Camille Finck

Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: International standards guideline statement

Intraoperative neural monitoring (IONM) during thyroid and parathyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual nerve identification. Despite the increasing use of IONM, review of the literature and clinical experience confirms there is little uniformity in application of and results from nerve monitoring across different centers. We provide a review of the literature and cumulative experience of the multidisciplinary International Neural Monitoring Study Group with IONM spanning nearly 15 years. The study group focused its initial work on formulation of standards in IONM as it relates to important areas: 1) standards of equipment setup/endotracheal tube placement and 2) standards of loss of signal evaluation/intraoperative problem‐solving algorithm. The use of standardized methods and reporting will provide greater uniformity in application of IONM. In addition, this report clarifies the limitations of IONM and helps identify areas where additional research is necessary. This guideline is, at its forefront, quality driven; it is intended to improve the quality of neural monitoring, to translate the best available evidence into clinical practice to promote best practices. We hope this work will minimize inappropriate variations in monitoring rather than to dictate practice options. Laryngoscope, 121:S1–S16, 2011

External branch of the superior laryngeal nerve monitoring during thyroid and parathyroid surgery: International Neural Monitoring Study Group standards guideline statement.

Intraoperative neural monitoring (IONM) during thyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual identification of the recurrent laryngeal nerve (RLN). Contrary to routine dissection of the RLN, most surgeons tend to avoid rather than routinely expose and identify the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy or parathyroidectomy. IONM has the potential to be utilized for identification of the EBSLN and functional assessment of its integrity; therefore, IONM might contribute to voice preservation following thyroidectomy or parathyroidectomy. We reviewed the literature and the cumulative experience of the multidisciplinary International Neural Monitoring Study Group (INMSG) with IONM of the EBSLN. A systematic search of the MEDLINE database (from 1950 to the present) with predefined search terms (EBSLN, superior laryngeal nerve, stimulation, neuromonitoring, identification) was undertaken and supplemented by personal communication between members of the INMSG to identify relevant publications in the field. The hypothesis explored in this review is that the use of a standardized approach to the functional preservation of the EBSLN can be facilitated by application of IONM resulting in improved preservation of voice following thyroidectomy or parathyroidectomy. These guidelines are intended to improve the practice of neural monitoring of the EBSLN during thyroidectomy or parathyroidectomy and to optimize clinical utility of this technique based on available evidence and consensus of experts.

Vocal Impact of a Prolonged Reading Task at Two Intensity Levels: Objective Measurements and Subjective Self-Ratings

OBJECTIVES The objectives of this study are to evaluate the impact on voice of both duration and intensity level of 2 hours of continuous oral reading. Voice modifications accompanying changes in intensity level during prolonged reading tasks are analyzed. METHODS Fifty normophonic women undergo two sessions of voice loading in which the required intensity level of voice varied between 60-65 dB(A) for the first session and 70-75 dB(A) for the second session. The effects of loading on objective data (average fundamental frequency [F0], jitter%, shimmer%, noise-to-harmonic ratio, maximum phonation time, lowest frequency [F-Low], highest frequency [F-High], frequency range [Range], lowest intensity [I-Low] level, and highest intensity level) and self-ratings (voice quality, phonation effort, vocal fatigue, and laryngeal discomfort) are assessed every 30 minutes during the loading tasks. RESULTS Results indicate that average F0, F-Low, I-Low, maximum phonation time, feeling of phonation effort, vocal fatigue, and laryngeal discomfort increase during prolonged reading, whereas shimmer% and self-rating of voice quality decrease. Average F0, F-High, and Range are the only parameters influenced by the required intensity of vocal load; they are significantly higher in the 70- to 75-dB session compared with the 60- to 65-dB session. Concerning the subjective self-ratings, similar results for the four ratings used suggest that only one would suffice in future studies. CONCLUSIONS These results confirm the importance of both duration and intensity level as loading factors, even if intensity level affects fewer variables than duration.

Implantation of esterified hyaluronic acid in microdissected Reinke's space after vocal fold microsurgery: first clinical experiences

Objective: In this pilot study are presented the first clinical experiences of the use of a resorbable bioimplant made of esterified hyaluronic acid inserted in the microdissected superficial layer of the lamina propria (SLLP), also called Reinkes space, after a flap excision procedure for a benign vocal fold lesion. Laryngeal and vocal evolution of implanted patients are depicted and discussed.

Vocal Impact of a Prolonged Reading Task in Dysphonic Versus Normophonic Female Teachers

OBJECTIVES This study evaluates the effect of a 2-hour reading task between 70 and 75 dB(A) in 16 normophonic and 16 dysphonic female teachers with vocal nodules. METHODS Objective measurements (acoustic analysis, voice range measurements, and aerodynamic measurements) and subjective self-ratings were collected before and every 30 minutes during the reading to determine the voice evolution in both groups. RESULTS Fundamental frequency, lowest frequency, highest frequency (F-High), highest intensity, and intensity range increase through the reading, whereas shimmer decreases. Maximum phonation time decreases after 30 minutes. Estimated subglottal pressure (ESP) and sound pressure level increase during the first hour. Afterward, ESP decreases. Self-ratings worsen through time. When comparing the normophonic and the dysphonic teachers, self-ratings reveal more complaints in the dysphonic group. Few differences in objective measurements are found between both groups: normophonic teachers show lower ESP, higher F-High, and greater frequency range. CONCLUSIONS Frequency modifications from acoustic analysis and voice range measurements suggest an increased laryngeal tension during vocal load, while subjects perceive a worsening of voice. Aerodynamic parameters depict first a deterioration of voice efficiency and then an adaptation to the prolonged reading. The comparison between both groups shows a discrepancy between objective measurements and self-ratings, suggesting that both approaches are necessary to have a complete view of vocal load effects. Surprisingly, both groups behave similarly through vocal load, without more or quicker deterioration of voice in the dysphonic group.

Implantation of Esterified Hyaluronic Acid in Microdissected Reinke's Space After Vocal Fold Microsurgery: Short- and Long-Term Results

In this study are reported the laryngeal and vocal results obtained after a microflap excision of benign vocal fold (VF) lesions and immediate implantation of esterified hyaluronic acid (EHA) in the surgical wound. In a previous pilot study on 11 cases, we have shown an excellent tolerance of this bioimplant. The objectives are to confirm the innocuity of the technique, to demonstrate the laryngeal and vocal evolution at short and long term, and to evaluate the eventual positive impact of EHA implantation on the pliability of the superficial layer of the lamina propria (SLLP) and on voice. This is a prospective and comparative study on 83 patients suffering from various benign VF lesions. Thirty-three patients were implanted with EHA, whereas 50 patients did not undergo implantation at the end of the microsurgical procedure. All patients undergo rigid laryngoscopy and microflap excision procedure under general anesthesia. After freeing up of the Reinkes space and creation of a mucosal microflap, a few fibers of EHA are inserted in the surgical wound, before closure of the incision with fibrin glue. Serial laryngeal and vocal assessments are performed in all patients using videostroboscopy (Wolff and Xion), perceptual and objective voice evaluation (MDVP software, Kay Elemetrics), and phonatory function measurements (Aerophone II). Pre- and early postoperative means are compared by analysis of variance. Delayed and long-term evolution of laryngeal and vocal data are compared by means of nonparametric statistical methods. The longest follow-up in the implanted group is 4 years. Early postoperative results are similar in both groups: a significant improvement of a majority of laryngeal and vocal data is observed after microsurgery. In the long term, the two groups exhibit a different behavior: further improvement of voice, as an ongoing process, is only observed in the EHA implanted group, together with improvement of some videostroboscopic characteristics. The nonimplanted group remains stable, with no further improvement of the voice quality obtained after microsurgery. Excellent short- and long-term tolerance of EHA implantation is confirmed by this larger series. The use of EHA implant in microdissected SLLP is safe and leads to good laryngeal and vocal outcomes in the treated patients. More interestingly, treated cases exhibit a continuous improvement over a long period of time.

Voice outcomes of laryngopharyngeal reflux treatment: a systematic review of 1483 patients

The aim of this study is to explore voice quality modifications in laryngopharyngeal reflux (LPR) disease and to understand better the pathophysiological mechanisms underlying the development of communicative disability. Biological Abstracts, BioMed Central, Cochrane database, PubMed and Scopus were assessed for subject headings using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) recommendations. Relevant studies published between January 1990 and December 2015 describing the evaluation of voice quality in LPR disease were retrieved. Issues of clinical relevance, such as LPR diagnosis method, treatment efficacy and outcomes, were evaluated for each study. We determined the grade of recommendation for each publication according to the Oxford Centre for Evidence-Based Medicine evidence levels. The search identified 145 publications, of which 25 studies met the inclusion criteria for a total of 1483 LPR patients. Data were extracted by 2 independent physicians who identified 16 trials with a IIb evidence level, 7 trials with a IIa evidence level and 2 RCTs with a Ib evidence level where 4 patient-based instruments and 5 clinician-based instruments were used. The main voice assessment outcomes reported were hoarseness assessments by physicians or patients, followed by acoustic parameters; 15 and 14 articles, respectively, demonstrated significant improvements in subjective and objective voice assessments after treatment. The methodology used to measure acoustic parameters (i.e. sustained vowel duration, the sample portion choice for measurement, etc.) varied from one study to another. The majority of studies indicated that voice quality assessments (especially acoustic parameters) remain an interesting outcome to measure the effectiveness of treatment, but further studies using standardised and transparent methodology to measure acoustic parameters are necessary to confirm the place of each tool in the LPR disease evaluation.

Laryngopharyngeal Reflux and Voice Disorders: A Multifactorial Model of Etiology and Pathophysiology

OBJECTIVE The aim of this paper is to shed light on the pathogenesis and pathophysiological mechanisms underlying the development of hoarseness related to laryngopharyngeal reflux disease (LPRD). MATERIAL AND METHODS PubMed, Embase, and The Cochrane Library were searched for the terms reflux, laryngopharyngeal, laryngitis, voice, and hoarseness. Experimental and clinical studies providing substantial information about the occurrence of voice disorders, laryngeal histologic changes, or any pathophysiological processes related to LPRD were included by two independent investigators. RESULTS Of the 104 studies reviewed, 47 studies that met our inclusion criteria were analyzed. LPRD leads to significant macroscopic and microscopic histopathologic changes in the mucosa of the vibratory margin of the vocal folds. More and more studies suspect that epithelial cell dehiscence, microtraumas, inflammatory infiltrates, Reinke space dryness, mucosal drying, and epithelial thickening are probably responsible for the hoarseness related to reflux and the impairment of the subjective and objective voice quality evaluations. CONCLUSION Future clinical studies examining the pathophysiology of hoarseness related to LPRD should take into consideration all potential mechanisms involved in the development of hoarseness.

Change of signs, symptoms and voice quality evaluations throughout a 3- to 6-month empirical treatment for laryngopharyngeal reflux disease

To assess the usefulness of voice quality measurements as a treatment outcome in patients with laryngopharyngeal reflux (LPR)‐related symptoms.

Structure and oscillary function of the vocal folds

Abstract Voice can be produced by the vibration of the vocal folds that together form a highly efficient oscillator. Sustained phonation and self-protection against vibratory stresses depend on the histological organization and molecular composition of the folds. Their connective tissue, the lamina propria, has a multilayered structure in humans and other mammalian species. The layered organization determines its biomechanical features. Laryngeal muscles can modify the biomechanical characteristics of the vocal folds, thus permitting the emission of a wide variety of sounds. Laminar organization of human and animal vocal folds is described and their biomechanical properties and relationship with the oscillatory function is explained.