Introduction
Bilateral vocal fold immobility (BVFI) is an uncommon condition with potentially significant negative effects on breathing and quality of life. Patients usually have symptoms of airway obstruction, such as biphasic stridor and dyspnea, with a normal or nearly normal voice. This is in contrast to patients with unilateral vocal fold immobility, who usually complain of a breathy voice and aspiration. Etiologies of BVFI include immobility from both neurogenic causes (vocal fold paralysis) and mechanical fixation of the cricoarytenoid (CA) joints.
Neurogenic causes of bilateral vocal fold paralysis (BVFP) may be due to (1) iatrogenic injury to the recurrent laryngeal nerve (e.g., thyroidectomy, anterior cervical disc surgery, carotid endarterectomy, esophageal surgery, cardiac surgery, mediastinal surgery), (2) progressive neurologic disorders (e.g., amyotrophic lateral sclerosis, Shy-Drager syndrome, syringomyelia, Guillain-Barré syndrome), or (3) idiopathic causes.
Mechanical fixation of the CA joints causing BVFI may be due to (1) fixation of the CA joint secondary to radiation therapy, rheumatoid arthritis and other connective tissue disorders, benign infiltrative disorders such as amyloidosis, granulomatous diseases; (2) trauma; or (3) posterior glottic stenosis (PGS).
PGS is a common cause of BVFI. It is typically associated with intubation, although extraesophageal reflux disease may be a cofactor. The development of PGS is characterized by progressive airway obstruction, usually 4 to 8 weeks after extubation. Granulation tissue can cover the arytenoid cartilages and interarytenoid cleft. If this is observed, prompt débridement, steroid injection, and antacid treatment may be associated with less scar tissue formation and consequently less airway stenosis. Laryngeal balloon dilation may also have a therapeutic role in the acute or subacute setting.
Bogdasarian and Olsen developed a classification system for PGS that is useful to characterize the nature and severity of the posterior laryngeal stenosis. The least severe group of patients has an interarytenoid synechiae and posterior sinus tract. The next group includes those with a posterior glottic web that limits movement of the arytenoids, without fixation of the CA joints and no posterior sinus tract. The third group appears similar to the second; however, one CA joint is fixed. The most severe group and the most difficult to treat consists of patients with fixation of both CA joints ( Fig. 9.1 ).
Correctly identifying the cause of BVFI (neurogenic or mechanical) is critical in guiding treatment and shaping the expectations of both the patient and surgeon. The aim of treatment is to improve the airway while minimizing adverse effects on the voice.
Key Operative Learning Points
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Patients with BVFI secondary to mechanical fixation of the CA joints typically have more severe airway restriction and require more aggressive surgical enlargement of the glottis than patients with BVFP.
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Laryngeal electromyography (LEMG) is crucial in determining the presence of neurologic injury and may guide the surgeon in determining the operative side.
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Palpation of the arytenoid, either in the office or in the operating room, to confirm passive motion or immobility is critical information that helps guide treatment.
- •
Endoscopic techniques have replaced larger, more destructive surgery and have resulted in decreased morbidity.
- •
Granulation tissue formation is minimized by the use of perioperative antacid medications and the application of mitomycin-C to any mucosal defects.
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Only patients with realistic expectations of the balance between voice and airway improvement should undergo surgery to enlarge the glottic airway.
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Overly aggressive primary surgery will probably leave the patient with more severe breathy dysphonia and dysphagia than was necessary for airway improvement or decannulation.
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Posterior glottic airway surgery may worsen glottic protection during swallowing, thereby increasing the risk of aspiration.
- •
BVFP must be differentiated from PGS because the initial surgical options may be different.
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Exposure of arytenoid cartilage during transverse cordotomy may lead to the formation of granulation tissue and the need for further treatment.
Preoperative Period
History
- 1.
History of present illness
- a.
What are the patient’s symptoms (e.g., dyspnea, dysphonia, dysphagia)?
- b.
When did their symptoms begin?
- 1)
Suddenly: After surgery where the recurrent laryngeal nerve is at risk? Remember that the endotracheal tube (ETT) cuff can also result in vocal fold paralysis, although bilateral paralysis is very rare from ETT cuff pressure itself.
- 2)
Progressive: Progressively worsening dyspnea 4 to 8 weeks after extubation suggests PGS as the more likely etiology for vocal fold immobility.
- 1)
- a.
- 2.
Past medical and surgical history
- a.
Previous surgery where the recurrent laryngeal nerve is at risk. Was hoarseness present after surgery?
- b.
Prolonged intubation? One to two days is sufficient to develop PGS in diabetic patients.
- c.
Neurologic diseases such as stroke or progressive neurologic diseases?
- d.
Previous external beam radiation to the head and neck region?
- e.
Rheumatologic diseases? Rheumatoid arthritis can result in CA joint fixation.
- a.
Physical Examination
- 1.
Flexible laryngoscopy is the most important part of the examination. It allows for evaluation of vocal fold motion during vocal fold adductory (saying /i/) and abductory (sniffing) tasks.
- 2.
Manual palpation of the CA joints, either in the office or in the operating room, can further help detect the cause of BVFI and assist in guiding surgical planning. When both joints are impaired, palpation can determine the CA joint with the least range of motion. This is the optimal side for static, glottic enlargement surgery.
Imaging
- 1.
Imaging studies can be important in evaluating a patient without obvious causes of vocal fold immobility.
- 2.
Enhanced computed tomography (CT) or magnetic resonance imaging (MRI) of the skull base, neck, and upper part of the chest can help identify the site of a lesion in the brainstem, vagus nerve, or recurrent laryngeal nerves, which results in BVFI.
- 3.
Enhanced CT with fine cuts through the larynx may be used to evaluate the CA joint for abnormalities or, in the case of PGS, the extent of stenosis, which may change the type of surgical intervention. Arytenoid subluxation or dislocation may also be identified.
- 4.
MRI of the brain is needed when brain or brainstem causes are suspected, such as stroke or Arnold-Chiari malformation.
Laryngeal Electromyography
- 1.
LEMG of both the thyroarytenoid–lateral cricoarytenoid (TA–LCA) muscle complexes is useful to determine the cause of BVFI.
- 2.
If BVFP is present, there will be evidence of significant neurologic injury, with or without partial recovery. If the neurologic pattern shows a new injury with a chance of recovery, delaying destructive surgery is prudent.
- 3.
The authors advocate that in an attempt to preserve the voice, surgery should involve the vocal fold with the worse neurologic status. This may improve voice outcomes by not altering the vocal fold that has a better neurologic status and thus possibly better muscle tone.
- 4.
Patients with BVFI and PGS, in contrast to those with BVFP, will have normal electromyographic activity of the TA–LCA muscle complexes.
- 5.
LEMG may also suggest a “mixed” etiology of the BVFI—one side neurogenic and the other mechanical.
Swallowing Studies
- 1.
Swallowing studies are crucial in patients who complain of dysphagia. Because the incidence of aspiration is high after many types of surgery to improve the airway, more conservative surgery or tracheostomy may be most appropriate for patients with dysphagia or compromised swallowing ability.
Indications
- 1.
Patients with symptomatic airway obstruction due to BVFI
- 2.
Patients desiring decannulation after tracheostomy to bypass airway obstruction due to BVFI
Contraindications
- 1.
Contraindications to directly treating the laryngeal obstruction of BVFI, other than performing a tracheostomy, are the presence of aspiration or a rapidly progressive neurologic disorder.
- 2.
Relative contraindications include compromised pulmonary status, uncontrolled diabetes, and previous radiation therapy.
- 3.
Unrealistic expectations on the part of the patient are a relative contraindication to treating all types of BVFI.
Preoperative Preparation
- 1.
Patients must understand and accept that to improve their glottal airway, the quality of their voice may be adversely affected. Therefore patients should expect to have worse vocal quality at the expense of an improved airway. Such counseling needs to be frank and well documented. A patient who is unwilling to accept any decrease in vocal function should be considered for tracheostomy and not glottic enlargement surgery.
- 2.
The patient should understand that multiple procedures may be necessary to optimize the airway with the least potential impact on the voice. This allows the surgeon to enlarge the glottic airway in a staged, conservative fashion, which hopefully will minimize the negative impact on both voice and swallowing.
Operative Period
Anesthesia
- 1.
General anesthesia: The patient’s airway is secured by one of the following, depending on the patient’s airway restriction, comorbid conditions, the surgery to be performed, and surgeon preference or comfort level.
- a.
Laser-safe ETT, if appropriate. A small ETT (i.e., 5.0 or 5.5 microlaryngeal tube) is needed if the ETT is to remain during surgical intervention.
- b.
Jet ventilation is also a common modality used for glottal airway surgery. Subglottic jet ventilation with a Hunsaker catheter is effective. Supraglottic jet ventilation through the laryngoscope is possible but is hampered by subsequent laryngeal desiccation and motion from the air puffs. Jet ventilation should only be used by anesthesiologists who are familiar and comfortable with this technique, as there are risks of hypercapnia and pneumothorax.
- c.
Intubation with intermittent extubation and subsequent apnea is less commonly used but is a good option for patients being treated with shorter duration procedures, such as dilation.
- d.
Tracheostomy provides the most stable airway and leaves the glottis devoid of accessory instrumentation. However, if the patient is without a tracheostomy, the goal is often to avoid it. Possible placement of a tracheostomy at the time of glottic airway surgery needs to be openly discussed with the patient and listed on the surgical consent form.
- a.
Positioning
- 1.
Supine: The patient is placed supine, with neck flexion and head extension. A shoulder roll does not help achieve this. Rather, the patient’s head is placed on a “donut” pillow, and the head of the bed is flexed as needed.
- 2.
If the patient is obese, then a “ramped” position may be needed. Blankets are placed below the patient’s head and upper back such that the tragus is in-line horizontally with the manubrium. This helps achieve the proper “sniffing” position required for optimal laryngeal exposure in patients with a larger body habitus.
- 3.
Proper surgeon ergonomic positioning is also important to reduce surgeon musculoskeletal injuries. After laryngeal exposure is achieved, the proper surgeon ergonomic position is achieved by moving the bed angle (usually Trendelenburg, “head down”) so the laryngoscope is ∼40 degrees off the horizontal plane. The surgeon’s neck should be in a neutral position or slightly flexed but never extended. Sometimes lowering the height of the bed is needed to allow for more comfortable placement of the surgeon’s arms and hands. Arm rest support while operating is also important.
Perioperative Antibiotic Prophylaxis
- 1.
Perioperative antibiotics are not necessary unless the patient’s medical history requires them—for instance, mechanical heart valves or stents.
Instruments and Equipment to Have Available
- 1.
Various sizes of laryngoscopes: The largest laryngoscope that fits the patient’s anatomy is best to provide optimal exposure.
- 2.
Standard microlaryngeal surgical tray
- 3.
Rigid telescopes (0-, 30-, and 70-degree; 30 cm length, 5 to 10 mm diameter): These are used to better visualize the extent of lateral extension of the surgical field.
- 4.
Laser: CO 2 laser is the most common type of laser used for glottic airway surgery.
- 5.
Airway dilators: Balloon and Jackson dilators
Key Anatomic Landmarks
- 1.
True vocal folds and arytenoids: Depending upon the position of the arytenoids and true vocal folds, the glottis, which is defined as the space between the vocal folds, may be too small for the patient to breathe without restriction. Scarring between the arytenoids can range from mild to severe, with complete obliteration with scar of the respiratory glottis up to the vocal processes.
- 2.
Cricoid cartilage: The cricoid cartilage is a complete cartilaginous ring located below the true vocal folds. There is no benefit to performing surgery outside the confines of the inner table of the cricoid cartilage.
Prerequisite Skills
- 1.
Microsuspension laryngoscopy
- 2.
Laser certification
- 3.
Balloon dilation
- 4.
Tracheotomy (see Chapter 19 ).
Operative Risks
- 1.
Airway compromise: Inability to properly secure the airway prior to the start of surgery requires the placement of an emergent surgical airway.
- 2.
Bleeding: Although bleeding is not usually a major concern, there is often increased bleeding experienced during the transverse cordotomy procedure. Defocused laser energy or suction cautery is usually sufficient for hemostasis.
- 3.
Laser airway fire: It is critical that laser safety precautions be followed at all times when using the laser—optimally FiO 2 less than 40%, saline readily available if case of fire (preferably in a bulb syringe within reach of the surgeon), wet towels over the patient’s head (avoiding air pockets under the towels), proper eye protection for the staff, laser-resistant ETT (or wrapped in tin foil) if applicable, and placement of a saline-soaked pledget over the ETT or tracheotomy tube cuff (if applicable). A laser operator is also to be in the room at all times while the laser is in use. All operating room staff must be trained on what to do in case of airway fire—turn off oxygen while removing the endotracheal, Hunsaker, or tracheotomy tube; place saline in the airway; use bronchoscopy to evaluate for injury; and reintubate. These types of laser surgeries should only be performed by surgeons who are comfortable performing airway laser surgery.
Surgical Technique
Surgical treatment of BVFI involves static enlargement of the glottic airway, given that no method exists presently to restore dynamic, purposeful motion of the vocal fold(s). A stepwise approach to create an adequate airway is prudent. The surgeon must integrate the patient’s comorbid problems into the surgical decision-making process. In general, patients with rapidly progressive neurologic disorders or other serious comorbid conditions tend to be best treated with a tracheostomy. Most other causes of BVFI can be treated with conservative endoscopic techniques. Transverse cordotomy, medial arytenoidectomy, or a combination of these procedures are ideal conservative options because the airway is enlarged with fewer detrimental effects on vocal quality and possibly swallowing ability than occur with more extensive total arytenoidectomy procedures (endoscopic or open). Total arytenoidectomy creates a larger posterior airway but is more likely to lead to aspiration and a substantive decrease in vocal quality. Endoscopic suture lateralization is useful as a temporary measure when there is no loss of mucosa in the posterior glottis. This procedure can be done with glottal enlargement procedures or a permanent treatment. Treatment of PGS, specifically, may be achieved by endoscopic or open techniques and consists of lysis of the interarytenoid synechiae, creation of a microtrapdoor flap, balloon dilation with steroid injections, or the techniques mentioned earlier. If the patient already has a tracheostomy before arytenoid surgery, it should remain in place until a proper capping trial for decannulation can be conducted, approximately 2 months after surgery.
Surgical outcomes vary upon the extent of surgery, location of surgery (i.e., arytenoid involvement), and patient factors. Patients with reduced wound healing, such as with diabetes, may have a compromised surgical outcome. The addition of acid suppression, mitomycin-C, and steroids is to improve the outcome, though direct studies of their effects are unclear.
Prognosis of glottic airway enlargement surgery varies, depending upon the type and severity of the clinical situation. A patient with an interarytenoid adhesion usually has an excellent result from lysis of the fibrotic adhesion, usually with no further intervention needed as long as there is no concurrent CA joint fixation. Treatment of patients with BVFP can differ from those with BVFI, because the addition of arytenoid procedures and temporary suture lateralization procedures are viable options, whereas patients with severe PGS have more restricted options of glottal airway surgery (transverse cordotomy, microtrapdoor flap). Healing after these surgeries is effected by the surgery performed and the patient’s general health status. If the patient is willing to have reduction in voice quality, and he or she does not have dysphagia complaints, the prognosis of tracheostomy tube decannulation is excellent after this type of surgery. However, sometimes the patient and surgeon decide that further glottal airway opening at the detriment of voice and swallowing quality is not acceptable. In those cases, the patients must be willing to accept long-term tracheostomy for airway management.
- 1.
Palpation of the CA joint
- a.
Place a sturdy instrument adjacent to the vocal process and push laterally. Both CA joints are evaluated to compare the degree of effort required to displace the vocal process and the speed of medial tissue recoil. If one CA joint displays better movement, surgery is initially performed on the contralateral (worse) side. If the interarytenoid region moves during this maneuver, then PGS is present.
- 1)
If the patient is awake and being evaluated with flexible laryngoscopy with the addition of topical anesthesia, an instrument such as an Abrams cannula can be used.
- 2)
If the patient is being evaluated under general anesthesia, a blunt laryngeal elevator or large cup forceps can be used to palpate the joint. During CA joint palpation under general anesthesia, the laryngoscope must be placed above the arytenoid to avoid artificial reduction in CA joint movement.
- 1)
- a.
- 2.
Tracheostomy
- a.
This is a reasonable option for patients with BVFI, especially those with dysphagia or rapidly progressive neurologic disease, as well as for patients who do not want decreased vocal function (see Chapter 19 ).
- a.
- 3.
Lysis of interarytenoid synechiae
- a.
When a bridge of scar tissue exists between the vocal processes with the presence of a posterior sinus tract, the bridge of scar tissue can be excised.
- b.
Suspension laryngoscopy with exposure of the posterior glottis is carried out after the airway is secured.
- c.
The mucosal integrity of the posterior glottis is assessed with the aid of 0, 30, and 70-degree angled telescopes.
- d.
The interarytenoid bridge of mucosa is excised using laser or cold knife technique.
- e.
Mitomycin-C can be applied to the defect in the mucosa to reduce the risk of reformation of synechiae.
- f.
Release of the bridge should restore at least some passive mobility of the arytenoid.
- g.
If patients do not achieve long-term improvement with this procedure, injury to the CA joint (fixation) is likely. A more aggressive static glottic enlargement procedure is then necessary.
- h.
Balloon dilation of the posterior larynx may further assist after the lysis of the synechiae.
- a.
- 4.
Transverse cordotomy
- a.
Described by Dennis and Kashima in 1989 as a more conservative surgery than total arytenoidectomy
- b.
The patient is intubated with a 5.0 or 5.5 laser-safe ETT if a pre-existing tracheostomy is not present.
- c.
Usually, the ETT can be placed in the posterior glottis to allow exposure of the vocal process on the side to be operated. Alternatively, the ETT can be placed anterior to the laryngoscope, or jet ventilation can be used.
- d.
The laryngoscope is suspended and angled toward the operative side.
- e.
CO 2 laser precautions are implemented.
- f.
Typical CO 2 laser settings depend upon the type of CO 2 laser, but in general, the least amount of energy needed to complete the cordotomy is recommended. For example, CO 2 laser setting could be 4 W, superpulse, with a small (0.25 to 0.4 μm) spot size to minimize collateral thermal damage.
- g.
After confirming the location of the vocal process, an incision is made just anterior to it. Care is taken to not expose the arytenoid cartilage in order to avoid the formation of a granuloma. The cordotomy extends across the entire width of the true vocal fold, extending to the inner table of the lateral cricoid cartilage. This completely separates the vocal fold from the vocal process/arytenoid and allows scarring to retract the muscular portion of the vocal fold anteriorly and laterally, thus leaving a triangular-shaped glottal airway.
- h.
Endoscopic evaluation with a 30-degree telescope should confirm that the cordotomy is flush with the lateral wall of the cricoid cartilage.
- i.
The incision may also include the medial 3 to 4 mm of the false vocal fold ( Fig. 9.2 ), if needed for proper visualization.
- a.
