The Role of Continuous Positive Airway Pressure in Acute Bilateral Vocal Cord Paresis or Paralysis Post-Thyroidectomy.

OBJECTIVES: Acute post-thyroidectomy bilateral vocal cord paresis or paralysis (BVCP) is often managed with observation, botulinum toxin injection or tracheostomy. However, only a few cases discuss obstructive sleep apnea (OSA) in the context of BVCP with limited exploration of home sleep test (HST) and continuous positive airway pressure (CPAP) as post-operative assessment and management tools. This study suggests CPAP as a less invasive approach while awaiting vocal cord recovery. METHODS: A retrospective chart review was conducted on 2 female patients who presented with dyspnea and sleep-disordered breathing (SDB) symptoms post-thyroidectomy. Both patients underwent laryngoscopy and HSTs, followed by CPAP prescription. RESULTS: Case 1 (body mass index [BMI]: 32.6 kg/m2) and Case 2 (BMI: 20.1 kg/m2), aged 66 and 77 respectively, presented with post-surgery dyspnea and SDB symptoms. Laryngoscopy revealed left vocal cord paresis and right vocal cord paralysis in both cases. Although tracheostomy could provide definitive treatment, both cases were deferred for non-invasive options, which led to HST, confirming moderate OSA (PAT-derived apnea-hypopnea index (pAHI): 18/hour and 27.1/hour) leading to CPAP recommendation. In Case 2, 5 weeks of CPAP use resulted in dramatic improvements in her sleep quality, with continued benefits at 3-month follow-up. CONCLUSION: These cases underscore the value of considering sleep studies and CPAP as adjunctive tools in acute post-thyroidectomy BVCP management while awaiting vocal motion recovery. This report also further supports that BVCP sufficiently narrows the glottic airway, predisposing patients to OSA.

Additional injection laryngoplasty as a salvage treatment for unilateral vocal fold paralysis.

OBJECTIVES: Injection laryngoplasty (IL) has been widely used as an initial treatment option for unilateral vocal fold paralysis (UVFP). An additional (second) IL is considered a salvage treatment for unsatisfactory outcomes of initial IL resulting from inadequate injection or early resorption of the injection material. This study aims to evaluate the efficacy of additional IL, distinguishing between "salvage" (within 4 months) and "repeated" injections (beyond 4 months), and to analyze prognostic factors for successful outcomes. METHODS: This retrospective study involved patients who received IL at Asan Medical Center from January 2014 to December 2020. Voice parameters were collected after each procedure, and those who conducted the statistical analysis were blinded to the study subjects. Among the 65 patients who underwent additional IL, 51 patients were enrolled in this study. Postinjection grade, roughness, breathiness, asthenia, strain (GRBAS) scales were used to determine satisfactory treatment outcomes. Success of the additional IL was defined as a postinjection grade of dysphonia score of 0 or 1, with a reduction in grade compared with the preinjection grade. RESULTS: The mean age of the patients was 61.6 years. Out of a total of 51 patients, 37 were men participating in the study. The odds ratio represents the likelihood of success in the second IL. Improved voice outcome after the additional IL was maintained in 23 (45%) patients. Compared with the failure group, the success group had a longer injection time interval between the initial and additional injection (9.1 vs. 7.4 months, respectively, p = 0.010). The success group had a higher proportion of patients with injection intervals >6 months (73.9% vs. 42.9%, p = 0.026). Logistic regression analysis revealed an injection interval >6 months had an odds ratio of 0.265 (confidence interval: 0.080-0.874, p = 0.029). CONCLUSIONS: Additional injections would benefit the patients whose voice outcomes are maintained for a longer period (>6 months) after the first injection.

Assessment of Voice Quality and Vocal Cord Paralysis After Endarterectomy.

Introduction: Recurrent laryngeal nerve palsy is a rare but important complication after endarterectomy (CEA). The impact on voice quality after this procedure is also important. The aim of the study was to assess voice quality and vocal cord function after CEA. Material and Methods: 200 patients were enrolled in the study. Inclusion criteria were indications for CEA and patient consent to the procedure. Endoscopic examination of the larynx was performed before the procedure, immediately after the procedure, on the 2nd day after the procedure, then 3 month and 6 months after the procedure. Voice was assessed by maximum phonation time (MPT), GRBAS scale, Voice Handicap Index (VHI) and the Voice-Related Quality of Life (V-RQOL) questionnaire. Results: In the study group, the results on the GRBAS scale were significantly worse and the average MPT was shorter compared to the control group. In the V-RQOL assessment, patients rated their voice as fair or good, significantly more often noticed that they had difficulty speaking loudly and being heard, and that they felt short of air when speaking. In VHI-30, the total score was significantly higher in the study group compared to the control group. Voice disorders after the procedure were reported by 68 patients, while a disorder of the recurrent laryngeal nerve was observed immediately after the procedure in 32 patients. Most vocal cord disorders were transient. Ultimately, 3% of patients were diagnosed with vocal cord paralysis. Conclusion: Cranial nerves paralysis, including the recurrent laryngeal nerve, are a common complication after CEA. Majority the paralysis is transient, but requires appropriate diagnostic and therapeutic procedures. Vocal cord evaluation is a non-invasive and widely available examination and should be performed pre- and postoperatively after all neck surgeries. The incidence of voice disorders after CEA significantly affects the quality of life of patients and requires voice rehabilitation and patient care with psychological support.

Asymmetric triangular body-cover model of the vocal folds with bilateral intrinsic muscle activation.

Many voice disorders are linked to imbalanced muscle activity and known to exhibit asymmetric vocal fold vibration. However, the relation between imbalanced muscle activation and asymmetric vocal fold vibration is not well understood. This study introduces an asymmetric triangular body-cover model of the vocal folds, controlled by the activation of bilateral intrinsic laryngeal muscles, to investigate the effects of muscle imbalance on vocal fold oscillation. Various scenarios were considered, encompassing imbalance in individual muscles and muscle pairs, as well as accounting for asymmetry in lumped element parameters. Measurements of amplitude and phase asymmetries were employed to match the oscillatory behavior of two pathological cases: unilateral paralysis and muscle tension dysphonia. The resulting simulations exhibit muscle imbalance consistent with expectations in the composition of these voice disorders, yielding asymmetries exceeding 30% for paralysis and below 5% for dysphonia. This underscores the relevance of muscle imbalance in representing phonatory scenarios and its potential for characterizing asymmetry in vocal fold vibration.

Stimulated Vocal Fold Immobility After Vagal Nerve Stimulator Placement: A Case Series.

INTRODUCTION: Vagal nerve stimulator (VNS) implantation is a vital therapy for epilepsy refractory to other treatments; however, it is associated with a very high rate of voice changes. Relatively few of these patients are evaluated for vocal fold motion impairments. In this series, we evaluate 5 such patients with a novel phenotype of forced abduction with VNS stimulation. METHODS: Retrospective case series. RESULTS: Five patients with a VNS implant who underwent operative direct or in-office rigid laryngoscopy and had vocal fold motion impairment associated with VNS activation are included. All 5 patients had vocal fold mobility with VNS off and a fixed with activation. All patients exhibited vocal fold abduction with VNS activation. Patient 2 has since undergone laryngeal reinnervation, which helped her intermittent dysphonia but left a small glottic gap. A type 1 thyroplasty corrected this gap and improved her voice further. Patient 3 has undergone laryngeal reinnervation for which early results show improvement in perceptual and patient reported outcomes. Patients 4 and 5 have both undergone laryngeal reinnervation with improvement in voice. CONCLUSION: Previous reported cases of stimulated immobility associated with VNS use describe only adduction of the vocal fold. This series expands the previous work showing the VNS activation can also cause stimulated immobility in an abducted position, for which reinnervation and other medialization procedures offer promising treatment.

Correlation of acoustic voice analysis and Voice Handicap Index in patients with postoperative unilateral vocal cord paralysis after thyroid surgery.

Unilateral vocal cord paralysis is frequently observed in patients who undergo thyroid surgery. This study explored the correlation between acoustic voice analysis (objective measure) and Voice Handicap Index (VHI, a self-assessment tool). One hundred and forty patients who had thyroid surgery with or without postoperative unilateral vocal cord paralysis (PVCP and NPVCP) were included. The patients were evaluated by the VHI and Dysphonia Severity Index (DSI) tools. VHI scores were significantly higher in PVCP patients than in NPVCP patients. Jitter (%) and shimmer (%) were significantly increased, whereas DSI was significantly decreased in PVCP patients. Receiver operating characteristics curve revealed that VHI scores were associated with the diagnosis of PVCP, of which VHI total score yielded an area under the curve (AUC) of 0.81. Among acoustic parameters, DSI was highly associated to PVCP (AUC=0.82, 95%CI=0.75 to 0.89). Moreover, we found a correlation between VHI scores and voice acoustic parameters. Among them, DSI had a moderate correlation with functional and VHI scores, as suggested by an R value of 0.41 and 0.49, respectively. VHI scores and acoustic parameters were associated with the diagnosis of PVCP.

Long-term stimulation by implanted pacemaker enables non-atrophic treatment of bilateral vocal fold paresis in a human-like animal model.

A wide variety of treatments have been developed to improve respiratory function and quality of life in patients with bilateral vocal fold paresis (BVFP). One experimental method is the electrical activation of the posterior cricoarytenoid (PCA) muscle with a laryngeal pacemaker (LP) to open the vocal folds. We used an ovine (sheep) model of unilateral VFP to study the long-term effects of functional electrical stimulation on the PCA muscles. The left recurrent laryngeal nerve was cryo-damaged in all animals and an LP was implanted except for the controls. After a reinnervation phase of six months, animals were pooled into groups that received either no treatment, implantation of an LP only, or implantation of an LP and six months of stimulation with different duty cycles. Automated image analysis of fluorescently stained PCA cross-sections was performed to assess relevant muscle characteristics. We observed a fast-to-slow fibre type shift in response to nerve damage and stimulation, but no complete conversion to a slow-twitch-muscle. Fibre size, proportion of hybrid fibres, and intramuscular collagen content were not substantially altered by the stimulation. These results demonstrate that 30 Hz burst stimulation with duty cycles of 40% and 70% did not induce PCA atrophy or fibrosis. Thus, long-term stimulation with an LP is a promising approach for treating BVFP in humans without compromising muscle conditions.

Outcomes of laryngeal framework surgeries for unilateral vocal cord paralysis in the elderly patients.

OBJECTIVE: Laryngeal framework surgery is a widely accepted treatment for unilateral vocal fold paralysis with good functional outcomes. Recently, with the aging of the population, opportunities to perform this procedure in elderly patients have increased; however, the safety and efficacy of this procedure in elderly patients has not been established. Therefore, this study aimed to investigate the safety and functional outcomes of laryngeal framework surgery in elderly patients. METHODS: Between January 2008 and December 2017, 97 patients with unilateral vocal fold paralysis underwent laryngeal framework surgery, and 71 among them completed pre- and post-operative voice function evaluations. The clinical course of these 71 patients were retrospectively reviewed. RESULTS: Out of 71 patients, 35 were assigned to the younger group (< 65 years) and 36 to the elderly group (≥ 65 years). Complications included post-operative edema and submucosal hematoma that were safely managed in all cases, and no differences were identified between the groups. Significant improvements were observed in maximum phonation time (MPT), mean flow rate, alternating current/direct current ratio, pitch perturbation quotient, amplitude perturbation quotient, and noise-to-harmonic ratio in both groups, and multivariate analysis of variance revealed greater improvement in the younger group in MPT. CONCLUSION: Laryngeal framework surgeries for unilateral vocal fold paralysis are safe and effective, regardless of age. Better improvement was observed in the younger group in the MPT suggesting that the effects of laryngeal framework surgeries is more likely to be present in the younger group than in the elderly.

Investigation of the Position and Angle of the Vocal Fold Projected onto the Thyroid Cartilage.

OBJECTIVE: To perform laryngeal framework surgery for unilateral vocal fold paralysis and obtain favorable voice improvement, it is necessary to accurately determine the vocal fold and arytenoid cartilage positions. Thus, the position and angle of the paralyzed vocal folds and arytenoid cartilage projected onto the affected thyroid plate were measured using computed tomography (CT) before and after surgery. METHODS: Forty-six male patients with thyroid cartilage ossification observed on preoperative CT and vocal fold paralysis were included. Using Adobe Illustrator®, the thyroid plate on the affected side was reconstructed from the continuous images of the sagittal section of the CT examination during participant's quiet breathing (reconstructed affected thyroid plate [RATP]). RESULTS: The anterior commissure mean position was slightly cranial to the midpoint of the thyroid cartilage midline. The paralyzed vocal fold angle was not parallel to the baseline. The average unaffected vocal fold angle during vocalization projected onto the affected thyroid plate was 13.83°, which differed significantly from the average paralyzed vocal fold angle before surgery (19.05°). However, no significant difference was observed in comparison with the average angle of the paralyzed vocal fold after arytenoid adduction. The average distance from the inferior notch of the affected side thyroid cartilage to the affected arytenoid cartilage was 16.7 mm. CONCLUSION: By understanding the positional relationship between the thyroid cartilage plate and internal structure from preoperative CT images, more effective surgery can be performed according to individual differences. LEVEL OF EVIDENCE: IV Laryngoscope, 134:4088-4094, 2024.

Airway and Voice Outcomes After Thyroarytenoid Myomectomy for Bilateral Vocal Fold Immobility.

INTRODUCTION: Type 4 posterior glottic stenosis and bilateral vocal fold paralysis are clinically challenging causes of bilateral vocal fold immobility (BVFI) that result in glottic airway obstruction. Established procedures for BVFI typically worsen dysphonia. We hypothesize the use of thyroarytenoid myomectomy (TAM) in the setting of BVFI will improve dyspnea with decreased detriment to voice. METHODS: Eleven unilateral TAM procedures were performed between April 2021 and June 2023 at a single institution. Pre- and postoperative patient reported outcomes were compared. Representative images of maximal glottic opening were analyzed in ImageJ to calculate ipsilateral bowing index (BI), total BI, maximum glottic surface area (MGSA), and maximum opening angle (MOA). Statistical comparisons were performed with paired t-tests when normality was confirmed with Shapiro-Wilk test and otherwise with Wilcoxon signed-rank tests, with threshold for significance of α = 0.05. Interrater reliability for objective glottal measures was compared with intraclass correlation coefficient (ICC). RESULTS: Dyspnea Index improved from mean (standard error) of 24.1 (3.8) to 9.1 (3.3), p = 0.004. Voice Handicap Index-10 improved from 20.0 (4) to 10.3 (3.8), p = 0.011. Glottal Function Index improved from 9.6 (1.4) to 6.3 (1.3), p = 0.017. There was no significant difference in ipsilateral BI, total BI, MOA, and median MGSA. There was good to excellent ICCs for all comparisons (0.83-0.95). CONCLUSIONS: TAM demonstrated significant improvement in symptoms from BVFI while not significantly altering glottal structure. These data suggest TAM improves dyspnea in patients with BVFI without significantly impairing voice. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:4307-4312, 2024.

A Retrospective Study of Acoustic Measures of Glottal Stop Production to Assess Vocal Function in Unilateral Vocal Fold Paresis/Paralysis Patients.

PURPOSE: The aim of this study was to determine (a) diagnostic accuracy of acoustic measures of glottal stop production (GSP; intensity differences, slopes, complete voicing cessation) to distinguish between unilateral vocal fold paresis/paralysis (UVFP) patients and controls; (b) if acoustic measures of GSP significantly correlated with an acoustic measure of voice disorder severity, acoustic voice quality index (AVQI); and (c) if acoustic measures from another type of voicing cessation, voiceless consonant production, also significantly differed between groups. METHOD: Ninety-seven patients with unilateral paresis/paralysis and 35 controls with normal laryngostroboscopic signs produced two sets of five repeated [i] and four repeated [isi]. Tokens were randomized by type between groups and analyzed blinded using a customized Praat program that computed intensity differences and slopes between vowel maxima and glottal stop minima for inter-[i] tokens and vowel maxima and voiceless consonant minima for intra-[isi] tokens. The number of voicing cessations for inter-[i] tokens was obtained. RESULTS: Onset and offset intensity differences and number of voicing cessations from inter-[i] tokens had the greatest areas under the curve (.854, .856, and .835, respectively). Correlation coefficients were significant (p < .01) between AVQI and all GSP acoustic measures with weak/medium effect sizes. No significant differences were found between controls and participants with UVFP for acoustic measures from intra-[isi]. CONCLUSIONS: Acoustic GSP measures demonstrated good diagnostic accuracy and some relationship to severity of voice disorder. No significant differences in acoustic measures for medial voiceless fricative consonants between controls and participants with UVFP suggested that voicing cessation for voiceless fricatives differs from voicing cessation for GSP.

[Analysis of vocal fold movement characteristics in patients with laryngeal neurogenic injury].

Objective:To analyze the characteristics of vocal fold movement and glottic closure in patients with laryngeal neurogenic injury. Methods:A total of 185 patients with vocal fold paralysis diagnosed by laryngeal electromyography as neurogenic damage to cricothyroid muscle, thyreoarytenoid muscle and posterior cricoarytenoid muscle were enrolled, they were divided into unilateral vocal fold paralysis group and bilateral vocal fold paralysis group, respectively, and superior laryngeal paralysis group, recurrent laryngeal nerve paralysis group and vagal nerve paralysis group according to nerve injury. The characteristics of vocal fold movement and glottic closure were analyzed under strobe laryngoscope. The qualitative evaluation of vocal fold movement was fixed vocal fold, reduced vocal fold movement and normal vocal fold movement, and the qualitative evaluation of glottic closure was glottic closure and glottic imperfection. The results were analyzed statistically. Results:The proportion of normal, reduced and fixed vocal fold motion in bilateral vocal fold paralysis group was significantly different from that in unilateral vocal fold paralysis group（P<0.05）, the composition of normal and reduced vocal fold motion in bilateral vocal fold paralysis group（47.70%） was significantly greater than that in unilateral vocal fold paralysis group（12.27%）. There was no significant difference between the proportion of glottic closure and glottic imperfecta in bilateral vocal fold paralysis group and unilateral vocal fold paralysis group（P<0.05）. The proportion of decreased vocal fold motion in superior laryngeal nerve paralysis group（50.00%） was higher than that in recurrent laryngeal nerve paralysis group（9.32%） and vagal nerve paralysis group（9.00%）. The proportion of decreased and fixed vocal fold motion in superior laryngeal nerve paralysis group, recurrent laryngeal nerve paralysis group and vagal nerve paralysis group was statistically significant（P<0.05）.There was no significant difference in glottic closure among the three groups（P<0.05）. Conclusion:Vocal fold movement characteristics of patients with laryngeal neurogenic injury were mainly vocal fold fixation, or normal or weakened vocal fold movement. There may be missed diagnosis of unilateral vocal fold paralysis in clinical practice. In half of the patients with superior laryngeal nerve palsy, vocal fold movement is characterized by vocal fold fixation.

Dysphagia as a predictor of voice handicap and voice restoration in unilateral vocal fold immobility.

OBJECTIVE: Dysphagia is multifactorial in unilateral vocal fold immobility (UVFI). Severe dysphagia could indicate greater functional deficits in UVFI. The purpose of this study is to evaluate the association of dysphagia with the need for surgical voice restoration in patients with UVFI. STUDY DESIGN: Retrospective chart review. SETTING: Single-institution, tertiary referral center. METHODS: Records of UVFI patients from 2008 to 2018 were examined. Dysphagia severity was extracted from patient history. Etiology of UVFI and other relevant variables were analyzed to determine their association with dysphagia. Dysphagia severity and other clinical variables were then analyzed for their association with surgical voice restoration. RESULTS: Eighty patients met selection criteria out of 478 patients with UVFI. There was significant concordance between dysphagia severity extracted from patient history and patient-reported EAT-10 scores (R = 0.59, p = 0.000035). Patients' EAT-10 scores were correlated with VHI-10 scores (R = 0.45, p = 0.011). Severe dysphagia (p = 0.037), high VHI-10 score on presentation (p = 0.0009), and longer duration of hoarseness before presentation (p = 0.008) were associated with surgical voice restoration in UVFI patients. CONCLUSION: In this pilot study, severe dysphagia and increased voice handicap on presentation were associated with the need for surgical voice restoration in UVFI patients. Presenting dysphagia may be an additional variable for clinicians to consider for management of UVFI.

Noticeable effect of lower baseline amplitude on the predictive accuracy of intraoperative amplitude changes for postoperative vocal cord palsy: a prospective cohort study.

BACKGROUND: To explore the effect of lower baseline amplitude on its predictive accuracy of postoperative vocal cord paralysis (VCP) in monitored thyroid surgery. MATERIALS AND METHODS: Clinical and electrophysiological data were collected during thyroid surgeries performed between November and December 2021 at China-Japan Union Hospital. Univariate/multivariate regression analysis were applied to these data to examine a possible correlation. A receiver operating characteristic curve was used to evaluate predictive efficacy. RESULTS: A total of 631 nerves-at-risk (NAR) were identified in 460 patients who were divided into two groups according to postoperative development of VCP. The VCP group included a higher percentage of NAR with V1<1000 (68.2 vs. 40.7%, respectively; P =0.014) and NAR with R1<1400 (77.3 vs. 47.0%, respectively; P =0.005) compared with the non-VCP group. Multivariate regression analysis further identified V1<1000 [odds ratio (OR)=2.688, P =0.038], R1<1400 (OR=3.484, P =0.018) as independent risk factors for postoperative temporary VCP. The receiver operating characteristic curve showed the AUC value of V signal decline for predicting VCP was 0.87. The diagnostic efficiency of R signal decline reached as high as 0.973. A multivariate logistic regression analysis identified independent risk factors for V1<1000 and these included: higher BMI (OR=1.072, P =0.013), hypertension (OR=1.816, P =0.015), smoking (OR=1.814, P =0.031), and male sex (OR=2.016, P =0.027). CONCLUSION: In our cohort, lower baseline amplitude was an independent risk factor for developing transient postoperative VCP. It also affected the predictive efficacy of intraoperative amplitude changes on VCP. Higher BMI, hypertension, smoking, and male sex may also be closely associated with lower initial amplitude. Thus, maintaining a higher initial amplitude is critical for patient safety during thyroid surgery.

Recovery of Recurrent Laryngeal Nerve Function With Neoadjuvant Treatment: Neural Characterization.

OBJECTIVES: Neoadjuvant targeted therapy has emerged as a promising treatment strategy for locally aggressive thyroid cancer. Its impact on tumor and adjacent tissues remains a nascent area of study. Here we report on a series of six subjects with locally advanced thyroid cancer and recurrent laryngeal nerve (RLN) paralysis who experienced recovery of RLN function with neoadjuvant treatment and describe the morphologic and electrophysiologic characteristics of these recovered nerves. METHODS: This is a multicenter retrospective review. Descriptive analysis was conducted to examine the following parameters for recovered nerves: (1) nerve morphology, characterized as Type A (involving epineurium only) versus Type B (extending beyond epineurium); (2) proximal stimulability (normal vs. abnormal vs. absent); and (3) surgical management (resection vs. preservation). RESULTS: Six subjects with unilateral VFP were identified. Median time to return of VF mobility was 3 months (range 2-13.5). All nerves (100%) were noted to have Type A morphology at surgery. Proximal stimulability was normal in four subjects (66.7%), abnormal in one (16.7%), and absent in one (16.7%). Nerves that had improvement of function through neoadjuvant therapy were able to be surgically preserved in five subjects (83.3%). CONCLUSIONS: This represents the first characterization of RLNs that have recovered function with neoadjuvant treatment of locally advanced thyroid cancer. Although much remains unknown, our findings indicate carcinomatous neural invasion is a reversible process and recovered nerves may demonstrate normal morphology and electrophysiologic activity. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3415-3419, 2024.

Comparison of 24-month voice outcomes after injection laryngoplasty with calcium hydroxylapatite or hyaluronic acid in patients with unilateral vocal fold paralysis.

PURPOSE: The objective was to evaluate the long-term voice outcomes in pa-tients with unilateral vocal fold paralysis treated with injection laryngoplasty using either cal-cium hydroxylapatite (CaHA) or hyaluronic acid (HA). METHODS: A single-centre retrospective study was performed. There were 75 patients with dysphonia due to unilateral vocal fold paralysis: injected with CaHA or injected with HA. We analysed Voice Handicap Index-30 (VHI), videostroboscopic images, auditory-perceptual (GRBAS), and acoustic measures (MDVP) in 6, 12, and 24 months after augmentation. RESULTS: The mean change in VHI 24 months after augmentation was 29.14 in the CaHA group, and 22.88 in the HA group. There was an improvement of glottal gap 6, 12, and 24 months after augmentation in both groups. The GRBAS parameters were similar in both groups throughout the whole period. The MDVP pa-rameters decreased 6 and 12 months after augmentation and were similar in both groups. There were 4 patients augmented with CaHA (12.5%) who needed reintervention within 2 years of surgery and another 4 (9.3%) augmented with HA. CONCLUSION: This study demonstrates that there are no long-term differences in voice outcomes or number of reaugmentations for injection laryn-goplasty with CaHA compared to HA.

Cord medialisation in unilateral vocal fold paralysis improves forced vital capacity.

OBJECTIVES: The lateralised vocal fold of unilateral vocal fold paralysis (ULVFP) is unphysiological for expiration wherein vocal folds normally adduct to increase expiratory resistance and prevent small airway collapse. ULVFP may therefore impair ventilatory function and ventilatory volume. This study seeks to test whether vocal fold medialisation improves forced vital capacity (FVC). DESIGN: Prospective inception cohort intervention study. SETTING: Academic Tertiary Care Institution. PARTICIPANTS: Twenty-five patients of ULVFP with a phonatory gap ranging from 2 to 6 mm. MAIN OUTCOME MEASURES: Vocal fold medialisation was undertaken with autologous fat injection. Forced vital capacity (FVC) assessments by spirometry were undertaken pre-treatment and 1-month post-treatment. RESULTS: Improvement in FVC was noted in all patients with the quantum of improvement ranging from 0.1 to 0.6 litres. Mean FVC improved from 3.10 L pre-injection to 3.45 L post-injection. (p < .001). A moderate correlation was noted between the degree of medialisation and improvement in FVC (r = .33, Pearson's correlation coefficient). CONCLUSIONS: Objective improvement in FVC is consistently noted in post vocal fold medialisation for ULVFP and is probably mediated by increased glottic expiratory resistance and consequent improvement in intrinsic PEEP.

New Developments in Anterior Laryngeal Recording Technique During Neuromonitored Thyroid and Parathyroid Surgery.

A recurrent laryngeal nerve (RLN) injury resulting in vocal fold paralysis and dysphonia remains a major source of morbidity after thyroid and parathyroid surgeries. Intraoperative neural monitoring (IONM) is increasingly accepted as an adjunct to the standard practice of visual RLN identification. Endotracheal tube (ET) surface recording electrode systems are now widely used for IONM; however, the major limitation of the clinical use of ET-based surface electrodes is the need to maintain constant contact between the electrodes and vocal folds during surgery to obtain a high-quality recording. An ET that is malpositioned during intubation or displaced during surgical manipulation can cause a false decrease or loss of electromyography (EMG) signal. Since it may be difficult to distinguish from an EMG change caused by a true RLN injury, a false loss or decrease in EMG signal may contribute to inappropriate surgical decision making. Therefore, researchers have investigated alternative electrode systems that circumvent common causes of poor accuracy in ET-based neuromonitoring. Recent experimental and clinical studies have confirmed the hypothesis that needle or adhesive surface recording electrodes attached to the thyroid cartilage (transcartilage and percutaneous recording) or attached to the overlying neck skin (transcutaneous recording) can provide functionality similar to that of ET-based electrodes, and these recording methods enable access to the EMG response of the vocalis muscle that originates from the inner surface of the thyroid cartilage. Studies also indicate that, during surgical manipulation of the trachea, transcartilage, percutaneous, and transcutaneous anterior laryngeal (AL) recording electrodes could be more stable than ET-based surface electrodes and could be equally accurate in depicting RLN stress during IONM. These findings show that these AL electrodes have potential applications in future designs of recording electrodes and support the use of IONM as a high-quality quantitative tool in thyroid and parathyroid surgery. This article reviews the major recent developments of newly emerging transcartilage, percutaneous, and transcutaneous AL recording techniques used in IONM and evaluates their contribution to improved voice outcomes in modern thyroid surgery.

Value of Neurostimulation Plus Laryngeal Palpation to Predict Postoperative Vocal Fold Motility.

BACKGROUND: The aim of this study was to evaluate the reliability of intraoperative neuromonitoring through recurrent laryngeal nerve stimulation and simultaneous laryngeal palpation (NSLP) in predicting postoperative vocal cord palsy and in providing useful information in the decision to perform a staged surgery in initially planned total thyroidectomy. MATERIALS AND METHODS: A retrospective review was performed involving 552 patients for whom a total thyroidectomy was planned. In all patients, preoperative and postoperative laryngoscopy was performed. The incidence of vocal cord palsy was calculated on 1104 nerves at risk. RESULTS: Sensitivity and specificity of NSLP were 0.9411 and 0.9925 respectively. The positive predictive value was 0.7804, the negative predictive value was 0.9981, the false positive rate was 0.8%. In 41 patients (7.4%) the initial surgical strategy was changed into a staged procedure. Nine patients (21.9%) were false positive, 32 patients (78.1%) were true positive. Finally, a two-stage thyroidectomy was performed in 27 of 41 patients. CONCLUSIONS: High sensitivity and specificity confirm the validity of NSLP in predicting postoperative vocal cord palsy and in driving a possible staged thyroidectomy, both in benign thyroid disease and in differentiated thyroid carcinoma.