A System of Operative Surgery Part 54

390).

OPERATIONS FOR STENOSIS OF THE EXTERNAL MEATUS

Stenosis, or stricture of the auditory ca.n.a.l, is practically always the result of traumatism or inflammatory conditions; it is only very rarely congenital.

=Indications.= (i) If there be deafness of the other ear, and the functionally good ear periodically becomes deaf from obstruction of the narrow pa.s.sage by cerumen or epithelial debris, and the patient is weary of conservative treatment.

(ii) If there be recurrent attacks of ot.i.tis externa.

(iii) If there be retention of pus, the result of inflammation of the external or middle ear, which is not relieved by conservative treatment.

_The operation is contra-indicated_ if there is accompanying deafness, due to chronic middle-ear or to internal-ear disease, provided there is no suppuration within the external or middle ear.

=Operation.= The method of operation depends on whether the stricture is membranous, fibrous, or bony in consistence, or whether it is limited or is causing a general narrowing of the auditory ca.n.a.l. It may take one of the following forms:--

_Dilatation._ This method is not very satisfactory, and is limited to recent cases of membranous or fibrous stricture of the annular variety.

After cleansing the meatus, a small laminaria tent is inserted through the stricture, and if the pain is not too severe it is left _in situ_ for at least twenty-four hours and then withdrawn. The ear is again carefully cleansed, and if possible a larger laminaria tent is subst.i.tuted. This procedure is repeated until the maximum amount of dilatation has been obtained.

_Incision of the stricture._ This also is limited to membranous or to fibrous strictures of the annular variety.

The operation, if necessary, may be performed under a local anaesthetic, produced by subcutaneous injections, although usually a general anaesthetic is preferable.

The ear and surrounding parts are surgically cleansed by the ordinary methods. The surgeon works by reflected light. The patient may be in either the sitting or the rec.u.mbent position, depending on whether a local or general anaesthetic is given. In the latter case the auditory ca.n.a.l should be filled with cocaine and adrenalin solution before the anaesthetic is administered in order to diminish bleeding as far as possible.

The ear having been dried, a conveniently large aural speculum is inserted, and with a tenotome or a furunculotome radiating incisions are made through the stricture. One of the small flaps thus made is grasped with a fine pair of tenaculum forceps, and the surgeon cuts through its base, keeping the knife as close as possible to the wall of the auditory ca.n.a.l. Each flap is treated in a similar fashion. Instead of making radiating incisions, the tissue forming the obstruction may be transfixed through its base, the knife being made to cut in a circular fashion right round the auditory ca.n.a.l, keeping as close as possible to its wall.

On completion of the operation, a piece of india-rubber tubing, of as large a size as possible, is inserted into the dilated ca.n.a.l. It should only be removed for the purpose of cleansing and should be at once reinserted. A silver canula, if necessary, can afterwards replace the india-rubber tubing. This canula may have to be worn for months.

This operation is often most unsatisfactory, as the stricture, instead of being annular as first supposed, may be found, on operation, to extend a considerable distance along the auditory ca.n.a.l and, in addition, to be partially due to a general thickening of the underlying bone.

_Excision of the stricture._ The auricle is reflected forward and the preliminary steps of the operation are performed as already described for removal of a deep-seated exostosis (see p. 319). The surgeon makes a transverse incision with a knife through the fibrous portion of the auditory ca.n.a.l, just external to the stricture, and carries it right round the meatus, thus separating the outer portion of the membranous from the bony ca.n.a.l. The fibrous portion is now pulled outwards by means of a retractor, and the thickened tissue, forming the stricture, is peeled off from the surrounding bony meatus with a small periosteal elevator and so removed. If the stenosis is partially due to thickening of the walls of the ca.n.a.l itself, it may also be necessary to chisel away a considerable portion of its upper posterior part. After completion of the operation a clear view of the tympanic membrane should be obtained.

In this operation a considerable portion of the bony ca.n.a.l is denuded of its epithelial lining membrane, so that there is a special tendency to the re-formation of cicatricial tissue. To prevent this taking place two methods may be employed:--(1) If much of the upper posterior wall of the bony meatus be removed, a post-meatal flap should be made and kept in position by means of a catgut suture carried through the skin behind the auricle. The formation of such a flap is described as a step in the complete mastoid operation (see p. 401).

(2) If no bone be removed, the membranous portion is replaced _in situ_, the posterior auricular wound closed, and as large an india-rubber tube as possible is inserted into the meatus. A week or ten days later, as soon as granulations begin to form, skin-grafting may be undertaken (see p. 410).

If grafting be not successful, the india-rubber tube or silver canula must be kept constantly within the meatus (only being removed for cleansing purposes) until healing takes place.

_The complete mastoid operation_ is indicated in the case of stenosis occurring in chronic middle-ear suppuration if symptoms of retention of pus occur.

In acute middle-ear suppuration, however, every attempt should be made to avoid operation, as the lumen of the auditory ca.n.a.l may again become patent after the acute inflammation has subsided.

OPERATIONS FOR ATRESIA

Atresia of the external meatus may be either congenital or acquired.

=Indications.= (i) _In congenital cases_ operation is only justifiable if the atresia is due to a _membranous web_ situated in the outer part of the auditory ca.n.a.l and if, as a result of tuning-fork tests and of inflation through the Eustachian tube, it is fairly certain that the middle ear is normal.

_Operation is contra-indicated in cases of bony atresia._ Although attempts have been made to make an artificial ca.n.a.l in order to restore the hearing power, a successful result has not yet been obtained. Apart from the difficulty of retaining the patency of any ca.n.a.l so made, the accompanying malformation of the middle ear renders a successful result impossible (Paper by author, _Journal of Laryngology, &c._, March, 1901). Although the tympanic membrane is said to have been exposed by operation in a few cases, experience has shown that the supposed tympanic membrane was really the capsule of the temporo-maxillary joint.

(ii) _In acquired cases_ operation is indicated if the other ear is deaf; if the site of the occlusion of the auditory ca.n.a.l is in its outer part and is due to membranous or fibrous tissue, and if there is no previous history of middle-ear disease, and if the labyrinth is still intact.

Operation is not advised if the other ear is normal, unless the patient particularly desires it.

_Operation is contra-indicated_ if there is internal-ear deafness on the affected side and if the other ear is normal; or if there is a definite history of the closure of the auditory ca.n.a.l having been the result of a previous middle-ear suppuration. In the latter case the destructive changes within the tympanic cavity will be so marked that the chances of improving the hearing will be very slight in spite of the most successful operation.

=Operation.= If the obstruction be due to a fibrous band, an attempt may be made to remove it by excising it by the intrameatal method. In other cases the post-auricular method is necessary.

The chief point to remember is to make a large opening. For this reason the post-auricular method is to be preferred, as a considerable portion of the upper posterior wall can be removed and a large meatal flap fashioned (see p. 401).

=Results.= If the stricture or point of occlusion of the auditory ca.n.a.l is limited and composed of membranous and fibrous tissues, a good result can be usually obtained, and there is no reason why complete recovery of hearing should not take place if the labyrinth and tympanic cavity are normal.

Unfortunately, as in all cases of stricture, there is a tendency for it to recur.

OPERATIONS FOR AURAL POLYPUS

In this section only the aural polypi which project from the tympanic cavity into the external auditory meatus will be considered; whereas the treatment of granulations, and with them the minute polypi which are still limited to the tympanic cavity, will be discussed in the chapter on operations within the middle ear.

=Indications.= An aural polypus should _always_ be removed because, apart from the fact that it is a symptom of underlying disease, it may obstruct free drainage of the purulent discharge, and therefore become a source of danger.

=Operation.= The simplest and the best method is _removal by the snare_.

In the case of small and soft polypi, the polypus is removed by traction--formerly called =avulsion=--after the snare has been tightened round its pedicle; with a large, tough, fibrous polypus considerable force may be required to tear through its pedicle. This procedure in the case of polypi arising from the region of the tegmen tympani has been known to give rise to fatal meningitis. In such cases the pedicle of the polypus should be cleanly cut through by the snare--so-called =excision=.

As aural polypi are always a.s.sociated with suppuration, it is especially necessary that the ear should be thoroughly cleansed before operation.

A local anaesthetic (see p. 310) is sufficient in the case of smaller polypi, but if the polypus be large and tough, it is wiser to give a general anaesthetic, such as gas and oxygen. Or a 3% solution of cocaine may be injected into the growth, which, according to Frey of Vienna, renders removal absolutely painless; this, however, has not always been my experience.

The size of the polypus and the origin of its pedicle should be determined before operating, if necessary by using a probe (Fig. 181); also it must be diagnosed from a bulging congested tympanic membrane, or from the inner surface of the tympanic cavity, which may be exposed to view owing to complete destruction of the membrane having already occurred.

[Ill.u.s.tration: FIG. 181. AURAL PROBE.]

[Ill.u.s.tration: FIG. 182. WILDE'S AURAL SNARE. The snare is held in the usual position for extraction of a polypus.]

A Wilde's snare is generally used. It is a fine angular snare fitted with soft copper wire. The loop of the snare should be bent downwards and forwards and should be of such a size as to just surround the growth. The snare is held between the thumb and the first and second finger of the right hand (Fig. 182). Under good illumination, and using the speculum and reflected light if necessary, the shaft of the snare is pa.s.sed along the upper portion of the auditory ca.n.a.l until the edge of the polypus is reached. The loop is made to encircle the polypus (Fig.

183), the snare is gradually pushed inwards with a gentle sinuous movement until it reaches the point of attachment of the growth. The loop is then tightened until it firmly grasps the neck of the polypus (Fig. 184). The friable tissue is torn through by gentle traction and the polypus is withdrawn in the snare. Care must be taken not to injure the tympanic membrane through which the polypus may be projecting; it is for this reason that the loop is bent at an angle to the shaft of the snare so that it may lie parallel to the tympanic membrane whilst in the act of grasping the polypus. If the polypus be very small its pedicle may be clearly defined before operation, and the snare pa.s.sed round it directly (Fig. 185).

If the polypus be very large and tough, the snare is made to cut clean through its pedicle as near to its attachment as possible, instead of employing traction. The snare is then withdrawn, the polypus being afterwards grasped and removed by means of forceps. In this latter case it may be necessary to use a stronger snare fitted with piano steel wire instead of the ordinary copper wire. On removal of the polypus there may be considerable haemorrhage. After it has ceased the ear is syringed out and dried. The auditory ca.n.a.l is then inspected, and if it is found that the growth has not been removed completely, this can be done now by reapplication of the snare.

After final cleansing of the meatus, a strip of gauze is inserted, and the ear protected with a pad of cotton-wool and a bandage.

=After-treatment.= The dressing should be removed within twenty-four hours, and the ear cleansed by syringing. After mopping it dry drops of rectified spirits should be instilled.

On removal of the first dressing, any polypoid tissue which remains may be cauterized under cocaine anaesthesia by the actual cautery, or by a bead of chromic or trichloracetic acid (see p. 348).

[Ill.u.s.tration: FIG. 183. WILDE'S SNARE BEING Pa.s.sED ROUND AN AURAL POLYPUS. (_Semi-diagrammatic._)]