Direct laryngoscopy allows you to examine the internal structure of the larynx in a direct image and to produce in a large enough amount of various manipulations on its structures (removal of polyps, fibroma, papillomas, cryosurgical or laser surgical methods), and to carry out emergency or planned intubation. The method is based on the use of a rigid directory, the introduction of which into the laryngopharynx through the oral cavity becomes possible due to the elasticity and compliance of surrounding tissues.
Indications for direct laryngoscopy are numerous, and their number is continuously growing. This method is widely used in pediatric otorhinolaryngology. For infants, a single laryngoscope with a fixed handle and a fixed spatula is used. For adolescents and adults, laryngoscopes are used with a removable handle and a pull-out spatula plate.
Contraindications include severe stenotic breathing, cardiovascular insufficiency, epilepsy with a low threshold of convulsive readiness, lesions of the cervical vertebrae that do not allow the head to be thrown back, the aortic aneurysm. Temporary or relative contraindications are acute inflammatory diseases of the oral mucosa, pharynx, larynx, bleeding from the pharynx and larynx.
In young children, direct laryngoscopy is performed without anesthesia; In young children - under anesthesia; In older children - either under anesthesia or under local anesthesia with appropriate premedication, as in adults. For local anesthesia, various anesthetics of the application can be used in combination with sedatives and anticonvulsants. To reduce the overall sensitivity, muscle tension and salivation, one tablet of phenobarbital (100 mg) and one sibazone tablet (5 mg) are given one hour before the procedure. For 30-40 minutes, subcutaneously inject 0.5-1.0 ml of 1% solution of promedol and 0.5-1 ml of a 0.1% solution of atropine sulfate. 10-15 minutes before the procedure, an anesthetic is applied (2 ml of a 2% solution of dicain). 30 minutes before this premedication, in order to avoid anaphylactic shock, intramuscular injection of 1-5 ml of a 1% solution of diphenhydramine or 1-2 ml of a 2.5% solution of diprazine (pipolpene) is recommended.
The position of the examinee can be different and is determined basically by the condition of the patient. The study can be carried out in the sitting position, lying on the back, less often in the position on the side or on the stomach.
The procedure of direct laryngoscopy consists of three stages.
The first stage can be carried out in three versions:
- When the tongue is extended, which is held by means of a gauze pad.
- At the usual position of the tongue in the oral cavity.
- When inserting a spatula from the angle of the mouth.
In all cases, the upper lip is moved upward and the patient's head is tilted back somewhat. The first stage is completed by squeezing the root of the tongue downwards and holding the spatula to the edge of the epiglottis.
At the second stage, the end of the spatula is slightly raised, wound behind the epiglottis and promoted by 0.5 inches; After that, the end of the spatula is lowered down, covering the epiglottis. The spatula during this movement presses on the upper incisors (this pressure should not be excessive, in the presence of removable dentures they are previously removed). The correctness of the insertion of the spatula is confirmed by the appearance in the field of vision of the vocal folds.
Before the third stage, the patient's head is turned back even more. The language, if kept, is released. The examiner increases the pressure of the spatula on the root of the tongue and the epiglottis, and, following the median plane, disposes of the spatula vertically (at the position of the patient being seated) or, respectively, the longitudinal axis of the larynx (at the position of the patient lying). In both cases, the end of the spatula is directed to the middle part of the respiratory slit. At the same time, the back wall of the larynx first appears in the field of vision, then the vestibular and vocal folds, the ventricles of the larynx. For a better view of the anterior larynx, you have to squeeze the root of the tongue somewhat downwards.
Special types of direct laryngoscopy include support and pendulous laryngoscopy.
Modern laryngoscopes for hanging and supporting laryngoscopy are complex complexes, which include spatulas of various sizes and sets of various surgical instruments specially adapted for endolaryngeal micromanipulation. These complexes are equipped with devices for injection ventilation, anesthesia and video equipment, which allows performing surgical procedures using an operating microscope and a video monitor.
For visual examination of the larynx, the method of microlaringoscopy is widely used, which allows increasing the internal structure of the larynx. More convenient for inspection of hard-to-reach areas are fiber-optic devices, which are used, in particular, for functional disorders of the larynx.
Indications for microlaryngoscopy are: doubt in the diagnosis of pre-tumoral formations and the need for biopsy, as well as the need for surgical removal of defects that violate the voice function. The contraindications are the same as with the usual direct laryngoscopy.
The use of micro-laryngoscopy requires the use of endotracheal anesthesia using a small intubation catheter. The pulmonary ventilation is indicated only in particularly cramped anatomical conditions.