A System of Operative Surgery Part 52

REMOVAL OF EXOSTOSES FROM THE EXTERNAL MEATUS

=Indications.= The indications vary, depending on whether there is a coexisting middle-ear suppuration or not.

=If there be no middle-ear suppuration.= Operation is not urgent, but is justifiable under the following conditions:--

(i) _When one ear only is affected._ (_a_) If there be complete deafness due to obstruction of the auditory ca.n.a.l. The question of operation, however, should be decided by the patient, because it may be postponed indefinitely so long as no symptoms occur.

(_b_) If there be recurring attacks of discomfort or of pain in the ear as a result of eczema, of ot.i.tis externa, or of actual pressure of the growth itself. The patient may desire operation to obtain permanent relief.

(_c_) If there be deafness of the opposite side from other causes, and the presence of the exostoses is causing deafness of the functionally good ear.

(ii) _When both ears are affected._ In addition to the indications already given, operation is advisable on the worse side if there be almost complete obstruction on both sides, accompanied by recurrent attacks of deafness, owing to the narrowed pa.s.sage of the auditory ca.n.a.l becoming repeatedly blocked from acc.u.mulation of cerumen or epithelial debris.

_Operation is contra-indicated_ if previous examination indicates that the deafness is due to a chronic middle-ear catarrh or internal-ear disease, as in these cases restoration of hearing, which is the primary object of the operation, will be impossible.

=If middle-ear suppuration be present= operation is generally advisable.

(i) _In acute middle-ear suppuration_ operation is urgent if there are signs of retention of pus, _provided_ it is impossible to dilate the lumen of the auditory ca.n.a.l. Before resorting to operation an attempt should always first be made to obtain free drainage, as the obstruction may be due merely to inflammatory swelling of the tissues lining the auditory ca.n.a.l. With cessation of the acute inflammation, this swelling may subside and the lumen of the auditory ca.n.a.l again become patent; and if recovery with healing of the tympanic membrane takes place the hearing may again become normal, rendering the operation no longer necessary.

(ii) _In chronic middle-ear suppuration_ operation is always indicated if there are symptoms of retention of pus. It is also advisable as a prophylactic measure, although not urgent, even although no acute symptoms are present.

=Operation.= =When there is no middle-ear suppuration.=

The operation may be performed either (_a_) through the external meatus or (_b_) by reflecting the auricle forward by a post-auricular incision.

=Through the external meatus.= This method is only indicated if the exostosis is situated at the entrance of the meatus and is pedunculated.

A general anaesthetic is given, the patient being in the rec.u.mbent position. The surgeon works by reflected light. After the ear has been thoroughly cleansed a large-sized aural speculum is inserted into the meatus and the outlines of the exostosis are defined with a probe. A small gouge or chisel is used. It is inserted into the meatus in such a fas.h.i.+on that its point presses between the pedicle of the exostosis and the wall of the bony meatus. With successive sharp taps of the mallet, the gouge is made to cut through the pedicle, care being taken that the instrument is not driven in too deeply, on to the tympanic membrane.

The growth, which can now be felt to be movable within the meatus, can usually be removed by grasping it between the blades of forceps, or can be expelled by syringing the ear. After its removal the auditory ca.n.a.l should be plugged for a few minutes with a solution of cocaine and adrenalin chloride. This checks all haemorrhage, and at the same time enables the surgeon to get a good view of the deeper parts to see if further growths are situated more deeply within the meatus. Such growths, provided they are pedunculated and do not abut on the tympanic membrane, can sometimes also be removed by the same method; much depends on their shape and situation. If sessile or too deeply placed, the operation may have to be completed by reflecting forward the auricle.

Before terminating the operation a clear view of the tympanic membrane should always be obtained.

The meatus is finally syringed out with a 1 in 5,000 aqueous solution of biniodide of mercury and dried, a strip of sterilized gauze being inserted into the auditory ca.n.a.l. A simple dressing is then applied to the side of the head.

_Other methods of operation through the external meatus._

(_a_) Perforation of the exostosis, or enlargement of the small pa.s.sage existing between multiple exostoses, by means of the burr.

Although successful results have been recorded, this method is not advised, as cicatricial tissue almost invariably causes closure of the opening made. To keep the opening patent it is necessary to insert a small lead or silver canula, frequently a source of great discomfort.

(_b_) If the exostosis has a very fine pedicle, it may be possible to nip through its base with a pair of forceps, but it is not so sure a method as the employment of a gouge and mallet.

(_c_) Such methods as attempts to destroy the growth by means of the galvano-cautery or by the pressure of laminaria tents should be avoided; they are useless and unsurgical.

=By reflecting the auricle forward.= This is indicated if the exostoses are multiple, have a broad base, and are deeply situated.

The position of the patient, and the anaesthetic, are the same as in the previous operation. Reflected light may not be necessary.

The ear and the surrounding parts are carefully cleansed and the head is shaved for a short distance over and beyond the mastoid process. A curved incision is made _close behind_ the auricle (Fig. 226), beginning at the upper level of its attachment and extending downwards along the retro-auricular fold. The incision goes down to the bone. The auricle is reflected forward and the soft tissues are separated from the bone until Henle's spine and the posterior upper margin of the auditory ca.n.a.l are brought into view. Any bleeding, chiefly from branches of the posterior auricular artery, is at once arrested by pressure forceps, ligatures being afterwards applied. The a.s.sistant's duty is to hold the auricle well forward and at the same time to keep the wound dry by swabbing.

The fibrous portion of the ca.n.a.l is carefully separated from the bony portion with the periosteal elevator, the growth, if possible, being exposed without tearing through the thin layer of skin which covers it.

The method of procedure now depends on the character and number of the exostoses present.

(_a_) If situated superficially, they are removed by chiselling through their base with a gouge. They should be thoroughly removed, if necessary cutting through the normal bone well behind their base.

(_b_) If deeply placed, they are more easily removed by first chiselling away a part of the upper posterior wall of the external meatus. This is done in the same manner as in the early stage of the complete mastoid operation (see p. 397). If possible the antrum should not be exposed, and care should be taken not to cut too deeply for fear of injuring the tympanic membrane.

(_c_) If the exostoses spring from the anterior wall, it is necessary to make a T-shaped incision through the posterior membranous portion of the auditory ca.n.a.l in order to bring them into view clearly. This is done with a tenotomy knife, the flaps being held apart by means of forceps.

The growths can now be removed by means of the gouge and mallet.

(_d_) If the obstruction is due to multiple small exostoses forming an annular stricture within the bony ca.n.a.l, it is better to separate the membranous portion completely from the bony meatus. In doing so the skin over the exostoses tears through, so that the membranous portion can be reflected outwards as a finger-like process. To give greater room for the operation, the auricle and fibrous portion are pulled well forward by means of a loop of gauze pa.s.sed through the lumen of the cartilaginous meatus.

If necessary, reflected light should now be used. To reach the exostoses it may be necessary, as in the previous case, to remove part of the posterior bony wall. With the gouge and mallet the exostoses are carefully chiselled away. They frequently abut on the tympanic membrane, so that their removal without injuring it may be well-nigh impossible.

It is of the utmost importance that the field of operation should be kept dry, if necessary by repeatedly mopping out the ca.n.a.l with pledgets of cotton-wool soaked in adrenalin solution. The chief difficulty is to determine the situation of the tympanic membrane. A fine probe is used to discover any existing c.h.i.n.k between the growths; this will be a guide to show the direction in which to work. As soon as a small pa.s.sage has been made, sufficient to allow of a view of the deeper-lying parts, the ear should be syringed out and dried, and a thorough inspection made.

The tympanic membrane can usually be seen as a greyish-blue membrane; at other times it can be recognized by touching it with a probe. After making certain of the position of the membrane, the rest of the operation is easy. A small seeker (Fig. 219), such as is used in the mastoid operation, is pa.s.sed through the opening already made, and with it the deeper limits of the exostoses can be felt. The opening is gradually enlarged by removing the growths piecemeal with the chisel or gouge.

Although the burr is contra-indicated when operating through the external meatus, it is frequently of great service in these cases in rendering the walls of the ca.n.a.l smooth. The disadvantages of using a burr are, that it is less easy to control (unless the surgeon has had considerable experience in using it), and that it destroys all the epithelial lining of the auditory ca.n.a.l with which it comes in contact.

It should, therefore, only be used in those cases in which there is a complete ring of exostoses, but should be avoided if the exostoses are limited and if it is still possible to leave untouched a portion of the epithelial lining of the auditory ca.n.a.l.

When the surgeon considers he has successfully removed the obstruction, he should verify this fact by syringing out and drying the ear, and again obtaining a clear view of the tympanic membrane.

The fibrous portion is now replaced by inserting a finger into the cartilaginous meatus and pressing it back into the bony ca.n.a.l, the auricle being meanwhile pulled back into its normal position. The edges of the posterior wound are sutured together and the auditory ca.n.a.l is gently packed with gauze which should be inserted right down to the tympanic membrane. It is not necessary to make special meatal skin flaps, as careful packing of the auditory ca.n.a.l should be sufficient to keep the parts in apposition.

=When middle-ear suppuration is present.= _In acute middle-ear suppuration_ the chief difficulty is to decide what operation to perform. As operation is only indicated if there is retention of pus, it is wiser to open the mastoid antrum; the exostosis, if superficial and pedunculated, can also be removed at the same time. If, however, the obstruction is due to multiple and deeply placed exostoses, this part of the operation should be deferred to a later date, that is, after the acute symptoms have subsided.

_In chronic middle-ear suppuration_ the only operation to be recommended is the complete mastoid operation (see p. 392).

=After-treatment.= The after-treatment is practically the same whatever operation has been performed. The first dressing need not be done until the third day. The gauze plugging is then withdrawn and the auditory ca.n.a.l is syringed out and dried. If only a single exostosis has been removed the wound surface is small, and it is usually sufficient to puff in some boracic powder and again insert a piece of gauze. This may be repeated every second day, healing usually taking place within two or three weeks. In the case of deeply situated multiple exostoses, especially if removed from the anterior wall, considerable swelling of the soft parts lining the auditory ca.n.a.l may occur as a result of the manipulations. In such cases, after syringing out any existing blood-clots, some cocaine and adrenalin solution should be instilled into the meatus. An aural speculum is then gradually worked into the auditory ca.n.a.l, which is gently mopped out with small pledgets of cotton-wool, and the deeper parts are carefully inspected. Sometimes the torn ends of the fibrous portion, instead of covering the bony walls, are found to project into the auditory ca.n.a.l and to cause considerable narrowing of its lumen. By careful manipulations with the probe or by stroking the edges with tiny pledgets of cotton-wool, these rough surfaces may be smoothed down. It is very important, in the early days of the after-treatment, to prevent any narrowing at the site of the operation. This is one of the chief causes of subsequent failure. The gauze should always be reinserted right down to the tympanic membrane, and if there is not much secretion it should be packed firmly against the posterior and outer portion of the ca.n.a.l in order to prevent subsequent stenosis from the tendency of the cartilage to prolapse forward owing to the soft parts having been separated from the bony ca.n.a.l at the time of the operation.

The wound behind the ear heals very quickly and the st.i.tches can generally be removed on the third or fourth day. Subsequent treatment consists in preventing the formation of granulations over the wound area. This is best accomplished by keeping the auditory ca.n.a.l aseptic and dry. If granulations occur they should be touched from time to time with a saturated solution of trichloracetic acid. If healing has not taken place within two weeks, it will frequently be advantageous to discontinue the gauze packing and, in its stead, to instil drops of pure rectified spirit.

If a middle-ear catarrh with secretion of fluid occurs, owing to the tympanic membrane having been injured, it may be impossible to continue the gauze packing. In these cases only a fine drain of gauze should be inserted into the meatus, the dressing being changed as frequently as may be necessary.

Provided asepsis is maintained, the middle-ear inflammation usually subsides rapidly with healing of the membrane. After healing has taken place, inflation of the middle ear is recommended twice a week, for two or three weeks, in order to aid recovery and to prevent adhesions forming within the tympanic cavity.

=Dangers.= 1. If the exostoses be deeply situated, the tympanic membrane may be injured.

2. If much of the anterior wall of the auditory ca.n.a.l be removed, the temporo-maxillary joint may be opened.

3. It is possible that the tympanic membrane may not be recognized, and, by working too deeply, the labyrinth or the facial nerve may be injured.

=Prognosis.= Provided no accident has occurred during the operation, a successful result should be obtained. Stenosis, however, may occur from cicatricial contraction if the operation has been incompletely performed.

REMOVAL OF FOREIGN BODIES