A System of Operative Surgery Part 55

Further treatment consists in keeping the ear clean and dry. For the first few days it should be syringed daily, dried, and spirit drops instilled. As the secretion becomes less the syringing should be diminished. If the perforation be large, instead of instilling drops, some finely powdered boric acid may be puffed in.

=Other methods of removal.= These are not recommended, but merely mentioned for the sake of completeness.

_By forceps._ The rough and ready method of extracting a polypus forcibly from the ear by means of forceps, although practised formerly, has now been discarded as being unsurgical and dangerous.

_Ligation._ The operation consisted in pa.s.sing a snare over the polypus and grasping it tightly as near to its base as possible. The snare was then twisted round its axis in order to tighten the loop further and so obliterate the blood-supply of the growth, the wire of the snare being afterwards cut through with pliers and the snare withdrawn. After a few days the polypus became gangrenous from want of blood-supply, and separated from its deep attachments.

_Curetting._ This method, which should only be made use of in the case of small multiple polypi within the tympanic cavity, will be considered when discussing the treatment of granulations within the middle ear (see p. 398).

=Dangers.= Haemorrhage is seldom profuse, but if it is, it can always be arrested by packing the meatus with cocaine and adrenalin solution.

[Ill.u.s.tration: FIG. 184. WILDE'S SNARE GRIPPING THE NECK OF POLYPUS.

(_Semi-diagrammatic._)]

[Ill.u.s.tration: FIG. 185. POLYPUS ARISING FROM THE ATTIC REGION. The snare is in position for the extraction of the polypus.

(_Semi-diagrammatic._)]

The chief dangers are injury to the contents of the tympanic cavity, such as dislocation or removal of the ossicles; or subsequent meningitis. These mishaps are usually the result of forcible extraction, or of blindly curetting the ear after this has been done. Meningitis, however, has been known to occur, in spite of every precaution being taken, if, owing to caries of the tegmen tympani, the polypus has its origin from the dura mater of the middle fossa.

=Prognosis.= If the polypus be single and of recent origin, the result probably of acute inflammation of the middle ear, its removal may cause complete recovery and cessation of the middle-ear suppuration.

In the case, however, of multiple polypi a.s.sociated with chronic middle-ear suppuration and usually signifying underlying bone disease, recurrences may be frequent and further operations may become necessary.

It may here be emphasized that a polypus in itself is not a disease, but merely a symptom of disease.

After removal of a large polypus, the patient should always be kept under observation for a day or two in case of symptoms of acute inflammation of the mastoid process arising and necessitating further operation.

CHAPTER III

OPERATIONS UPON THE TYMPANIC MEMBRANE AND WITHIN THE TYMPANIC CAVITY

SURGICAL ANATOMY OF THE TYMPANUM

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

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

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

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

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

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

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

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

[Ill.u.s.tration: FIG. 186. ANATOMICAL PREPARATION OF THE MIDDLE EAR. 1-1/2 nat. size. 1, Antrum; 2, Aditus; 3, Attic, containing head of malleus and body of incus; 4, Chorda tympani nerve; 5, Middle fossa of intracranial cavity; 6, Eustachian tube; 7, Carotid ca.n.a.l; 8, Jugular vein in jugular fossa; 9, 'Cellar' or floor of tympanic cavity; 10, Ca.n.a.l of facial nerve; 11, Sigmoid groove for lateral sinus. (From the Author's _Diseases of the Ear_.)]

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

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

OPERATIONS UPON THE TYMPANIC MEMBRANE

PARACENTESIS

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

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

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

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

(iii) _As a preliminary to intratympanic operations._

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

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

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

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

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

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

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

[Ill.u.s.tration: FIG. 187. PARACENTESIS KNIFE HELD IN POSITION IN THE HAND.]

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

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

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

In acute middle-ear catarrh with exudation, a Siegle's speculum (Fig.

194) should be inserted into the meatus after free incision of the membrane, and as much fluid as possible extracted by suction. In addition, gentle inflation by means of Politzer's method will help to expel from the middle ear the fluid, which should then be mopped out of the external meatus. This should be repeated daily.