Generality
Laryngoscopy is the medical procedure used to diagnose, and possibly cure, laryngeal and vocal cord disorders.
It can be performed in various ways: there is indeed an indirect laryngoscopy, which involves the use of very simple instrumentation, and a direct variant in which a particular instrument called a laryngoscope is used.
Brief anatomical reference to the larynx
Figure: the larynx and the main cartilaginous structures that constitute it are highlighted in red. As can be seen, the larynx is placed at the beginning of the trachea, bordered at the top with the pharynx and is in front of the esophagus, which is the first tract of the digestive canal. From the site: ponsuke2.s98.xrea.com
Figure: the larynx and vocal cords. From the site: ponsuke2.s98.xrea.com
The larynx is an unequal tube of tubular form, located at the level of the neck before the beginning of the trachea . It represents the last tract of the upper airways (the trachea is in fact considered the first tract of the lower airways) and consists of different cartilaginous structures, held together by a series of muscles and ligaments.
Seat of the vocal cords, the larynx performs three fundamental functions:
- It channels the air towards the trachea, then towards the lungs.
- It allows speech, through the vibration of the vocal cords.
- Thanks to a cartilage valve called epiglottis, it prevents food, which is about to be swallowed, from entering the trachea and obstructing the airways.
Externally, the larynx can be placed at the so-called Adam's apple (anterior protrusion of the neck more evident in men than in women).
What is laryngoscopy?
Laryngoscopy is the medical procedure that allows you to see the larynx and the vocal cords contained in it; if needed, with the aid of certain instruments, it can also be used as a therapeutic procedure.
There are two types of laryngoscopy: indirect and direct.
INDIRECT LARYNGOSCOPY AND DIRECT LARYNGOSCOPY
Indirect laryngoscopy can also be performed in the doctor's office; in fact, it requires the use of a simple laryngeal mirror and a light source.
Direct laryngoscopy, on the other hand, requires the use of a special instrument, called a laryngoscope, and - because it requires anesthesia - must take place in a specialized environment.
LARYNGOSCOPE
Figure: Flexible direct laryngoscopy.
Modern laryngoscopes are fiber-optic instruments that allow, thanks to a light source and a camera connected to an external monitor, to observe the larynx and every constituent structure (epiglottis, vocal cords, etc.) in great detail.
They can be flexible or rigid: flexible laryngoscopes are inserted into the throat through the nose, after local anesthesia; rigid laryngoscopes, on the other hand, are introduced into the throat through the mouth and after general anesthesia.
Laryngoscopy performed using a flexible laryngoscope (or direct flexible laryngoscopy ) is generally exploratory, while that performed with a rigid laryngoscope ( direct rigid laryngoscopy ) can be both exploratory and therapeutic.
An alternative to the external monitor: the binocular microscope
Some rigid laryngoscopes are connected, instead of to an external monitor, to a binocular microscope, which the examiner can consult freely during the procedure ( suspended laryngoscopy ).
NB: According to some sources, the only direct laryngoscopy is performed by a rigid laryngoscope, while the one performed with a flexible laryngoscope should be considered a different type of indirect laryngoscopy.
WHO EXECUTES LARYNGOSCOPY?
Laryngoscopy is a specialized procedure that must be performed by an otolaryngologist, or a doctor experienced in the treatment of ear, nose and mouth diseases.
When practicing
Laryngoscopy is used to:
- Identify the causes that trigger persistent voice problems, such as chronic hoarseness, chronic voice loss etc.
- Identify the causes of a chronic sore throat or persistent ear pain.
- Identify the reasons that cause a difficult swallowing or the formation of mucus containing blood.
- Assess the extent of a throat injury.
- Track down any airway obstructions.
SPECIAL PURPOSES OF RIGID DIRECT LARYNGOSCOPY
Direct rigid laryngoscopy has singular uses, which differentiate it from all other laryngoscopy procedures; in fact, it can be used for:
- Collect a sample of tissue from the throat ( biopsy )
- Eliminate any polyps that may form at the level of the vocal cords.
- Remove any foreign bodies that have been inadvertently inhaled and obstruct the upper airway.
- Remove any laryngeal tumor using a laser.
- Facilitate intubation in preparation for surgery under general anesthesia or mechanical ventilation
For these reasons, direct as well as exploratory laryngoscopy can also be therapeutic.
risks
All types of laryngoscopy can cause edema (swelling) and block the airways. This drawback, due to the irritation of the anatomical traits traversed by the instrument, is however not very common; it is, however, more likely to occur if the patient under examination is affected by some pharyngolaryngeal tumor, has polyps at the level of the vocal cords or possesses the explored and partially inflamed and irritated tract.
WHAT TO DO IF THE PATIENT IS NOT ABLE TO BREATHE?
If, due to laryngoscopy, the patient can no longer breathe, he must be immediately intubated to restore the passage of air.
In very rare cases, a tracheotomy may be required instead of intubation.
COMPLICATIONS RELATED TO RIGID DIRECT LARYNGOSCOPY
Direct rigid laryngoscopy is riskier than other types of laryngoscopy for at least two reasons:
- Requires general anesthesia . Some side effects of general anesthesia:
- Adverse reaction to anesthetic drugs
- After anesthesia, nausea and vomiting appear
- Interaction between anesthetic drugs and drugs taken by the patient due to particular health problems
- Lung problems
- Stroke (rare)
- Heart attack (rare)
- If it is performed to collect a tissue sample ( biopsy ), it could cause blood loss (bleeding), infections and small lesions in the respiratory tract.
Preparation
Indirect laryngoscopy and flexible direct laryngoscopy do not require specific preparatory measures, except for the possibility of removing any mobile dental prostheses.
Direct rigid laryngoscopy, on the other hand, requires the same particular preparation required for surgical operations performed under general anesthesia. This implies:
- Conducting a series of clinical tests, including a thorough physical examination, a blood test and an electrocardiogram.
- Evaluation of the patient's clinical history . Evaluating the clinical history means questioning the patient to know if he suffers or has suffered from cardiovascular problems; if you know you are allergic to some anesthetic drug; if you take drugs at the time of evaluation; if you have already undergone throat surgical treatment; if, in the case of a woman, she is pregnant, etc.
- The elucidation of intervention methods and possible risks .
- The recommendations of:
- suspend, before laryngoscopy, any treatment based on antiplatelet agents (aspirin), anticoagulants (warfarin) and anti-inflammatory drugs (NSAIDs), because these drugs, by reducing the coagulation capacity of the blood, predispose to serious blood loss;
- on the day of the procedure, appear at full fast from at least the previous evening, as general anesthesia is provided.
- after the intervention, be assisted by a trusted person .
- The current information about recovery times .
NB: even in the case of direct rigid laryngoscopy, any mobile dental prostheses must be removed.
Procedure
Indirect laryngoscopy
Executable also in a medical clinic, it is a very simple procedure, which requires the use of two objects: a laryngeal mirror, to be inserted in the patient's throat, and a light source, with which to illuminate the mirror and see the larynx reflexively . Obviously, during the examination the patient must keep the mouth open and the tongue out.
Usually, no anesthesia is provided; however, if the patient under examination is bothered by the laryngeal mirror, it may be useful to perform local type anesthesia using a spray.
Duration: 5-10 minutes
Sensations: the laryngeal mirror could be very annoying and, if the local anesthetic is used (NB: it tastes bitter), it is possible that there is a strange sensation when swallowing.
Flexible direct laryngoscopy
Before inserting the flexible laryngoscope in one of the two nasal cavities and leading it up to the larynx, the doctor practices, through spray, the local anesthesia; in addition, it uses a medicine (also in the form of a spray) to cleanse the nose and throat from mucous secretions.
The patient may be asked to: pull the tongue out, breathe deeply, speak and / or inflate the cheeks.
Duration: 5-10 minutes
Sensations: the insertion of the laryngoscope could cause a slight discomfort, however the patient can breathe. The anesthetic is bitter and could make swallowing strange for several minutes.
Direct rigid laryngoscopy
The doctor inserts the rigid laryngoscope only after the patient has been made to lie down on the bed of the operating room and has fallen asleep due to general anesthesia. As we said at the beginning of the article, the insertion of the instrumentation takes place by mouth and there is the possibility not only to explore the larynx, but also to treat possible disorders of the same.
Duration: 15-30 minutes
Sensations: during the operation, the patient sleeps and does not feel any discomfort. Upon awakening, you may experience nausea, vomiting, fatigue, sore throat and have a hoarse voice.
Post-operative phase
Indirect laryngoscopy . If a local anesthetic has been used, do not drink or eat until the end of its effects (about 30 minutes).
Flexible direct laryngoscopy . The effects of the local anesthetic vanish after about 30-60 minutes; as in the previous case, during this time it is good not to take liquids or food.
Direct rigid laryngoscopy . Hospitalized as a rule for at least one night, the patient, after the procedure, is required to:
- Refrain from eating and drinking for at least a couple of hours. Otherwise it could choke.
- Avoid clearing your throat and coughing too strongly, even if you feel the need.
- Speak low and never long for at least a few days.
- To practice, at least until the disappearance of the sore throat, of the gargles with solutions based on hot water and salt.
Some special cases of direct rigid laryngoscopy:
- If you have inadvertently hit the vocal cords with the instrument, do not talk (or speak as little as possible) for at least 3 days.
- If a part of the larynx has been removed, it is likely that the voice is hoarse for at least 3 weeks.
- If a polyp is removed from the vocal cords, the voice should be kept at rest for at least 2 weeks.
- If a biopsy has been performed and the bleeding does not calm down after 24 hours, you should contact your doctor immediately.
Results
Indirect laryngoscopy is, today, a less common practice than a few decades ago. The reason is to be found in the availability of modern optical fiber laryngoscopes, which allow a better view of the larynx (and adjacent areas) without damaging the person.
If the laryngoscopy has a biopsy, the results are generally available after 7 days.
