The subglottic lymphatics perforate the crico-thyreoid membrane in two places (a) anteriorly, near the middle line, ending in (1) a prelaryngeal gland which lies in the V-shaped space between the crico-thyreoid muscles or under one of the same (a gland above the isthmus of the thyreoid gland is rarely present), and (2) a pretracheal gland (or glands) below the isthmus; (b) laterally, to end in (1) the glands which lie parallel to the recurrent laryngeal nerve, from which trunks run to (2) the substerno-mastoid group and (3) the supraclavicular glands.
It is important also to consider the question from the clinical aspect. With ‘intrinsic’ growths, involvement of glands is very uncommon unless the posterior (cricoid) zone is affected; it seems to be equally rare with tumours of both supra- and infraglottic zones; extension to the lymphatics of the opposite side is likewise improbable. With ‘extrinsic’ growths, the glands are rapidly involved; tumours that were originally intrinsic follow this rule as soon as they begin to affect the cartilages and extrinsic lymphatics of the larynx. These facts must be remembered because palpation of the neck may be quite misleading in early stages of the disease. On the other hand, in many advanced cases, such as those requiring palliative tracheotomy, the glands become massive and form definite tumours. The substerno-mastoid chain is, clinically, the situation that is specially affected; and any of its glands, from the digastric muscle above to the supraclavicular region below, may be involved. The prelaryngeal gland is rare, as are likewise the pretracheal and recurrent forms; nevertheless, the recurrent glands become attacked by advanced disease, affecting the upper part of the trachea.
TOTAL LARYNGECTOMY
Indications. This operation is performed for malignant tumours which have affected (a) the whole of the interior of the larynx, including the cartilages, or (b) the posterior portion of the larynx, including the arytenoid cartilages and pharyngeal aspect of the cricoid plate. In other words, it is employed in cases of extrinsic cancer in which the growth is not too advanced to render the prospect of its eradication hopeless. The operation should not be performed for tuberculosis.
It is essential that the patient should be in good health; one who is emaciated or who has organic disease, especially incurable bronchitis, is quite unsuitable for laryngectomy. On no account ought the operation to be undertaken unless the diagnosis of malignant disease has been confirmed, and unless the growth is known to be too extensive for thyrotomy. In many instances, therefore, thyrotomy is the first stage in the operation of total laryngectomy.
Operation. The instruments, anæsthetic, and position require the same consideration as with thyrotomy (see [p. 489]).
First stage. A vertical incision is made, in the middle line, from the hyoid to a point one inch above the sternum, and the anterior aspects of the thyreoid cartilage and trachea are exposed, with complete division of the isthmus of the thyreoid gland. The infrahyoid muscles are dissected from the larynx and widely retracted. By blunt dissection the upper part of the lateral lobes of the thyreoid gland is separated and bleeding arrested. The trachea, having been isolated in this manner, is divided obliquely from the front, upwards and backwards, as close to the cricoid cartilage as the disease allows without injury to the œsophagus; the lower end is carefully freed from the œsophagus, and two strong catgut sutures are passed through it with which the divided stump can be drawn forwards. If possible, a small transverse incision is made through the skin immediately above the suprasternal notch and made to communicate with the upper incision; the trachea is brought beneath the bridge of skin into the button-hole thus formed, and firmly attached by means of sutures. In some cases the trachea is sewn into the lower part of the original incision. A tracheotomy tube is inserted, through which the anæsthetic is continued. By this means the lower air-passages are completely cut off from the region of the tumour, and no blood or septic matter can pass into the lungs.
Fig. 262. Total Laryngectomy. A, Crico-thyreoid muscle; B, Attachment of inferior constrictor of pharynx to thyreoid cartilage; C, Cut edge of inferior constrictor; D, Thyreo-hyoid membrane; E, Œsophagus; F, Trachea.