Microlaryngeal Surgery – Anesthetic Considerations

Microlaryngeal surgery (MLS) refers to minimally invasive procedures performed on the larynx using an operating microscope and microlaryngeal instruments. These surgeries are commonly performed for vocal cord lesions, laryngeal papillomas, benign or malignant tumors, vocal cord paralysis, and subglottic stenosis.

Anesthesia for microlaryngeal surgery presents unique challenges due to:

✅ Shared airway between the surgeon and anesthetist.

✅ Need for a clear surgical field to visualize delicate vocal cord structures.

✅ Risk of airway fire due to use of lasers in some procedures.

1. Indications for Microlaryngeal Surgery

• Benign vocal cord lesions (polyps, nodules, cysts).

• Laryngeal papillomatosis (caused by HPV).

• Recurrent respiratory papillomatosis (RRP).

• Malignant lesions (early-stage laryngeal carcinoma).

• Subglottic stenosis.

• Vocal cord paralysis (medialization procedures).

• Foreign body removal.

2. Preoperative Considerations

A. Airway Assessment

✅ History of airway obstruction symptoms (hoarseness, stridor, dyspnea).

✅ Direct or indirect laryngoscopy to evaluate vocal cord lesions.

✅ History of previous surgeries or radiation (fibrosis, difficult airway).

B. Comorbidities

✅ COPD, smoking history → Higher risk of laryngospasm, airway hyperreactivity.

✅ GERD (gastroesophageal reflux disease) → Increased aspiration risk.

3. Intraoperative Anesthetic Considerations

A. Choice of Anesthesia

✅ General anesthesia with endotracheal intubation is preferred.

✅ TIVA (Total Intravenous Anesthesia) or inhalational anesthesia may be used.

✅ Spontaneous or controlled ventilation depending on airway approach.

B. Airway Management Techniques

Technique	Advantages	Disadvantages
Microlaryngeal Tube (MLT) – Smaller diameter ETT (4.0–5.0 mm)	Provides a clear surgical field	Higher resistance, risk of airway edema
Jet Ventilation (High-Frequency Jet Ventilation – HFJV)	No endotracheal tube obstructing view	Requires skill, risk of hypercapnia, barotrauma
Apneic Oxygenation	Excellent surgical view	Limited time, risk of desaturation
Laser-resistant ETT (if laser is used)	Prevents airway fire	Rigid, can obstruct the view

✅ Choice depends on the surgeon’s preference and lesion location.

C. Ventilation Strategies

✅ If using an MLT, allow permissive hypercapnia to reduce ventilation difficulty.

✅ If using HFJV, avoid high pressures to prevent barotrauma.

4. Special Considerations for Laser Surgery

A. Risk of Airway Fire

✅ Avoid flammable ETTs → Use laser-resistant tubes (e.g., Xomed, Norton).

✅ Minimize oxygen concentration (<30% FiO₂) to reduce fire risk.

✅ Use Heliox (Helium + Oxygen) mixture to lower FiO₂ requirement.

✅ Have saline-soaked pledgets nearby to extinguish potential fires.

B. Laser Safety Precautions

✅ Use protective eyewear for staff and patients.

✅ Avoid N₂O (supports combustion).

✅ Ensure laser is in standby mode when not in use.

5. Intraoperative Monitoring

✅ Standard ASA monitoring (ECG, SpO₂, NIBP, EtCO₂).

✅ EtCO₂ is crucial in jet ventilation cases.

✅ Neuromuscular monitoring (to ensure adequate paralysis for ventilation).

6. Postoperative Care

A. Airway & Respiratory Monitoring

✅ Risk of laryngospasm due to airway irritation → Extubate deep or fully awake.

✅ Monitor for airway edema (especially after prolonged intubation).

B. Postoperative Voice Rest & Swallowing

✅ Voice rest is advised for 24-48 hours after vocal cord surgery.

✅ Assess swallowing function (risk of aspiration in vocal cord surgeries).

C. Pain & Nausea Management

✅ Minimal pain (mostly throat discomfort).

✅ Dexamethasone 8–10 mg IV reduces airway swelling.

✅ Ondansetron for PONV prophylaxis (especially in jet ventilation cases).

D. Complications

✅ Airway compromise (edema, bleeding, laryngospasm).

✅ Vocal cord damage (permanent hoarseness).

✅ Laser-related airway burns (rare but serious).

MCQs on Microlaryngeal Surgery

1. The preferred endotracheal tube for microlaryngeal surgery is:

A) Standard 7.5 mm ETT

B) Microlaryngeal Tube (MLT) 4.0–5.0 mm

C) Laryngeal Mask Airway (LMA)

D) Rigid bronchoscope

✅ Answer: B (MLT allows surgical access while maintaining ventilation).

2. Which ventilation technique provides the best surgical view in microlaryngeal surgery?

A) Conventional ETT ventilation

B) High-Frequency Jet Ventilation (HFJV)

C) Noninvasive ventilation

D) Nasal cannula oxygenation

✅ Answer: B (HFJV provides an unobstructed surgical field).

3. Which precaution is essential when performing laser laryngeal surgery?

A) Using high FiO₂ for adequate oxygenation

B) Using a laser-resistant endotracheal tube

C) Avoiding IV anesthetics

D) Using N₂O for better analgesia

✅ Answer: B (Laser-resistant tubes prevent airway fire).