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

Abstract

Objectives/Hypothesis 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. Study Design Descriptive study. Methods 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. 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. Conclusion 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. Level of Evidence 4. Laryngoscope, 131:E1605–E1610, 2021

A comparative analysis of laryngeal nerve damage in patients with idiopathic vocal cord paralysis exhibiting different paralytic sides

“…Conversely, regenerative potential was more commonly observed in patients with a disease duration exceeding 3 months. 18 That is also the reason why The involvement of SLN and CM in IVCP is a topic of interest.…”

“…It was found that denervated potential was frequently observed in the PCM and TM of patients with unilateral vocal cord paralysis who had a disease duration of 1–3 months, and our findings indicate that the average disease duration of IVCP patients with paralysis on the left or right side was similar (nearly 45 days), and both of them were less than 3 months. Conversely, regenerative potential was more commonly observed in patients with a disease duration exceeding 3 months 18 . That is also the reason why we chose 3 months as a differentiation point for disease course to analyze the differences of voice indicators and LEMG results in IVCP patients with left or right vocal fold paralysis.…”

“…Conversely, regenerative potential was more commonly observed in patients with a disease duration exceeding 3 months. 18 That is also the reason why we chose 3 months as a differentiation point for disease course to analyze the differences of voice indicators and LEMG results in IVCP patients with left or right vocal fold paralysis. Husain et al found that two‐thirds of patients with IVCP recovered vocal function within 6 months of onset, and laterality, age and gender, did not influence recovery rate.…”

Selective Electrical Surface Stimulation to Support Functional Recovery in the Early Phase After Unilateral Acute Facial Nerve or Vocal Fold Paralysis

“…This is important, since the patterns of synkinetic reinnervation in the larynx seem to be etiology-dependent. The rates of synkinetic activity in the posterior cricoarytenoid (PCA) muscle in comparison to the thyroarytenoid (TA) muscle are different dependent on the etiology ( 31 ), and the laryngoscopic classification might be different from the EMG classification ( 32 ). As it is the case for facial nerve injuries, not much is known about the time course of the laryngeal muscle atrophy.…”