Laryngoscopy

Overview of Treatment

Laryngoscopy is a medical procedure that utilizes specialized endoscopic instruments to observe the structures of the larynx. It is primarily used for diagnosing voice abnormalities, breathing difficulties, or suspected laryngeal lesions. This technique allows direct visualization of the laryngeal mucosa, vocal cords, and surrounding tissues, enabling immediate detection of tumors, inflammation, or foreign body obstructions, while also facilitating tissue biopsies or therapeutic interventions. Its non-invasive design makes the procedure relatively safe and a crucial tool in otolaryngology clinical assessments.

This examination can be categorized into diagnostic and therapeutic types. The former mainly involves visual assessment, while the latter combines minimally invasive surgical functions. Physicians may adjust the endoscope angle or spray medication during the procedure to thoroughly observe the laryngeal anatomy and formulate subsequent treatment plans based on findings.

Types of Treatment and Mechanisms

Direct Laryngoscopy

Uses metallic or plastic rigid endoscopes inserted through the mouth or nose, requiring local anesthesia to prevent gag reflex. This type provides high-resolution images suitable for vocal cord vibration analysis or foreign body removal.

Indirect Laryngoscopy

The patient is asked to open their mouth, and the physician reflects the laryngeal image using a handheld mirror. This method does not require anesthesia but demands higher operator skill and is commonly used for initial emergency assessments.

Indications

Suitable for diagnosing lesions such as vocal cord nodules, polyps, vocal cord paralysis, and evaluating persistent sore throat, difficulty swallowing, or unexplained breathing noises. When patients experience abnormal voice for more than three weeks without improvement or imaging shows laryngeal shadows, physicians typically recommend this examination.

Other indications include early suspected laryngeal cancer, post-intubation laryngeal injury assessment, and congenital laryngeal anomalies in children. In emergency cases suspected of laryngeal trauma or foreign body impaction, this examination can quickly confirm the lesion location.

Usage and Dosage

Fasting for 2-4 hours before the procedure and signing informed consent are required. Local anesthesia is usually administered with 1% lidocaine spray or gel, with dosage adjusted based on mucosal sensitivity. The examination lasts approximately 5-20 minutes, during which the patient should remain seated and cooperate by vocalizing as instructed.

Therapeutic procedures such as vocal cord polypectomy involve the use of micro scissors or laser devices, extending the procedure time to within 30 minutes. The physician will adjust instrument parameters according to lesion size, such as setting laser power between 15-30W.

Benefits and Advantages

  • Provides real-time visual diagnosis with accuracy exceeding 95%
  • Allows simultaneous tissue biopsy or treatment, reducing the need for repeat examinations
  • Lower cost compared to CT/MRI and no radiation exposure risk

The dynamic observation feature can assess vocal cord closure, playing a key role in diagnosing vocal cord paralysis. For voice professionals, it enables precise lesion localization to develop rehabilitation plans.

Risks and Side Effects

Common temporary discomforts include sore throat (about 20% incidence), difficulty swallowing, or increased saliva production, usually resolving within 24-48 hours. A few patients may experience allergic reactions to anesthetic drugs, such as rash or breathing difficulties, requiring immediate medical attention.

Serious risks include mucosal tears (incidence 0.5%) or anesthesia-induced arrhythmias. Patients with poorly controlled diabetes should delay the procedure. Those with a history of laryngeal surgery may face increased difficulty due to tissue adhesions.

Precautions and Contraindications

  • Recent severe sinusitis may cause nasal obstruction, increasing difficulty in scope insertion
  • Patients with coagulation disorders should discontinue anticoagulants 48 hours prior
  • Patients with neuromuscular diseases may be unable to cooperate with mouth opening and require general anesthesia

Contraindications include acute laryngeal edema, active bleeding lesions, and patients unable to control cough reflex. Detailed medication history, especially steroid or immunosuppressant use, should be provided before the procedure.

Interactions with Other Treatments

Local anesthetics may interact with tricyclic antidepressants, causing blood pressure fluctuations. Patients undergoing radiation therapy should inform the physician to avoid misjudging mucosal inflammation severity.

Compared to bronchoscopy, laryngoscopy has a more limited scope but can be complemented with ultrasound examinations. When using laser therapy, attention should be paid to the timing relative to chemotherapy to prevent delayed tissue healing.

Treatment Outcomes and Evidence

Multicenter studies show that laryngoscopy has a diagnostic accuracy of 98% for vocal cord tumors, with a misdiagnosis rate below 2%. Dynamic laryngoscopy has a sensitivity of up to 85% in assessing vocal cord function disorders, making it the gold standard in voice medicine.

Compared to traditional endoscopy, fiberoptic laryngoscopy reduces the risk of nerve injury by 40% and increases patient acceptance by 30%. Long-term follow-up indicates that combining therapeutic procedures reduces recurrence rates by 60% compared to medication alone.

Alternative Options

Imaging techniques such as MRI of the pharynx and larynx can reveal deep tissue lesions but lack immediate therapeutic capabilities. Acoustic analysis devices can evaluate voice patterns but cannot replace visual diagnosis. Bronchoscopy extends to the trachea but involves higher anesthesia risks.

Ultrasound has diagnostic value for superficial lesions but cannot assess submucosal structures. Patients unable to undergo endoscopy may consider CT scans of the pharynx and larynx, though radiation exposure should be considered.

Frequently Asked Questions

What preparations are needed before the examination? Is fasting or anesthesia required?

Before laryngoscopy, fasting for 4 to 6 hours is generally recommended to reduce the risk of vomiting. Local anesthesia with spray can be applied 10 minutes prior to numb the throat; for general anesthesia (used in children or highly anxious patients), fasting and transportation arrangements should follow anesthesiology instructions. Avoid anticoagulants on the day of the procedure and inform medical staff of any allergies.

Is sore throat or hoarseness after the examination normal? How long will it last?

Minor sore throat or hoarseness is common and usually resolves within 1-2 days. If pain persists beyond 3 days, or if there is fever or difficulty breathing, seek medical attention immediately. It is recommended to avoid hot drinks, spicy foods, and vigorous throat clearing within 24 hours post-examination. Lozenges can help soothe the throat.

How should I communicate with medical staff if I feel anxious or uncomfortable during the procedure?

You can prearrange a signal (such as raising your hand) with the doctor to pause or adjust the position. If local anesthesia is used, breathe deeply and relax, following the doctor’s instructions for head positioning. If sedatives are used, a family member should accompany you, and driving or operating machinery on the same day should be avoided.

When can I resume normal speech after the examination? Should I rest or stop working?

It is advisable to reduce speaking for 24 hours post-examination, using whispering instead of normal voice, and avoid strenuous activities. If abnormalities are found and require treatment (such as removing vocal cord polyps), follow the doctor’s recommended rest period (usually avoiding singing or long conversations for a week). Mild cases can typically return to work the next day but should avoid high-stress environments.

What are the differences in indications and risks between local and general anesthesia during laryngoscopy?

Local anesthesia is suitable for alert, cooperative adults, allowing immediate observation of vocal cord movement and quick recovery, but may cause a foreign body sensation. General anesthesia is used for uncooperative patients (such as children or severe anxiety), enabling detailed tissue biopsies but involves anesthesia risks and recovery time. The physician will choose the safest option based on lesion location, patient health, and examination purpose.