CHAPTER VI

THE COMPLETE MASTOID OPERATION

Before considering the question of the radical operation, it is assumed that conservative treatment has been attempted and has failed, and that the middle-ear suppuration has existed for a considerable period.

=Indications.= (i) As a prophylactic measure. If there be merely a perforation of the tympanic membrane and no evidence of disease of the ossicles nor the walls of the tympanic cavity, the probability is that the continuance of the suppuration is due to an affection of the mucous membrane rather than of the underlying bone; for example, to a chronic empyema of a large antrum cavity which, owing to its anatomical structure, will not drain freely.

In such cases the complete mastoid operation is only indicated if the deafness is extreme, the bone conduction diminished, and the high tuning-forks not well heard, or if the ossicles are bound down by adhesions to the inner wall of the tympanic cavity, as it is then obvious that the hearing power cannot be restored completely.

It must, however, be remembered that in many cases a slight discharge may exist for years without giving rise to any complications. If the patient be made aware of the slight danger which exists in every case of middle-ear suppuration, and be in a position to obtain medical attention if retention of pus occurs, then operative measures may be deferred indefinitely. If, on the other hand, the patient intends going to some remote country where medical attendance is impossible, then it is probably wiser to submit to the complete operation rather than risk future trouble.

(ii) If there be recurrent attacks of giddiness, nausea, or headaches radiating up the affected side which are not arrested by the ordinary methods of treatment. These symptoms of retention of pus within the antrum and mastoid process should be considered as danger signals. In this case also it is assumed that the hearing cannot be restored, and in consequence there is no object in performing Schwartze’s operation.

(iii) If there be recurrence of polypi and granulations within the tympanic cavity in spite of curetting, especially if the operation of ossiculectomy has already been performed.

(iv) If there be symptoms of retention of pus due to want of free drainage in the case of stenosis of the external meatus, whether due to fibrous contraction of its soft parts, or from the presence of exostoses.

(v) If cholesteatomatous formation be present. Even if there be no symptoms necessitating immediate interference, operation is usually indicated owing to the fact that cholesteatoma is the commonest predisposing cause of intracranial suppuration and septic thrombosis of the lateral sinus.

(vi) If there be a fistula of the bony wall of the mastoid process, whether it extends anteriorly into the auditory canal or externally through the skin over the region of the mastoid process. It must not be forgotten, however, that simple opening of the antrum and mastoid cells will be quite sufficient if the condition is the result of a recent and acute inflammation of the mastoid process.

(vii) If there be facial paralysis occurring in the course of a chronic middle-ear suppuration. This may mean either that there is bone disease involving the facial canal, or that the inflammatory process has spread through the Fallopian canal towards the inner ear. In either case operation is indicated.

(viii) As a preliminary step in intracranial suppurative lesions of otitic origin.

(ix) In tuberculosis of the middle ear. If the patient’s general condition permits of it, and if the pulmonary disease be slight or arrested, the complete operation should always be done. The difficulty is to remove all the diseased bone. If this can be done the wound will heal quite well.

(x) In acute inflammation of the mastoid process occurring in the course of chronic middle-ear suppuration, the complete mastoid operation should be performed, as in these cases the attic, aditus, and antrum are always involved.

(xi) Amongst the rarer conditions for which the complete operation may be necessary are removal of a foreign body which has been pushed inadvertently into the region of the attic and aditus and cannot otherwise be removed; and actinomycosis of the temporal bone.

METHODS OF OPERATION

The actual method of carrying out this operation varies. For those who have not had great experience the best method is first to open the antrum, as in Schwartze’s operation, and then to remove the ‘bridge’ of bone between it and the tympanic cavity (Küster-Bergmann operation, sometimes called the Schwartze-Stacke operation). Instead of doing this, the upper posterior part of the auditory canal may be chiselled away simultaneously during the act of exposing the antrum (Wolf’s operation). On the other hand, the mastoid and antrum may be exposed from within outwards by removing the outer attic wall and working backwards (Stacke’s operation).

=The Küster-Bergmann (or Schwartze-Stacke) operation.= The preliminary preparation, the position of the patient, and the instruments required are the same as in opening the antrum.

The =incision= is begun just above the upper insertion of the pinna, and is carried downwards in a curved direction behind the auricle along the margin of the skin and scalp. Some authorities prefer to make the incision close behind or even along the post-auricular fold. In favour of the incision being placed far back is the concealment of the scar by the hair. Also, as it is situated on healthy bone somewhat posterior to the actual wound cavity, it should heal by primary union and with no after-displacement of the auricle. In addition, if it be necessary to expose the lateral sinus, this can usually be done by simple retraction of the soft parts.

The exposure of the field of operation is the same as in the simple opening of the antrum, excepting that the soft tissues should be separated a little further forwards and above the external bony meatus, as in this operation the upper posterior wall has to be removed.

The antrum is opened as already described (see p. 382).

The fibrous portion of the external meatus is separated carefully from the posterior wall of the bony meatus by means of a periosteal elevator, and is pulled forward by a retractor. The external portion of the posterior wall is now removed in a wedge-shaped fashion by alternate strokes of the chisel from above downwards (Fig. 221) and from below upwards. The upper level of the bone to be removed corresponds with the zygomatic ridge. After a small portion has been removed, a pair of forceps is passed into the auditory meatus and its point made to project into the wound posteriorly through the end of the now detached fibrous portion of the auditory canal. With the forceps a piece of gauze is drawn through the auditory meatus in the form of a loop. By its means the auricle and fibrous portion are pulled well forward, thus exposing to view the tympanic cavity. Two openings are now seen: one, the auditory canal and tympanic cavity, in front, and the other, the antrum and mastoid cavity, behind. Between them is the ‘bridge’; that is, the innermost portion of the posterior wall of the auditory canal.

Any granulations present are curetted away gently from the tympanic cavity. The seeker is next passed into the tympanic cavity, and its point directed upwards and backwards into the aditus, so that it rests on the floor of the latter, or its point may be inserted into the aditus through the mastoid wound. Beneath it lies the eminence of the external semicircular canal and the facial nerve. This is a most important landmark. Provided the seeker is kept in this position, all the bone lying superficially to it can be removed without injury to the semicircular canal or facial nerve.

In this connexion may be mentioned Stacke’s probe or ‘protector’ (Fig. 222). Although historically an instrument of importance, I do not make use of it. It is so large and of such sharp outline that, unless used with extreme care, it is itself very liable to injure the facial nerve. For this reason I prefer the seeker, a much finer and more delicate instrument, which will serve the purpose without the same risk (Fig. 219).

The ‘bridge’ is now carefully removed by the gouge or chisel, frequent use being made of the seeker meanwhile. As the roof of the antrum, aditus, and attic is a continuous one, the bone to be removed is necessarily at a higher level than the roof of the bony meatus. This is a point which must not be forgotten, as the great fault of the beginner is to remove the bone too low down.

As the aditus is approached, the strokes of the chisel must be very gentle. If too much force be used, the chisel, on breaking through the innermost portion of the ‘bridge’, may injure the deeper-lying parts, more especially the facial nerve.

Some authorities advocate removal of the ‘bridge’ by means of bone forceps. This, however, is not so sure a method as by the chisel or gouge.

After removal of the bridge, the tympanic cavity, antrum, and mastoid will form a continuous cavity. As a rule the outline of the external semicircular canal appears as a well-marked white eminence, and projecting beyond it are the remains of the posterior wall of the auditory canal. In removing this ridge good illumination is essential. The bone is removed in layers with the chisel, beginning at the tip of the mastoid process, and working parallel to the auditory canal and the underlying facial canal. If necessary the seeker may be used as a guide, its point being allowed to rest on the floor of the aditus, superficial to the semicircular canal (Fig. 223).

The amount of bone removed should be such that at the end of the operation the auditory canal is only separated from the main cavity of the mastoid antrum by a slight eminence, the remainder of the posterior wall, which is continuous with that of the external semicircular canal.

Occasionally the facial canal and the stylo-mastoid canal are abnormally superficial. Provided the bone be removed in the manner just described, the facial nerve should not be injured, even though it may be exposed inadvertently. A warning of this occurrence is given by bleeding from the vessels within the canal (see p. 374).

If the malleus and incus be still _in situ_, they can now be seen and can usually be removed by the curette. No force must be used. Removal of the incus is a matter of no difficulty. In the case of the malleus there may be some resistance owing to the attachment of the tendon of the tensor tympani muscle. If so, the malleus should be grasped by a fine pair of forceps and the tendon severed by means of Schwartze’s tenotomy knife.

The overhanging edge of the outer wall of the attic can now be felt by means of the seeker. It is best removed by gentle taps of the chisel or small gouge. Especial care must be taken not to drive the gouge too far inwards. If this be done inadvertently, the transverse portion of the facial nerve passing along the inner wall of the tympanic cavity may be injured. As a safeguard some surgeons use an attic punch-forceps or a burr, others a Stacke’s protector which should be inserted into the attic before chiselling away its outer wall.

After the outer attic wall has been removed, the roof of the auditory canal and the attic should be continuous. This is verified by inserting the seeker, with its point turned upwards, within the attic, and then withdrawing it; no ridge of bone should now prevent its withdrawal.

Granulations or the epithelial lining of cholesteatomata should be removed from the recesses of the tympanic cavity with a small curette. Care must be taken not to injure the surface of the promontory, or the region of the fenestra ovalis and fenestra rotunda. It is especially important to curette away the mucous membrane from the orifice of the Eustachian tube in order that scar tissue may obliterate its lumen and so prevent reinfection of the middle ear from the naso-pharynx. For this purpose a narrow curette is necessary (Fig. 224).

Removal of the innermost portion of the floor of the auditory canal is not always necessary. Sometimes, however, the ‘hypotympanum’ is well marked, and in order to ensure a good result it is wiser to remove this projecting piece of bone. If the ridge of bone be removed piecemeal, and if the gouge or chisel be kept parallel to the floor of the canal, there should be no danger of wounding the bulb of the jugular vein. Cases, however, have been recorded in which this has occurred.

The final step is to see that no pockets nor overhanging ledges or ridges of bone remain, and that all the diseased area has been removed. The cavity, although irregular in outline, should be a continuous one with a smooth surface (Fig. 225).

=Wolf’s operation.= This slight modification of the Küster-Bergmann operation requires merely a note of description. The position of the patient and the preliminary steps of the operation are the same as in the former operation.

In this operation, instead of first exposing the antrum cavity and afterwards removing the posterior wall of the external meatus, this procedure is performed in one step.

The chisel or gouge is first brought into contact with the bone just behind the upper posterior margin of the auditory canal. The bone is removed in layers by chiselling it away in a forward direction and in such a manner that each stroke of the chisel is carried directly into the auditory canal (Fig. 226). With each successive stroke, begun a little more posterior and inferior to the one preceding it, more bone is removed until at length the antrum is exposed. There should be no risk of injuring the external semicircular canal nor the facial nerve, owing to the fact that the outer wall of the antrum lies superficial to the tympanic cavity and aditus.

After the antrum has been exposed, the technique of the operation is the same as that already described in the Schwartze and Küster-Bergmann operation.

=Advantages.= 1. If the surgeon be experienced it saves much time, as the preliminary steps of the operation can be carried out very rapidly.

2. If the mastoid be sclerosed and there are no landmarks, the antrum, however small, is bound to be reached by making use of this method, by keeping high up, and, if necessary, exposing the dura mater. To verify the depth to which the bone may be removed and also the position of the antrum, the seeker should be inserted occasionally through the tympanic cavity into the aditus.

=Disadvantages.= If the surgeon be not experienced, it is not so safe a method as that of first exposing the antrum.

=Stacke’s operation.= After exposure of the field of operation, as in the Küster-Bergmann operation, the fibrous portion of the auditory canal is separated posteriorly from the bony portion.

Any granulations, together with the malleus and incus, are removed from the tympanic cavity (see p. 353). Under a good illumination, using a head-lamp if necessary, the surgeon passes a seeker along the auditory canal, its point being made to project into the attic in order to define its limits and that of the aditus. The innermost portion of the upper posterior wall of the auditory canal, that is, the outer wall of the attic, is now removed piecemeal by means of a small gouge (Fig. 227). By working backwards the aditus is approached, the bone being removed carefully in small fragments. The seeker is inserted repeatedly into the entrance of the aditus so as to rest on the external semicircular canal, in order that the position of the latter and the underlying facial nerve may be kept constantly in mind. More bone above and external to this point is removed in small fragments, until at length the upper and innermost portion of the antral wall is removed and its cavity thus exposed. The cavity is gradually enlarged by removing still more bone in a backward and outward direction, until finally it resembles that left after the complete operation. Stacke originally devised this method in those cases in which he considered that the disease was limited to the ossicles, the walls of the attic, aditus, and innermost portion of the antrum. It was, indeed, merely a more radical method of performing ossiculectomy.

=Advantages.= Although this operation has practically been abandoned as a method of performing ossiculectomy, yet under the following conditions it may be adopted during the performance of the complete operation:--

1. If the mastoid be very sclerosed and if the antrum cannot be exposed, although the bone has been removed to a depth corresponding to its usual position.

2. If there be difficulty in exposing the antrum in the performance of the radical operation owing to the lateral sinus projecting far forwards and the middle intracranial fossa overlapping it externally.

=Disadvantages.= The chief disadvantage is that it is more difficult and tedious to begin the operation within the depth of the wound, and if the meatus is very deep and narrow it may be almost impossible to carry out.

=Preservation of the ossicles and tympanic membrane after performing the complete mastoid operation.=

This method of operation is well known and has been performed for some years, especially by Jansen of Berlin, and in America.

The only indication for this modification of the complete mastoid operation is disease involving the antrum and mastoid process so extensively as to require complete removal of the posterior wall of the auditory canal, without there being any coexisting bone disease of the walls of the attic or of the ossicles.

As the complete mastoid operation is only performed for some condition due to chronic middle-ear suppuration, it is difficult to imagine that the ossicles and attic region could remain unaffected when the extent of the disease necessitates the complete operation.

In my opinion, if it be necessary to remove the ‘bridge’ it is also necessary to remove the outer wall of the attic and with this the malleus and incus. If, on the other hand, there be no bone disease of the attic region or of the ossicles, Schwartze’s operation, or some modification of it, should be sufficient. The majority of aurists agree that, excepting in those cases in which the continuance of the suppuration is due to an empyema of the antral cavity, the ossicles are almost invariably carious to a greater or lesser extent in chronic middle-ear suppuration. This view is supported by Grunert’s researches (_Archiv für Ohrenheilkunde_, Band 40), who found that the ossicles were only normal in five cases in a series of 113 cases in which the complete operation had been performed.

Although removal of the ‘bridge’ may eradicate the disease within the mastoid process and antrum, yet, if the ossicles are left, post-suppurative adhesions will almost certainly afterwards bind them down and so cause a greater deafness than if they had been removed originally. Still, a few isolated cases have been reported in which hearing to the extent of 20 feet or more has been obtained as the result of this operation. The same results, however, frequently occur after the performance of the complete operation with removal of the malleus and incus. Until we have a large and consecutive series, recording the results of this particular operation in detail, together with information regarding the duration of the symptoms, the previous treatment, and the condition of the ear before operation, it is impossible to judge the value of this method.

THE FORMATION OF POST-MEATAL SKIN FLAPS

This is done for two reasons: firstly, to prevent stenosis of the auditory canal; and secondly, to aid the growth of the epithelium over the wound surface, so that the latter will heal as rapidly as possible.

These flaps may be formed in several different ways. The following is the technique I adopt: A long, narrow, curved bistoury is passed down the auditory meatus so that it projects through the detached end of the fibrous portion, its point being directed backwards. The auricle is held well forward and the fibrous portion of the meatus cut through posteriorly, from within outwards, for a short distance (Fig. 228). The edge of the bistoury is then directed in a slanting direction upwards and outwards, and the incision continued as far as the cartilaginous portion of the meatus, care being taken not to cut into the concha. The bistoury is then withdrawn and reinserted at the point at which it was first made to turn upwards. It is now directed downwards and outwards and, in a similar manner, the incision is made in a slanting direction towards the inferior margin of the cartilaginous meatus. In carrying out these manipulations care must be taken that the outer portion of the bistoury does not injure the tragus or other portion of the auricle, a mistake which can easily occur. The fibrous portion of the meatus is thus divided by a Y-shaped incision into three small flaps; namely, a posterior or external V-shaped flap, and a superior and an inferior flap (Fig. 229).

The outer flap is fixed to the skin behind the auricle by means of a catgut suture (Fig. 230), and the auricle is then pulled back into its normal position. By inserting the tip of a finger into the meatus, the upper and lower flaps are pressed upwards and downwards against the roof and floor of the mastoid cavity, and can be kept in position afterwards by suturing the flaps to the subcutaneous tissue or by packing the cavity through the meatus with a strip of ribbon gauze.

Amongst other methods the following may be mentioned:--

=Körner’s method= (Fig. 231). Two parallel incisions are made in a longitudinal direction through the fibrous portion of the posterior wall of the meatus and are prolonged outwards as far as the concha. On the auricle being restored to its normal position, this posterior flap is pressed backwards and so covers a large area of the posterior wound surface. The chief objection to it is that, owing to involvement of the concha, there is considerable enlargement of the meatal opening and therefore subsequent disfigurement.

=Panse’s method= (Fig. 232). A transverse incision is carried through the posterior margin of the meatus, at the junction of the concha and auditory canal posteriorly. With a pair of scissors or knife, the posterior wall of the fibrous portion of the canal is now split by a longitudinal incision. In this way two flaps are formed, a superior and inferior one. They are fixed into position by catgut sutures through the subcutaneous tissues at the upper and lower angles of the wound.

=Stacke’s method= (Fig. 233). This consists of a large inferior flap, formed by making a longitudinal incision along the posterior upper border of the fibrous portion of the auditory canal and a transverse incision meeting it at right angles, the latter cutting through the fibrous portion of the meatus at its junction with the concha.

In order that these flaps may be thinner and more adaptable, the subcutaneous tissue should be cut away. Of these flaps the Y-shaped one is the most practicable, as it is suitable whether the posterior wound is closed or left open.

Körner’s method has the objection that there is subsequent disfigurement owing to the large meatal opening formed by cutting into the concha. It has the advantage, however, that the large posterior flap will cover the posterior surface of the wound cavity to a considerable extent, and also that it will permit a good view of the surface.

Panse’s flap is only of service if the posterior wound is left open and if there is not sufficient tissue left to make a posterior flap owing to previous destruction of the posterior wall of the auditory canal.

Stacke’s method is good if skin-grafting is afterwards employed.

CLOSURE OF THE WOUND

Excepting under the conditions mentioned below, the posterior wound is closed by bringing together the edges of the skin incision with fine silkworm-gut sutures (Fig. 230). Before this is done, the wound cavity should be irrigated with a weak solution of biniodide of mercury, dried, and the deeper parts of the wound plugged with a strip of gauze inserted through the external meatus. This will not only arrest the hæmorrhage and keep the inner part of the wound dry, but at the same time will keep the skin flaps in position. After the wound has been closed, firm pressure should be applied in front and behind the ear to press out any blood from the cavity.

As a final step the gauze which has been inserted into the meatus is removed, and the cavity again packed evenly and lightly from the bottom of the wound with a fresh strip. The ear and surrounding parts are protected with a pad of sterilized gauze covered with cotton-wool and kept in position with a bandage.

_The posterior wound should be left open under the following circumstances_:--

1. If there be an abscess over the mastoid process. Although it may be possible to excise the whole of the lining membrane of the abscess cavity, it is wiser to leave the wound open for the first few days. The innermost portion of the wound cavity is packed through the external meatus, only the superficial part being packed through the posterior wound incision. As healthy granulations appear, the posterior packing is diminished, so that the edges of the incision gradually come together. If necessary, the edges of the wound can also be freshened and brought together by silkworm-gut sutures under cocaine anæsthesia.

2. If there be extensive disease of the bone, especially if the dura mater and lateral sinus are covered with septic granulations.

3. If there be bone disease of the anterior and inferior parts of the tympanic cavity. The after-treatment of packing or the curetting away of granulations can be carried out more easily through the posterior wound than through the external meatus, as it gives a better view of these regions.

4. In young children it is frequently advisable to leave the posterior wound open owing to the difficulty of packing the wound cavity through the small external meatus.

SKIN-GRAFTING AFTER THE MASTOID OPERATION

In order to shorten the duration of healing, a large Thiersch’s skin graft may be transplanted into the wound cavity. If this procedure be adopted it may be carried out in several ways. The skin may be transplanted in one large piece or in several small portions, and it may be introduced into the wound cavity either immediately after the completion of the mastoid operation or from seven to ten days later.

There is considerable diversity of opinion as to whether skin-grafting should be employed or not, and also when it should be done.

This may be partially accounted for by the fact that although, theoretically, the application of skin grafts is easy, yet, practically, the technique is difficult. Those who favour skin-grafting point to the fact that healing of the wound may take place within five weeks, whereas, if grafting be not undertaken, cicatrization of the cavity, even under favourable conditions, can hardly be expected to occur before eight to twelve weeks.

The skin-grafting operation as suggested by Charles Ballance is generally performed as a second stage, some ten or more days after the primary operation. This, from the patient’s point of view, is a serious matter; and the disappointment caused by the grafting not being always successful has induced many to give it up and to be content with what seems to be a more certain, though more prolonged, after-treatment.

More recently, however, it has been shown that in suitable cases skin grafts, if applied at the time of the completion of the primary operation, will take just as well as at a later date. This altogether alters the aspect of the case. If at the end of the primary operation it be certain that all the diseased bone has been removed and the cavity has been rendered aseptic, there can be no objection to the immediate application of skin grafts. If the result be successful, the period of after-treatment is considerably curtailed. If, on the other hand, it be not successful, the patient, beyond having a raw surface on his arm or leg for a few days, is no worse off than if the graft had not been applied.

Skin-grafting, however, cannot be done in every case. Two conditions are necessary for its success: firstly, that all the diseased bone has been removed; and secondly, that the wound cavity is aseptic.

Immediate skin-grafting, therefore, should not be employed if, in addition to the chronic disease, there be acute inflammation of the mastoid process, or of the subcutaneous tissues covering it; nor should it be done if it has been necessary to expose the dura mater over a large area, nor if there be any possibility of some subsequent intracranial complication. In such cases it may be justifiable to do skin-grafting after the acute symptoms have subsided. If, however, the case be progressing satisfactorily, the advisability of submitting the patient to a second operation should be a matter of careful consideration.

Disease of the inner wall of the tympanic cavity, or around the orifice of the Eustachian tube, is also a contra-indication against grafting, as the graft, if applied, will not take over these areas. The author’s opinion with regard to skin-grafting is that, if it can be applied immediately after the completion of the primary operation (and the conditions justifying this are limited), it may be done. If, however, the conditions be such that they will not permit of this, it should not be done at all.

=Technique.= _When the grafting is done at the completion of the mastoid operation._ The first step is to see that the mastoid wound cavity is rendered thoroughly aseptic and dry. All bleeding points in the soft tissues are arrested by means of pressure forceps. The mastoid cavity is then filled with hydrogen peroxide lotion, which is afterwards syringed out with a warm saline solution, the cavity being dried with sterilized strips of gauze, and finally packed from the bottom with a fresh strip.

The size of the graft, which is usually taken from the thigh, should be at least 2 inches in width and 4 inches in length. The skin is cleansed by washing it with soap and water, then with ether, and finally with normal saline solution, the part being afterwards dried with a sterilized towel. It does not matter what type of razor is used to remove the graft, so long as it is sharp. The chief point to observe, in order to secure success, is to see that the skin is kept uniformly stretched--the tighter the better. The technique of removal of grafts is described elsewhere (see Vol. I, p. 670). The graft taken from the leg is transferred to a large spatula and smoothed out over its surface. The auricle is now pulled forward, and the gauze strip is removed from the mastoid cavity. The spatula is laid across the surface of the cavity so that it rests on the anterior margin of the wound surface (Fig. 234). With a sharp probe the edge of the graft, which just overlaps the spatula, is held in position at this point, the spatula being gently retracted so as to leave the graft stretched across the surface of the wound cavity. With a ‘stopper’ (Fig. 235), the graft is now pushed inwards towards the tympanic cavity.

A glass pipette (Fig. 236), having a curved beak, is then passed inwards beneath the graft until its point, directed downwards, lies within the tympanic cavity (Fig. 237). Any blood which has accumulated between the bone and the graft is now sucked out, and in doing this the graft becomes closely applied to the bone surface (Fig. 238). After removing the pipette, any part of the graft which is not adherent to the bone is smoothed out over its surface. The tympanic cavity and the innermost portion of the mastoid cavity are then plugged with sterilized pellets of cotton-wool wrapped in gauze and dusted with aristol powder. The outer portion of the cavity is filled up with a strip of gauze, its end being brought out through the external auditory meatus.

The posterior part of the graft, still projecting beyond the posterior margin of the wound, is now turned forwards so as to form a covering over the gauze filling up the wound cavity (Fig. 239). On the auricle being restored to its normal position, this portion of the graft is brought into contact with the subcutaneous tissues of the skin forming the post-aural flap, which now forms the outer wall of the mastoid cavity. The posterior incision is closed with sutures and a dry dressing and bandage are applied to the ear.

_If skin-grafting be performed a week or more after the primary operation._ The post-aural wound, now healed, has to be reopened. In doing so there may be considerable bleeding, which must be arrested. The mastoid cavity is usually found to be covered with a fine layer of granulations. They are curetted away carefully, special attention being paid to the region of the Eustachian tube and the floor of the tympanic cavity. After removal of the granulations, the bone should appear uniformly smooth though somewhat vascular. If any points of carious bone be found they should be removed freely with the gouge or burr. Considerable time may have to be spent in arresting the oozing from the surface of the bone cavity. This is best done by washing out the cavity with hydrogen peroxide solution and then plugging it tightly for a few moments with adrenalin solution. The gauze is withdrawn in a few moments. If there be still oozing, the pressure will have to be repeated until it ceases. The method of applying the graft is the same as already described.

=After-treatment.= The outer dressing may be changed every second day, but the wound itself is not interfered with until the eighth day. If asepsis has been obtained, the posterior wound has usually completely healed, so that the stitches can be removed at the first dressing. Owing to the secretion from within the cavity there may be a certain amount of odour, and as a rule some purulent discharge from the meatus. Under good illumination the strip of gauze is gently removed through the meatus and afterwards the small pellets of cotton-wool. In order to make certain that all are removed, a note should be made at the time of transplanting the graft as to how many were inserted in the wound cavity. The ear is now syringed out gently with a weak solution of hydrogen peroxide and afterwards dried by mopping it out with small wicks of cotton-wool.

A speculum is next inserted into the meatus and the cavity thoroughly examined. Any portions of the graft not in absolute contact with the bone or which overlap the skin of the meatus will have died, and can be removed by forceps. Care, however, must be taken not to pull off these portions too forcibly, as in doing so other pieces of the graft may be torn away. The external meatus is then plugged with a tiny piece of gauze and a dry dressing applied. If the graft has not taken and has died, it will be expelled at the first dressing on syringing.

Further treatment consists in syringing and afterwards drying the cavity daily. From day to day the outer layer of the graft will gradually come away piecemeal. At the end of the second week the patient can usually go home and carry out the treatment for himself, but he should be seen by the surgeon at least once a week until complete healing has taken place. If the graft has not taken uniformly over the surface of the bone, small patches of granulations may be seen covering these areas. Under cocaine anæsthesia these patches should be curetted. If the granulations recur repeatedly, it means that there is some underlying carious bone, and that healing will not take place until the tiny fragment is eventually exfoliated.

=Results.= Statistics vary. There is no doubt that the results are better according to the experience of the surgeon with regard to grafting. If it be only applied in those cases in which it is certain that all the diseased bone has been eradicated at the primary operation, then the percentage of success with relation to failure is very high. If, however, skin-grafting be adopted as a matter of routine, the ultimate result is probably not so good as in a similar series of cases in which grafting has not been done.

=Skin-grafting through the external meatus.= This has been advised chiefly in order to avoid a second operation.

The technique of applying the graft is practically the same as that for transplanting a large graft. The same care must be taken to get the interior of the mastoid cavity aseptic and dry. To avoid a general anæsthetic, the small grafts may be removed from the arm or leg under local anæsthesia produced by a subcutaneous injection of Schleich’s solution. The graft is transferred from a small spatula to the edge of the meatus and then coaxed into position within the cavity by means of probes. The grafts are kept in position by small pellets of cotton-wool covered with gauze. If successful, the grafting may shorten the duration of the after-treatment. It is not, however, so satisfactory a procedure as applying a large graft directly through the post-aural wound.

In order to keep the grafts in position, Drew has suggested laying the graft on sterilized gold-beater’s skin, and in this way applying it to the interior of the mastoid cavity.

More recently, Stoddart Barr of Glasgow has introduced an ingenious method of getting the grafts into position. The graft is manipulated over the end of a suitably-bent glass tube, having attached to the other end a piece of rubber tubing with a glass mouthpiece or small rubber bag. The graft at the end of the tube is passed through a wide speculum to the inner wall of the tympanum, when, by blowing air through the tube, the graft is spread out over the inner surface, including the tympanic walls, aditus, and antrum.

AFTER-TREATMENT OF THE CASE

_If the posterior wound has been closed._ Provided the temperature keeps normal and there be no pain and no head symptoms, the first dressing need not take place until the fifth or sixth day. By this time the edges of the skin incision have usually united, so that the stitches can be removed, although occasionally the wound may have to be opened up to permit of drainage on account of septic infection. The withdrawal of the gauze from the auditory canal may cause considerable pain, which, however, can be prevented by continuous irrigation of the ear before and during its removal (see p. 315).

After the gauze has been removed, the ear is mopped out with pledgets of cotton-wool. To relieve the pain a few drops of a sterilized 1% solution of cocaine may be instilled and left within the ear for a few minutes.

Under good illumination, the largest possible speculum is inserted into the meatal orifice. The cocaine solution is mopped out, and the cavity dried, in order that careful inspection of the deeper parts may be made. The chief point is to see that the flaps are in position. There may be slight oozing from the surface of the wound, but as a rule the bone appears almost white, owing to the fact that granulations have not yet begun to form. The wound is then packed gently and evenly with gauze and the ear protected again with an external dressing and bandage.

Until the first dressing has taken place, the patient should be kept in bed. After this, provided the condition be satisfactory, he may be allowed to get up for a few hours every day, the period being gradually increased; by the tenth day or so he is practically well. In an uncomplicated case there is seldom any shock or discomfort after the operation, so that frequently the patient is anxious to be up and about even before the first dressing has been performed. It is wiser, however, to insist on rest for the first few days.

The subsequent dressings should be done every second or third day, depending on the condition found. If the wound cavity be clean, and if there be no odour, it is sufficient to irrigate it with a simple saline or boric lotion. Granulations begin to cover the bone about the tenth day, when there may be some purulent discharge necessitating daily dressings. To keep the parts sweet, an ear-bath of hydrogen peroxide (10 vols. %) may be given, the ear being subsequently irrigated with a 1 in 5,000 solution of biniodide of mercury.

Provided the patient be doing well there should be no temperature, pain, nor headaches. If any of these symptoms occur, or if the patient feels ill, or has attacks of sickness and becomes drowsy, the surgeon should at once be suspicious of some impending intracranial complication.

If the case be progressing favourably and all the diseased area of bone has been completely removed, granulations do not become exuberant, but form a fine smooth layer over the wound surface, the last portion to become covered being the region of the external semicircular canal and the ridge forming the remains of the posterior wall of the bony meatus. Exuberant granulation tissue is significant of underlying bone disease. If patches be observed, a 10% or stronger solution of cocaine should be applied to the part, which should afterwards be curetted. This process may have to be repeated on several occasions until, perhaps, a small spicule of bone is removed, after which granulations usually cease. As a rule the bone is completely covered with granulations by the fifth or sixth week. Meanwhile, owing to the growth of epithelium from the edges of the flaps, the raw surface within the wound cavity gradually becomes smaller, and with this there is diminished secretion.

The gauze packing can usually be discontinued about this period, or considerably earlier, perhaps even by the third week. In its stead an aqueous solution containing 50% of rectified spirit with 10 grains of boric acid to the ounce may be instilled into the wound cavity after it has been cleansed and dried.

Complete cicatrization of the cavity should take place within two or three months, depending on the size of the cavity.

_If the posterior wound has been left open_, the first dressing should be done on the second or third day.

The subsequent treatment depends on each individual case. If the wound has been left open on account of its septic condition, or owing to the dura mater having been exposed and found covered with granulations, its edges may be brought together by sutures after a period of ten days or so, when the wound cavity looks clean, and the packing carried out through the meatus.

On the other hand, if the wound has been left open on account of bone disease involving the inner wall of the tympanic cavity or region of the Eustachian tube, the packing should be continued through the posterior opening until the patches of carious or necrosed bone heal or are exfoliated. In these cases the granulation tissue tends to become fibrous in character in consequence of the necessary curettings, and eventually to form a thickened pad covering the inner wall.

After complete healing has taken place, the patient, before being dismissed, should be warned to visit the surgeon at least once in three months. Owing to the large cavity being lined with epithelium, desquamation takes place to a greater or lesser extent, so that the wound cavity may gradually become filled with masses of epithelial débris or cerumen. In consequence the cavity may become septic, and on removal of the epithelial débris underlying ulceration may be found. This can usually be cured by aseptic treatment, but if granulations have already occurred, curetting and the application of trichloracetic and chromic acid may be necessary.

DIFFICULTIES AND DANGERS OF THE OPERATION

_Anatomical difficulties._ The chief difficulties are due to a middle fossa overlapping the antral cavity, a lateral sinus projecting far forwards and lying superficially, and a sclerosed mastoid having no landmarks to indicate the way into the antrum. Unfortunately these conditions are frequently associated.

Formerly it was advised that it was wiser not to proceed further if the antral cavity could not be discovered after chiselling to a depth of three-quarters of an inch. This advice, however, is no longer reliable, as by the combination of the Stacke, Wolf, or Küster-Bergmann method any anatomical difficulties should certainly be overcome.

An inexperienced operator may mistake a large mastoid cell for the antrum and in this way may get into difficulties. The opening into the antrum, however, can always be identified by passing a bent malleable silver probe in an inward and forward direction into the aditus. If only a large cell has been opened, the probe will show that it is a limited cavity.

_Hæmorrhage._ In the majority of cases this is more of an inconvenience than a danger, being chiefly due to a general oozing from the soft tissues. It is, however, very necessary that the surgeon should have a clear view of the deeper parts whilst operating. If he works blindly in a pool of blood he courts disaster.

The hæmorrhage is best prevented by first curetting away any granulation tissue and then packing the cavity firmly with a strip of gauze. If this be not sufficient, it may be again packed with gauze containing adrenalin solution. It will repay the surgeon to have a good assistant to keep the field of operation dry. Troublesome bleeding, coming from a small vessel in the bone, may be arrested by the local application of a small fragment of Horsley’s sterilized wax (see Vol. I, p. 437).

_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 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.

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 masses 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 partition 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 canal, 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.