Laryngoscopy: examination of the larynx

Laryngoscopy is a visual examination of the larynx and vocal folds using a speculum, flexible endoscope, or rigid optical instrument. This method allows for an assessment of the structure and mobility of the vocal folds, as well as the detection of inflammation, nodules, polyps, tumors, paralysis, and other causes of hoarseness, shortness of breath, and noisy breathing. Laryngoscopy can be performed in the office without general anesthesia or in the operating room under general anesthesia, depending on the purpose and scope of the procedure. [1]

Current guidelines emphasize that if dysphonia persists for more than 4 weeks, a laryngeal examination is indicated, and if a serious pathology is suspected, an immediate examination is necessary. Early imaging speeds diagnosis, helps avoid unnecessary medications, and directs patients to targeted treatment. For a more in-depth assessment of vocal fold vibration, stroboscopy is added to standard laryngoscopy. [2]

Flexible nasopharyngolaryngoscopy, performed through the nose, has become the mainstay of outpatient practice. It allows for comfortable examination of the entire supraglottic region and dynamic video recording. Narrow-band imaging, which enhances vascular contrast and helps identify early neoplastic changes, is available at specialized centers. [3]

If a targeted biopsy, removal of granulation tissue, or extensive microscopic examination is required, microlaryngoscopy is performed under general anesthesia. This is an operator-dependent technique, but it provides tissue samples and allows for simultaneous diagnosis and treatment. The choice of route is determined by the clinical objective, the experience of the team, and the available equipment. [4]

Types of laryngoscopy and what each method provides

There are several approaches. Indirect laryngoscopy with a speculum is less commonly used but is useful as a quick, preliminary examination. Flexible nasal laryngoscopy is the first-line method in the office, as it ensures normal breathing and voice production during the assessment, including speech tests and phonation. Rigid oral laryngoscopy provides high-quality images and is often used under general anesthesia for therapeutic procedures. [5]

Stroboscopy synchronizes flashes of light with the frequency of vocal fold vibration, creating a "slow-motion" pattern of vibrations. This is indispensable for microfunctional disorders that are not visible under constant light, and for assessing the effectiveness of phoniatric therapy. A number of professional societies strongly recommend adding stroboscopy to laryngoscopy for persistent dysphonia. [6]

Narrow-band imaging enhances the visibility of superficial vessels and intrapapillary capillary lines, aiding in the early detection of laryngeal dysplasia and carcinoma. Validated scales and classifications of vascular patterns have emerged, allowing for standardization of findings and improved expert agreement. This is not a substitute for histology, but it is a useful triage for biopsy site selection. [7]

A separate group are video laryngoscopes, which are used primarily for tracheal intubation. Their use increases the likelihood of a successful first attempt in patients with predictors of difficult intubation and improves visualization, which is reflected in difficult airway guidelines. Video optics are also widely used in diagnostic otolaryngology, as they facilitate documentation and training. [8]

Table 1. Main types of laryngoscopy: capabilities and limitations

Method	What shows best	When to choose	Restrictions
Flexible nasolaryngoscopy	Structures of the epiglottis, mobility of the folds in speech	First line in the office, dynamic tests	Risk of nasal discomfort; mucosal depletion and local anesthesia are required.
Rigid laryngoscopy	Detailed structures with direct access	Microsurgery, biopsy under a microscope	Requires anesthesia and an operating room
Stroboscopy	Mucous wave, periodicity, symmetry	Long-term dysphonia, professional voices	Stable phonation is required and does not replace a biopsy.
Narrow Band Imaging	Vascular pattern and areas of suspicion	Triage of suspicious areas, biopsy planning	Interpretation according to classifications, no histology
Videolaryngoscope	Imaging during intubation	Predictors of difficult intubation, training	Does not provide tissue morphology

Source: clinical guidelines and current reviews. [9]

Indications and what to expect from the result

Laryngoscopy is most often prescribed for hoarseness, foreign body sensation, discomfort with vocal exertion, noisy inhalation, episodes of suffocation, suspected vocal fold paralysis, after inhalation injuries, and suspected tumors. Examination is also necessary before and after phoniatric therapy to objectively document progress. Early visualization saves time and reduces the risk of prolonged dysphonia. [10]

Specific indications include monitoring after removal of benign lesions, post-intubation assessment, risk stratification in chronic laryngitis, and assessment before planned nasal and sinus surgery to rule out concomitant laryngeal problems. In oncology, laryngoscopy helps to precisely select a biopsy site and prevent missed biopsies. [11]

Contraindications are relative and depend on the method. Severe intolerance to endoscopy, uncontrolled coagulopathy, and unstable cardiorespiratory conditions are contraindications for in-office use. If necessary, specimens are collected in the operating room, ensuring a clear airway and monitoring hemostasis. The decision is made by a multidisciplinary team. [12]

The results report should be standardized: anatomical description, mobility, presence of contact lesions, vibration assessment with stroboscopy, and a map of suspicious areas with narrow-band imaging. This template facilitates communication with the speech therapist, oncologist, and anesthesiologist. [13]

Table 2. Indications and relative contraindications

Indications	Examples	Relative contraindications	What to do
Persistent dysphonia ≥ 4 weeks	Nodules, polyps, paralysis	Uncontrolled coagulopathy	Transfer to the operating room, correction of coagulation
Noisy breathing, stridor	Subglottic stenosis, laryngomalacia	Severe respiratory instability	In collaboration with the anesthesiologist, oxygen monitoring
Suspected tumor	Leukoplakia, contact ulcers	Intolerance to endoscopy	Sedation, pain relief, experienced team
Post-treatment assessment	After phoniatrics or surgery	Active mucosal infection	Postponement until stabilization

Source: recommendations of professional communities. [14]

Preparation and pain relief: what is important to consider

Flexible laryngoscopy typically does not require a special diet, but it is best to avoid large meals for 2-3 hours beforehand to reduce the risk of discomfort. A vasoconstrictor spray and local anesthetic are administered to the nasal passages, which improves tolerability and image quality. The patient is warned about the possible numbness and the moderate bitter taste of the anesthetic. [15]

A key issue is safe doses of lidocaine for topical anesthesia. For awake intubation in adults, the recommended upper limit is approximately 9 mg per kilogram of body weight, based on lean body mass. For office endoscopy, lower total doses are usually sufficient. It is important to consider all routes of administration and the patient's sensitivity. [16]

During a planned biopsy, anticoagulants and antiplatelet agents are discussed, the risk of bleeding is assessed, and, if necessary, the procedure is moved to the operating room. Patients with bronchial hyperreactivity are advised on measures to prevent bronchospasm in advance, and oxygen saturation is monitored during the procedure. In children, dosages and anesthesia approaches are selected individually, taking into account age and weight. [17]

Hand hygiene and proper endoscope reprocessing are essential. Current ENT UK documents confirm the equivalence of high-level disinfection using validated wipes and automated systems when following instructions, and also emphasize the sequential nature of manual cleaning and drying as critical safety steps. This reduces the risk of cross-transmission and improves route sustainability. [18]

Table 3. Topical anesthesia of the upper respiratory tract: guidelines

Drug and form	Approximate limits for adults	Practical notes
Lidocaine spray and gel	Up to approximately 9 mg per kilogram of lean mass when combined with all pathways	Plan the total dose, test the effectiveness, avoid overdose
Cocaine nasal solution	Up to approximately 1.5 mg per kilogram	Use with caution in cardiovascular diseases
Mucosal deficient (eg, oxymetazoline)	According to the instructions	Reduces the risk of bleeding and improves visibility
Pediatric dosages	Individual calculation	Consider weight, age and route of administration

Source: awake intubation guidelines and reviews of airway analgesia.[19]

How the procedure works: from the office to the operating room

Flexible laryngoscopy in the office typically takes a few minutes. After administering a vasoconstrictor and anesthetic, a thin endoscope is inserted through the nose. The patient is asked to pronounce sounds, take breaths of varying depth, and sing a note. This allows for assessment of the symmetry of movement, glottal closure, and the induced phenomena. A brief feeling of numbness may occur afterward, so abstain from food for approximately 30-60 minutes. [20]

Stroboscopy is added to flexible or rigid optics. The physician records parameters such as periodicity, regularity, amplitude, and mucosal wave. These indicators help differentiate functional from organic disorders, as well as objectively monitor progress after speech therapy. Video archiving facilitates collaborative discussions with a phoniatrist and speech therapist. [21]

If a biopsy or microsurgery is necessary, direct microlaryngoscopy is performed under general anesthesia. Equipment includes a microscope, microinstruments, and hemostatic devices. Biopsies are sent for histology and immunohistochemistry. For suspicious areas, targeted samples are taken using narrow-band imaging. [22]

If difficult intubation is anticipated, the team discusses the strategy in advance. During the airway management phase, video laryngoscopes increase the likelihood of a successful first attempt and improve laryngeal visibility in patients with predicted difficulty, reducing the risk of hypoxemia. In cases of significant difficulty, awake intubation with thorough topical anesthesia is considered. [23]

Table 4. Stages of flexible laryngoscopy in the office

Step	The essence	Quality control
Preparation of the mucous membrane	Deficient and anesthetic	Assess tolerability, take into account the total dose
Insertion of the endoscope	Through the inferior nasal passage	Minimize contact with the partition, control comfort
Assessment at rest and during phonation	Speech, breaths, samples	Record video, describe symmetry and closure
Documentation and recommendations	Protocol, plan	Decide on stroboscopy, HBI and biopsy

Source: standards of outpatient endoscopy of ENT organs. [24]

Choosing Optics for Airway Management: What the Data Say

Guidelines for difficult airways recommend videolaryngoscopy as the preferred instrument for patients with predictors of complications. Meta-analyses show improved laryngeal visibility and increased first-pass success rates compared with direct laryngoscopy in selected groups. This does not negate the importance of direct technique skills, but it does change the priorities in algorithms. [25]

A Cochrane review and major recent reviews have confirmed that videolaryngoscopy reduces visualization failure and, in some scenarios, complications, although results depend on patient phenotype, device, and team experience. In some populations, differences in first-pass accuracy are negated, necessitating local audit and training. [26]

In emergency and critical care settings, effectiveness may vary depending on anatomy, obesity, and the presence of secretions. Therefore, equipment and a plan B should be prepared in advance, including emergency oxygen access and alternative methods. The key emphasis is on team preparation and limiting the number of attempts. [27]

For awake intubation, a checklist, mandatory oxygen administration, and strict control of the total lidocaine dose are essential. Guidelines suggest aiming for an upper limit of approximately 9 mg per kilogram of lean body mass for adults and using the minimum necessary sedation. This reduces the risk of local anesthetic toxicity and ventilation impairment. [28]

Table 5. Videolaryngoscopy and direct laryngoscopy: comparative benchmarks

Criterion	Videolaryngoscope	Direct laryngoscopy
Overview of the laryngeal inlet	Better with difficulty predictors	Below in case of unfavorable anatomy
Probability of first successful entry	Higher in selected groups	Depends on experience and conditions
Training and documentation	Screen and recording make supervision easier	It's harder to share a review
Complication profile	Potentially lower with good visualization	Higher on repeated attempts

Source: guidelines and systematic reviews. [29]

Safety, risks and prevention of complications

The most common adverse events during flexible laryngoscopy are transient discomfort, sneezing, lacrimation, and mild nosebleeds. Rarely, severe vomiting, vasovagal episodes, and allergic reactions to local anesthetics are reported. Prevention involves gentle technique, adequate mucosal preparation, and minimizing the total anesthetic dose. [30]

Intraoperative microlaryngoscopy carries the added risks of general anesthesia, including difficult intubation and hypoxemia. Preoperative stratification, availability of a video laryngoscope, an alternative access plan, and team preparation are helpful. Limiting the number of attempts and early transition to Plan B reduces the incidence of serious complications. [31]

Infection safety depends on adherence to endoscope reprocessing standards: pre-cleaning, manual cleaning, rinsing, high-level disinfection, secondary rinsing, drying, and storage. Audits show high compliance with recommendations and the absence of infection clusters when performed correctly. [32]

A separate topic is environmental sustainability and the choice between single-use and reusable optics. ENT UK documents emphasize that safety and compliance with the reprocessing process are primary, while the decision must consider the impact on waste and water. A key principle is adherence to validated procedures and local policies. [33]

Table 6. Common and rare complications of laryngoscopy

Complication	How often	Prevention
Discomfort, coughing, sneezing	Often	Mucosal anesthesia, gentle technique
Nosebleed	Sometimes	Decongestant spray, choosing a wider nasal passage
Vasovagal reaction	Rarely	Patient preparation, observation, readiness for relief
Allergic reactions to anesthetic	Very rarely	History taking, dose control, treatment readiness

Source: guidelines and observational studies. [34]

Special groups: children, professional voices, pregnancy

In children, anatomical variations and dynamic phenomena such as laryngomalacia are more common. Flexible laryngoscopy allows for the assessment of obstruction under natural respiratory conditions, and in cases of severe symptoms, the procedure is performed in conditions where immediate airway support is available. Anesthetic doses are calculated individually. [35]

Professional voice technicians emphasize stroboscopy and objective vibration parameters. It's important to document stress tests, record videos, and coordinate the plan with a voice specialist. Narrow-band imaging helps detect early vascular changes and correctly select a biopsy site for suspicious areas. [36]

During pregnancy, outpatient flexible laryngoscopy is possible with minimally adequate sedation or without it, depending on indications. If necessary, local anesthesia is used within safe dose ranges, and decisions regarding biopsy and anesthesia are made individually, taking into account the timing and multidisciplinary discussion. [37]

In emergency situations with a risk of airway compromise, respiratory safety remains a priority. Diagnostic laryngoscopy is then combined with airway readiness, preferably using a video laryngoscope and a difficult intubation checklist. [38]

Table 7. What to consider in special groups

Group	Key points	Additionally
Children	Individual doses of anesthetics, dynamic assessment	Availability of respiratory support
Professional voices	Standard stroboscopy, video protocol	Narrow Band Imaging for Triage
Pregnancy	Minimizing sedation, safe doses of lidocaine	Multidisciplinary decision about biopsy
Emergency conditions	Airway priority	Videolaryngoscope and plan B

Source: specialized guides and reviews. [39]

Interpretation and next steps

Following laryngoscopy, a report is generated describing the anatomy and function. For functional disorders without organic causes, voice therapy and observation with control stroboscopy are prescribed. If a neoplasm is suspected, a targeted biopsy and oncological route are indicated. Narrow-band imaging helps to precisely select the site for tissue sampling. [40]

Vocal cord paralysis requires an investigation of the underlying cause, including thyroid and chest evaluation as indicated, and early involvement of a speech therapist during rehabilitation. Monitoring laryngoscopy allows for monitoring spontaneous recovery and promptly addressing the need for injection mediation. [41]

For contact lesions and chronic laryngitis, it is important to eliminate triggers and assess acid reflux and vocal strain. A video protocol facilitates monitoring of effectiveness and encourages adherence to recommendations. If there is no improvement, the plan is revised in consultation with specialists. [42]

If signs of difficult intubation are detected during the examination, this is recorded in the medical records and the patient receives a reminder. It is recommended to inform the anesthesiologist before any interventions to ensure the appropriate strategy and equipment are selected in advance. This approach reduces risks in future procedures. [43]

Table 8. Typical scenarios and tactics after laryngoscopy

Find	The next step	Target
Functional vibration disorder	Voice therapy, control stroboscopy	Restoring voice quality
Suspected neoplasia	Targeted biopsy, oncomort	Confirmation of diagnosis and staging
Vocal fold paralysis	Finding the cause, injection correction according to indications	Restoration of voice function and airway protection
Signs of difficult intubation	Markings in the chart, plan for the anesthesiologist	Prevention of complications during anesthesia

Source: Clinical guidelines and patient routing. [44]

Short answers to frequently asked questions

Is it painful?
It's usually felt as mild discomfort in the nose and throat. Local anesthesia and mucosal depletion make the procedure well-tolerated, and the procedure itself takes only a few minutes. [45]

When can I eat and drink after the procedure?
If an anesthetic was used, it's best to refrain from eating or drinking hot drinks for 30-60 minutes to avoid irritating the numb mucosa. Afterward, resume your normal routine. [46]

Is the procedure dangerous in terms of infection?
When validated endoscope reprocessing protocols are followed, the risk is extremely low. Audits show the high safety of outpatient endoscopy with proper disinfection and drying. [47]

How does a video laryngoscope help during anesthesia?
It improves visibility of the laryngeal inlet and increases the likelihood of a successful first attempt in patients with predictors of difficult intubation, reducing the risk of hypoxemia and injury. The decision on the choice of instrument is made by the anesthesiologist. [48]