Part 77 (1/2)
The affected half of the larynx must now be considered as a tumour to be removed. The infrahyoid muscles are dissected away from the 'tumour' and retracted; the upper part of the lateral lobe of the thyreoid gland (the isthmus having been previously divided) is displaced outwards by blunt dissection, and the soft tissues above the thyreoid are similarly treated: the larynx should be pulled well over to the opposite side while this is being effected, great care being necessary to avoid wounding the carotid artery in the deeper part of the dissection. The branches of the superior thyreoid artery, the crico-thyreoid artery, and the veins of this region are ligatured with catgut. In some instances, when the growth has not perforated the cartilage, the separation can be performed subperiosteally. Superiorly, the thyreo-hyoid membrane is completely divided on the same side, and the mucosa is cut through above the upper limit of the growth. If the growth extends upwards, the epiglottis may be removed either totally or partially. Inferiorly, a transverse incision must be made through the crico-thyreoid or crico-tracheal membrane, or lower in the trachea. The inferior constrictor of the pharynx is divided as close to the attachment to the thyreoid as possible, and the cavity of the pharynx is opened behind the growth. The cricoid plate is split with bone scissors in the interarytenoid interval, and the final attachments are rapidly divided with a few touches of the knife.
In this operation, as with other operations for cancer, the main thought of the surgeon must be to remove the tumour thoroughly, including the soft tissues of the neck when these are diseased, the lateral wall of the pharynx, and the cervical glands upon the same side, whether they are known to be affected or not. In this respect the operation differs materially from thyrotomy; and I agree with Semon that, if hemi-laryngectomy is necessary, the lymphatic glands of the same side should in all cases be removed. The two dissections may be accomplished at the same time, or one may be performed later at a second operation; in the latter event an incision along the anterior border of the sterno-mastoid muscle is preferred. The operation must be very complete in order to be successful, and requires a knowledge of the anatomy of the lymphatics.
THE ANATOMY OF THE LARYNGEAL LYMPHATICS.
The following description is Cuneo's[14] and has been confirmed by de Santi.[15]
[14] Poirier and Cuneo, _Lymphatics_, Eng. ed., 1903, p. 286.
[15] De Santi, _Malignant Disease of the Larynx_, 1904, p. 10.
The lymphatics which drain the mucous membrane of the larynx are divided into two distinct regions, namely, the supraglottic and the infraglottic zones. These regions are separated by the inferior vocal cords, and injection of the cords themselves generally pa.s.ses into the upper zone.
The upper region is most densely supplied, and covers the epiglottis, the aryteno-epiglottidean folds, the superior vocal cords, and the ventricles.
The lymphatics communicate freely in the posterior wall of the larynx (not in the anterior commissure), but though an injection into one half of the larynx easily pa.s.ses into the mucous membrane of the other side, it is exceptional for it to pa.s.s as far as the corresponding glands of that side. The lymphatics of the larynx anastomose to a large extent with the networks of the adjacent organs (tongue, pharynx, trachea).
The supraglottic lymphatics perforate the thyreo-hyoid membrane where the superior laryngeal arteries enter, and end in (1) a substerno-mastoid gland under the posterior belly of the digastric; (2) glands on the internal jugular vein opposite the bifurcation of the carotid artery; and (3) glands on the same vein opposite the middle of the lateral lobes of the thyreoid gland. The glands in the front of the thyreo-hyoid membrane receive lymphatics from the pharynx, but none from the larynx.
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 s.p.a.ce 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 ma.s.sive 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, anaesthetic, 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 sophagus; the lower end is carefully freed from the sophagus, and two strong catgut sutures are pa.s.sed 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 b.u.t.ton-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 anaesthetic is continued. By this means the lower air-pa.s.sages are completely cut off from the region of the tumour, and no blood or septic matter can pa.s.s into the lungs.
[Ill.u.s.tration: 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, sophagus; F, Trachea.]
_Second stage._ The lateral aspect of the larynx is freely separated so that the attachment of the inferior constrictors is defined. The superior laryngeal artery is ligatured on each side, and divided, together with the internal laryngeal nerves. The thyreo-hyoid membrane is transversely divided, and the pharynx is opened so as to expose the upper limit of the growth; this may necessitate a transverse incision through the skin, or a vertical division of the hyoid bone in the middle line with retraction of its two halves. The larynx having been isolated above, below, and laterally, its removal can be completed according to the situation of the growth, in most cases from below. The lower end of the larynx is hooked forward, and dissected away from the sophagus by means of scissors or a sharp scalpel (Fig. 262). While this is being effected, the extent of the growth must be constantly examined by inspection and palpation, so that the whole ma.s.s is removed, including, if necessary, the pharynx and upper part of the sophagus. It is important not to drag upon the sophagus; C. Jackson has shown experimentally that this causes severe shock by affecting the depressor fibres of the vagus, which may result in death. It follows, therefore, that this part of the operation, though easy in the dead body, requires the utmost care and detailed technique. The division of the constrictors should be as close to their attachment as possible, and the final division of the pharyngeal mucosa should be half an inch beyond the limit of the growth. The epiglottis should generally be removed.
_Third stage._ The toilet of the pharynx and sophagus remains to be decided. In order to restore the cavity of the pharynx, the upper end of the sophagus is brought upwards whenever possible and accurately united to the pharynx in the region of the hyoid bone, this being accomplished by a double layer of catgut sutures uniting the mucous membranes. The infrahyoid muscles are then brought together by a vertical row of st.i.tches, so as to cover and support the line of union. The wound having been thoroughly packed with gauze, the skin is sutured, excepting the lower end, which remains open for drainage. In cases where the pharynx is thus completely closed, a tube must be pa.s.sed previously through the nose into the sophagus, and retained for purposes of feeding. This is preferable to sewing the tube into the wound itself, and is rarely troublesome if the tube is sufficiently stiff to prevent its displacement by retching. At the conclusion of the operation the tracheotomy tube is replaced by an ordinary silver canula, and the wounds are lightly dressed.
=After-treatment.= This is conducted upon similar lines to those adopted in the after-treatment of thyrotomy. During the first ten days, until the pharyngeal wound is firm, the patient must be fed through the tube and by rectal administration. Sterilized water may be sucked uphill, and, as swallowing improves, food may be administered by the mouth. In most cases a pharyngeal fistula results, which may require a later plastic operation. A second operation is necessary for the removal of lymphatic glands, probably on both sides of the neck.
The complications are similar to those following thyrotomy (see p. 494).
=Modifications.= The above operation, which in the main has been planned by surgeons in America (S. Cohen, Keen, &c.), is preferable to the numerous modifications, of which the following may be mentioned as examples:--
Gluck's operation. In this there is no preliminary tracheotomy. A large rectangular flap is turned to one side to expose the front of the larynx and trachea, the latter being isolated laterally and the thyreoid isthmus divided. A transverse incision is made through the thyreo-hyoid membrane in order to expose the upper aperture of the larynx thoroughly.
By plugging the pharynx and adopting a low position for the head, saliva and blood are prevented from running into the air-pa.s.sages. The interior of the larynx having been cocainized, a tracheotomy tube is inserted between the vocal cords. This is sutured in position in such a manner that the cavity of the larynx is completely shut off from the pharynx.