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Botox in the management of bilateral vocal cord synkinesis
Operative Techniques in Otolaryngology (2012) 23, 92-95
Botox in the management of bilateral vocal cord synkinesis Todd G. Dray, MD From the Department #296, Head and Neck Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, California. KEYWORDS Botox; Synkinesis; Bilateral vocal cord; Laryngeal; Paralysis
Botox is a non-invasive treatment option to improve glottic laryngeal opening in the case of laryngeal synkinesis. © 2012 Elsevier Inc. All rights reserved.
Impaired bilateral vocal cord mobility is less common than its unilateral counterpart. The etiology of this finding is often known on presentation to the otolaryngologist, and in instances when it is not, a thorough head and neck examination, accompanied by a neurological evaluation, nearly always identifies the basis for the problem. Impaired bilateral mobility may result from bilateral vocal cord paralysis/paresis, cricoarytenoid joint ankyloses or dislocations, vocal cord infiltrative lesions, glottic webs, and laryngeal synkinesis. Laryngeal electromyography (LEMG) will permit the differentiation between vocal cord paralysis/paresis, laryngeal fixation, and synkinetic activity of the laryngeal muscles.1 Synkinesis is defined by Blitzer et al2 as the unintentional movement accompanying a volitional movement; this simultaneous contraction of muscles that usually has independent neural stimulation is related to misdirected reinnervation of muscles. Maronian et al3 presented a new awake, needle EMG-based definition of laryngeal synkinesis: synkinesis of the thyroarytenoid muscle is recruitment during a sniff that is greater than or equal to recruitment during “eee”s. Damrose et al4 observed that patients with unilateral vocal cord paralysis who require treatment do not have synkinesis produced by recurrent laryngeal nerve reinnervation. The unilateral cords atrophy and remain flaccid, Address reprint requests and correspondence: Todd G. Dray, MD, Department #296, Head and Neck Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA 95051-5173. E-mail address: [email protected]. 1043-1810/$ -see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2011.11.003
unable to position the vocal process near midline, as opposed to those vocal cords that develop synkinetic reinnervation. Azadarmaki et al5 and Woo et al6 have demonstrated that the rare case of upper airway obstruction from unilateral true vocal cord paralysis may be successfully treated with botulinum toxin. Later work confirmed previous findings by Marie et al7 that bilateral vocal cord synkinesis responds better to botulinum toxin compared with unilateral synkinesis. It represents a nondestructive treatment option, instead of invasive surgeries that compromise the voice.3 It enables the otolaryngologist to selectively neutralize adductory tone in larynges where simultaneous isometric contraction of antagonistic muscles of the larynx causes vocal cord immobility, thus allowing any abductory tone that is present to manifest.
Indications After the diagnosis of bilateral vocal cord, or laryngeal, synkinesis is established with laryngeal EMG, the otolaryngologist has the opportunity to use botulinum toxin injections in the treatment of upper airway obstruction symptoms. Not every patient with bilateral vocal cord immobility secondary to synkinesis needs airway intervention; however, for those who are tracheostomy dependent or for patients whose trips to the emergency room suggest impending upper airway obstruction, botulinum toxin injections should be considered as a treatment option.
Dray
Botox in the Management of Bilateral Vocal Cord Synkinesis
Figure 1 Example of an electromyographic (EMG) recording, demonstrating equal thyroarytenoid muscle recruitment during “eee” and sniff.
The patient should have a flexible fiberoptic laryngoscopy to confirm glottic narrowing secondary to vocal cord immobility, carefully noting any degree of lateral movement on either side. Monopolar LEMG should confirm synkinesis (Figure 1). Both vocal cords should be studied, and the level of recruitment of muscle unit action potentials related to adductory synkinesis should be compared. Often, only one vocal cord needs to be injected, which is fortunate, given that even a small amount of vocal cord edema will further compromise the airway. In choosing which vocal cord to inject, the first option is the side that demonstrates the greater level of synkinesis, as this vocal cord likely will abduct more when the adductory forces are neutralized. If both vocal cords show the same degree of adductory synkinesis on LEMG or it cannot be determined, then the vocal cord with any degree of lateral or abductory movement should be chosen. Pulmonary medicine consultation should be considered to rule out significant lower airway disease. The marginal upper airway improvement from botulinum toxin injections will generally not help the patient if there is lower airway comorbidity. In these instances, a different intervention like laser vocal cordotomy or tracheostomy is appropriate.
93
CT approach is the very clear distinction between the intratracheal air signal and the intramuscular signal, as the needle is advanced into the vocal cord. With the CT approach, the EMG needle is advanced through the CT membrane in the midline. After an air signal is detected, the needle is advanced 1-2 mm and then directed superiorly at a 45 degree angle and slowly advanced (Figure 3). The submucosal approach differs in that the needle is positioned just lateral to midline on the ipsilateral side. The EMG needle is advanced immediately under the thyroid cartilage, slightly laterally and superiorly until corresponding muscle unit action potentials are noted (Figure 4). Generally, the needle does not need to be advanced as deeply with the submucosal approach (Figure 4). A 27-gauge monopolar botulinum toxin needle (Allergan Inc, Irvine, CA) is used, and continuous EMG activity is followed and recorded. Sensitivities of 200-500 V per division and sweep speeds of 200 ms per division for the recordings from the electromyographic instrumentation are used. The surface reference disk electrode and the surface ground disk electrode are placed on the clavicle and sternum, respectively. The range of botulinum toxin type A (Allergan Inc) doses is 1-10 U. The average adult dose for this indication in my practice is 3 U, unilaterally. The concentration of botulinum toxin is 25 U per mL, similar to that used for most spasmodic dysphonia patients. This results in an average volume of 0.12 mL per injection. The main doselimiting factor is side effects. Too large a dose will cause dysphagia and breathy hoarseness. After a conservative first injection with 2.5 U, the patient can assist with weighing the pros and cons of increasing the subsequent dosages. Increasing the botulinum toxin dose, injecting the opposite vocal cord, and performing bilateral injections are all measures
Technique The patient and the clinic should be prepared for airway support during these injections. The patient is positioned as one does for LEMG and botulinum toxin injections for spasmodic dysphonia (Figure 2). Local subcutaneous and transtracheal 2% lidocaine hydrochloride administration may be used to minimize the risk of laryngospasm. One’s favorite approach to the vocal cord may be chosen— either submucosal or cricothyroid (CT). The submucosal approach is less stimulating and traumatic, whereas the advantage of
Figure 2 Patient positioning for laryngeal EMG and botulinum injections, with neck extended.
94
Operative Techniques in Otolaryngology, Vol 23, No 2, June 2012 Full respiratory support, including the ability to intubate the patient, should be available. One of the most important precautions to be observed before the procedure though is that patients must be chosen carefully. Patients with concomitant lower respiratory disease will likely benefit from a tracheostomy rather than laryngeal botulinum toxin injections. Patients who prefer definitive treatment rather than periodic botulinum toxin injections should be offered tracheostomy, laser vocal cordotomy, or other management. However, for patients who do not need immediate upper airway obstruction relief and prefer not to risk permanent voice change, botulinum toxin injections are a good option when they are symptomatic from bilateral vocal cord immobility and synkinesis.
Outcomes Good outcomes may take several forms. For patients with bilateral vocal cord immobility and tracheostomy dependency, success includes the ability to cap the tracheostomy tube and decannulation. For nontracheostomy patients, a good outcome includes improved tidal volumes and peak flows and avoiding emergency room visits, courses of steroids, and invasive procedures. In my practice, I have treated 3 children and 6 adults with botulinum toxin for their laryngeal synkinesis, for a total of
Figure 3 (A) Cricothyroid approach with needle in the membrane at the midline. (B) Cricothyroid approach—anterior view.
that may be pursued if the patient is not responding to the treatment approach.
Precautions As mentioned previously, airway precautions should be observed in the space in which the injections are performed.
Figure 4
EMG needle under the thyroid cartilage.
Dray
Botox in the Management of Bilateral Vocal Cord Synkinesis
65 injections. The children’s EMGs and some of their botulinum toxin injections were performed in the operating room. The average dose for the children was 1.5 U and for the adults was 3.0 U. There have been no airway complications requiring hospital treatment, although an occasional course of prednisone has been prescribed postinjection, as a precaution. All patients have improved subjectively. The children’s parents describe less stridor and restriction with playful exertion. The adults follow peak flows daily or weekly, which demonstrate the improvement in laryngeal airflow and notify them when the botulinum toxin effect is waning. Despite improvement in their condition, 2 patients ultimately opted for vocal cordotomy to pursue definitive treatment. No patients in this cohort have needed, or opted for, tracheostomy.
Conclusions Many cases of bilateral vocal cord immobility that are assumed to be secondary to paralysis are in reality laryngeal synkinesis. Using laryngeal EMG, the otolaryngologist may confirm this diagnosis and take advantage of the synkinetic activity by counteracting the adductory muscle forces with
95
botulinum toxin. The improvement in the glottic laryngeal opening affords some patients a noninvasive treatment option and has proven to be safe and effective.
References 1. Dray TG, Robinson LR, Hillel AD: Idiopathic bilateral vocal fold weakness. Laryngoscope 109:995-1002, 1999 2. Blitzer A, Jahn AF, Keidar A: Semon’s law revisited: An electromyographic analysis of laryngeal synkinesis. Ann Otol Rhinol Laryngol 105:964-969, 1996 3. Maronian NC, Robinson L, Waugh P, et al: A new electromyographic definition of laryngeal synkinesis. Ann Otol Rhinol Laryngol 113:877886, 2004 4. Damrose EJ, Huang RY, Blumin JH, et al: Lack of evoked laryngeal electromyography response in patients with a clinical diagnosis of vocal cord paralysis. Ann Otol Rhinol Laryngol 110:815-819, 2001 5. Azadarmaki R, Mirza N, Soliman AM: Unilateral true vocal fold synkinesis presenting with airway obstruction. Ann Otol Rhinol Laryngol 118:587-591, 2009 6. Woo P, Mangaro M: Aberrant recurrent laryngeal nerve reinnervation as a cause of stridor and laryngospasm. Ann Otol Rhinol Laryngol 113:805-808, 2004 7. Marie JP, Navarre I, Lerosey Y, et al: Bilateral laryngeal movement disorder and synkinesia: Value of botulism toxin. Apropos a case. Rev Laryngol Otol Rhinol (Bord) 119:261-264, 1998
Botox in the management of bilateral vocal cord synkinesis Todd G. Dray, MD From the Department #296, Head and Neck Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, California. KEYWORDS Botox; Synkinesis; Bilateral vocal cord; Laryngeal; Paralysis
Botox is a non-invasive treatment option to improve glottic laryngeal opening in the case of laryngeal synkinesis. © 2012 Elsevier Inc. All rights reserved.
Impaired bilateral vocal cord mobility is less common than its unilateral counterpart. The etiology of this finding is often known on presentation to the otolaryngologist, and in instances when it is not, a thorough head and neck examination, accompanied by a neurological evaluation, nearly always identifies the basis for the problem. Impaired bilateral mobility may result from bilateral vocal cord paralysis/paresis, cricoarytenoid joint ankyloses or dislocations, vocal cord infiltrative lesions, glottic webs, and laryngeal synkinesis. Laryngeal electromyography (LEMG) will permit the differentiation between vocal cord paralysis/paresis, laryngeal fixation, and synkinetic activity of the laryngeal muscles.1 Synkinesis is defined by Blitzer et al2 as the unintentional movement accompanying a volitional movement; this simultaneous contraction of muscles that usually has independent neural stimulation is related to misdirected reinnervation of muscles. Maronian et al3 presented a new awake, needle EMG-based definition of laryngeal synkinesis: synkinesis of the thyroarytenoid muscle is recruitment during a sniff that is greater than or equal to recruitment during “eee”s. Damrose et al4 observed that patients with unilateral vocal cord paralysis who require treatment do not have synkinesis produced by recurrent laryngeal nerve reinnervation. The unilateral cords atrophy and remain flaccid, Address reprint requests and correspondence: Todd G. Dray, MD, Department #296, Head and Neck Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA 95051-5173. E-mail address: [email protected]. 1043-1810/$ -see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2011.11.003
unable to position the vocal process near midline, as opposed to those vocal cords that develop synkinetic reinnervation. Azadarmaki et al5 and Woo et al6 have demonstrated that the rare case of upper airway obstruction from unilateral true vocal cord paralysis may be successfully treated with botulinum toxin. Later work confirmed previous findings by Marie et al7 that bilateral vocal cord synkinesis responds better to botulinum toxin compared with unilateral synkinesis. It represents a nondestructive treatment option, instead of invasive surgeries that compromise the voice.3 It enables the otolaryngologist to selectively neutralize adductory tone in larynges where simultaneous isometric contraction of antagonistic muscles of the larynx causes vocal cord immobility, thus allowing any abductory tone that is present to manifest.
Indications After the diagnosis of bilateral vocal cord, or laryngeal, synkinesis is established with laryngeal EMG, the otolaryngologist has the opportunity to use botulinum toxin injections in the treatment of upper airway obstruction symptoms. Not every patient with bilateral vocal cord immobility secondary to synkinesis needs airway intervention; however, for those who are tracheostomy dependent or for patients whose trips to the emergency room suggest impending upper airway obstruction, botulinum toxin injections should be considered as a treatment option.
Dray
Botox in the Management of Bilateral Vocal Cord Synkinesis
Figure 1 Example of an electromyographic (EMG) recording, demonstrating equal thyroarytenoid muscle recruitment during “eee” and sniff.
The patient should have a flexible fiberoptic laryngoscopy to confirm glottic narrowing secondary to vocal cord immobility, carefully noting any degree of lateral movement on either side. Monopolar LEMG should confirm synkinesis (Figure 1). Both vocal cords should be studied, and the level of recruitment of muscle unit action potentials related to adductory synkinesis should be compared. Often, only one vocal cord needs to be injected, which is fortunate, given that even a small amount of vocal cord edema will further compromise the airway. In choosing which vocal cord to inject, the first option is the side that demonstrates the greater level of synkinesis, as this vocal cord likely will abduct more when the adductory forces are neutralized. If both vocal cords show the same degree of adductory synkinesis on LEMG or it cannot be determined, then the vocal cord with any degree of lateral or abductory movement should be chosen. Pulmonary medicine consultation should be considered to rule out significant lower airway disease. The marginal upper airway improvement from botulinum toxin injections will generally not help the patient if there is lower airway comorbidity. In these instances, a different intervention like laser vocal cordotomy or tracheostomy is appropriate.
93
CT approach is the very clear distinction between the intratracheal air signal and the intramuscular signal, as the needle is advanced into the vocal cord. With the CT approach, the EMG needle is advanced through the CT membrane in the midline. After an air signal is detected, the needle is advanced 1-2 mm and then directed superiorly at a 45 degree angle and slowly advanced (Figure 3). The submucosal approach differs in that the needle is positioned just lateral to midline on the ipsilateral side. The EMG needle is advanced immediately under the thyroid cartilage, slightly laterally and superiorly until corresponding muscle unit action potentials are noted (Figure 4). Generally, the needle does not need to be advanced as deeply with the submucosal approach (Figure 4). A 27-gauge monopolar botulinum toxin needle (Allergan Inc, Irvine, CA) is used, and continuous EMG activity is followed and recorded. Sensitivities of 200-500 V per division and sweep speeds of 200 ms per division for the recordings from the electromyographic instrumentation are used. The surface reference disk electrode and the surface ground disk electrode are placed on the clavicle and sternum, respectively. The range of botulinum toxin type A (Allergan Inc) doses is 1-10 U. The average adult dose for this indication in my practice is 3 U, unilaterally. The concentration of botulinum toxin is 25 U per mL, similar to that used for most spasmodic dysphonia patients. This results in an average volume of 0.12 mL per injection. The main doselimiting factor is side effects. Too large a dose will cause dysphagia and breathy hoarseness. After a conservative first injection with 2.5 U, the patient can assist with weighing the pros and cons of increasing the subsequent dosages. Increasing the botulinum toxin dose, injecting the opposite vocal cord, and performing bilateral injections are all measures
Technique The patient and the clinic should be prepared for airway support during these injections. The patient is positioned as one does for LEMG and botulinum toxin injections for spasmodic dysphonia (Figure 2). Local subcutaneous and transtracheal 2% lidocaine hydrochloride administration may be used to minimize the risk of laryngospasm. One’s favorite approach to the vocal cord may be chosen— either submucosal or cricothyroid (CT). The submucosal approach is less stimulating and traumatic, whereas the advantage of
Figure 2 Patient positioning for laryngeal EMG and botulinum injections, with neck extended.
94
Operative Techniques in Otolaryngology, Vol 23, No 2, June 2012 Full respiratory support, including the ability to intubate the patient, should be available. One of the most important precautions to be observed before the procedure though is that patients must be chosen carefully. Patients with concomitant lower respiratory disease will likely benefit from a tracheostomy rather than laryngeal botulinum toxin injections. Patients who prefer definitive treatment rather than periodic botulinum toxin injections should be offered tracheostomy, laser vocal cordotomy, or other management. However, for patients who do not need immediate upper airway obstruction relief and prefer not to risk permanent voice change, botulinum toxin injections are a good option when they are symptomatic from bilateral vocal cord immobility and synkinesis.
Outcomes Good outcomes may take several forms. For patients with bilateral vocal cord immobility and tracheostomy dependency, success includes the ability to cap the tracheostomy tube and decannulation. For nontracheostomy patients, a good outcome includes improved tidal volumes and peak flows and avoiding emergency room visits, courses of steroids, and invasive procedures. In my practice, I have treated 3 children and 6 adults with botulinum toxin for their laryngeal synkinesis, for a total of
Figure 3 (A) Cricothyroid approach with needle in the membrane at the midline. (B) Cricothyroid approach—anterior view.
that may be pursued if the patient is not responding to the treatment approach.
Precautions As mentioned previously, airway precautions should be observed in the space in which the injections are performed.
Figure 4
EMG needle under the thyroid cartilage.
Dray
Botox in the Management of Bilateral Vocal Cord Synkinesis
65 injections. The children’s EMGs and some of their botulinum toxin injections were performed in the operating room. The average dose for the children was 1.5 U and for the adults was 3.0 U. There have been no airway complications requiring hospital treatment, although an occasional course of prednisone has been prescribed postinjection, as a precaution. All patients have improved subjectively. The children’s parents describe less stridor and restriction with playful exertion. The adults follow peak flows daily or weekly, which demonstrate the improvement in laryngeal airflow and notify them when the botulinum toxin effect is waning. Despite improvement in their condition, 2 patients ultimately opted for vocal cordotomy to pursue definitive treatment. No patients in this cohort have needed, or opted for, tracheostomy.
Conclusions Many cases of bilateral vocal cord immobility that are assumed to be secondary to paralysis are in reality laryngeal synkinesis. Using laryngeal EMG, the otolaryngologist may confirm this diagnosis and take advantage of the synkinetic activity by counteracting the adductory muscle forces with
95
botulinum toxin. The improvement in the glottic laryngeal opening affords some patients a noninvasive treatment option and has proven to be safe and effective.
References 1. Dray TG, Robinson LR, Hillel AD: Idiopathic bilateral vocal fold weakness. Laryngoscope 109:995-1002, 1999 2. Blitzer A, Jahn AF, Keidar A: Semon’s law revisited: An electromyographic analysis of laryngeal synkinesis. Ann Otol Rhinol Laryngol 105:964-969, 1996 3. Maronian NC, Robinson L, Waugh P, et al: A new electromyographic definition of laryngeal synkinesis. Ann Otol Rhinol Laryngol 113:877886, 2004 4. Damrose EJ, Huang RY, Blumin JH, et al: Lack of evoked laryngeal electromyography response in patients with a clinical diagnosis of vocal cord paralysis. Ann Otol Rhinol Laryngol 110:815-819, 2001 5. Azadarmaki R, Mirza N, Soliman AM: Unilateral true vocal fold synkinesis presenting with airway obstruction. Ann Otol Rhinol Laryngol 118:587-591, 2009 6. Woo P, Mangaro M: Aberrant recurrent laryngeal nerve reinnervation as a cause of stridor and laryngospasm. Ann Otol Rhinol Laryngol 113:805-808, 2004 7. Marie JP, Navarre I, Lerosey Y, et al: Bilateral laryngeal movement disorder and synkinesia: Value of botulism toxin. Apropos a case. Rev Laryngol Otol Rhinol (Bord) 119:261-264, 1998