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Introduction: The treatment of bilateral vocal fold paralysis (BVFP) includes cordotomy, suture lateralization, arytenoidectomy, or tracheostomy. Laryngeal pacing, a novel method of treating BVFP, works by direct electrical stimulation of the Posterior Cricoarytenoid Muscle (PCA), thereby resulting in abduction of the vocal fold

Methods: A total of seven patients with iatrogenic BVFP were assessed in the study. The laryngeal pacing patients have previously been published on in 1999. Four patients were in the laryngeal pacing arm and three were in the cordotomy arm. All patients underwent pulmonary function testing (PFTs) for peak inspiratory flow (PIF) measurement as well as voice testing using the GRBAS scale.

Results: Patients in the laryngeal pacing arm had an average PIF of 1.53 L/s, while the cordotomy arm had an average of 1.02 L/s. The average GRBAS of the cordotomy group was 2.66 compared to 1.25 in the laryngeal pacing group.

Discussion: The results of our study show that laryngeal pacing provides an adequate airway while preserving voice in patients with iatrogenic BVFP. The structure of the endolarynx and the true vocal folds is preserved while allowing for functional abduction of the vocal folds through direct electrical stimulation of the PCA muscle.

Conclusions: In a subset of patients who have iatrogenic injury to the RLN and subsequent BVFP, laryngeal pacing may be an option for providing an adequate airway while preserving voice.. With the advent of newer, more reliable NMS devices, an upcoming clinical trial comparing bilateral laryngeal pacing to bilateral cordotomy will hopefully prove the benefit of laryngeal pacing for treatment of BVFP.

Voice and Ventilation: Unilateral Laryngeal Pacing Versus Unilateral Cordotomy for the Treatment of Iatrogenic Bilateral Vocal Fold Paralysis

1Sanjay M. Athavale, MD, 1Yike Li, MD, 1Jennifer Dang, BA, 1,2Bernard Rousseau, PhD, 1,2Thomas Cleveland, PhD,1Cheryl Billante, PhD, 1,2C. Gaelyn Garrett, MD, 1David Zealear, PhD

1Vanderbilt University Medical Center, Department of Otolaryngology - Head and Neck Surgery, 2Vanderbilt Voice Center

The results of our study show that laryngeal pacing provides an adequate airway while preserving voice in patients with BVFP. The structure of the endolarynx and the true vocal folds is preserved while allowing for functional abduction of the vocal folds through direct electrical stimulation of the PCA muscle.

There are several drawbacks to the study presented here. First and foremost, the patients come from two different time points. The pharyngeal pacing patients were done in the mid-1990s and were previously reported in a publication by Zealear et al. The cordotomy patients were analyzed in 2010 and serve as comparisons.

It is worth noting that 3 of the 4 laryngeal pacing patients suffered malfunction of their pacing device that required their inactivation or removal. That being said, all 4 of these patients were candidates for decannulation prior to hard failure of the devices.

Another drawback of this study is that the patients voices were evaluated by two different speech pathologists, since the patients were evaluated at two different time points. However, both speech pathologists were board certified and quite senior.

Overall, laryngeal pacing for the treatment of BVFP has distinct advantages over the current gold standard, and with improved device design will hopefully become the wave of the future.

A total of seven patients were identified, four in the laryngeal pacing arm, and three in the cordotomy arm. All seven patients had undergone a thyroidectomy leading to BVFP. The patients in the laryngeal pacing arm were previously presented in the 2003 article by Zealear et al [6]. The four patients in the cordotomy arm were treated at the Vanderbilt Voice Center since that time. All patients underwent post-operative pulmonary function testing (PFTs) and post-operative voice assessment by a board certified Speech Pathologist. The PFTs were performed to determine the peak inspiratory flow (PIF), a well known marker of inspiratory airway resistance [6]. The speech pathologists specifically analyzed each patients voice and rated the quality of their voice using the GRBAS scale (Table 1) [7].

In a subset of patients who have iatrogenic injury to the RLN and subsequent BVFP, laryngeal pacing may be an option for providing an adequate airway while preserving the voice. The patients that were analyzed in our study were analyzed at two separate time points and most of the patients required inactivation or removal of their laryngeal pacing device. However, with the advent of newer, more reliable NMS devices, an upcoming clinical trial comparing bilateral laryngeal pacing to bilateral cordotomy will hopefully prove the benefit of laryngeal pacing for treatment of BVFP.

Currently, the treatment of bilateral vocal fold paralysis (BVFP) is mediocre at best. Options include cordotomy, suture lateralization, arytenoidectomy, or tracheostomy. The problem with these treatment modalities is that they leave the patient and the otolaryngologist in the uncomfortable position of choosing between good voice and tracheotomy, or a good airway and bad voice [1-3].

Laryngeal pacing, a novel method of treating BVFP, has been studied for several years. Laryngeal pacing works by direct electrical stimulation of the Posterior Cricoarytenoid Muscle (PCA), thereby resulting in abduction of the vocal fold [4]. Laryngeal pacing leaves the endolarynx unharmed and is a functional means of treating BVFP (Figure 1). To date, laryngeal pacing has been studied extensively in the canine model [5]. A study by Zealear et al. in 2003 also proved the validity of the technology in humans [6].

However, to date, there have been no clinical studies comparing laryngeal pacing to the current gold standard of treatment for BVFP, cordotomy (Figure 2). Therefore, we felt it necessary to compare unilateral laryngeal pacing to unilateral CO2 laser cordotomy for the treatment of BVFP.

INTRODUCTION

METHODS

[1] Aynehchi BB, McCoul ED, Sundaram K. Systematic review of laryngeal reinnervation techniques. Otolaryngol Head Neck Surg. 2010 Dec;143(6):749-59.[2] Zealear DL, Billante CR. Neurophysiology of vocal fold paralysis. Otolaryngol Clin North Am. 2004 Feb;37(1):1-23, v.[3] Rubin AD, Sataloff RT. Vocal fold paresis and paralysis. Otolaryngol Clin North Am. 2007 Oct;40(5):1109-31, viii-ix.[4] Katada A, Van Himbergen D, Kunibe I, Nonaka S, Harabuchi Y, Huang S, Billante CR, Zealear DL. Evaluation of a deep brain stimulation electrode for laryngeal pacing. Ann Otol Rhinol Laryngol. 2008 Aug;117(8):621-9.[5] Nomura K, Kunibe I, Katada A, Wright CT, Huang S, Choksi Y, Mainthia R, Billante C, Harabuchi Y, Zealear DL. Bilateral motion restored to the paralyzed canine larynx with implantable stimulator. Laryngoscope. 2010 Dec;120(12):2399-409.[6] Zealear DL, Billante CR, Courey MS, Netterville JL, Paniello RC, Sanders I, Herzon GD, Goding GS, Mann W, Ejnell H, Habets AM, Testerman R, Van de Heyning P. Reanimation of the paralyzed human larynx with an implantable electrical stimulation device. Laryngoscope. 2003 Jul;113(7):1149-56.[7] Kreiman J, Gerratt BR. Validity of rating scale measures of voice quality. J Acoust Soc Am. 1998 Sep;104(3 Pt 1):1598-608.

CONCLUSIONS

DISCUSSIONRESULTS

REFERENCES

Table 4. The destructive nature of cordotomies if evidenced by the poor GRBAS scores in the cordotomy group.

Table 2. The PIF is minimally improved in the cordotomy group, owing to the marginal improvement in the size of the airway with the cordotomy

procedure.

ABSTRACT

Sanjay M. Athavale, M.D.Vanderbilt University Medical CenterDepartment of Otolaryngologysanjay.m.athavale@vanderbilt.edu615-322-5000

CONTACT

Table 3. PIF values in patients with laryngeal pacing devices shows the clear decrease in airway resistance seen with electrical stimulation of the

PCA muscle and lateralization of the vocal cord.

Table 5. The above table shows the excellent voice that patients with laryngeal pacers maintain.

Cordotomy Group

Laryngeal Pacing Group

Table 1. A board certified speech pathologist rated all patients voices using the GRBAS scale seen above.

Table 6. A comparison of the average number of procedures in the cordotomy versus the laryngeal pacing groups shows the unpredictability

of cordotomy for the treatment of BVFP.

Peak Inspiratory Flow (PIF)

Perceptual Analysis of Voice (GRBAS)

Cordotomy Group

Laryngeal Pacing Group

Overall Number of Procedures