Time Course of Recovery of Iatrogenic Vocal Fold Paralysis

Abstract

Objective To clarify the time course of recovery in patients with iatrogenic vocal fold paralysis. Study Design Retrospective chart review. Methods Medical records for all patients with iatrogenic vocal fold paralysis over a 10‐year period were reviewed to obtain demographic and clinical information, including onset of disease and recovery of vocal function. Stroboscopic exams of patients who recovered voice were reviewed blindly to assess return of vocal fold motion. Results One hundred and two patients of 114 (89%) recovered vocal function. Time to recovery could be assessed in 39 patients who did not undergo injection augmentation. The mean time to recovery was 181.8 ± 109.3 days (left: 166.4 ± 106.7 days; right: 221.8 ± 115.6 days; P value = 0.095). Patients were analyzed according to anatomical site of surgery (skull base, carotid endarterectomy, thoracic, neck and intubation); there was no significant difference in time to recovery (P value = 0.60). Twelve of the 39 patients had recovery of vocal fold motion. The mean time to vocal recovery did not differ between patients with return of motion versus no return of motion (140.6 ± 118.0 days vs. 200.1 ± 102.2 days; P value = 0.147). Conclusion Age, gender, laterality, and anatomical site of injury do not influence recovery rate in iatrogenic vocal fold paralysis. The probability of recovery decreases over time but more slowly in comparison with idiopathic vocal fold paralysis, reflecting the greater heterogeneity of injury type in the iatrogenic population. Commonly available aggregate recovery rates overstate the potential for recovery. Level of Evidence 4 Laryngoscope, 129:1159–1163, 2019

Pathophysiology of iatrogenic and idiopathic vocal fold paralysis may be distinct

“…Finally, the reproducible fitting of the vocal recovery data in iatrogenic vocal fold paralysis to the previously described recovery model further supports the notion that in focal axonal injuries, it is the severity of the RLN lesion, not the distance between the lesion and the larynx, that determines the time required for reinnervation . The time‐honored assumption that the farther the injury is from the larynx, the longer the time it takes to recover, has been challenged by theoretical modeling, experimental RLN injury in animal model, and clinical data . Paniello et al showed that a difference of 5 cm in RLN lesion location did not translate into a substantial difference in time to electromyographic recovery in a canine model of RLN injury.…”

“…Paniello et al showed that a difference of 5 cm in RLN lesion location did not translate into a substantial difference in time to electromyographic recovery in a canine model of RLN injury. Tracy et al showed that the vocal fold motion recovery times between those with cervical injuries and thoracic injuries were comparable, a finding echoed by Husain et al The small difference between the median recovery times (2 weeks) in Tracy et al was much less than would have been expected based on the traditional 1 mm/day assumption for the speed of peripheral nerve regeneration, if the distance between the RLN lesion and the larynx determined the recovery time. It is more likely that longer times to recovery reflect more severe RLN injuries and the longer times it takes for repair across the injured segment.…”

“…The study was approved by the institutional review boards of the two respective institutions. Data analyzed in this work include those already published as well as data not previously published. Data collection methods were detailed in the published works and are briefly summarized here.…”

“…Less common causes of vocal fold paralysis, such as sarcoidosis, pulmonary tuberculosis, or Ortner's syndrome would also be considered before the diagnosis of IVFP is made. Despite its nature as a diagnosis of exclusion and cryptic etiology, IVFP may be less heterogeneous than iatrogenic vocal fold paralysis . Common association of IVFP with upper respiratory infections hints at a possible viral pathophysiology, and differences between idiopathic and iatrogenic vocal fold paralysis point to a distinct clinical presentation for IVFP .…”

“…Common association of IVFP with upper respiratory infections hints at a possible viral pathophysiology, and differences between idiopathic and iatrogenic vocal fold paralysis point to a distinct clinical presentation for IVFP . Husain et al showed that the time course of vocal recovery in IVFP follows a different pattern than that of iatrogenic vocal fold paralysis, with higher rates of recovery in the first 5 months in IVFP. Laryngeal electromyographic studies have shown that patients with IVFP have less severe denervation than those with vocal fold paralysis of known causes .…”