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 ma.s.sage 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 pa.s.sing 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 otorrha 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 pa.s.sed 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 bra.s.s 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.

CHAPTER V

OPERATIONS UPON THE MASTOID PROCESS: WILDE'S INCISION AND SCHWARTZE'S OPERATION

With few exceptions the conditions requiring operative procedures on the mastoid process are the result of some suppurative lesion which has originated within the tympanic cavity.

The object of such operations is to arrest or eradicate the disease which, by further extension through the bony walls of the temporal bone, might eventually cause death by giving rise to some suppurative intracranial complication.

For their successful performance a knowledge of the anatomical relationships of the mastoid process is essential. It is sufficient here to remind the reader of the main surgical points in this connexion (Fig.

215).

SURGICAL ANATOMY OF THE MASTOID AREA

=The mastoid antrum.= At birth the mastoid antrum is almost fully developed. In infancy it is situated superficially and at a much higher level in relation to the auditory ca.n.a.l than in the adult. In the infant, also, the petro-squamous and the squamo-mastoid suture are still patent. As the mastoid cells develop, the antrum gradually becomes more deeply placed, so that in the adult it is from half to three-quarters of an inch from the surface.

Its roof, the tegmen tympani, is continuous with that of the attic.

Anteriorly it is separated from the external auditory meatus by the posterior wall of the auditory ca.n.a.l, whose innermost margin forms the outer wall of the aditus. On its inner wall lie the semicircular ca.n.a.ls, whilst posteriorly the lateral sinus is separated from it by an intervening layer of mastoid cells or compact bone. Between the semicircular ca.n.a.ls and the lateral sinus is a small area composed of a thin layer of bone, separating the antrum from the posterior fossa of the cranial cavity.

=The mastoid process.= In the infant this is undeveloped and is merely represented by a small bony protuberance. By the fourth year it has practically reached the adult type.

Anatomically the mastoid process can be subdivided into three chief types: (1) the pneumatic, in which the cells are few and large; (2) the diploic, containing numerous small cells; and (3) the compact, in which the bone is extremely dense. Mixed types are frequently found, the cortex, as a rule, being more dense than the deeper portion.

Occasionally it is uniformly sclerosed, almost of the consistence of ivory, but in these cases the condition is usually pathological, the result of chronic inflammation of the mastoid process.

[Ill.u.s.tration: FIG. 215. LEFT TEMPORAL BONE, SHOWING ANATOMY OF THE MIDDLE EAR AND MASTOID PROCESS. 1, Anterior wall of external meatus, partly removed; 2, Ca.n.a.l for tensor tympani muscle, ending in processus cochleariformis; 3, Attic; 4, Aditus; 5, External semicircular ca.n.a.l; 6, Posterior root of zygoma; 7, Tegmen tympani; 8, Antrum; 9, Fallopian ca.n.a.l for facial nerve; 9', Stylo-mastoid foramen; 10, Mastoid cells; 11, Fenestra rotunda; 12, Fenestra ovalis; 13, Promontory. Dotted line shows outline of sigmoid groove for lateral sinus.]

The mastoid cells converge towards the antrum and may be divided into two groups: (1) those extending vertically downwards to the tip of the mastoid process; and (2) those lying between the antrum and the sigmoid process of the lateral sinus. In addition to these two groups, it must not be forgotten that cells may extend in other directions; for instance, (_a_) anteriorly, along the root of the zygoma; (_b_) posteriorly, communicating with the cells of the occipital bone; (_c_) inferiorly, between the floor of the tympanic cavity and the jugular fossa; (_d_) internally, spreading inwards towards the apex of the petrous bone and surrounding the labyrinth; or (_e_) enveloping the orifice of the Eustachian tube.

_The facial nerve_, after dipping beneath the external semicircular ca.n.a.l, pa.s.ses vertically downwards through the mastoid process to emerge at the stylo-mastoid foramen. Entering this foramen and running along the ca.n.a.l are the stylo-mastoid branches of the posterior auricular artery. These vessels, if cut through by the chisel, may bleed in a marked manner, thus drawing the attention of the operator to the fact that he is in close proximity to the facial ca.n.a.l and nerve.

=Surface anatomy.= Although it is impossible to foretell with certainty before operation what the anatomical structure of the mastoid process may be, yet some information may be gathered from the formation of the skull.

In the dolichocephalic type, the mastoid process is broad and frequently contains large cells, especially at its tip and round the lateral sinus, which is usually deeply placed. In the brachycephalic type, on the other hand, there is a greater tendency for the mastoid process to be narrow and to consist of dense bone, for the middle fossa to extend low down and to overlap the outer wall of the antrum, and for the lateral sinus to project forward and superficially, even to within 2 or 3 millimetres of the posterior border of the external meatus.

The posterior root of the zygoma may be considered approximately the line of demarcation between the roof of the antrum and mastoid process, and the floor of the middle fossa of the skull. This, however, is only a rough guide, as in some cases, especially of the brachycephalic type, the middle fossa may dip below this point. If this ridge is not well marked, then Reid's base-line must be taken as the guide.

Just behind the auditory meatus, at its upper posterior margin, is the spine of Henle, which forms the anterior boundary of the suprameatal triangle. Macewen, who first described this triangle, gave it as a guide for the exposure of the antrum. Experience, however, has shown that no reliance can be placed on this as a landmark, as, if the bone is chiselled through at this point, it is by no means uncommon to expose the dura mater of the middle fossa. A point 10 millimetres (two-fifths of an inch) behind the spine of Henle corresponds to the anterior border of the sigmoid sinus. Behind the suprameatal triangle and beneath the zygomatic ridge is the body of the mastoid process, which has a smooth surface and is perforated by small foramina through which pa.s.s tiny vessels.

The antrum, in the adult, is situated at a slightly higher level than the tympanic membrane, its floor roughly corresponding with a line drawn horizontally backwards through the middle of the posterior wall of the bony meatus.

HISTORY OF THE MASTOID OPERATION

Although opening of the mastoid process as an operative measure dates back to the eighteenth century, yet Schwartze, in 1873, was the first to establish the operation as a practical procedure.

Schwartze's operation consisted in the simple opening of the antrum and mastoid cells, leaving the middle ear untouched. This procedure was carried out no matter whether the disease was recent or long standing.

It soon became recognized, however, that this operation did not effect a cure in all cases, more especially in those in which the disease involved the walls of the tympanic cavity.

Kuster, in 1889, suggested removal of the posterior wall of the external auditory meatus, and about the same time von Bergmann advocated removal of the outer attic-wall. The Kuster-Bergmann operation, first practised by Zaufal, may therefore be considered to be the origin of the complete mastoid operation.

Stacke's name is frequently though wrongly mentioned in a.s.sociation with the complete operation, which is sometimes termed the Schwartze-Stacke operation. Stacke's operation was devised with a view to removal of the ossicles and outer wall of the attic in those cases in which the bone disease was limited to these regions. This operation, however, is occasionally of service in the performance of the complete mastoid operation (see p. 397).

Thus the year 1889 may be considered as the starting-point of the complete mastoid operation. Since that date many modifications have been introduced, the majority of which are not worthy of reference.

After the technique of the operation had been developed and practised for some time, more careful attention was directed to the after-treatment. In the earlier days of the radical operation it was the rule to leave the wound open and to plug it with gauze, or to insert a drainage tube which was carried through the membranous portion of the external meatus.

The next step was the making of post-meatal skin flaps, with closure of the posterior incision and packing of the wound through the auditory ca.n.a.l; and the names most prominently a.s.sociated with this are Panse, Korner, and Stacke.

Still more recently, in order to shorten the after-treatment, the wound cavity has been skin-grafted by the method first suggested by Siebenmann and afterwards amplified by Charles Ballance.