When operating upon the larynx the surgeon must use every precaution to prevent blood from running into the lower air-passages, and this may be accomplished by a tampon in the trachea or by keeping the head of the patient lower than the body. The former method appears to me to be more reliable than the latter; and I prefer to use a Hahn’s canula, although the sponge requires from ten to fifteen minutes to swell. This canula is more reliable than Trendelenburg’s, whose inflated bag is apt to slip or collapse suddenly. As soon as the thyreoid cartilage has been opened, a second sponge should be inserted above the canula, and by this means the air-passages are completely blocked.
If an ordinary tracheotomy tube be used, the operation must be performed either with the head lower than the body (Rose’s position), or with the whole body inclined (Trendelenburg’s position), or with a combination of the two; and in any case a sponge should be placed in the upper part of the trachea after the thyreoid has been opened. Many surgeons prefer the combined method. Under no conditions must blood be allowed to pass below the tube. Whatever form of canula is used, it should be fitted with a Hahn’s tube and funnel ([Fig. 266]), so that the anæsthetist can give the chloroform without interfering with the surgeon. The patient should lie upon the back on a flat table, the head extended slightly over a small cushion in the position for tracheotomy.
Fig. 261. Thyrotomy. Showing exposure of the larynx, and tube for the anæsthetic.
First stage. A vertical incision is made in the middle line from the hyoid almost to the sternum, so as to expose the thyreoid cartilage and the pretracheal muscles; these are retracted, so that the anterior aspect of the trachea is exposed; the isthmus of the thyreoid gland is completely divided, and search made for bleeding points until the wound is quite dry. A large opening is made accurately in the middle line of the trachea; this will be at least two rings below the cricoid cartilage in order that the tube may be well away from the region of the growth. In adults, if a Hahn’s tube be employed, the section should include at least three rings of the trachea.
Second stage. The anterior aspect of the thyreoid cartilage, and the crico-thyreoid membrane, are freely exposed, the infrahyoid muscles being separated by at least one inch and, if necessary, retracted. Ten minutes after the tube has been inserted, the crico-thyreoid membrane is punctured, exactly in the middle line, in order to admit the inner blade of the bone forceps; the latter is pushed upwards, slowly and without force, between the posterior portions of the vocal cords, until the whole length of the thyreoid cartilage is included between the blades; the forceps are then forcibly closed, great care being taken that the outer blade is cutting exactly in the middle line. By quickly opening the cartilage in this manner, there is practically no danger of destroying the anterior attachments of the vocal cords, or cutting through the substance of one of them. The two halves of the larynx are forcibly separated and retained in this position by hooked retractors, so that the interior of the larynx is exposed. In order to give a free exposure, it is necessary, as a rule, to divide with a knife the crico-thyreoid membrane; but the thyreo-hyoid membrane should not be touched, nor should the attachments of the epiglottis be disturbed. The separation must be performed carefully in order to avoid a fracture of the cartilages. The pharynx is plugged with gauze, so that no saliva can enter the wound, and after all secretion has been removed from the larynx a small sponge or plug is inserted into the upper end of the trachea. Cocaine, 20%, is freely applied with a swab of wool to every part of the larynx in order to constrict the vessels; persistent hæmorrhage can be controlled by plugging the cavity with wool soaked in cocaine; ‘this fully suffices . . . and the employment of adrenalin, as I have personally experienced in one case, increases the risk of secondary parenchymatous hæmorrhage’ (Semon). Further, and this is of importance, by the use of cocaine the irritability of the larynx and the laryngeal reflex are destroyed. The tumour can now be inspected; it must be thoroughly exposed by cutting through the soft or hard structures (cricoid if necessary) so that its limits can be determined, thus enabling the surgeon to decide whether it is possible to obtain a satisfactory result by local removal.
Third stage. In the words of Butlin[13]: ‘an incision is carried around it (the tumour) with knife or scissors, including more than half an inch of the surrounding apparently healthy tissues, without respect to the after use of the voice or any other consideration except the complete removal of the disease. The included area is cut out right down to the cartilage, which is laid bare and finally scraped absolutely bare with Volkmann’s sharp spoon.’ The cavity is then plugged for a few moments until the bleeding has been controlled. The hæmorrhage is never serious, and can be controlled by catgut ligature if necessary. The wound must be completely dry. It is then dusted with a powder such as orthoform; the retractors are removed, and the alæ of the thyreoid cartilage allowed to fall together. In relation to the removal of the tumour, Butlin has shown that there is ‘little liability of malignant disease infiltrating the cartilage of the larynx’, so that, as a general rule, the latter can be left if all the soft tissues, including the perichondrium, are removed from its surface; this is comparatively easy to accomplish in the case of the thyreoid, but more difficult with the arytenoids and cricoid cartilage. C. Jackson has criticized the use of a sharp spoon as likely to cause infection of the cartilage.
Fourth stage. In some instances it is possible partially to unite the divided mucous membrane, and so to lessen the granulating area: when this is done it is of the utmost importance that the lumen of the larynx should not be constricted, as any constriction will increase the danger of stenosis. In many instances it is not advisable to attempt to repair the wound that has been produced.
In suturing the external wound the alæ of the thyreoid are brought accurately into the position which they occupied before division, in order that the anterior attachments (if left) of the vocal cords should heal at their proper level. In some instances the cartilages fall naturally into the desired position, especially if one or two catgut sutures are inserted into the thyreo-hyoid membrane; in other cases it may be advisable to insert one or two similar sutures through the cartilage itself and thus obtain correct apposition. These sutures should lie on the outer aspect of the mucosa, so as not to traverse the cavity of the larynx itself. In cases where only the anterior portion of a vocal cord has been removed, Semon recommends that the divided end be sutured to the ventricular band; it is reasonable to suppose that, by attention to this detail, a better voice will be afterwards obtained. The infrahyoid muscles are approximated with one or two catgut sutures in the upper part of the wound; the skin is united with a continuous silk suture, as far downwards as the lower part of the thyreoid cartilage. The lower part of the wound is left open, to procure free drainage through the crico-thyreoid and tracheal openings. The whole of this lower wound is packed very loosely with gauze, so that discharges are not retained. It is necessary to emphasize the importance of not plugging the cavity of the larynx. The Hahn’s tube is removed as soon as the operation is completed, and replaced by a tracheotomy canula; the whole wound is covered by a loose pad of antiseptic gauze, which is kept in position by tapes or loosely applied bandages. No dissection for removal of lymphatic glands is required.
The above may be called the typical operation for malignant disease in which the growth is intrinsic; it gives a better exposure of the parts than other operations such as transverse laryngotomy (division of the thyreoid cartilage at the level of the ventricles), subhyoid pharyngotomy, partial thyrotomy, cricotomy, and crico-tracheotomy; the removal of tumours is therefore easier, and better after-results are obtained. If the growth be found more extensive, it may be necessary to modify the procedure. For example: