Introduction
The term vocal fold injection (VFI) typically refers to global vocal fold augmentation for purposes of addressing glottic insufficiency, although superficial injection into the lamina propria is performed occasionally (e.g., steroids, as for the treatment of vocal fold scar). In situations where the impact of global augmentation on symptoms is unpredictable, a trial VFI with a temporary material may also be beneficial. Many options for augmentation material are currently available, with variable advantages, disadvantages, and durations of benefit. Advances in technology and techniques now allow Otolaryngologists to perform VFI under either local or general anesthesia. This chapter focuses on VFI via microlaryngoscopy under general anesthesia.
Selection of injection material, type of anesthesia, and location of procedure (e.g., office, operating room, or endoscopy/procedure suite) should be determined on a case-by-case basis. Factors to consider include the patient’s medical comorbidities and candidacy for the procedure, patient and/or surgeon preference, expected duration of symptoms/vocal fold motion abnormality (i.e., immediate postoperative period following surgery with high hopes for spontaneous recovery of motion vs. underlying malignancy), need or preference for hemodynamic monitoring, goal of the procedure (e.g., symptom treatment vs. trial), and insurance-related considerations.
VFI via microlaryngoscopy remains an important tool in the care of patients with symptomatic glottic insufficiency. Key advantages of this technique include immobility of the vocal folds and improved precision of injection material placement, complete airway control, and more detailed investigation of the vocal folds (including direct palpation to assess for vocal fold scar or cricoarytenoid joint fixation). Results of VFI are typically excellent in patients with glottic insufficiency related to vocal fold immobility/paralysis; outcomes of VFI for other laryngeal conditions such as vocal fold atrophy or scar tend to be more variable.
Key Operative Learning Points
- 1.
Adequate laryngeal exposure is critical.
- 2.
Familiarity with different types of laryngoscopes
- 3.
Familiarity with different injection material options
- 4.
Typically the goal is global augmentation. (It is important to know when to use superficial injection.)
- 5.
Superficial injection is to be avoided when global augmentation is the goal.
Preoperative Period
History
- 1.
History of present illness
- a.
Voice
- 1)
Characteristics: breathy, raspy, decreased volume/projection, increased effort, vocal fatigue, vocal strain, tightness, pain with speaking
- 2)
Aggravating or alleviating factors
- a)
For example, voice rest versus prolonged speaking, change in weather/temperature/humidity, stress, medications
- a)
- 1)
- b.
Swallowing
- 1)
Characteristics: dysphagia to liquids versus solids versus pills, coughing or choking episodes, need for Heimlich maneuver, weight loss, change in diet
- 2)
Aggravating or alleviating factors
- a)
Impact of compensatory strategies: head turn, chin tuck, double swallow, liquid wash
- a)
- 3)
Asking about history of recent pneumonia is of critical importance.
- 1)
- c.
Breathing
- 1)
Characteristics: dyspnea with speaking versus exertion versus rest
- 2)
Aggravating or alleviating factors
- 1)
- d.
Precipitating factors
- 1)
Surgery
- a)
Thyroid
- b)
Cervical spine
- c)
Lung
- d)
Esophagus
- a)
- 2)
Intubation
- a)
Size of endotracheal tube
- b)
Duration of intubation
- a)
- 3)
Upper respiratory infection
- 4)
Accident/trauma
- 5)
None identifiable
- 1)
- e.
Other associated symptoms
- 1)
Cough
- 2)
Globus sensation
- 3)
Throat clearing
- 4)
Mucus
- 5)
Other symptoms including reflux-related (e.g., heartburn, burning sensation in nose/mouth/throat, or bitter/sour taste)
- 1)
- a.
- 2.
Past medical history
- a.
Prior treatment and its efficacy
- 1)
Surgery
- 2)
Speech therapy
- 3)
Over-the-counter (OTC) medications (mucolytics, antihistamines, throat sprays, lozenges)
- 4)
Voice rest
- 5)
Steroids
- 6)
Antibiotics
- 7)
Gargling
- 8)
Increased fluids (e.g., water, tea)
- 1)
- b.
Medical history
- 1)
General assessment regarding candidacy for surgical procedure
- 1)
- c.
Surgery
- 1)
Especially important to include cervical spine, other neck, and/or chest surgery
- 1)
- d.
Family history: usually not helpful
- e.
Medications
- 1)
Antiplatelet drugs
- a)
Not a specific contraindication. Important to make sure that patient is counseled appropriately about risk of hemorrhage and even airway compromise.
- a)
- 1)
- f.
Social history
- 1)
Tobacco use
- a)
Active tobacco use can increase the risk of postoperative coughing (at extubation and in the early postoperative period), which may increase the risk of premature implant extrusion.
- a)
- 2)
Occupation and associated vocal demands (e.g., teacher, cashier, call center worker, attorney, social worker, waiter/bartender)
- 1)
- a.
Physical Examination
- 1.
Examination of the head and neck with focused areas as listed here
- 2.
Examination of the neck
- a.
Evidence of prior surgery (e.g., scars) or trauma
- b.
Degree of cervical range of motion and any restrictions (flexion or extension); this may affect ease of intubation and/or exposure with the laryngoscope
- a.
- 3.
Oral cavity
- a.
Evaluate for trismus.
- b.
Assess status of patient’s dentition. Pay particular attention to the presence of any of the following: caps, crowns, partial dentures, bridges, missing/loose/broken teeth.
- c.
Look for torus mandibularis (may require a smaller laryngoscope).
- a.
- 4.
Flexible laryngoscopy
- a.
Flexible laryngoscopy is critical in the evaluation of patients with voice, swallowing, or breathing symptoms.
- b.
Flexible laryngoscopy is superior to rigid oral laryngoscopy in the assessment of vocal fold motion. The use of a rigid Hopkins rod telescope or high-definition chip-tip flexible laryngoscope may allow improved magnification and visualization of specific vocal fold abnormalities (e.g., vocal fold scar, lesions, sulcus vocalis).
- c.
Specific task: repeated alternating sniff-/i/ maneuvers are especially useful for assessing vocal fold ABDuction (opening) and ADDuction (closing).
- a.
Imaging
- 1.
Typically imaging is indicated only in cases of vocal fold immobility of uncertain etiology.
- 2.
Computed tomography (CT) of the neck can serve to evaluate the course of the recurrent laryngeal nerve.
- a.
CT may not be indicated if the history is strongly suggestive of an etiology of vocal fold immobility/paralysis (e.g., anterior cervical diskectomy and fusion (ACDF), thyroidectomy, esophagectomy, lung surgery).
- a.
- 3.
Modified barium swallow if indicated to evaluate dysphagia
- a.
MBS may be useful in situations where the surgeon is trying to decide whether to proceed with VFI versus continuing with observation alone; the presence of aspiration is a strong indication to proceed. If there is no aspiration, observation may be a reasonable alternative.
- a.
Indications
- 1.
Symptomatic glottic insufficiency (which may be due to vocal fold immobility, paresis, atrophy)
- a.
Voice
- b.
Swallowing
- c.
Breathing
- d.
Some combination of these symptoms
- a.
- 2.
Trial VFI
- a.
In some cases it is not obvious whether vocal fold augmentation alone will improve voice symptoms. In these patients, the use of a temporary augmentation material as a “trial” VFI may be helpful in clarifying the degree of benefit that may be achieved after vocal fold augmentation.
- b.
Examples of situations in which trial VFI may be helpful: vocal fold scar, atrophy, paresis, or concurrent neurologic disease (e.g., causing dysarthria)
- a.
Contraindications
- 1.
Patients with medical comorbidities that carry an increased risk for general anesthesia need to carefully weigh the potential risks versus benefits of VFI. The presence of such a risk is not an absolute contraindication, but in such patients VFI under local anesthesia may be a good alternative option. The reader is referred to Chapter 94 and also item 3 under Additional Resources at the end of this chapter.
- 2.
Although not an absolute contraindication, it is strongly suggested that VFI be considered with great caution in cases of a unilateral vocal fold immobility, which is associated with a contralateral vocal fold hypomobility, as these patients will have a baseline decrease in glottic airway size. Further vocal fold augmentation (either unilateral or bilateral) may additionally narrow this already restricted airway and should be undertaken with extreme care.
- a.
It is uncommon that the benefits would outweigh the risks in patients with these vocal fold motion abnormalities. (An example might be a patient with documented aspiration who refuses a tracheostomy.) This issue should be considered in depth prior to proceeding.
- b.
Extensive counseling of all parties including the patient, his or her family, and other associated services (e.g., Thoracic Surgery) is critical. It is particularly important to discuss the risk of airway compromise and the possibility of requiring urgent intubation and/or tracheostomy.
- c.
If VFI is pursued, this should be performed very conservatively, as anteriorly as possible, and under as carefully controlled circumstances as possible.
- a.
Preoperative Preparation
- 1.
Flexible laryngoscopy is imperative; additionally, stroboscopy is strongly recommended.
- a.
Know which side to augment (critical in cases of planned unilateral injection).
- b.
Know the size of the glottic gap (helps to guide the degree of augmentation to be performed).
- c.
Evaluate the presence of vocal fold height mismatch. This may guide the location of injection material in an attempt to improve “matching” up of vocal fold levels.
- d.
Flexible stroboscopy is superior to laryngoscopy alone for the assessment of vocal fold closure, size of the glottic gap, and the presence of vocal fold height mismatch.
- a.
- 2.
Counseling to establish expectations (for both patient and family)
- a.
The goal is to recover the patient’s normal voice, but it is possible that the patient’s symptoms may be improved or even resolved without a complete return to “normal.” Use of patient self-report questionnaires (i.e., Voice Handicap Index [VHI], VHI-10, Voice Related Quality of Life [VRQOL]) may be helpful in monitoring the patient’s degree of symptomatology and response to treatment. I assess pre- and postinjection VHI-10 scores in all patients.
- b.
The patient is advised about the potential need for additional procedures. This may be especially appropriate in cases of temporary VFI (such as following acute-onset vocal fold immobility), but it may even be needed following long-term augmentation, as with adipose tissue.
- c.
In cases of trial VFI, the patient is counseled that voice symptoms may improve, decline, or remain unchanged.
- a.
- 3.
Discontinue antiplatelet drugs if possible.
Operative Period
Anesthesia
- 1.
VFI is traditionally performed under general endotracheal anesthesia (GETA). More recent techniques to perform VFI under local anesthesia have been described; the reader is referred to Chapter 1 for further details. This chapter focuses on VFI under GETA.
- 2.
Use as small an endotracheal tube as possible to permit maximal visualization of the vocal folds during laryngoscopy. I prefer a 5.0 microlaryngoscopy tube (MLT) for all laryngeal surgery. This should be taped to the oral commissure, preferably along the upper lip. Taping to the lower lip can sometimes affect oral opening and thus laryngoscopic exposure. Moving the “tube tree” or endotracheal tube holder further down the body (not immediately next to the head and neck) is helpful for keeping the anesthesia circuit out of the way.
- 3.
Perioperative medications: one-time dosing at the start of the case
- a.
Dexamethasone (Decadron)—decreases laryngeal edema
- b.
Ondansetron (Zofran)—decreases nausea and associated risk for postoperative emesis
- c.
Glycopyrrolate—decreases secretions and facilitates visualization during laryngoscopy
- a.
- 4.
Laryngotracheal anesthesia (plain lidocaine, either 4% or 2%, based on availability and/or surgeon preference. I prefer 4% spray).
- a.
Administered once at intubation (can be done by anesthesia)
- b.
Administered a second time at the end of the procedure prior to extubation—decreases risk of laryngospasm and coughing upon extubation
- a.
- 5.
A short-duration muscle relaxant is helpful during the procedure.
Positioning
- 1.
Supine
- 2.
No shoulder roll—it would place the patient in a suboptimal position for laryngoscopy
- 3.
It is helpful to have an adjustable headboard to allow neck flexion if needed. Having the operative bed backward can allow this.
Perioperative Antibiotic Prophylaxis
Not indicated
Monitoring
- 1.
Routine anesthesia monitoring
- 2.
Short-duration muscle relaxant
Instruments and Equipment to Have Available
- 1.
Multiple sizes and types of laryngoscopes
- a.
Small-caliber laryngoscopes
- b.
Longer laryngoscopes
- c.
Laryngoscope with anterior “lip”
- a.
- 2.
Small-caliber suction (5, 6, or 7 Fr)
- 3.
Head light box depending on the type of light source
- 4.
Reinforced dental guard to prevent injury to the teeth
- 5.
Rigid telescope(s) versus microscope
- a.
With camera equipment and monitor—especially helpful in teaching situations
- a.
Key Anatomic Landmarks:
- 1.
Superior arcuate line Fig. 4.1
- 2.
