CHAPTER IV

OPERATIONS UPON THE EUSTACHIAN TUBE

Under this heading may be considered manipulations requiring special technical knowledge and skill: (1) Catheterization; (2) passing of bougies; and (3) washing out the tympanic cavity through the Eustachian tube.

CATHETERIZATION OF THE EUSTACHIAN TUBE.

=Indications.= (i) _As a means of diagnosis_ in order to determine (_a_) the amount and character of the obstruction within the Eustachian tube; (_b_) the condition of the mucous membrane and whether any exudation is present within the middle ear.

(ii) _For the purpose of treatment._ (_a_) In order to instil medicated drops or vapours into the Eustachian tube and tympanic cavity; (_b_) as a preliminary measure to the passage of bougies into the Eustachian tube or to washing out the tympanic cavity through the Eustachian tube.

(iii) _Catheterization is preferable to Politzer’s method_ if only one ear is affected. Politzer’s method, on the other hand, is preferable to catheterization (_a_) in small children; (_b_) in the case of slight middle-ear catarrh if both ears are affected; (_c_) if the passing of the catheter is very difficult and causes pain owing to nasal obstruction; (_d_) in nervous individuals who object to the catheter; (_e_) if the sudden inflation by means of Politzer’s method is more effectual than by catheterization.

_Points to notice before inflation._ 1. Care must be taken that the lumen of the catheter is not obstructed, and that the compressed air bag and auscultation tube are also in working order.

2. The nose must be cleansed of all secretion; if filled with crusts or in a septic condition, inflation must be avoided.

3. The patient should be sitting. Sometimes on inflation of the ear, especially for the first time, an attack of giddiness or faintness may occur.

4. The nose should always be examined to see that the passage is free. If it be obstructed catheterization may be impossible, or some special manipulation will be required in order to pass the catheter through the nose.

5. In order to prevent muscular contraction of the palatal muscles, which may grip the end of the catheter and so prevent its entrance into the orifice of the Eustachian tube, the patient should be told to breathe quietly and keep the eyes open.

A short silver or plated catheter is usually used. It is 5 inches in length and curved at its extremity. To indicate the position of the point of the catheter in the post-nasal space, a ring is attached to its outer and wider extremity corresponding with the concavity of the curvature of its beak (Fig. 209). The size of the catheter varies in diameter from Nos. 1 to 4 English size, that is, the same scale as used for urethral catheters. The source of compressed air used for the inflation is usually a Politzer bag having an india-rubber tube attached. At its end is a vulcanite pointed nozzle which accurately fits into the wider extremity of the catheter.

=Technique.= The patient is seated facing the surgeon, the head being supported by a prop or by an assistant. If the patient be at all sensitive, it is wiser to spray a very small quantity of a 2 or 5% solution of cocaine or eucaine into the nose, or, better still, to pass gently a probe tipped with a small pledget of cotton-wool soaked in the cocaine solution along the inferior meatus. This will effectively anæsthetize the region of the pharyngeal orifice of the Eustachian tube, which is the most sensitive part.

The surgeon stands in front of the patient. The larger extremity of the catheter is held lightly between the thumb and first finger of the right hand, its beak being turned downwards, whilst the tip of the nose is tilted up by the thumb of the left hand (Fig. 210). In introducing the catheter into the nostril, the right hand is kept low down so that the stem of the catheter is almost in a vertical position. In this way the tip passes over the floor of the vestibule. As the catheter is gently pushed through the nose the right hand is raised so that the instrument assumes the horizontal position and passes backwards between the septum and the inferior turbinal, its beak being kept in close contact with the floor of the nose (Fig. 211). As the beak of the catheter enters the post-nasal space, it will be felt to glide over the soft palate.

With regard to the best method of introducing the beak of the catheter into the orifice of the Eustachian tube, opinions vary. Of the many methods advised only two will be given.

The first is more suitable to those who have not had much experience in using a catheter; the second is the one naturally adopted by an expert.

_The first method._ The catheter is pushed backwards until it is felt to impinge against the posterior wall of the naso-pharynx. The beak, which at this stage is directed downwards, is next rotated a quarter of a circle inwards so that it points horizontally towards the opposite side; the position is shown by the ring at its outer extremity (Fig. 212). The catheter is now gently withdrawn until the beak is felt to catch against the posterior edge of the vomer. During these procedures the stem of the catheter should rest on the floor of the nasal cavity. The manipulations are carried out with the right hand whilst the outer extremity of the catheter is kept fixed in position by means of the thumb and finger of the left hand.

The catheter is next pushed a short distance backwards to free it from the soft palate and rotated downwards, and finally round in an outward direction until the ring points to the outer canthus of the eye on the side to be catheterized (Fig. 213).

The point of the instrument should now engage the Eustachian tube; if, however, inflation shows this not to be the case the probability is that the catheter has been pushed too far backwards and rests on its posterior lip. This can be remedied by drawing it a little further outwards.

_The second method._ The catheter, with its beak turned downwards, is passed gently and rapidly along the inferior meatus of the nasal cavity, and at the same time rotated slightly outwards against the inferior turbinal bone. Whilst the catheter is within the nose, this outward rotation is prevented by the narrowness of the inferior meatus, but as soon as the beak of the catheter has passed behind the level of the inferior turbinal into the free post-nasal space, it will revolve outwards and upwards and in so doing will enter the Eustachian tube, which lies just behind and above the posterior end of the inferior turbinal bone.

Provided there be no abnormal obstruction within the nose, this method is an exceedingly simple one. With the practised hand the manipulation can be carried out so smoothly and quickly that the catheter will be in position before the patient has had time to realize the fact.

=Difficulties.= 1. _Irritability of the mucous membrane._ The passing of the catheter through the nose may set up a violent spasm of sneezing or coughing. When the beak has entered the post-nasal space, the irritation may cause such intense contraction of the palatal muscles that the point of the catheter may become fixed and its movement rendered impossible. If this takes place, the catheter should be withdrawn and the part anæsthetized by means of cocaine and eucaine solution, which is best applied locally on a pledget of wool at the end of a probe.

2. _Partial nasal obstruction._ On inspecting the nose the obstruction is usually found to be due to a deviated septum or spur, or to adhesions situated at its anterior part. Sometimes a passage can be effected by simply diminishing the curve of the catheter. At other times the obstruction can be overcome by introducing the catheter with its stem held upwards and outwards, so that on entering the nose the beak dips in beneath the anterior end of the inferior turbinal. As the catheter is pushed gently inwards its outer extremity is brought round with a circular movement so that it gradually assumes the horizontal position. No force must be used. As the catheter is pushed farther in, it may rotate to a varying degree according to the formation of the nasal cavity. Sometimes, indeed, the catheter may make a complete rotation during its passage through the nose. At other times, after the obstruction is passed, the catheter is best pushed through the nose with the beak pointing directly upwards. The great point is gentleness; the catheter should be allowed to take whatever position suits it best, but after the beak has entered the post-nasal space the stem should lie horizontally along the floor of the nose and its beak should point downwards.

3. _Complete nasal obstruction._ If the obstruction be one-sided, then the catheter must be introduced into the nasal space through the opposite side.

This is performed in the ordinary manner, except that the catheter must be longer and possess a larger curvature. On reaching the post-nasal space, its beak is turned round so as to point towards the outer canthus of the eye on the affected side. It may be necessary to alter the curve more than once in order to get the point of the catheter to exactly engage into the orifice of the Eustachian tube.

If both sides be completely obstructed, the only method to adopt is catheterization from the mouth. The ordinary catheter is used. It is passed into the mouth, its beak being directed upwards, until it reaches the posterior wall of the pharynx. The catheter is then pushed directly upwards until its stem impinges against the soft palate. The beak is then turned outwards until it lies almost horizontally. In this position it should enter Rosenmüller’s fossa. The catheter is now withdrawn a little and should be felt to pass over a slight obstruction--the posterior lip of the Eustachian orifice. By gently pressing the beak slightly outwards, it should engage within the entrance of the Eustachian canal.

4. _Obstruction within the post-nasal space._ A common error in introducing the catheter is to push it too far backwards, so that on rotation of the beak outwards it passes behind the Eustachian tube and lies in Rosenmüller’s fossa. In this position the sounds referred to the examiner’s ear through the auscultation tube during the act of inflation differ from the normal sounds in that they are soft and distant. In a case of doubt inflation should again be practised with the catheter in varying positions. If the catheter be in the correct position, the patient should be able to talk without discomfort, and there should be no tendency to retching or coughing. If, however, the beak lies in Rosenmüller’s fossa, considerable irritation is caused, and on inflation the patient feels the air in the throat and not in the ear.

Catheterization may be rendered difficult by the presence of a large pad of adenoids or of a tumour; or inflation of air into the Eustachian tube may be quite impossible owing to the occlusion of its pharyngeal orifice, the result of scarring.

=Mishaps.= 1. _Rupture of the tympanic membrane._ With a normal membrane this is difficult to produce, in spite of even forcible inflation. Such an accident usually occurs at the site of some previous scar or atrophic patch in the membrane. If it occurs, there may be a temporary feeling of giddiness, noises, and pain in the ear. Inflation, of course, should be stopped at once and the ear protected for a day or two by plugging the meatus with a piece of cotton-wool.

2. _Severe epistaxis._ This is usually the result of trying to force the catheter through an obstructed nose, but it may also take place, though rarely, when manipulations have been carried out in a gentle fashion.

3. _Syncope._ This is fortunately of rare occurrence and usually only happens on the first occasion that the catheter is passed. For this reason the patient should always be in a sitting posture, and on the slightest appearance of pallor or faintness the catheter should be withdrawn. The attack invariably passes off, but for the moment it is very unpleasant.

4. _Surgical emphysema._ If the point of the catheter lacerates the mucous membrane, the air may be forced into the submucous tissue. This mishap, however, rarely occurs as the result of simple catheterization, but is more likely to follow forcible attempts to pass a bougie into the Eustachian tube.

PASSING OF THE EUSTACHIAN BOUGIE

=Indications.= This may be done for the following reasons:--

(i) As a means of diagnosis, to demonstrate the existence and position of a stricture.

(ii) To dilate a stricture.

(iii) As a therapeutic measure, to treat the mucous membrane of the Eustachian tube by means of a medicated bougie.

Bougies are made of various materials, but for ordinary purposes the gum-elastic is the best. They are about 7 inches in length with a slightly bulbous point.

In the adult the length of the Eustachian tube is approximately 1-1/2 inches, of which 1 inch forms the cartilaginous and 1/2 inch the osseous portion. The narrowest part of its lumen is known as the isthmus, and is situated at the junction of its cartilaginous and bony portion. On passing the bougie through the catheter into the Eustachian tube, it is essential to know how far its point is projecting beyond the point of the catheter. For this purpose the bougie may be marked at its outer extremity. Five inches from the point of the bougie, that is, the same length as the catheter, is a black band a centimetre in length; a centimetre farther up is another black band; and again after an intervening space of a centimetre is a third black band (Fig. 214).

=Technique.= The catheter is introduced in the ordinary way, and its position within the entrance of the Eustachian orifice is verified by means of inflation. It is kept fixed with the left hand, and the bougie is pushed into the catheter until the beginning of the first mark on the former just reaches the outer extremity of the latter; the tip of the bougie will now be flush with the point of the catheter. If there be no pain and no resistance, the bougie is very gently pushed on until the beginning of its second black band just enters the catheter. Its point will now project 2 centimetres within the Eustachian tube; that is, to about the region of the isthmus. If the bougie has been successfully introduced into the Eustachian tube, the patient generally states that the instrument is felt within the ear itself. No force should be used for fear of making a false passage, and with gentle manipulation it is very rare for actual pain to occur. On reaching the isthmus resistance may be met with, but by the exercise of slight pressure the bougie can usually be made to pass through it; if there be much resistance the bougie should be withdrawn and a finer one substituted. After passing through the isthmus, the bougie may be pushed in another centimetre, but no further, in case it may actually enter and injure the contents of the tympanic cavity.

After the tip of the bougie has passed through the isthmus the surgeon will hear its movements through the auscultation tube as a rub or crackling sound. It is left in position for five or ten minutes and then withdrawn. The ear should then be gently inflated, when the air entry into the tympanic cavity will probably be found to be much more free.

As the passage of the bougie causes a certain amount of reaction, it should not be passed oftener than once a week. Although no force should ever be employed, the largest possible bougie should be passed at each successive sitting until complete dilatation has been obtained.

=Difficulties.= 1. If the catheter be not in position, the bougie may pass behind the tip of the Eustachian orifice and enter Rosenmüller’s fossa. This can usually be felt by the patient as a pricking sensation in the throat, and may produce retching and coughing.

2. A stricture of the Eustachian tube may be so great as to prevent entrance of the bougie.

=Dangers.= (_a_) Surgical emphysema. If the mucous membrane be lacerated by the bougie, air may be forced into the subcutaneous tissues on inflation, after its withdrawal. In some cases the surgical emphysema is so considerable as to involve the side of the neck and face, and indeed has been known to necessitate the performance of laryngotomy.

The best treatment is to make the patient suck ice and to forbid all attempts at blowing the nose and coughing. Sometimes it is also necessary to scarify the pharynx and soft palate with a small bistoury. Recovery may be hastened by gentle massage of the neck and face. Inflation should not be attempted again for at least a week.

(_b_) The bougie may be pushed in too far and cause injury to the contents of the tympanic cavity.

(_c_) The tip of the bougie may break off whilst in the Eustachian tube. With a gum-elastic bougie this is very rare, but it is more likely to occur if the brittle celluloid bougies are used. To prevent this unfortunate disaster the bougie should be carefully examined before passing it, to see that it is not cracked nor broken. If such an accident does happen it is wiser to do nothing, because as a rule the fragment is afterwards expelled spontaneously.

=Results.= If the obstruction be fairly recent and limited to the pharyngeal end of the Eustachian tube, excellent results may be obtained by using either the simple bougie or the catgut variety moistened with a 5% solution of silver nitrate.

Owing to the general thickening of the tube, there is a marked tendency for further stricture to take place in the more chronic cases, even if a temporary improvement is obtained, and for this reason the use of the bougie is seldom to be recommended.

WASHING OUT THE TYMPANIC CAVITY THROUGH THE EUSTACHIAN TUBE

=Indications.= (i) In chronic middle-ear suppuration in which the perforation is situated in the anterior inferior quadrant and the continuance of the otorrhœa is apparently due to the secretion not being able to drain from the tympanic cavity. This method may be employed to effect drainage and in order to cleanse the tympanic cavity thoroughly before the instillation of medicated drops. In these cases the floor of the tympanic cavity is usually at a considerable depth beneath the lower limit of the membrane (Fig. 186).

(ii) In order to remove a small foreign body lying on the floor of the tympanic cavity which cannot be expelled by syringing. The operation is only tentative and is seldom successful.

=Contra-indications.= (i) If there be acute middle-ear suppuration; (ii) if the perforation be very small, as there will be a considerable risk of the fluid being driven into the mastoid antrum and further infecting it.

=Technique.= A catheter of wide calibre is passed in the ordinary manner. Inflation is practised to see if it is in the right position. The left hand fixes the outer extremity of the catheter at its entrance within the nose and keeps it in position. The patient inclines the head over to the affected side and holds a receiver beneath the ear. A small brass syringe whose nozzle accurately fits the outer extremity of the catheter is used. Slight force may be required during the act of syringing, but must not be sufficient to cause pain within the ear. A certain amount of fluid always escapes into the throat although the catheter is in its right position, and this may set up an attack of retching and coughing. To avoid this the patient should incline his head slightly forward as well as to the affected side and breathe gently with the mouth open. If the manipulation be successful the fluid will trickle out of the external meatus.

A foreign body is rarely expelled by this method, as the force of fluid syringed into the Eustachian tube is seldom sufficient, and it is not wise to use too great pressure. In order to expel all the fluid from the tympanic cavity, the ear is afterwards inflated by Politzer’s method, and at the same time the fluid is mopped out of the ear by means of pledgets of cotton-wool.

=Results.= If the continuance of the middle-ear suppuration has been chiefly due to the retention of the purulent secretion in the lower part of the tympanic cavity, this method of treatment is frequently most satisfactory. In other cases no benefit is obtained owing to the suppuration being due to other causes.

=Dangers.= The chief danger is the infection of the mastoid cells.