A System of Operative Surgery Part 58

[Ill.u.s.tration: FIG. 197. LUCAE'S PROBE.]

=Results.= It is difficult to foretell what the result will be, as it is chiefly dependent on the extent of the adhesions already existing within the tympanic cavity and on the mobility of the stapes within the fenestra ovalis. If the latter is already fixed, then improvement is impossible. If, however, the adhesions are limited, a better result may be obtained by this method than by pneumo-ma.s.sage and inflation. The surgeon must be guided by the extent and duration of the improvement as to how long to continue the treatment. Unfortunately, relapses are not uncommon, though temporary benefit may be obtained.

=Ma.s.sage of the stapes.= This is only done as a last resource in the hope of obtaining some improvement in hearing.

=Indications.= (i) In cases in which mobilization of the malleus has caused no improvement, and it is hoped, from the history of the case, that this is due to fibrous adhesions fixing the stapes within the fenestra ovalis. This condition must be carefully distinguished from otosclerosis or bony ankylosis of the stapes, in which latter conditions any such procedure is absolutely contra-indicated.

(ii) Direct mobilization may be undertaken as a preliminary step previous to removal of the stapes itself. If the stapes is movable and slight improvement occurs, then its removal may be justifiable under certain conditions. If, however, the stapes is fixed and no improvement occurs, then its removal will be attended with such difficulty as to almost negative this being attempted.

=Operation.= If a perforation of the upper posterior quadrant be present, a small pledget of cotton-wool soaked in a 20% solution of cocaine is brought into contact with the inner wall of the tympanic cavity. After a few minutes Lucae's probe is placed in position against the head of the stapes and the vibratory movements are carried out. If no perforation of the drum exists, then it is first necessary to excise a flap in the upper posterior quadrant of the membrane.

=Difficulties.= The chief difficulty is anatomical. Projection forward of the upper posterior part of the tympanic ring or a deeply placed niche of the fenestra ovalis may prevent a view of the stapes.

If the membrane has to be incised, the slight amount of bleeding may also prevent a good view being obtained.

There is no actual danger in the operation, but if the stapes is fixed or if much force is used, it is by no means difficult to fracture the crura of the stapes.

[Ill.u.s.tration: FIG. 198. TO SHOW SITES OF PERFORATION IN ATTIC SUPPURATION AND CARIES OF THE OSSICLES. 1. Perforation in front of malleus. 2. Perforation behind malleus. 3. Perforation involving posterior attic region and upper posterior part of membrane. (From the Author's _Diseases of the Ear_.)]

REMOVAL OF THE OSSICLES

Except under the most rare conditions only the malleus and incus are removed; the stapes, if possible, being left undisturbed.

These operations will therefore be considered separately.

=Removal of the malleus and incus.= This operation was first proposed by Schwartze in 1873, and later by Kessel, Ludewig, s.e.xton, and Zeroni.

=Indications.= The indications for operation may be considered with regard to (1) chronic middle-ear suppuration and (2) non-suppurative middle-ear disease, whether the result of a previous middle-ear suppuration or of a chronic middle-ear catarrh.

In chronic middle-ear suppuration, the chief object of the operation is to ensure drainage and if possible to remove the cause of the suppuration; in non-suppurative conditions, to improve the hearing.

It may here be mentioned that the position of the perforation in the attic region is frequently of importance when considering the question of treatment. If situated in front of the malleus, the disease is probably limited to the outer attic region and malleus; if just behind the malleus, then probably both the malleus and incus are affected; but if the perforation extends farther back, involving the upper posterior quadrant of the drum, especially its bony margin, it suggests disease not only of the ossicles together with the walls of the aditus and antrum, but perhaps also of the mastoid process (Fig. 198).

(i) _In chronic middle-ear suppuration._ Before operation is considered, it is presumed that conservative measures, such as syringing, instillation of astringent and antiseptic drops, and was.h.i.+ng out of the attic by means of Hartmann's canula with various solutions, have been given a thorough trial and failed.

(_a_) If the suppuration be limited to the attic region (although the main portion of the tympanic membrane is intact), provided there is marked deafness and there are symptoms of lack of free drainage indicated by recurrent attacks of headache, a feeling of heaviness or giddiness, or pain radiating up the head on the affected side.

(_b_) If there be caries of the malleus and incus, and the outer attic wall, with recurrence of granulations after repeated removal, especially if accompanied by cholesteatomatous formation, provided there is no evidence of disease of the mastoid process itself.

(_c_) Although the general symptoms and the condition found on examination justify the complete mastoid operation, yet if the patient refuses to have this operation performed, the simpler operation of ossiculectomy may be undertaken if desired. This will permit of free drainage and diminish the risk of future intracranial complications. It should, however, be clearly explained to the patient that no guarantee can be given with regard to effecting a permanent cure as a result of this operation.

(ii) _In non-suppurative conditions._

(_a_) If there be marked middle-ear deafness, the result of adhesions, and the malleus is fixed to the promontory. Operation is justifiable if it is found that after each inflation of the middle ear, improvement of hearing is obtained which, however, is not permanent but only temporary.

(_b_) If, as the result of artificial perforation, made under the conditions already laid down, improvement takes place temporarily, but a relapse occurs from closure of the perforation (see p. 340).

(_c_) If tinnitus and attacks of vertigo, due to marked retraction of the membrane, are temporarily relieved by inflation. In this case operation should only be carried out as a last resource after all other measures have failed to cure and if the symptoms are very severe and distressing.

(_d_) If there be marked middle-ear deafness with extensive adhesions on both sides and evidence points to the stapes being freely movable. The operation is justifiable, as an experiment, on the worse side.

=Operation.= The only operation to be considered is the intrameatal one. Stacke originally suggested a post-auricular incision, and reflecting the auricle forward, and, after removing the ossicle, to remove also the outer attic-wall by means of the chisel. This method, however, has now been given up as being too radical, but will be mentioned later on in connexion with the mastoid operation (see p. 397).

Unless contra-indicated, a general anaesthetic should be given, as it is not always possible to foretell whether the operation will be difficult or easy. In addition it may be necessary to curette out granulations and also to remove the outer wall of the attic. Unless the patient is very insensitive, this is almost impossible under local anaesthesia (see p.

311).

Before the anaesthetic is given, the ear should be filled with a 5% solution of cocaine containing a 1 in 2,000 solution of adrenalin chloride in order to diminish the bleeding during the operation.

The field of operation is isolated from the surrounding parts by covering the head with a sterilized towel having an opening cut in it just sufficient to expose the auricle and meatus.

The following are the steps of the operation: (1) freeing the malleus from its attachments to the tympanic membrane, and from the inner wall of the middle ear, if adherent to it; (2) cutting through the tendon of the tensor tympani muscle; (3) removal of the malleus; (4) removal of the incus; (5) removal of the outer wall of the attic; (6) curetting out of granulations, if present. The method of operation varies slightly according to the condition found.

=Removal of the malleus.= In post-suppurative and non-suppurative conditions the chief cause of failure is the recurrence of adhesions, so for this reason it is wisest to remove the membrane as completely as possible.

With a paracentesis knife, the membrane is incised below and behind the malleus. The incision is then carried upwards along its posterior border to the posterior fold, then round the complete margin of the tympanic membrane and along the anterior fold and border of the malleus, so as to meet the original point of the incision. The knife is then reinserted just in front of the processus brevis and cuts through the anterior ligament in an upward direction; in a similar fas.h.i.+on the posterior fold is also cut through (Fig. 190).

The next step is tenotomy of the tensor tympani muscle (see p. 345).

The malleus thus freed can easily be removed by seizing its handle with a pair of s.e.xton's (Fig. 193) or crocodile forceps (Fig. 179). In removing the malleus it is necessary to remember that its head is situated within the attic and therefore cannot be pulled out directly, but must first be drawn downwards until it is seen within the tympanic cavity. If this precaution be not taken, the neck of the malleus may be broken, leaving the head behind. If this takes place its extraction may be a matter of difficulty.

[Ill.u.s.tration: FIG. 199. REMOVAL OF THE MALLEUS BY WILDE'S SNARE. _First position._ After cutting through the tensor tympani muscle by Schwartze's method.]

[Ill.u.s.tration: FIG. 200. REMOVAL OF THE MALLEUS BY WILDE'S SNARE.

_Second position._ Malleus pulled down from attic--about to be withdrawn from auditory ca.n.a.l.]

Instead of using s.e.xton's forceps, the malleus may be removed by means of Wilde's snare. This is the method advocated by Schwartze. After cutting through the tensor tympani muscle, the loop of the snare is threaded over the head of the malleus and guided upwards until it embraces its neck. The loop is then drawn tight so as to hold the malleus firmly in its grasp. The ossicle is extracted by first pulling it downwards (Fig. 199), so as to dislodge it from the attic, and then outwards (Fig. 200).

[Ill.u.s.tration: FIG. 201. DELSTANCHE'S RING-KNIFE.]

Another method of extracting the malleus, and in my opinion the one to be preferred, is by Delstanche's ring-knife (Fig. 201). This instrument differs from the ordinary ring-knife in that the upper border of its anterior part is especially sharpened so as to form a fine cutting surface. After the malleus has been freed from the membrane by means of the paracentesis knife, Delstanche's ring-knife is made to encircle its handle. It is then pushed gradually upwards, keeping as close to the posterior border of the malleus as possible, until it cuts through the attachment of the tensor tympani. In doing this the instrument will embrace the neck of the malleus (Fig. 202). This permits of sufficient leverage to extract the malleus by gentle traction in a downward and outward direction without danger of fracturing its shaft. If much resistance be felt, probably the tensor tympani muscle has not been cut through, and another attempt should be made to do this before trying further extraction. The advantage of this instrument is, that once the knife has encircled the malleus it should be possible not only to cut through the tensor tympani, but to extract the bone itself without the use of any other instrument. If Schwartze's tenotomy knife be used, two tenotomy knives are required, one for the right and one for the left ear. Delstanche's ring-knife is equally good for either ear.

[Ill.u.s.tration: FIG. 202. REMOVAL OF MALLEUS BY DELSTANCHE'S RING-KNIFE.

A, Curette inserted round handle of malleus; B, Curette pushed upwards, in act of cutting through tendon of tensor tympani muscle.]

=Extraction of the incus.= Although it is frequently stated that extraction of the incus is more difficult than that of the malleus, in reality it is the easier part of the operation as, unlike the malleus, it has no firm attachments.

After removal of the malleus all haemorrhage must be arrested and a view obtained of the inner wall of the tympanic cavity. If it be possible to see the long process of the incus and its articulation with the head of the stapes, the articulation should be cut through with a small sickle-shaped knife. The knife is inserted just in front of the long process of the incus and, keeping close to it posteriorly, is made to cut downwards and backwards, thus separating its connexion with the stapes. Frequently the long process cannot be seen, or it may indeed have already disappeared as a result of caries. Theoretically this delicate manuvre is performed in order to prevent injury or dislodgment of the stapes during the act of removal of the incus. From a practical point of view, however, it does not appear to make any difference whether the incudo-stapedial articulation is cut through or not.

[Ill.u.s.tration: FIG. 203. LUDEWIG'S INCUS HOOK.]

[Ill.u.s.tration: FIG. 204. ZERONI'S INCUS HOOK.]

A variety of instruments have been described for the purpose of removal of the incus. Ludewig's incus hook (named after Ludewig, who was one of the first to draw attention to this operation) is still recommended by many as being the best. It consists of a solid curved hook, having a length of 5 millimetres and a width of 2 millimetres, bent at right angles to its shaft (Fig. 203). A pair of these are necessary, one for each ear; also several sets of different sizes may be required owing to the variation in depth, height, and roof of the attic region. I, however, prefer Zeroni's (Fig. 204). This hook, instead of being solid, consists of a steel eyelet having a backward curve similar to that of Ludewig's.

[Ill.u.s.tration: FIG. 205. REMOVAL OF INCUS BY ZERONI'S HOOK. A, Diagrammatic section showing opening in tegmen tympani: _b_, processus cochleariformis; _c_, external semicircular ca.n.a.l; _d_, aditus and antrum. B, Diagrammatic section, through the auditory ca.n.a.l, just beyond the tympanic membrane: _e_, long process of incus; _f_, incudo-stapedial joint; _g_, tympanic ring; _h_, remains of the tympanic membrane; _i_, fenestra rotunda; above it is the promontory.]

The technique is the same whichever pattern is employed. The instrument is inserted in such a fas.h.i.+on that the hook is directed upwards, having its concavity backwards. It is pa.s.sed into the attic at the point previously occupied by the head of the malleus. The shaft of the instrument is then rotated backwards so that the hook pa.s.ses over the body of the incus (Fig. 205). As the rotatory action is continued downwards and finally forwards, the incus is dislodged from its position and forced into the tympanic cavity. It can now be seized by a pair of s.e.xton's or crocodile forceps and removed. If it falls into the floor of the tympanum, it can usually be dislodged by syringing, or else by means of a small hook pa.s.sed in circular fas.h.i.+on along the floor of the cavity.