Age-dependent treatment effect of vocal fold steroid injection for benign vocal fold lesions.

Objective: Benign vocal fold lesions (BVFLs) cause voice disorders and impair social life. Recently, office-based vocal fold steroid injection (VFSI) has gained attention as a minimally invasive treatment for BVFLs. This study aimed to analyze the age-dependent treatment effect of VFSI and to clarify the indications for treatment. Methods: In this retrospective cohort study, a total of 83 patients with BVFLs were treated with a similar regimen of VFSI. Three or four months after the injection, age-dependent phonological functions were evaluated. The differences between pre- and post-treatment findings were analyzed using the Wilcoxon matched-pair signed-rank test, and the correlation between patient age and improvement rates were determined by Pearson's correlation coefficient. Results: Improvement in voice handicap index (VHI), which was the primary endpoint, was observed. Subjective and objective voice quality measurements also showed significant improvements. Subgroup analyses revealed that there was no age-related difference in the improvement of voice quality and that there was no improvement in aerodynamic effect in patients over 45 years of age. Conclusion: This study clarified the age-dependent treatment effect of VFSI and provided the important suggestion of establishing indication criteria for BVFLs. The study results provided clarity on the indication criteria of VFSI and served as an important indicator for tailoring treatment to patients' needs. Level of Evidence: 4.

Impact on swallowing functions of arytenoid adduction in patients with unilateral vocal fold paralysis.

OBJECTIVE: Although the pathophysiology of swallowing dysfunction in patients with unilateral vocal fold paralysis (UVFP) remains uncertain, glottal insufficiency is known to be a possible major cause, and other factors due to vagus nerve or recurrent laryngeal nerve damage may contribute to dysphagia or aspiration. This study aimed to evaluate the effect of arytenoid adduction (AA) surgery on the swallowing functions of UVFP patients and to investigate the important role of glottic closure during swallowing. METHODS: We prospectively analyzed the data of thirteen patients with UVFP who underwent AA in combination with medialization laryngoplasty (ML) for improving voice quality. The subjects received a series of examinations for not only voice function but also swallowing function and cough strength both preoperatively and approximately 6 months after surgery. The evaluations of voice function included the Voice Handicap Index and aerodynamic measures; the evaluations of swallowing function included the Eating Assessment Tool-10, liquid aspiration, a videofluorographic examination of swallowing study, and high-resolution manometry; and the evaluation of cough strength included the measurement of cough peak flow. All measurements before and after surgery were statistically compared and examined. RESULTS: Considerable improvements in voice measures were observed after the procedure, as sufficient glottic closure was achieved during phonation and swallowing. In terms of swallowing evaluation, there were significant differences in the subjective assessment methods after the operation. Additionally, our intervention improved two cases of aspiration according to abnormal findings on the videofluorographic examination of swallowing. There was a significant difference in cough peak flow, with all participants having better values after surgery. High-resolution manometry revealed no significant differences between pre- and postsurgery in any parameters at the level of the mesopharynx or upper esophageal sphincter. CONCLUSION: The findings of our study suggest an important effect on the dysphagia of UVFP patients who undergo AA combined with ML. In addition, we revealed improvements in swallowing by strengthening incomplete glottic closure; thus, we consider that sufficient glottic closure must play an important role in swallowing function in patients with UVFP.

Analysis of Dysphagia and Cough Strength in Patients with Unilateral Vocal Fold Paralysis.

The association between swallowing function and cough strength in patients with unilateral vocal fold paralysis (UVFP) is unknown. We evaluated the relationship between voluntary cough strength and dysphagia among patients with UVFP (UVFP group) by comparing their data with that of corresponding healthy participants (healthy control [HC] group) in a prospective observational study. From February 1st, 2018 to March 30th, 2019, we recruited patients with a voice disorder due to UVFP, who were referred to our university hospital. Patients with a history of laryngeal surgery, vagal nerve paralysis, or cardiac and respiratory failure were excluded. Descriptive and clinical data regarding swallowing, voice, and cough peak flow (CPF) were collected as a measure of cough strength. The UVFP group comprised six women and seven men (median age, 68.0 years), and the HC group comprised six women and eight men (median age 65.5 years). The groups differed significantly in the Eating Assessment Tool (EAT)-10 scores and CPF rates (P < 0.001). Among patients with UVFP, 84.6% had an abnormal EAT-10 score of ≥ 3. Additionally, 16.7% of the patients exhibited liquid aspiration with contrast medium on a videofluorographic swallowing study (VFSS). There was no correlation between the CPF values, EAT-10 scores, or the VFSS results. Therefore, patients with severe UVFP, whose condition had been fixed, had difficulties when swallowing (85% of cases), and some even presented with aspiration on VFSS (20% of cases), while receiving a regular diet.

Characteristics of the Voice Handicap Index for Patients With Unilateral Vocal Fold Paralysis Who Underwent Arytenoid Adduction.

PURPOSE: This study was performed to evaluate the characteristics of the Voice Handicap Index (VHI), a self-assessment measure, for patients with unilateral vocal fold paralysis (UVFP) who underwent arytenoid adduction (AA), in comparison with postoperative vocal function examinations. METHODS: A retrospective chart review was conducted for patients who underwent AA at Tohoku University Hospital during the period between 2014 and 2017. VHI was compared before and after surgery; moreover, correlations were assessed between the VHI and other voice measurements, including perceptual assessment of voice, as well as aerodynamic and acoustic measures. Factors involved in the VHI score were explored by multivariate analysis. RESULTS: Forty-three UVFP patients (28 males, age 32-81 years; 15 females, age 34-80 years) were enrolled in the study; the average age of all patients was 61.5 years (32-81 years). Among the enrolled patients, 33 (76.7%) left and 10 (23.3%) right vocal folds were impaired. After surgery, nearly all of the patients exhibited significantly improved VHI score; each of the three subscales (functional, physical, and emotional) was also improved. The postoperative VHI correlated mildly with several values of the other voice measurements, with the exception of the mean flow rate. Multivariate analysis showed that the sole variable associated with postoperative VHI score was preoperative VHI. CONCLUSIONS: The postoperative VHI likely reflects improvement in the voices of the patients with UVFP. Although there were weak correlations with other voice measures, postoperative VHI is a relatively independent measurement parameter for patients with UVFP who underwent AA.

Complications of using Gore-Tex in medialization laryngoplasty: case series and literature review.

PURPOSE: This study was performed to evaluate the incidence and contributing factors of complications associated with medialization laryngoplasty using Gore-Tex in patients with unilateral vocal fold paralysis. METHODS: A retrospective chart review was conducted for all patients who underwent medialization laryngoplasty using Gore-Tex at Tohoku University Hospital between January 2014 and April 2018. A search of series and case reports in PubMed was performed to determine the incidence of complications following medialization laryngoplasty using Gore-Tex. RESULTS: Sixty-eight patient charts were reviewed. Two patients (2.9%) had complications (infection and extrusion into the airway) related to the Gore-Tex implant after surgery. In the 555 medialization laryngoplasty cases reported in both our current data and eight additional articles, there were 11 complications related to the Gore-Tex implant (2.0%). The most common event was extrusion into the lumen, which occurred in six cases (1.1%), followed by persistent inflammation with the granulation formation (0.5%). There were 12 cases of Gore-Tex extrusion (one male, six female, and five of unknown gender). The interval to onset ranged from 1 month to 10 years (median, 49 months). CONCLUSIONS: Our findings serve as a reminder that complications can occur with Gore-Tex implants following medialization laryngoplasty in patients with unilateral vocal fold paralysis, even in the long-term. We suggest that the use of excessively large implants in women and occurrence of postoperative hematoma followed by infection are factors that may cause complications. Nevertheless, Gore-Tex has been proven to be a relatively safe and reliable material for medialization laryngoplasty.

Injection of basic fibroblast growth factor for unilateral vocal cord paralysis.

OBJECTIVE: Unilateral vocal cord paralysis (UVCP) not only induces severe dysphonia, but aspiration as well. Although laryngeal framework surgery is usually performed to treat this condition, the procedure is not tolerated by some patients. In the previous study, basic fibroblast growth factor (bFGF) injections for vocal cord scarring and sulcus have been reported to provide favorable outcomes while being minimally invasive. In this study, the authors retrospectively investigated phonological outcomes after bFGF injection in patients with UVCP. METHODS: This study was registered in University hospital Medical Information Network - Clinical Trials Registry (UMIN000019347). Nineteen patients with unilateral cord paralysis were treated with bFGF injection. The treatment regimen involved a single injection of 50 µg of bFGF into the muscle layer. More than six months after the injection, aerodynamic and acoustic outcomes were examined. RESULTS: The voice handicap index, maximum phonation time, mean airflow rate, and pitch range improved significantly after injection of bFGF. No sex-related differences were observed in any phonological parameter. CONCLUSION: bFGF injection, an easy method and suitable as an office procedure, significantly improved the hoarseness caused by UVCP. It is expected to be widely adopted and effective adjunctive drugs, and procedures are anticipated to be developed.

Central-part laryngectomy is a useful and less invasive surgical procedure for resolution of intractable aspiration.

A novel narrow-field laryngectomy procedure known as central-part laryngectomy (CPL) for less invasive laryngeal diversion in patients with intractable aspiration is introduced. We conducted retrospective case reviews of 15 patients who underwent CPL. In this procedure, an area of the glottis including the mid-part of the thyroid cartilage and cricoid cartilage is removed to separate the digestive tract from the air way. The lateral part of the thyroid cartilage, the entire hypopharyngeal mucosa and epiglottis are preserved. The superior laryngeal vessels and nerve are not invaded. All fifteen patients were relieved of aspiration without major complications. In good accordance with cutting of the cricopharyngeal muscles and removal of the cricoid cartilage, postoperative videofluoroscopy demonstrated smooth passages of barium. Ten of 12 patients who had hoped to resume oral food intake became able to do so after CPL and two others also achieved partial oral deglutition. CPL is a useful procedure for treatment of intractable aspiration and offers considerable advantages over other laryngotracheal diversion procedures from the view point of oral food intake.

Fission-fusion bat behavior as a strategy for balancing the conflicting needs of maximizing information accuracy and minimizing infection risk.

Fission-fusion behavior, which is widely reported in social animals, has been considered as a mechanism for adapting to changing environmental conditions. Although several hypotheses have been proposed to explain the potential benefits of fission-fusion behavior, there are only a few theoretical studies that have systematically explored its mechanism or quantitatively examined the potential forces shaping its evolution. We developed a social learning model to investigate the mechanism and evolutionary forces that underlie a fission-fusion society. In particular, we focused on the day-roost choices of bat individuals because bat societies represent one of the most sophisticated fission-fusion systems. The assumptions of the study were as follows. Each individual selects a single day-roost to use, and forms a roosting group with roost mates. Bats randomly choose a roost to visit in order to inspect its quality. Inspection is not always accurate, i.e., it includes some error. After inspection, bats return to the current day-roost and share the new information with roost mates. Each bat estimates the quality of each potential roost by social learning and chooses which one to use based on the relative value of expected roost quality. The size distribution of sub-colonies is determined by this choice behavior. Three roost-switching behaviors (settlement, synchronized movement, and fission-fusion grouping) were predicted depending on two factors (the level of difficulty of evaluating roost quality and the capacity to remember roost quality information). Settlement behavior, in which most bats remain in the best roost, led to the highest fitness because the accuracy of estimating roost quality was improved when bats exchanged information with members in a large group. However, when disease transmission was combined with learning dynamics, the cost of infection significantly increased under both settlement and synchronized movement behaviors, and eventually fission-fusion behavior led to the highest fitness. These results highlight two conflicting factors: learning in a large group improves information accuracy, but living in a small group effectively reduces the risk of spreading disease. Dynamic change of group size by fission-fusion can resolve the dilemma between these two conflicting factors.