There are four varieties of the operation, viz.:
1. Crico-tracheotomy (with division of the cricoid cartilage).
2. High tracheotomy (involving section of the trachea above the isthmus of the thyreoid gland).
3. Low tracheotomy (section of trachea below the isthmus of the thyreoid gland).
4. Median tracheotomy (section of trachea through the isthmus of the thyreoid gland).
Crico-tracheotomy is an easy operation owing to the superficial position of this portion of the air-passage, but is inadvisable for the following reasons:—
(1) The larynx being narrower than the trachea, a smaller tube is required; (2) the swelling of the mucosa often extends downwards and causes constriction of this region; (3) the tube is not well tolerated; (4) pressure ulcers, necrosis of the cricoid, and granulations are frequent complications; and (5) retained tube is more common than with other operations, this really being the most important consideration. The comparative value of the remaining operations is largely a matter of opinion.
It is not uncommonly stated that tracheotomy is better done by touch than by sight: the object to be achieved is to find the trachea, and there are two methods of doing this. The first is the deliberate method, suitable for patients in good condition when there is no urgent dyspnœa; it can be performed entirely by sight, and the greater the experience of the surgeon the fewer his difficulties. In such cases skilful technique is of far greater value than haste. The high operation is preferred, because the trachea is more superficial, less movable, and easier to find; it has less complicated relations, the blood-vessels are less numerous, the fasciæ are not so loose, the tube is easier to fit and unlikely to slip out, healing of the wound is more rapid, and complications seldom occur. In cases where the isthmus is very broad or highly placed, so that the upper parts of the trachea and cricoid are covered, a median operation is recommended. Low tracheotomy is rarely necessary.
The second is the rapid method, to be applied in cases of emergency. Turner, of the South Eastern Hospital, strongly advocates such an operation without an anæsthetic. The incision made is from ½-5/8 of an inch in length, this being repeated without attention to the bleeding until the trachea is reached. The latter is opened in the usual manner. The tip of the finger is placed in the wound in order to control the hæmorrhage, and as a guide to the dilators. When these have been introduced, the child is at once drawn beyond the end of the table so that the head hangs downwards. The bleeding usually ceases in a few moments, though in some cases the tube is inserted to control it. The advantages claimed for this method are that the operation is quicker, and that no distinction between ‘high’ and ‘low’ is required. The wound is smaller, there is less danger of sepsis, and the eventual scar is hardly visible; no hooks or retractors are used, so that the trachea cannot be displaced. If the wound be in the middle line it is impossible to miss the trachea. This operation is performed entirely by touch, and the bleeding is not considered. Its adoption may be necessary to save the patient’s life, but in the hands of an inexperienced surgeon the operation is attended with great difficulties.
High tracheotomy. The incision must be exactly in the middle line; this can be accomplished easily if the surgeon keeps in mind two important landmarks, namely, the point of the chin, and the suprasternal notch. To determine the upper end of the incision, a point is chosen midway between the anterior borders of the sterno-mastoid muscles at the level of the cricoid cartilage. The thyreoid cartilages being steadied between the fingers and thumb of the left hand, a bold incision is made from the upper point, 1½ inches in length, extending in a young child almost to the suprasternal notch. A long incision is generally preferable, and, when the neck is fat, should commence over the middle of the thyreoid cartilage. The skin and superficial fascia are divided between the two anterior jugular veins, and any bleeding is controlled. The incision is repeated so as to divide the deep fascia lying between the sterno-hyoid muscles, close to one another in the upper part of the incision, and these are separated with the knife. It is now advisable to pause and to seize the bleeding points, allowing the pressure forceps to fall on both sides of the wound to act as retractors. The infrahyoid muscles are separated by at least an inch, and, if retractors are necessary, care must be taken that the muscles alone are included and that the retraction is equal on the two sides. If there has been no ‘tailing’ of the wound the following structures are then exposed from above downwards: the lower border of the thyreoid cartilage, and the front of the cricoid, both easily seen or felt; and a vascular mass, namely, the isthmus of the thyreoid gland, covered by fascia and completely concealing the trachea. The landmark that is required at this stage is the cricoid arch; this should be found, and a small transverse incision should be made along its lower border to divide the suspensory ligament; the handle of the scalpel or a blunt hook is introduced beneath the pretracheal fascia, and the isthmus dragged downwards into the lower portion of the wound, an operation which can be accomplished easily if done without hesitation. The upper rings of the trachea are now exposed; and, unless the superficial veins have been divided, there should be no bleeding. The trachea should not be opened until it has been exposed completely and all bleeding has been arrested. It is unnecessary to ligature the vessels at this stage unless the forceps have been so placed as to interfere with the part of the trachea chosen for section, or an artery of considerable size is encountered; in the latter instance there is a danger of subsequent hæmorrhage if the ligature is applied close to the tube. While the trachea is being opened, it is necessary to overcome the movements of the larynx by grasping the cricoid with the finger and thumb of the left hand. The scalpel should be gently stabbed into the middle of the trachea to ensure puncturing the mucous membrane as well as the outer wall, and the opening should be quickly enlarged in an upward direction until three rings have been divided, preferably the first, second, and third. It is imperative that this incision should be in the middle line, should not be too small, and should only pass through the anterior tracheal wall; if force be used there is danger of puncturing the œsophagus, or even of striking the bodies of the vertebræ.