, until the outer blade is felt to pass over the outer wall of the attic. The handle is then depressed so that the end of the forceps is forced upwards and embraces the outer wall between its points (Fig. 207). This is confirmed by attempting to withdraw the forceps, which the outer bony wall of the attic will now prevent. The position of the forceps being assured, its blades are brought together by pressure on the handle, and in this manner a small portion of the bone is punched out. In this way the outer wall of the attic is gradually cut away in small fragments. Sometimes this is extremely easy, owing to the auditory canal being large and the outer wall of the attic being thin and easily cut through. In other cases, owing to the thickness of the bony walls or to the narrowness of the canal, it is extremely difficult. If the outer wall of the attic has been completely removed, a fine probe, whose point is bent upwards, can be inserted into the attic and then withdrawn without encountering any obstruction, owing to the roof of the attic and outer wall of the auditory canal being now continuous. In some cases this part of the operation may not be necessary, as the outer wall of the attic may have already disappeared as a result of the caries.

Into the larger opening thus made, small curettes are passed upwards and backwards and any granulations in the region of the aditus and entrance to the antrum are curetted away. Finally the cavity is thoroughly swabbed out with the pledgets of cotton-wool soaked in a 1 in 2,000 alcoholic solution of biniodide of mercury. The cavity is then dried and a small drain of sterilized gauze inserted within the auditory canal, the ear being afterwards covered with a pad of gauze kept in position by a bandage.

=After-treatment.= In cases of non-suppuration there is rarely any pain, and if asepsis has been maintained, there is seldom much discharge beyond slight sanious oozing. Unless there is considerable discomfort the dressing need not be changed for two or three days. If possible the ear should not be syringed, but merely mopped out with pledgets of cotton-wool moistened with boric lotion and then dried, the gauze drain being afterwards inserted. This process may be repeated daily until healing is complete.

In middle-ear suppuration there may be considerable pain, owing to the forcible bruising of the tissues of the inner part of the auditory canal during the act of removal of the outer wall of the attic. Sometimes, indeed, there is much swelling of the lining membrane of the canal, with the occurrence of furuncles as the result of septic infection.

If there be no pain, the after-treatment is the same as above described, excepting that it may be necessary to syringe out the ear at each dressing owing to the discharge. If there be much pain, with swelling of the canal, the gauze drain should be removed and a 10% solution of carbolic acid in glycerine frequently instilled into the meatus. Subsequently drops of rectified spirit may be substituted.

=Difficulties.= 1. If the auditory canal be very small there may not be sufficient room to insert the instruments through the speculum. In such cases, if there be no middle-ear suppuration, it is wiser to leave the condition alone. If, however, suppuration exists, either the conservative treatment must be continued or the complete mastoid operation recommended.

2. Hæmorrhage, especially on curetting away the granulations, may be sufficient to prevent a view of the deeper parts. It can, however, usually be arrested quickly by plugging the auditory canal with gauze soaked in adrenalin and cocaine solution. Even if the surgeon has to wait a few moments, this must be done, as it is very necessary to obtain a clear view of the field of operation.

3. Extensive adhesions between the membrane and inner wall may render it difficult to separate the shaft of the malleus without fracturing its neck.

4. In old-standing cases in which there is a large perforation of the membrane, the malleus may be so retracted as not only to be difficult to see but difficult to seize. In this particular case, division of the tensor tympani with Schwartze’s tenotome and then extraction of the malleus by means of Sexton’s forceps is a better procedure than trying to encircle its shaft with Delstanche’s ring-knife.

5. Removal of the incus by the ordinary instruments may be rendered impossible owing to the narrowness of the attic posteriorly from chronic thickening of its walls. In these cases a seeker, such as Schwartze uses in the mastoid operation (Fig. 219), may be employed with advantage. It is passed over the incus in the same manner as an incus hook.

=Accidents.= 1. _Fracture of the handle of the malleus._ This is the result of too forcible extraction. If a Delstanche’s ring-knife has been used, this may be due to the tensor tympani not having been cut through; this should now be done. The head of the malleus is then removed either by means of a small hook or some form of curette bent at right angles to its shaft, depending on what is most suitable for the case in question.

2. _Failure to extract the incus._ In the course of a chronic middle-ear suppuration, the incus may become exfoliated or gradually disappear as the result of caries. It does not therefore always follow that inability to extract the incus means that the surgeon has failed in his manipulations, although frequently this is the case, the instruments failing to extract the incus, or perhaps dislodging it into the mastoid antrum, a fact which is difficult to determine and may only be discovered if the subsequent performance of the complete mastoid operation becomes necessary.

3. _Facial paralysis._ This accident is usually due to the incus hook not being inserted high enough up, so that, instead of entering the attic, it presses on the inner upper border of the tympanic cavity, and on being rotated in a backward and downward direction, it follows the line of the facial canal (Fig. 208). If much force be employed the frail wall of the facial canal will be fractured or pressed in on the underlying facial nerve. It is very rarely, however, that the nerve is completely crushed or torn through, and therefore recovery almost invariably takes place.

The facial nerve may also be injured whilst curetting away granulations in the upper posterior part of the tympanic cavity.

4. _Injury to or removal of the stapes._ This very rarely occurs during the act of removal of the incus, but is generally the result of too violent curetting. If only the crura be broken off, it does not matter; but if the stapes itself be dislodged from the fenestra ovalis, the subsequent symptoms may be attacks of vertigo, nausea, and vomiting. As a rule these symptoms subside. If, however, the internal ear becomes infected (although judging from literature and my own experience this is of very rare occurrence), complete deafness or even meningitis may occur as the result of labyrinthine inflammation or suppuration.

=Results.= (_a_) _With regard to arrest of the disease._ If the disease be limited to the ossicles themselves and to the anterior and outer part of the attic, a favourable prognosis may be given. Complete cessation of the discharge and scarring over of the affected part may take place within a month, or after a much longer period.

If, however, the disease be more extensive and involves the walls of the attic posteriorly and the region of the aditus, as shown by the presence of a fistula or granulations, the prognosis is uncertain and continuance of the discharge and recurrence of the granulations may eventually necessitate the complete mastoid operation.

(_b_) _With regard to hearing._ In the case of chronic attic suppuration the hearing power may be increased to a distance of 12 feet off for conversation, provided the internal ear is not affected and the stapes is not fixed within the fenestra ovalis; occasionally the result is much better. On the other hand, the hearing power may be made worse.

In post-suppurative conditions, the prognosis is not so favourable, as frequently the stapes is already bound down by adhesions; this is the more probable in the case of chronic middle-ear catarrh. In both these conditions the operation should never be performed without first explaining to the patient that it is practically experimental. The chief cause of failure is the recurrence of adhesions, which even the most complete and careful operation cannot always prevent.

=Removal of the stapes.= This operation is still in its infancy and it is, as yet, impossible to express an opinion with regard to its success or failure, and therefore the indications laid down are only tentative.

The objects of the operation are: (1) to improve the hearing in cases of deafness presumably due to fixation of the stapes within the fenestra ovalis, and (2) to relieve symptoms of tinnitus and vertigo due to the same cause.

Before this operation is advised careful examination must be made in order to determine whether the labyrinth is intact, especially if the operation is undertaken with the view of improving the hearing.

=Indications.= (i) If there be ankylosis of the stapes on both sides, accompanied by marked deafness and distressing subjective symptoms, operation is justifiable on the worse side.

(ii) In a one-sided affection provided the subjective symptoms of noises and giddiness are so oppressive as to render the patient’s life unbearable. The operation, of course, must not be attempted unless every other form of treatment has failed.

=Operation.= The operation may be performed either through the meatus, or by reflecting forward the auricle by means of the post-aural incision, and chiselling away the upper posterior part of the bony meatus in the manner suggested by Stacke (see p. 397).

The choice of the operation depends principally on the existing anatomical and pathological conditions.

If the meatus be very narrow the intrameatal method may fail to bring the stapes into view. If, on the other hand, the meatus be wide and there be a large perforation, the result of previous middle-ear suppuration, the incudo-stapedial joint or the head of the stapes itself may be actually within the field of operation.

_The intrameatal method._ The patient should be fully anæsthetized and the operation performed under good illumination. A portion of the tympanic membrane in its upper posterior quadrant is excised in order to bring into view the incudo-stapedial joint. The incision is begun just behind the handle of the malleus and is carried upwards and backwards in a circular fashion through the tympanic membrane along the posterior fold, and then downwards for a little distance along its margin. The flap so made either falls downwards, or can be pressed downwards so as to expose to view the inner wall of the tympanic cavity. With a small knife, curved on the flat, the incudo-stapedial joint is cut through. With a fine hook the long leg of the incus is dislocated forwards or backwards from the stapes. The head of the stapes will now be seen, with the tendon of the stapedius muscle running horizontally backwards. With a paracentesis knife, the tendon is cut through close to its attachment to the stapes.

A fine, blunt-pointed hook is now inserted between the crura of the stapes. If the stapes be not firmly ankylosed it can usually be removed by slight traction. If, however, it be firmly fixed, its crura will probably be broken. To determine whether the stapes is ankylosed or not, direct pressure of the probe on the head of the stapes may be necessary. If the head of the stapes cannot be seen, it is advisable, as suggested by Dench of America, to punch out part of the upper posterior margin of the attic-wall with the attic forceps (see p. 357).

_The post-aural method._ The preliminary steps of the operation are the same as have been already described for removal of an exostosis (see p. 318).

After separating and reflecting forward the membranous from the bony portion, the upper posterior part of the tympanic ring is chiselled away until a view of the stapes can be obtained. The incus is then disarticulated from the stapes.

If the stapes be ankylosed by fibrous adhesions to the margins of the fenestra ovalis, an attempt may be made to free it by cutting through the adhesions with a fine bistoury. If this be impossible, a sharp hook may be fixed into the margin of the plate of the stapes in the hope of forcibly extracting it. Some authorities advise chiselling away of the margins of the fenestra ovalis. If an opening can be made into the vestibule by this means, it is hoped that the resulting scar tissue will form a membrane more resilient than the ankylosed stapes, and, in this way, permit vibrations of sound to enter the labyrinth. This operation, however, necessitates the complete mastoid operation in order to freely expose the region of the fenestra ovalis.

=After-treatment.= It is sufficient to protect the ear with a small gauze drain. Occasionally there may be considerable vomiting and vertigo as an immediate result of the operation; this usually passes off within two or three days. Meanwhile the patient should be kept in a recumbent position and, if necessary, given small subcutaneous injections of morphine.

=Difficulties.= The chief difficulty is to obtain a good view; even if this be obtained it is difficult to extract the stapes without fracture of its crura.

=Dangers.= As a result of opening up the labyrinth, one would expect considerable risk of infecting the internal ear. Judging from recorded cases, this, however, seldom occurs.

=Results.= The chief advocate of the removal of the stapes is Jack of Boston (_Boston Med. and Surg. Journ._, January, 1895), who again in 1902 (_Archives of Otology_, vol. xxxi, p. 407) stated: (1) that removal of the stapes did not destroy the hearing but sometimes improved it; (2) that the operation upon cases of moderate deafness might give brilliant results but was also attended with some risk to the hearing; (3) that the operation on the profoundly deaf was not advisable, as usually the stapes could not be removed owing to surrounding adhesions, and even if it were, no improvement was likely to occur owing to the sound-perceiving apparatus having probably already undergone irremediable changes.

Blake (_Archives of Otology_, vol. xxii), on the other hand, states emphatically that stapedectomy is harmful rather than beneficial.

The question, therefore, of removal of the stapes from the point of view of hearing is purely experimental. If there be bony ankylosis, it will be found impossible to remove the bone, and an attempt to do so will result in fracture of its crura. If, on the other hand, it be not ankylosed but movable, probably massage or, in cases of perforation of the tympanic membrane, direct mobilization of the bone will give results as good as those following stapedectomy.

The most favourable results are to be expected in those cases in which the operation is performed to relieve symptoms the result of previous middle-ear suppuration. In otosclerosis no benefit is ever obtained, and therefore the operation is absolutely contra-indicated.

On the other hand, there is ample evidence that the hearing power, in spite of removal of the stapes, may be retained. As an example may be quoted a case in which the stapes was removed accidentally in curetting out the ear after the removal of the malleus and incus, and in which I afterwards performed the complete mastoid operation owing to the continuance of the middle-ear suppuration. In spite of this, whispering could be heard at a distance of 20 feet (_Journal of Laryngology, &c._, vol. xxii, p. 33).