Microlaryngoscopy

Currently, microlaryngoscopy is widely used for visual examination of the larynx, a method of precise recognition and differential diagnosis, as well as microlaryngosurgical interventions for various laryngeal diseases. As noted by the director of the otolaryngological hospital of the Philips University of Marburg (Germany), Prof. Dr. Oskar Kleinsasser, this method has proven itself in identifying malignant tumors of the larynx at an early stage. According to O. Kleinsasser, microlaryngoscopy and microlaryngosurgery require the performer to have the appropriate knowledge and skills, as well as considerable practical experience for their successful and safe use. These studies and operations are not as easy to perform as doctors with insufficient experience and operating skills often believe. Therefore, the number of irreversible damage to the larynx due to improper interventions is still quite high today.

Various laryngoscopes are used to perform microlaryngoscopy. Thus, the so-called loupe laryngoscopy is currently a routine diagnostic method, which uses a telelaryngoscope with cylindrical lenses that provide not only excellent illumination of the larynx and laryngopharynx, but also a slightly magnified image.

More convenient for examining hard-to-reach areas of the larynx is a fiber-optic rhinopharyngolaryngoscope. This instrument is recommended for use, in particular, in cases of laryngeal dysfunction. Special additional eyepieces on the operating microscope, especially when using so-called sectional optics, allow parallel observation of the operation and documentation of its progress using a video camera or a camera equipped with an automatic exposure meter. Illumination of the larynx is carried out only by a halogen lamp ("cold" light) of the operating microscope or by means of a microcomputer-controlled pulsed lighting device.

Indications for microlaryngoscopy

Indications for microlaryngoscopy are questionable cases in the diagnosis of precancerous conditions of the larynx and the need to take a biopsy, as well as for surgical elimination of defects that impair vocal function. Microlaryngoscopy and especially direct laryngoscopy are contraindicated in patients with severe cardiac and circulatory disorders (bradyarrhythmia, post-infarction condition), in which each anesthesia is associated with an increased risk. Microlaryngoscopy is practically impossible in the case of significant pathological changes in the cervical spine area that do not allow contracture or trismus, preventing opening the mouth and inserting the laryngoscope into the larynx.

The use of microlaryngoscopy requires endotracheal anesthesia using a small-caliber intubation catheter. Jet artificial ventilation is indicated only in particularly constrained anatomical conditions.

The technique for performing microlaryngoscopy involves a number of stages, including the following items.

Giving the patient the correct position

O. Klensasser recommends the following method of patient positioning: the patient should lie on a horizontal table on his back; cup-shaped headrests that hinder head movements should not be used, and the head should not hang down. After intubation of the trachea and insertion of protective pads for the teeth, the head of the completely relaxed patient is tilted as far as possible in the dorsal direction. Only after making sure that the patient's lips and tongue are not pinched, insert the laryngoscope with the conical end forward, up to the glottis, following the intubation catheter. The intubation catheter should be dorsal to the laryngoscope, in the posterior "commissure", when manipulating in the area of this commissure, it should be in the anterior commissure. The laryngoscope should be advanced carefully, avoiding lever movements. With optimal positioning of the laryngoscope, an unrestricted view of the vocal folds from the anterior commissure to the vocal processes of the arytenoid cartilages is ensured. When positioning the laryngoscope with a chest support, excessive pressure of the laryngoscope on the larynx should be avoided. To achieve a better view of its cavity, the assistant should be asked to push the larynx backwards. For a detailed examination of the lateral surface of the larynx, it can be moved to the side in the same way.

In cases of particularly difficult access, for example, long teeth, pronounced upper prognathism, rigidity of the occipital muscles, the laryngoscope is inserted into the larynx slightly obliquely from the corner of the mouth, turning the patient's head tilted in the dorsal direction to the left or right.

After fixing the laryngoscope in the desired position, the light guide is removed and the operating microscope is set in the working position. After suctioning the mucus, the laryngeal cavity is examined at different magnifications. Before the start of the surgical intervention, photo documentation of the detected pathological changes is performed through the operating microscope.

Video microlaryngoscopy

In recent years, the method of video microlaryngoscopy has become increasingly widespread as the most high-quality method for diagnosing various endolaryngeal diseases and laryngeal microsurgery. Laryngeal microsurgery using video microlaryngoscopy was first introduced into practice in 1989. The principle of this method is to use a miniature video camera that allows visualizing the endoscopic picture of the larynx from different angles on the monitor screen and to perform surgical interventions, guided by the “picture” obtained on the screen in a significantly enlarged form, which, with certain skills, significantly simplifies the manipulations performed and increases the effectiveness of the operation. As noted by prof. J. Tomessey, one of the pioneers of laryngeal microsurgery, video microlaryngoscopy provides the best conditions for examining the anterior commissure of the larynx and its vestibular section, while creating opportunities for an excellent overview of this hollow organ even in individuals whose examination is difficult due to a number of insurmountable circumstances: short neck, obesity, childhood, etc. In addition, video microlaryngoscopy makes it possible to provide photo and video documentation of the endoscopic picture of the larynx and the surgical intervention being performed, providing high-quality visual materials as teaching aids. The use of a monitor screen during surgery allows you to control the course of the operation, which is extremely important for training young specialists.