GENERAL CONSIDERATIONS WITH REGARD TO OPERATIONS

In this connexion two points must be borne in mind: (1) The surgeon must have a good view of the part operated upon. For this reason when operating upon the auditory ca.n.a.l, the tympanic membrane, and tympanic cavity, he will usually require to work by reflected light.

(2) There must be no movement of the patient's head during the operation. If the operation is performed under a local anaesthetic, it is therefore very important that the patient's head should be kept fixed by means of an a.s.sistant.

=Preliminary surgical toilet.= If there be no existing suppuration, the ear should be cleansed, some twelve hours before the operation, by first giving an ear-bath of hydrogen peroxide lotion. This is done by making the patient incline the head to the opposite side so that the affected ear is uppermost. The warm solution is then poured into the meatus.

After ten minutes the ear is syringed out with a 1 in 5,000 aqueous solution of biniodide of mercury, and a strip of sterilized gauze is then inserted into the auditory ca.n.a.l. The auricle and surrounding parts should also be surgically cleansed, and afterwards protected by a simple aseptic compress. If, as in furunculosis of the external meatus, syringing or cleansing of the ear is very painful, drops of a 10% solution of carbolic acid in glycerine may be instilled frequently into the meatus instead. If there is an existing otorrha, it is obviously impossible to render the field of operation absolutely aseptic. The ear, however, should be cleansed, but the auditory ca.n.a.l should not be plugged with gauze. The existence of a purulent discharge is no excuse for lack of cleanliness. Failure of such precautions may lead to disaster; for example, to perichondritis of the auricle as a sequel of the mastoid operation.

Before the actual operation takes place, if necessary after the anaesthetic has been given, the ear and surrounding parts should again be carefully cleansed, and the auditory ca.n.a.l syringed out with biniodide of mercury solution.

In intrameatal operations the head should be wrapped in a sterilized towel, and a square of sterilized lint, having an aperture in the centre so as to expose only the auricle and meatus, should be placed over the side of the head and face. In operations on the mastoid process, and in those involving a post-auricular incision, the head should also be shaved for at least two or three inches beyond the region of the ear.

=Anaesthesia.= Both local and general anaesthesia are used. Unless contra-indicated for some special reason, and unless the operation is a very trivial one, it is wiser to give a _general anaesthetic_. Of these, chloroform is the most suitable in adults and infants, and the A. C. E.

mixture in children. Ether, although it may be safer, is frequently a source of annoyance to the operator, as it tends to increase the haemorrhage.

In order to produce _local anaesthesia_ two methods may be employed: (1) The instillation of fluids into the meatus; (2) subcutaneous injection of fluids beneath the lining membrane of the meatus and into the surrounding parts of the auricle.

The solution usually employed is a sterilized aqueous solution of cocaine hydrochloride in varying strengths up to 20%, to which may be added equal parts of 1 in 1,000 adrenalin chloride solution; the latter not only increases its a.n.a.lgesic properties, but also acts as a powerful haemostatic.

_Instillation._ As the auditory ca.n.a.l and the tympanic membrane are lined with epithelium which is very resistant to the absorption of fluids, complete anaesthesia is almost impossible to obtain. This method, therefore, is practically limited to such trivial operations as the curetting away or snaring off of granulations or polypi from the external or middle ear. To render anaesthesia more complete, the affected part may be finally rubbed over with a crystal of solid cocaine hydrochloride just before the operation--is begun. On the other hand, if the raw surface is large--for example, the wound left after a recently performed complete mastoid operation--the cocaine employed should not be stronger than a 5% solution in order to minimize the risk of poisoning.

Gray of Glasgow has suggested, as a more penetrating anodyne solution, a mixture consisting of a 10% solution of cocaine hydrochloride in equal parts of aniline oil and absolute alcohol, a solution which he especially advocates in order to produce anaesthesia of the tympanic membrane before doing paracentesis.

_Subcutaneous injection._ This is a modification of Schleich's method, and was first introduced by Neumann of Vienna. It consists in injecting a very weak solution of cocaine and adrenalin chloride subcutaneously beneath the periosteum lining the auditory ca.n.a.l. By this method even the complete mastoid operation has been performed, and in certain clinics it is used continually in the minor operations of paracentesis of the tympanic membrane, division of intratympanic adhesions, extraction of polypi, and ossiculectomy. A solution of beta-eucaine or novocaine may be used in preference to cocaine, as being less dangerous.

According to Neumann, three solutions are necessary: (_a_) a 1 in 2,000 solution of adrenalin chloride containing a 1% solution of beta-eucaine; (_b_) a 1 in 3,000 solution of adrenalin chloride containing a 1% solution of cocaine; (_c_) a 20% solution of cocaine.

The syringe for injecting the solution has a capacity of I cubic centimetre, and for convenience its needle is fixed at an obtuse angle to the body of the syringe (Fig. 177). The technique of the injection depends on whether the operation is to be limited to the auditory ca.n.a.l and tympanic cavity, or is to involve the mastoid process.

[Ill.u.s.tration: FIG. 177. NEUMANN'S SYRINGE FOR SUBCUTANEOUS INJECTION.]

If the complete mastoid operation is going to be performed, the needle of the syringe, now filled with the eucaine solution, is thrust through the skin about the middle point of the mastoid process, and a few drops of the solution are injected. The needle is then forced upwards towards the temporal ridge, at the same time being thrust in deeply until it touches the bone, so that a syringeful of the solution is injected beneath the periosteum. The needle is then withdrawn and reinserted at the same point, but in a backward direction, the solution being injected along the posterior portion of the mastoid process; in a similar manner the solution is injected downwards towards the tip of the mastoid. The ear being now pulled well forward, the needle is made to pierce the fold between the auricle and the mastoid process, just above the posterior ligament, and is pushed inwards between the anterior border of the mastoid process and the cartilage of the meatus, and a further syringeful of the solution is injected. A large speculum is now inserted into the ear, so that by pressing it against the wall of the meatus the skin, at the termination of the cartilaginous portion, is made to project in folds. The needle of the syringe, filled with cocaine solution, is pushed into this fold, and a few drops of the solution injected. By degrees the needle is still further pushed inwards, keeping it in close contact with the bony wall so that the fluid is injected beneath the periosteum. If the injection has been successful, a white bulging of the superior wall of the auditory ca.n.a.l will be noticed. To render anaesthesia complete, further injections may be made into the inferior and anterior walls of the auditory ca.n.a.l. Finally, a pledget of cotton-wool soaked in a 20% solution of cocaine is pushed into the tympanic cavity.

In the case of simple opening of the mastoid, subcutaneous injections into the auditory ca.n.a.l are not necessary. On the other hand, if the operation is limited to the auditory ca.n.a.l and tympanic cavity, the injections into the mastoid process are not required, but a primary injection of a small quant.i.ty of eucaine solution into the auriculo-mastoid fold considerably diminishes the pain produced during the act of injection into the auditory ca.n.a.l. Fifteen minutes should be allowed to elapse before the operation is begun. The anaesthesia lasts about half an hour.

_Difficulties._ It is by no means easy to inject fluid beneath the periosteum of the auditory ca.n.a.l, owing to its close adherence to the bone. The needle by mistake may repierce the skin at a point farther in, so that the fluid, instead of being injected beneath the periosteum, is injected into the auditory ca.n.a.l itself. In these cases anaesthesia will not be obtained, and the operator may possibly blame the principle of subcutaneous injection, rather than his own faulty technique.

In favour of subcutaneous injection it is urged that most of the minor operations within the tympanic cavity, including ossiculectomy, may be performed with the patient sitting up in the chair in the consulting room, and further, that the patient can afterwards go home; that the operation is rendered more easy owing to there being practically no bleeding; and that in the case of the more severe operations, such as opening of the mastoid antrum, the surgeon, in a case of emergency, may make use of this method if he cannot possibly obtain the services of an anaesthetist.

Against subcutaneous injection is the pain of the injection, which may be so great that the patient will not submit to it, and in consequence the proposed operation may have to be postponed.

In the case of the mastoid operation, it is difficult to believe that local anaesthesia, however efficient, will be looked upon with favour either by the surgeon or by the patient, except when a general anaesthetic is absolutely contra-indicated. The discomfort produced by retraction of the parts, the jarring caused by chiselling, and the consciousness of what is taking place, are far more unpleasant and more of a shock to the patient, than a general anaesthetic carefully given.

Further, it is not always possible to foretell the extent of the operation, and if repeated injections become necessary, there is danger of eucaine or cocaine poisoning being produced.

=Position of the patient and the surgeon=

1. In the minor operations the patient may be operated on whilst in the sitting posture, whether a local anaesthetic or a general one of gas and oxygen is employed. The relative positions of the patient and the surgeon are then the same as for the ordinary routine examination of the ear. Special care, however, should be taken that the patient's head is supported by the anaesthetist or a.s.sistant in order to prevent involuntary movements.

2. If the patient is operated on in the rec.u.mbent position, the head may rest comfortably on an ordinary pillow, but if chiselling is going to take place, the best support is a loosely filled sand-bag. The head should be turned towards the opposite side so that the affected ear is uppermost, and the surgeon stands at the side to be operated on. The lamp, the source of reflected light, should be held about six inches above the patient's shoulder on the opposite side.

CHAPTER II

OPERATIONS UPON THE EXTERNAL AUDITORY Ca.n.a.l

OPERATIONS FOR FURUNCULOSIS

The operative treatment consists in incising the furuncles and, if necessary, curetting out their contents.

=Indications.= (1) If, in spite of palliative treatment for two days, the pain be so intense as to prevent sleep, and be accompanied by pyrexia.

(2) If there be accompanying dema of the auricle and surrounding parts.

(3) If the furuncles occur during the course of a middle-ear suppuration, and occlusion of the external meatus prevents free drainage of the purulent secretion.

When possible, it is always preferable to operate under a general anaesthetic, such as gas and oxygen. If, however, the patient objects to a general anaesthetic, it should be explained that, in spite of the application of anodynes, the operation, although of momentary duration, will be excessively painful.

=Operation.= After the ear has been thoroughly cleansed, a large aural speculum is inserted within the meatus and the auditory ca.n.a.l dried with pledgets of cotton-wool.

The instrument usually used for this operation is a small and narrow sharp-pointed knife known as Hartmann's furunculotome (Fig. 178, C).

Equally suitable, however, is a fine bistoury; or, if necessary, a small tenotome or the ordinary paracentesis knife.

The surgeon holds the speculum in position within the meatus with the left hand, and with the right inserts the knife through the lumen of the speculum along the meatus until its point pa.s.ses the innermost limit of the furuncle. It is then quickly withdrawn, at the same time _incising the furuncle_ freely down to its base. Another method is to _transfix the furuncle_ by pa.s.sing the knife through its base and making it cut outwards through the skin. In a similar manner any other furuncles that may be present are incised or transfixed.

If the inflammatory process, instead of being localized as a furuncle, extends to the subcutaneous tissues, and especially if it is accompanied by much pain, pyrexia, and occlusion of the external meatus, _linear scarification_ may become necessary.

After incision, the contents of the furuncle are rapidly scooped out with the curette (Fig. 178, A). Slight haemorrhage may occur, but can be arrested at once by plugging the meatus for a minute with a strip of sterilized gauze. The auditory ca.n.a.l is finally syringed out with a warm aqueous 1 in 5,000 solution of biniodide of mercury and firmly plugged with gauze soaked in a 10% solution of carbolic acid in glycerine; a hot fomentation being afterwards applied to the side of the head.

[Ill.u.s.tration: FIG. 178. BURKHARDT-MERIAN'S AURAL INSTRUMENT.

A. Curette. B. Myringotome. C. Furunculotome.

D. Hook for removal of foreign body.

If the operation has been performed under a local anaesthetic (and this should only be done if a solitary furuncle is present), the pain is usually too great to permit of firm packing of the auditory ca.n.a.l. This after-packing, however, should be carried out, if possible, for the following reasons: firstly, it presses out the contents of the furuncle; secondly, it prevents auto-infection from one hair follicle to another; and thirdly, it tends to dilate the auditory ca.n.a.l.

=After-treatment.= If the furuncles have occurred during the course of a middle-ear suppuration, the gauze plugging must be removed within a few hours after the operation. The ear is then syringed out once or twice daily with a warm solution of lysol or carbolic acid, a small wick of gauze soaked in a 10% solution of carbolic acid in glycerine being afterwards inserted along the meatus.

If there be no accompanying middle-ear suppuration, the packing should not be removed for at least twenty-four hours. The pain produced by the first dressing may be severe, but can be usually avoided by first soaking the gauze with 5% solution of cocaine for a few minutes before removal and then gently withdrawing it whilst the ear is being syringed with a warm aseptic lotion. For the next two or three days it is sufficient to insert a drain of gauze soaked in a 1 in 3,000 alcoholic solution of perchloride of mercury.

=Results.= Although cure may be expected, it is not uncommon for further furuncles to occur in crops at repeated intervals. This is due to auto-infection of the hair follicles, which to a large extent may be prevented by painting the surface of the auditory ca.n.a.l daily, for at least two or three weeks, with an oil containing a drachm of nitrate of mercury to the ounce.

In the case of diffuse inflammation, although relapses are uncommon, superficial necrosis of a portion of the bony meatus may afterwards occur as a result of involvement of its periosteal lining. If this takes place, stenosis of the auditory ca.n.a.l may afterwards occur from subsequent cicatrization.

=Dangers.= With ordinary precautions no accident should occur, but the following may be mentioned: (1) if the furuncles are deeply placed, the tympanic membrane may be incised inadvertently, and a middle-ear suppuration may result; (2) a too violent incision may cut through the meatal cartilage posteriorly, and, as a result of septic infection, may give rise to perichondritis of the auricle. This, fortunately, is rare.