Anesthesia for Laryngeal Surgery

Issues of Concern

Laryngeal Anatomy

The larynx consists of a cartilaginous skeleton, intrinsic and extrinsic musculature, and a mucosal lining. The larynx is central for phonation, airway protection and maintenance, and the generation of the Valsalva maneuver. Key anatomic components include the laryngeal cartilages, vocal folds (or cords), associated muscles, and neural innervation.

Laryngeal cancer and its treatment can produce anatomic changes that complicate airway management. Involvement of the structures or spaces around the epiglottis or areas lateral to the vocal folds may reduce tissue compliance, narrow the airway, and make passage of an endotracheal tube  (ETT) difficult or impossible. Airway management strategies in patients with laryngeal cancer depend on tumor stage and anatomic location. The airway is often adequate for ETT passage in patients with early laryngeal cancer, whereas more advanced tumors may significantly narrow the airway lumen and decrease tissue compliance, complicating ETT passage.[2] Please see StatPearls' companion resource, "Anatomy, Head and Neck, Thyroid," for more information.

Preanesthetic Assessment

A comprehensive medical history and focused physical examination should be performed, with particular attention to airway anatomy and comorbid conditions that may increase the risk of complications during or after the procedure. Airway assessment should include evaluation of the oral cavity, including dentition, visualization of the uvula, and palatal structure; assessment of the length, thickness, and range of motion of the neck; and evaluation of mandibular space compliance. Additionally, relevant radiological studies should also be performed to identify anatomic features that may complicate airway management during anesthesia, as patients undergoing head and neck procedures are at increased risk of airway difficulty.[3]

Because the surgeon and anesthesiologist share the airway during laryngeal surgery, anesthesia management requires close coordination with the surgical team. A preoperative discussion should address device selection, planned intubation technique, ventilation strategy, use of neuromuscular blockade, mitigation of airway fire risk, and operating table orientation.[4] 

Patients with head and neck cancer frequently have a history of current or prior alcohol and tobacco use, which may increase the risk of cardiopulmonary, hepatic, or other systemic comorbidities relevant to anesthetic management. Radiation therapy is commonly used in the treatment of laryngeal cancer and can further complicate airway management. Cutaneous changes may reflect underlying tissue fibrosis, which can further affect airway anatomy. Baroreceptor reflex dysfunction also may occur following radiation treatment.

Common Procedures

Phonosurgery includes procedures that are designed to treat voice disorders such as hoarseness and changes in laryngeal sound production.[5] Some of these procedures may require patients to remain awake during surgery to allow intraoperative assessment of vocal function. Microlaryngoscopy, surgical innervation of the larynx, and excision of soft tissue lesions require general anesthesia. In contrast, selected procedures that do not involve microsurgical techniques may be performed under regional or topical anesthesia.[6] Common pathologies addressed during these interventions include glottic lesions, such as papillomatosis, as well as vocal fold nodules and polyps, which are often associated with voice overuse.[7]

Laryngoplasty

Laryngoplasty includes surgical interventions designed to improve respiratory or phonatory function by enlarging the glottic aperture or bringing the vocal folds together. Laryngoplasty is broadly classified as either an injection or an operative technique.

• Injection laryngoplasty is an endoscopic procedure used to treat glottic insufficiency and related voice disorders. A bulking agent is injected to medialize the vocal folds, thereby improving voice quality. This procedure typically requires 15 to 20 minutes of operative time and is often performed under local anesthesia, unless immobility of the surgical field is required or the patient is unable to tolerate an awake technique.

• Operative laryngoplasty, commonly referred to as thyroplasty, may also be performed without sedation. In cases of unilateral vocal fold paralysis, the impaired vocal cord can be medialized by implanting a permanent wedge. Moderate sedation is frequently used to facilitate intraoperative voice assessment, which takes approximately 45 to 90 minutes. Mild postoperative throat discomfort is common following laryngoplasty; therefore, opioid use should be avoided whenever possible following both injection and operative laryngoplasty techniques.

Laryngeal Cancer Surgery

Anesthetic planning for laryngeal cancer surgery must prioritize reliable intraoperative ventilation and oxygenation. The choice of ventilatory mode depends on patient characteristics, type of laryngeal disease, and the duration of the procedure.[8] Procedures expected to last longer than 1 hour generally require airway management with an ETT to facilitate jet ventilation or controlled mechanical ventilation. Shorter procedures may be more amenable to apneic intermittent ventilation. Neuromuscular blockade may be avoided for shorter surgeries, but omission has been associated with increased failure rates and worsened surgical conditions.[9]

Laryngeal cancer itself may impede airway management due to mass effect, local tissue inflammation, radiation-induced edema or fibrosis, and scarring from prior surgery. Patients also may present with preoperative anxiety, malnutrition, or hypovolemia, all of which warrant perioperative assessment and optimization. Excision of vocal fold lesions is typically performed using microlaryngeal techniques with specialized laryngoscopes under general anesthesia, and operative time is generally less than 2 hours.

Ventilation Technique

The anesthesiologist and surgeon should establish a coordinated plan for intraoperative ventilation based on the planned surgical procedure.[4] Total intravenous anesthesia may be used to avoid concerns related to an open airway.[1] Continuous infusions of propofol or remifentanil may be administered, with or without a superior laryngeal nerve block.

Maintenance of spontaneous ventilation can provide surgeons with unobstructed surgical access during suspension microlaryngoscopy. Avoiding neuromuscular blockade allows for quicker emergence following short procedures.[9] Supplementation support with mask ventilation, jet ventilation, or mechanical ventilation via an ETT may be necessary during periods of hypoventilation or desaturation.[10] High-flow nasal cannula oxygen therapy, typically at flow rates greater than 15 L/min, may also be used to maintain spontaneous ventilation during upper airway procedures.[11] Reported complications of this technique include hypoxemia, hypercapnia, and airway fire, although this technique may be associated with shorter operative times.[11][12]

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) may be clinically useful before securing a definitive airway in patients with a short apneic window and unfavorable pharyngeal anatomy.[13] Many patients undergoing laryngeal surgery have pathology or previous therapy that may complicate intubation. Use of THRIVE has been associated with apneic periods of up to 17 minutes without signs of carbon dioxide toxicity. The reported rate of carbon dioxide accumulation is 0.15 kPa per minute with THRIVE, compared with 0.45 kPa per minute in patients receiving traditional apneic oxygenation or those with airway obstruction. Delivery of continuous positive airway pressure at approximately 7 cm H₂O is believed to splint the upper airways and reduce shunting. Continuous insufflation facilitates carbon dioxide clearance by promoting gas mixing and flushing the anatomic dead space.[13]

Subglottic (Transoral-Translaryngeal-Infraglottic Access) Jet Ventilation

Advances in jet ventilation tube design have improved the safety of anesthesia for laryngeal surgery.[14] High-frequency jet ventilation (HFJV) delivered through a catheter inserted via the cricothyroid membrane is effective for oxygenating patients undergoing microlaryngoscopic and laser procedures. Unlike endotracheal tubes, which may obscure the posterior glottis and increase the risk of airway fire, HFJV minimizes these limitations. HFJV may also be continued postoperatively to support oxygenation as the patient recovers from anesthesia.[15] The cricothyroid membrane is relatively avascular and poses a low risk of bleeding. Transtracheal ventilation should be administered in the midline to reduce the risk of complications.

Complications most often involve cricothyroid membrane puncture, mechanical issues, and low oxygen saturation. Carbon dioxide retention may occur, especially in patients with preexisting chronic obstructive pulmonary disease or obesity. Rare complications of HFJV include pneumomediastinum, subcutaneous emphysema, and pneumothorax.[15] Patients with a history of laryngeal surgery or those undergoing longer procedures may be at increased risk of complications following HFJV during endolaryngeal surgery.[16]

Endotracheal Intubation

A cuffed ETT secures the airway and prevents leakage of anesthetic gas or oxygen, but it may interfere with visualization and dissection of the laryngeal lesion. Special attention is required to avoid trauma to laryngeal lesions during intubation. The smallest ETT capable of supporting ventilation should be used. In most cases, a 5.0- or 5.5-mm microlaryngeal tube is adequate; however, care should be taken to prevent air leaks when using a small-diameter ETT. Laser-resistant ETTs are used during laryngeal laser procedures to reduce the risk of airway or operating room fire. Tube selection should be based on compatibility with the specific laser employed. Due to their protective coatings, laser-resistant tubes have a larger external diameter than standard tubes.

Intraoperative Laser Use

Most laryngeal surgeries are performed using carbon dioxide lasers. The most commonly used laser-resistant ETT is designed for carbon dioxide and potassium titanyl phosphate lasers and incorporates dual cuffs. The distal cuff serves as a backup seal if the proximal cuff is damaged. The cuff position should be carefully rechecked after the patient is positioned for surgery, as laser-resistant ETTs have no depth markings. Laryngeal laser surgery is indicated for stenosis, recurrent respiratory papillomatosis, leukoplakia, malignant or benign laryngeal tumors, or polypoid degeneration (such as Reinke edema).[17] Although carbon dioxide lasers reduce the risk of airway fire, they cannot precisely cut the delicate subepithelial vocal fold tissue without causing trauma.[7]

According to the American Society of Anesthesiologists practice advisory on the prevention and management of operating room fires, the ETT cuff should be filled with saline tinted with methylene blue to alert the clinician of a rupture during laser surgery.[18] The surgeon should alert the anesthesiologist before laser activation so that the inspired oxygen concentration can be reduced to less than 30% and nitrous oxide discontinued. Adequate time should be allowed for equilibration, which typically requires approximately 5 minutes, depending on fresh gas flow, circuit length, and the initial oxygen concentration.[19]

Replacement of nitrogen with helium may shorten the time to ignition during operating room fires involving carbon dioxide lasers. Fire risk is primarily related to the pervasive use of incendiary surgical tools, including diathermy and lasers, in an oxygen-enriched environment.[20] Complications associated with laser use in the operating room include gas embolism, laser plume creation, retinal injury, operating room fire, and damage to vascular structures. Up to 32% of operating room fires during laryngeal surgery are attributed to lasers.[20]

Clinical Significance

Laryngeal surgery presents unique challenges for anesthesiologists, particularly the need to coordinate closely with the surgeon while sharing the airway during the procedure. Treatment of common laryngeal pathology may limit neck mobility and increase tissue friability. Therefore, a comprehensive history and physical examination should be performed to evaluate for changes to the airway (eg, from radiation therapy). Associated comorbidities must also be incorporated into the anesthetic plan.

The underlying pathology, such as a vocal fold tumor, may further complicate airway management and often warrants preoperative visual assessment. Multiple ventilation strategies are available depending on the procedure length and the patient's specific needs. Additionally, the use of lasers during laryngeal surgery presents a considerable fire risk, which must be minimized whenever possible.

Enhancing Healthcare Team Outcomes

Laser ablation and other laryngeal procedures require carefully controlled ventilation, typically using laser-resistant endotracheal tubes or apneic ventilation using various respiratory devices. Close collaboration among the anesthesiologist, anesthetic providers, and otolaryngologist is essential during preparation for laryngeal surgery, as anatomy, tissue friability, and physiology may be altered by cancer or prior radiation therapy to the neck and airway.

The intubation and extubation plan, along with the chosen ventilation strategy, should be clearly discussed and communicated to all members of the operating room team. Coordination with the respiratory therapy team is also essential when postoperative ventilatory support is anticipated.

Nursing, Allied Health, and Interprofessional Team Interventions

As laryngeal surgery is an aerosol-generating procedure, appropriate use of personal protective equipment (PPE) is essential for infection prevention. A prior study analyzing communication in the pediatric operating room during airway surgery found that enhanced PPE use was associated with detrimental effects on communication among operating room personnel.[21] Although communication aids have been proposed to address this issue, no specific device, speech-to-text application, or software platform has been validated for this purpose.

Nursing, Allied Health, and Interprofessional Team Monitoring

Effective communication among nursing staff, allied health professionals, and the broader interprofessional healthcare team is essential. Identifying and addressing barriers to communication, including those related to PPE, should occur alongside coordinated planning for airway management and patient positioning to support safe anesthetic care during laryngeal surgery. Clear communication and ongoing assessment of fire risk during the preoperative time-out and throughout the procedure are critical to promote patient safety and optimal surgical outcomes.