Laryngoscopy

Laryngoscopy (from Greek larynx-larynx and skopeo-I look), a method for examining the larynx, by means of which it can be examined through the opening of the mouth. Since the axes of the larynx and mouth intersect at almost a right angle, examination can only be performed with the help of special devices. There are two methods of L.: direct and indirect, or optical. In the first method, the principle of examination is that the oral and laryngeal cavities are positioned in relation to each other in such a way that both can be examined with the naked eye. In 1894, Kirstein proposed for this purpose a wide, strong spatula, the end of which is bent slightly downward, and the handle is attached at a right angle (Fig. 1). The patient sits on a low chair with the head tilted back slightly. The doctor stands opposite him and inserts the spatula at the root of the tongue between its base and the epiglottis; by pushing the tongue forward and downward, one can sequentially see the entrance to the larynx, the area of the arytenoid cartilages, the vocal cords, and the glottis. Illumination is usually done with an ordinary frontal reflector. Killian in 1897 was the first to appreciate the significance of Kirstein's method and, using his idea, constructed a tubular spatula with a beak-like end, which he began to insert on the posterior surface of the epiglottis into the laryngeal opening and into deeper parts and the trachea, and thus laid the foundation for direct bronchoscopy. Due to the fact that illumination with a frontal reflector in the depth of the tube was insufficient, Bruenings adapted a special illuminator with an electric light bulb (electroscope) to the handle of the tubular or grooved spatula, which is now used everywhere for bronchoscopy (see). Recently, Citelli and Seiffert (1922) arranged a special instrument made on the model of an expanding uterine mirror, one blade of which, when the instrument is inserted into the pharynx with the head tilted back, rests against the III or IV cervical vertebra, while the other, lying on the inner surface of the epiglottis, presses it to the root of the tongue, so that the entrance to the larynx and its cavity become accessible not only for examination but also for intralaryngeal operative intervention with grasping and cutting instruments. The direct method of examining the larynx has not found wide practical application, since in most cases it is technically difficult to perform, requires great skill of the operator, mandatory deep cocaine anesthesia, and is extremely unpleasant and painful for the patient. However, it still has to be used in children and in persons who do not respond to other methods of examination. The direct method of examination received the name of autoscopy, because the examiner conducts the examination directly with his own eye, without mirror devices. The suspended L. differs from ordinary autoscopy in that the force of the operator's hand, pushing the root of the tongue forward, is replaced by the weight of the subject's head: the handle of the electroscope is suspended by a special hook to a crossbar attached to the operating table after the spatula is inserted into the oral cavity; the head raised by the hook in the supine position of the patient pushes the tongue and larynx forward. Suspended L. allows especially good visualization of the posterior parts of the larynx and can also be used in children under general anesthesia. Indirect L. is performed with the help of laryngeal mirrors; usually small flat circular mirrors with a diameter of 1.5-2 cm are used, the handle of which is bent at an angle of 120° to the plane of the mirror (Fig. 2). For convenience of holding the mirror during examination, the stem is inserted into a handle (Fig. 3). Examination of the laryngeal opening with a mirror is usually performed with the patient sitting with the head thrown back and the mouth open. The doctor stands on the patient's right side, holding the mirror in his right hand, and with his left hand he lifts the tip of the tongue and pulls it forward. The mirror is introduced into the oral cavity, and its surface is warmed by the breath or by rubbing it with the fingers. The mirror is then inserted into the pharynx behind the uvula, and the posterior pharyngeal wall is examined. To examine the larynx, the mirror is tilted so that its plane is parallel to the axis of the larynx, and the patient is asked to say 'ah' or 'ee', which brings the vocal cords into view. The laryngeal mirror is illuminated by a frontal reflector.

at an angle of 120° to the plane

of the mirror (Fig. 2). For

convenience of holding the

mirror during examination, the stem is inserted into a handle (Fig. 3).

Examination of the lumen

of the larynx with a mirror is usu-

ally performed with the patient sitting with the head thrown back and the mouth open. The doctor stands on the patient's right side, holding the mirror in his right hand, and with his left hand he lifts the tip of the tongue and pulls it forward. The mirror is introduced into the oral cavity, and its surface is warmed by the breath or by rubbing it with the fingers. The mirror is then inserted into the pharynx behind the uvula, and the posterior pharyngeal wall is examined. To examine the larynx, the mirror is tilted so that its plane is parallel to the axis of the larynx, and the patient is asked to say 'ah' or 'ee', which brings the vocal cords into view. The laryngeal mirror is illuminated by a frontal reflector.

Fig. 2.

Figure 3. is based on the physical law according to which light rays falling at an angle onto a flat mirror are reflected from it at the same angle. If with the mouth wide open a small mirror is placed in the area of the uvula with its reflective surface downward, then by setting it at a 45° angle to the horizontal line, it can be positioned in such a way that the image of the entrance to the larynx and its cavities will be reflected in the mirror. - Technique of examination: the doctor with a head reflector on the head positions himself opposite the patient and opposite the light source, which is located to the right of the patient. The subject protrudes the tongue with some force and with the help of a cloth pulls it even further forward and downward. In this position, examination of the larynx becomes more accessible, as the epiglottis moves somewhat forward and upward, the palatine arches diverge to the sides, and the soft palate is elevated. If the patient cannot hold the tongue, the doctor does it himself with his left hand. When the mirror is between the root of the tongue and the soft palate, it is necessary to ensure that it does not touch either the arches or the posterior wall of the pharynx to avoid the gag and cough reflex, which often greatly complicates laryngoscopy. Sometimes by moving the mirror, the soft palate and the uvula can be pushed upward and backward to the posterior wall of the pharynx. If at this time the patient is made to vocalize on the vowel e, i, or ы, the epiglottis protrudes even more forward and the larynx opens for free examination. Before introducing the mirror into the mouth, its reflective surface must be heated on a lamp or in warm water so that it does not fog up in the humid air of the oral cavity. The handle of the laryngoscopic mirror is held like a writing pen in the doctor's right or left hand, with the shaft at the corresponding corner of the mouth throughout the examination. During the process of laryngoscopy, even an experienced doctor may encounter a number of difficulties. A major obstacle is the slight reflex excitability of the pharynx, which may depend not only on increased sensitivity of the mucous membrane but also on psychological causes; often the gag reflex occurs even when opening the mouth and protruding the tongue. Individual anatomical conditions can also pose significant obstacles, among which a thick, short, and immobile tongue and its tendency to elevate upward in the middle and posterior parts with each attempt to introduce the mirror should be particularly noted. An equally great obstacle may come from the epiglottis, which due to its abnormal position and irregular shape may completely cover the laryngeal opening; in such cases, it is sometimes necessary to resort to lubricating it with cocaine and pushing it forward with a special curved hook. With pronounced lordosis of the spine, it is often impossible to insert the mirror far enough and push aside the palatal curtain, so that the entrance to the larynx cannot be illuminated. Laryngoscopy presents great difficulty in children, especially those who resist the examination. In small children up to 2-3 years old, it may be difficult to grasp the tongue, but even after overcoming this obstacle, examination is also impossible due to the retroposition of the epiglottis and the accumulation of a large amount of mucus in the pharynx; to this is added vomiting. In such cases, it is necessary to abandon optical laryngoscopy and switch to the direct method by Kirshhtein. In infants, it is sometimes possible to perform examination during crying with the nose pinched; in them, the entrance to the larynx and the arytenoids can also be palpated with the index finger. The laryngoscopic picture [see separate table (pp. 487-488), figures 4-9 and volume VII (pp. 783-784)]. When introducing the laryngeal mirror, usually not the entire inner surface of the larynx is visible in the field of view; therefore, to orient oneself relative to the general laryngoscopic picture, examination has to be done in parts, maneuvering the mirror in different directions. In the first moment, the root of the tongue is reflected in the mirror, on which the lingual tonsil with its papillary surface almost always clearly protrudes, with tortuous, sometimes knotted superficially located veins; then the upper part of the epiglottis catches the eye, the shape and thickness of which can be very varied. Its surface facing forward is pale pink, while the posterior laryngeal surface is colored in a brighter red. Attention is also paid to the space between the epiglottis and the root of the tongue and to the depressions located here. The next, most important moment of the examination is to look behind the epiglottis and see the true vocal cords. The latter appear as two symmetrically located yellowish-white bands, resembling tendons, and sharply standing out in color against the red background of the surrounding mucous membrane. Since during the examination the patient alternately phonates and inhales, the approximation and separation of the vocal cords are clearly visible. By changing the position of the mirror and making the patient produce sounds and breathe deeply but calmly, the vocal cords can be examined from their attachment to the vocal process of the arytenoid to the anterior commissure. During phonation, the free edges of the cords meet along their entire length and appear shorter than during inspiration. The true vocal cords are the most important landmark during the examination, as they serve as the starting point from which observation of other parts of the larynx is conducted. Outwardly and above the true cords are the false cords, which appear as wide ridges covered with red mucous membrane. Between them and the true cords there are slit-like depressions - Morgagni's ventricles; they are visible in the mirror as a dark narrow slit 1-2 mm wide. The mobility of the false cords compared to the true ones is significantly limited. On the posterior wall of the larynx, the arytenoid cartilages, colored like the surrounding mucous membrane, protrude upward; on their apices, the translucent Santorini's cartilages are noticeable. The arytenoids move together with the true cords. During inspiration, the posterior wall of the larynx covered with smooth mucosa - the interarytenoid space - is discovered between both arytenoids. With strong closure of the glottis, the mucosa forms small folds. To complete the internal examination of the larynx, attention must be paid to the glottis, which at the entrance appears as a triangular space that disappears during phonation. With strong separation of the cords, the subglottic space can be examined through the glottis and the transverse rings of the trachea can be seen, and in people with a wide trachea, the eye can penetrate to the bifurcation. Finally, a little attention must be paid to the pyriform sinuses, which lie on the sides of the arytenoids and outward from the aryepiglottic folds; they appear pale pink or yellowish. On their lateral wall, the greater horn of the hyoid bone, which is also easily palpated during finger examination and can be mistaken for a foreign body, can sometimes be seen. It must be remembered that in the mirror image of the larynx, its posterior parts together with the arytenoids appear in the mirror as lying below, while the anterior part is above. The right and left sides remain unchanged and are considered relative to the person being examined.