Innervation status in chronic vocal fold paralysis and implications for laryngeal reinnervation.

Treatment options for symptomatic unilateral vocal fold paralysis (VFP) include vocal fold augmentation, laryngeal framework surgery, and laryngeal reinnervation. Laryngeal reinnervation (LR) has been suggested to provide "tone" to the paralyzed VF. This implies a loss of tone as a result of denervation without reinnervation. We performed laryngeal electromyography (LEMG) in patients with chronic VFP to understand the innervation status associated with a chronically paralyzed vocal fold. Retrospective review of LEMG data in adult patients with chronic VFP from January 2009 to December 2014. LEMG was performed at least 6 months after-onset of VFP. Qualitative LEMG, quantitative LEMG, and adductory synkinesis testing were performed, and the parameters were collected. Twenty-seven vocal folds were studied (23 unilateral VFP and 2 bilateral VFP). Average age was 59 ± 17 years. The median duration from recurrent laryngeal nerve injury to LEMG was 8.5 months (range 6-90 months). The majority of patients, 24 of 27 (89%), had motor unit potentials during phonation tasks on LEMG, and only 3 of 27 (11%) patients were electrically silent. Quantitative LEMG showed 287.8 mean turns per second (normal ≥ 400). Motor unit configuration was normal in 12 of 27 (44%), polyphasic in 12 of 27 (44%), and absent in the electrically silent patients. Adductory synkinesis was found in 6 of 20 (30%) patients. Chronic vocal fold paralysis is infrequently associated with absent motor-unit recruitment, indicating some degree of preserved innervation and/or reinnervation in these patients. LEMG should be part of the routine workup for chronic VFP prior to consideration of LR. 4. Laryngoscope, 128:1628-1633, 2018.

Lin RJ ，Smith LJ ，Munin MC ，Sridharan S ，Rosen CA ... -  《-》

Effect of intralaryngeal muscle synkinesis on perception of voice handicap in patients with unilateral vocal fold paralysis.

Intralaryngeal muscle synkinesis associated with unilateral vocal fold paralysis (UVFP) is thought to preserve thyroarytenoid-lateral cricoarytenoid muscle complex tone, resulting in a better voice despite the presence of vocal fold paralysis (VFP). This study compares voice handicap in patients with unilateral VFP (UVFP) with and without evidence of adductory synkinesis on laryngeal electromyography (LEMG). Retrospective review of LEMG data and Voice Handicap Index-10 (VHI-10) scores of patients diagnosed with permanent UVFP. LEMG was performed within 1 to 6 months post onset of UVFP. Patients were stratified into two groups: 1) recurrent laryngeal nerve (RLN) neuropathy with synkinesis and 2) RLN neuropathy without synkinesis. Synkinesis was diagnosed when the sniff to phonation maximum amplitude ratio was ≥0.65. VHI-10 scores at 6-month follow-up were recorded. Four hundred forty-nine patients with UVFP and who had an LEMG were reviewed. Eighty-three patients met the inclusion criteria, with 16 in group 1 and 67 in group 2. There was no significant difference between the groups with regard to age, timing of LEMG from onset of VFP, number of patients undergoing temporary vocal fold injection or use of off-label nimodipine. Average VHI-10 scores at 6 months post onset of VFP were 14.4 ± 10.6 for patients with LEMG-identified synkinesis (group 1) and 21.0 ± 10.1 for patients with no LEMG evidence of synkinesis (group 2). This was statistically significant (P = .02). Patients with unilateral vocal fold paralysis and LEMG evidence of laryngeal synkinesis are more likely to have less perceived voice handicap than those without synkinesis. 4. Laryngoscope, 127:1628-1632, 2017.

Lin RJ ，Munin MC ，Rosen CA ，Smith LJ ... -  《-》

Electromyographic laryngeal synkinesis alters prognosis in vocal fold paralysis.

Statham MM ，Rosen CA ，Smith LJ ，Munin MC ... -  《-》

Vocal fold motion outcome based on excellent prognosis with laryngeal electromyography.

As laryngeal electromyography (LEMG) becomes more refined, accurate predictions of vocal fold motion recovery are possible. Focus has been on outcomes for patients with poor prognosis for vocal fold motion recovery. Limited information is available regarding the expected rate of purposeful vocal fold motion recovery when there is good to normal motor recruitment, no signs of denervation, and no signs of synkinetic activity with LEMG, termed excellent prognosis. The objective of this study is to determine the rate of vocal fold motion recovery with excellent prognosis findings on LEMG after acute recurrent laryngeal nerve injury. Retrospective review. Patients undergoing a standardized LEMG protocol, consisting of qualitative (evaluation of motor recruitment, motor unit configuration, detection of fibrillations, presence of synkinesis) and quantitative (turns analysis) measurements were evaluated for purposeful vocal-fold motion recovery, calculated after at least 6 months since onset of injury. Twenty-three patients who underwent LEMG for acute vocal fold paralysis met the inclusion criteria of excellent prognosis. Eighteen patients (78.3%) recovered vocal fold motion, as determined by flexible laryngoscopy. Nearly 80% of patients determined to have excellent prognosis for vocal fold motion recovery experienced return of vocal fold motion. This information will help clinicians not only counsel their patients on expectations but will also help guide treatment. 4. Laryngoscope, 126:2310-2314, 2016.

Smith LJ ，Rosen CA ，Munin MC 《-》

Crumley's Classification of Laryngeal Synkinesis: A Comparison of Laryngoscopy and Electromyography.

Applying the principles of misdirected nerve regeneration to the larynx, Roger Crumley in 1989 coined the term laryngeal synkinesis (LS) which he later (2000) classified into 4 types (type I - good voice, type II - involuntary twitches and poor voice, type III - adduction during inspiration, type IV - abduction during phonation). Neurophysiological data were not available for all LS patients at that time. The current study was undertaken to utilize and test the Crumley classification for a clinical interrater comparison and, secondly, compare predicted with actual laryngeal electromyography (LEMG) results. Descriptive study. Laryngoscopic and LEMG data of patients with unilateral vocal fold paralysis (VFP) of 6 months duration or longer were combined for retrospective evaluation. Forty-five data sets were available for laryngoscopic classification by two local laryngologists and by Roger Crumley. Twenty-three data sets with complete thyroarytenoid (TA) and posterior cricoarytenoid (PCA) - EMG data were used to compare predicted with actual LEMG results. Local laryngologists were able to classify 24 of 45, Crumley 30 of 45 cases into one of the 4 synkinesis types. There was substantial agreement between examiners (Cohens Kappa 0.66 [P < .001]). Comparison of predicted and actual LEMG data showed only moderate agreement. EMG sykinesis rates were lower in TA than in PCA and highest in Crumley type I cases. The Crumley classification is helpful in describing and understanding synkinesis. It does not always correlate predictably with actual LEMG data. A complete LEMG mapping of all intrinsic muscles may improve understanding of chronic VFP. 4. Laryngoscope, 131:E1605-E1610, 2021.

Foerster G ，Podema R ，Guntinas-Lichius O ，Crumley RL ，Mueller AH ... -  《-》