Durability of Titanium Implants Following Type II Thyroplasty for Adductor Type Spasmodic Dysphonia.

OBJECTIVE: To determine the durability of current titanium implants (TI) used in voice improvement surgery for adductor spasmodic dysphonia (ADSD), which is type II thyroplasty (T2T), and identify the effects of their fractures on vocal functions. METHODS: A total of 36 ADSD patients who underwent T2T had the following exams: The CT scans of the larynx were performed 1 year after the surgery to assess the fractures of TI. The improvement in the mean voice handicap index 10 (VHI-10) scores and the success rate between nonfractured (NFR) and fractured (FR) groups were compared. RESULTS: It was indicated that TI was broken in 21 cases (58.3%). In one case (2.7%), a fracture on the part of the bridge that connects both sides of the plates was observed, and fractures at holes placed on the plates in the other 35 cases (55.6%). The mean VHI-10 score improved from 27.2 ± 8.1 to 11.4 ± 7.9 in the NFR group and from 26.3 ± 4.9 to 9.7 ± 7.9 in the FR group. The success rates were 66.6% in the NFR group and 71.5% in the FR group. No statistical difference was observed in the improvement in the mean VHI-10 scores, and the success rate between the two groups. However, two cases resulted in failure in the FR group, whereas no worsened case was observed in the NFR group. CONCLUSION: The current TI used in T2T has low durability and could result in the worsening of vocal symptoms after the surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:3028-3033, 2023.

Dynamics of vitamin A uptake, storage, and utilization in vocal fold mucosa.

OBJECTIVE: Extrahepatic vitamin A is housed within organ-specific stellate cells that support local tissue function. These cells have been reported in the vocal fold mucosa (VFM) of the larynx; however, it is unknown how vitamin A reaches and is disseminated among VFM target cells, how VFM storage and utilization vary as a function of total body stores, and how these parameters change in the context of pathology. Therefore, in this study, we investigated fundamental VFM vitamin A uptake and metabolism. METHODS: Using cadaveric tissue and serum from human donors representing the full continuum of clinical vitamin A status, we established a concentration range and analyzed the impact of biologic and clinical covariates on VFM vitamin A. We additionally conducted immunodetection of vitamin A-associated markers and pharmacokinetic profiling of orally dosed α-retinyl ester (a chylomicron tracer) in rats. RESULTS: Serum vitamin A was a significant predictor of human VFM concentrations, suggesting that VFM stores may be rapidly metabolized in situ and replenished from the circulatory pool. On a vitamin A-sufficient background, dosed α-vitamin A was detected in rat VFM in both ester and alcohol forms, showing that, in addition to plasma retinol and local stellate cell stores, VFM can access and process postprandial retinyl esters from circulating chylomicra. Both α forms were rapidly depleted, confirming the high metabolic demand for vitamin A within VFM. CONCLUSION: This thorough physiological analysis validates VFM as an extrahepatic vitamin A repository and characterizes its unique uptake, storage, and utilization phenotype.

Reversal of Vocal Fold Mucosal Fibrosis Using siRNA against the Collagen-Specific Chaperone Serpinh1.

Vocal fold (VF) mucosal fibrosis results in substantial voice impairment and is recalcitrant to current treatments. To reverse this chronic disorder, anti-fibrotic therapies should target the molecular pathology of aberrant collagen accumulation in the extracellular matrix. We investigated the therapeutic potential of siRNA against Serpinh1, a collagen-specific chaperone that enables cotranslational folding and assembly of procollagens in the endoplasmic reticulum. We implemented a previously validated siRNA construct, conducted transfection experiments using in vitro and in vivo rat models, and measured knockdown efficiency, dose responses, delivery strategies, and therapeutic outcomes. Liposome-mediated delivery of Serpinh1-siRNA downregulated collagen production in naive and scar VF fibroblasts as well as naive VF mucosa; moreover, sustained Serpinh1 knockdown in fibrotic VF mucosa reversed scar-associated collagen accumulation within 4 weeks. Analysis of therapeutic effects at the transcriptome level showed evidence of cell cycle upregulation, catabolism, matrix disassembly, and morphogenesis. These findings indicate that Serpinh1-siRNA holds potential as a molecular therapy for chronic VF mucosal fibrosis.

Serum retinyl esters are positively correlated with analyzed total liver vitamin A reserves collected from US adults at time of death.

Background: Minimal human data exist on liver vitamin A (VA) compared with serum biomarkers. Cutoffs of 5% and 10% total serum VA as retinyl esters (REs) suggest a VA intoxication diagnosis. Objectives: We compared total liver VA reserves (TLRs) with the percentage of total serum VA as REs to evaluate hypervitaminosis with the use of US adult autopsy samples. Secondary objectives evaluated serum retinol sensitivity, TLRs among lobes, and hepatic α-retinol concentrations, an α-carotene cleavage product. Design: Matched serum and liver samples were procured from cadavers (n = 27; mean ± SD age: 70.7 ± 14.9 y; range: 49-101 y). TLRs and α-REs were quantified by ultra-performance liquid chromatography. Pearson correlations showed liver and serum associations. Sensitivity and specificity were calculated for >5%, 7.5%, and 10% total serum VA as REs to predict TLRs and for serum retinol <0.7 and 1 µmol/L to predict deficiency. Results: Serum RE concentrations were correlated with TLRs (r = 0.497, P < 0.001). Nine subjects (33%) had hypervitaminosis A (≥1.0 µmol VA/g liver), 2 of whom had >7.5% total serum VA as REs; histologic indicators corroborated toxicity at 3 µmol/g liver. No subject had >10% total serum VA as REs. Serum retinol sensitivity to determine deficiency (TLRs <0.1 µmol VA/g) was 83% at 0.7 and 1 µmol/L. Hepatic α-retinol was positively correlated with age (P = 0.047), but removing an outlier nullified significance. Conclusions: This study evaluated serum REs as a biomarker of VA status against TLRs (gold standard), and abnormal histology suggested that 7.5% total serum VA as REs is diagnostic for toxicity at the individual level in adults. The long-term impact of VA supplements and fortificants on VA status is currently unknown. Considering the high prevalence of hypervitaminotic TLRs in this cohort, and given that many countries are adding preformed VA to processed products, population biomarkers diagnosing hypervitaminosis before toxicity are urgently needed. This trial was registered at clinicaltrials.govas NCT03305042.

The Ferret as a Surgical Model for Vocal Fold Scar Creation and Treatment.

OBJECTIVES: To develop a vocal fold (VF) scarring procedure in the ferret, characterize the scars histologically, and test the injectability of the lamina propria (LP). Secondarily, to compare laryngeal anatomy of the ferret with rat and rabbit. MATERIALS AND METHODS: The larynges of 18 male ferrets were prepared by unilateral scarring, and normal larynges from 6 female Wistar rats and 5 male albino rabbits were used for comparative purposes. For scarring, the right VF were electrocauterized, ablating the entire LP. Prior to harvesting the larynges at 4 and 16 weeks, each ferret was re-anesthetized, and in 3 animals, India ink was injected into the LPs of both normal and scarred VFs. RESULTS: Laryngoscopic methods and instrumentation for precise visualization, scarring, and injection were developed. The scarred VFs had reduced hyaluronic acid and increased collagen type I, III, and fibronectin compared with normal VFs. The 2 timepoints (4 and 16 weeks) differed significantly only in collagen type III level (levels were higher at 4 weeks). Injected ink migrated from scarred LP to muscle layer just beneath the scarred tissue 3 hours after injection. CONCLUSION: The ferret is a promising species for creation and experimental treatment of vocal fold scar.

Potential treatment for vocal fold scar with pirfenidone.

OBJECTIVES/HYPOTHESIS: Pirfenidone (PFD) is a strong antifibrotic agent that has been clinically approved in Japan for idiopathic pulmonary fibrosis. We examined the antifibrotic effects of PFD on fibroblasts isolated from scarred vocal folds (VFs) of ferrets in vitro. STUDY DESIGN: Prospective animal experiments with controls. METHODS: Scar fibroblasts (SFs) were isolated from scarred VFs that had been electrocauterized 2 weeks before harvesting (N = 4). Normal fibroblasts (NFs) were isolated from intact VFs (N = 4). SFs and NFs were incubated in the presence of 10 ng/mL transforming growth factor ß1 (TGF-ß1), with or without PFD. After the 48-hour incubation, mRNA expression levels of α smooth muscle actin (αSMA), TGF-ß1, collagen type I, and hyaluronan synthase 2 (HAS2) were examined by real-time polymerase chain reaction. Immunohistochemistry with anti-αSMA anti-collagen type I and phosphorylated Smad (p-Smad)2/3 antibodies in SFs with or without PFD was performed. SFs and NFs were cultured in collagen gel with or without PFD for 48 hours, and the extent of gel contraction was examined quantitatively. RESULTS: PFD treatment significantly (P < .05) decreased mRNA expression of collagen type I, significantly increased mRNA expression of TGF-ß1 and HAS2, and significantly suppressed collagen gel contraction. However, it did not have a significant effect on the expression of αSMA. The expression of p-Smad2/3 in the nucleus was faded with PFD, possibly demonstrating the suppression of translocation of p-Smad2/3 from cytoplasm to nucleus with PFD. CONCLUSIONS: This is the first report to demonstrate the in vitro antifibrotic effects of PFD on fibroblasts isolated from scarred VFs of ferrets. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:E171-E177, 2018.

Radiotherapy for T3N0 glottic carcinoma without cord fixation: elective nodal irradiation or not?

BACKGROUND: Although the T3 category has been changed in the sixth edition of the TNM staging system proposed by the Union for International Cancer Control (UICC), the appropriate clinical target volume (CTV) of elective nodal irradiation (ENI) for T3N0 glottic carcinoma without cord fixation, which was formerly treated as a T1-2N0 disease, is not fully discussed. MATERIALS AND METHODS: We retrospectively analyzed 64 patients staged or restaged as T3N0 disease without cord fixation. All patients received irradiation to the primary lesion alone using opposed lateral fields. Surgery was performed in 10 patients without tumor regression after the delivery of 40 Gy. The other 54 patients received a median total dose of 66 Gy. Concurrent chemoradiotherapy (CRT) with low-dose cisplatin and UFT (low-dose CRT) and docetaxel, cisplatin, and 5-fluorouracil (TPF-CRT) were performed in 23 and 19 patients, respectively. RESULTS: Eighteen (28.1%) patients suffered treatment failure; all were recorded as local failure alone. The 5-year local control rates for RT alone, low-dose CRT, and TPF-CRT groups were 51.7%, 61.6%, and 93.8%, respectively (p = 0.027). The 5-year laryngeal preservation rates for RT alone, low-dose CRT, and TPF-CRT groups were 57.4%, 81.6%, and 89.5%, respectively (p = 0.048). CONCLUSIONS: The rate of regional failure was zero when irradiating the primary lesion alone using opposed lateral fields. This treatment technique covers the most level III regions; hence, CTV for ENI should include level III alone.

Voice tuning with new instruments for type II thyroplasty in the treatment of adductor spasmodic dysphonia.

OBJECTIVE: Adductor spasmodic dysphonia is a rare voice disorder characterized by strained and strangled voice quality with intermittent phonatory breaks and adductory vocal fold spasms. Type II thyroplasty differs from previous treatments in that this surgery does not involve any surgical intervention into the laryngeal muscle, nerve or vocal folds. Type II thyroplasty intervenes in the thyroid cartilage, which is unrelated to the lesion. This procedure, conducted with the aim of achieving lateralization of the vocal folds, requires utmost surgical caution due to the extreme delicacy of the surgical site, critically sensitive adjustment, and difficult procedures to maintain the incised cartilages at a correct position. During surgery, the correct separation of the incised cartilage edges with voice monitoring is the most important factor determining surgical success and patient satisfaction. METHODS: We designed new surgical instruments: a thyroid cartilage elevator for undermining the thyroid cartilage, and spacer devices to gauge width while performing voice monitoring. These devices were designed to prevent surgical complications, and to aid in selecting the optimal size of titanium bridges while temporally maintaining a separation during voice monitoring. RESULTS: We designed new surgical instruments, including a thyroid cartilage elevator and spacer devices. Precise surgical procedures and performing voice tuning during surgery with the optimal separation width of the thyroid cartilage are key points for surgical success. CONCLUSION: We introduce the technique of voice tuning using these surgical tools in order to achieve a better outcome with minimal surgical complications.

Bioengineered vocal fold mucosa for voice restoration.

Patients with voice impairment caused by advanced vocal fold (VF) fibrosis or tissue loss have few treatment options. A transplantable, bioengineered VF mucosa would address the individual and societal costs of voice-related communication loss. Such a tissue must be biomechanically capable of aerodynamic-to-acoustic energy transfer and high-frequency vibration and physiologically capable of maintaining a barrier against the airway lumen. We isolated primary human VF fibroblasts and epithelial cells and cocultured them under organotypic conditions. The resulting engineered mucosae showed morphologic features of native tissue, proteome-level evidence of mucosal morphogenesis and emerging extracellular matrix complexity, and rudimentary barrier function in vitro. When grafted into canine larynges ex vivo, the mucosae generated vibratory behavior and acoustic output that were indistinguishable from those of native VF tissue. When grafted into humanized mice in vivo, the mucosae survived and were well tolerated by the human adaptive immune system. This tissue engineering approach has the potential to restore voice function in patients with otherwise untreatable VF mucosal disease.

Interspecies comparison of stellate cell-containing macula flavae and vitamin A storage in vocal fold mucosa.

The macula flavae (MF), populated by vitamin A-storing stellate cells (SCs), are believed to play a fundamental role in development, maintenance and repair of the vocal fold (VF) mucosa; however, to date, they have mostly been examined in observational human cadaver studies. Here, we conducted an interspecies comparison of MF and SC phenotype, as well as vitamin A quantification and localization, in human, pig, dog, rabbit and rat VF mucosae. MF containing vitamin A-positive SCs were only identified in human and rat specimens. Pig, dog and rabbit VF mucosae contained no discernable MF, but rather exhibited preferential vitamin A localization to mucous (pig), serous (dog) or mixed (rabbit) glands. This glandular vitamin A storage corresponded to exceedingly high concentrations of retinol in pig and dog mucosae, and retinyl ester in dog mucosa. These findings have significant implications for the presumed role of the MF and SCs in VF biology, the nature of vitamin A storage within the VF mucosa, and the selection of an appropriate animal model for future experimental studies.

Videolaryngoscopic assessment of laryngeal edema after arytenoid adduction.

OBJECTIVES/HYPOTHESIS: Arytenoid adduction (AA) as surgical treatment for unilateral vocal fold paralysis (UVFP) is associated with higher morbidity from airway complications due to postoperative laryngeal edema compared with other laryngeal framework surgeries. The aim of this study was to evaluate postoperative laryngeal edema after AA using a new videolaryngoscopic (VL) scoring assessment. STUDY DESIGN: Prospective case series. METHODS: Nineteen patients with UVFP (14 males and five females; mean age, 56 years) who were treated with AA alone or combined with ansa cervicalis (AA/AC) nerve anastomosis or nerve-muscle pedicle (AA/NMP) flap implantation were evaluated. Laryngeal edema was assessed by VL scoring for 10 days postoperatively. Degree of edema was scored in three subsites: the membranous vocal fold, arytenoid mound, and pyriform sinus on the operated side. Statistical significance was defined as P < .05. RESULTS: No patient experienced postoperative airway compromise. Interexaminer reliability was generally high (Spearman r > 0.75). The mean degree of edema increased steadily from postoperative day (POD) 1 to 3, peaking on POD 3 at all subsites. It then declined significantly from POD 3 to 7 (P < .05) and gradually through POD 10. The maximum degree of edema, maximum edema time, and operative time were not correlated significantly at any subsite. Maximum edema time and surgery type (AA vs. AA/AC or AA/NMP) were not correlated at any subsite. CONCLUSIONS: Inter-rater reliability for the proposed VL scoring was significant at all subsites. The VL findings suggest that AA alone or AA combined with reinnervation showed maximum laryngeal edema on POD 3 but added no significant morbidity.

Modulation of nerve fibers in the rat thyroarytenoid muscle following recurrent laryngeal nerve injury.

CONCLUSION: Regeneration of nerve fibers in the thyroarytenoid (TA) muscle occurred actively after damage on the recurrent laryngeal nerve (RLN) compared with the vagus nerve (VN). However, remyelination did not occur after damage on the RLN. OBJECTIVES: To determine the regeneration process of nerve fibers in the TA muscle following transection and immediate anastomosis of the RLN or VN. METHODS: Three types of animal model were prepared: an RLN anastomosis model (RLNa), a VN anastomosis model (VNa), and a peroneal nerve anastomosis model (PNa). Animals were sacrificed at five time points following the procedure. The modulation of axons, myelin sheaths, Schwann cells (SCs), nerve terminals (NTs), and acetylcholine receptors (AchRs) in the TA or tibialis anterior muscles was examined by immunohistochemical analysis. The ratios of the expression areas in axons, myelin sheaths, and SCs, and the number of NTs and AchRs in the treated (T) and untreated (U) sides (T/U) were evaluated. RESULTS: At 18 weeks, the T/U ratios of expression in RLNa, VNa, and PNa were 68.5, 0, and 100.4%, respectively, in axons; 0, 0, and 97.6% in myelin sheaths; 53.7, 0, and 93.6% in SCs; 61.0, 0, and 96.4% in NTs; and 99.4, 67.0, and 101.2% in AchRs.

Nerve-muscle pedicle flap implantation combined with arytenoid adduction.

OBJECTIVES: To describe a new technique of nerve-muscle pedicle (NMP) flap implantation combined with arytenoid adduction (AA) to treat dysphonia due to unilateral vocal fold paralysis and to examine postoperative vocal function. STUDY DESIGN: Retrospective review of clinical records. SETTING: Tertiary academic center. PATIENTS: Twenty-two consecutive patients underwent NMP flap implantation with AA and were followed up short term over a period of 1 to 6 months (mean, 2.9 months) and long term over a period of 7 to 36 months (mean, 21.4 months). INTERVENTIONS: An NMP flap was made using an ansa cervicalis branch and a piece of the sternohyoid muscle. A window was opened in the thyroid ala at the level of the vocal fold. Then, AA was performed and the NMP flap was securely implanted onto the thyroarytenoid muscle through the window under microscopic guidance. MAIN OUTCOME MEASURES: The maximum phonation time, mean airflow rate, pitch range, and acoustic parameters (jitter, shimmer, and harmonics to noise ratio) were evaluated before surgery and twice after surgery. RESULTS: All parameters improved significantly after surgery (P < .01). The measurements for maximum phonation time, mean airflow rate, and harmonics to noise ratio were within normal ranges after surgery. Furthermore, the maximum phonation time and jitter were significantly improved after long-term follow-up compared with early postoperative measurements (P < .01 and P < .05, respectively). CONCLUSIONS: Precise harvest of an NMP flap and its placement directly onto the thyroarytenoid muscle combined with AA provided excellent vocal function. The NMP method may have played a certain role in the improvement of postoperative vocal function, although further study with electromyographic examination is required to clarify the innervation status of the thyroarytenoid muscle.

Changes in respiratory function after thyroplastic surgery.

CONCLUSIONS: A certain degree of subclinical extrathoracic airway compromise may ensue after thyroplastic surgery, although none of the patients reported the presence of dyspneic symptoms in their normal daily lives. OBJECTIVES: To determine the effects of thyroplastic surgery on respiratory function and compare them with the improvement of vocal function. PATIENTS AND METHODS: The study included 53 patients; 7 had type I thyroplasty (type I), 9 had arytenoid adduction (AA), 10 had AA with type I, and 27 had AA with neuromuscular pedicle flap implantation (NMP). Phonatory and respiratory functions were measured preoperatively and postoperatively. The presence of dyspnea during daily activities was determined postoperatively. RESULTS: The difference between the pre- and postoperative values was statistically significant in five comparisons. Forced expiratory volume in 1 s/forced expiratory volume (FEV(1%)) in the AA with type I group, FEV(1)/peak expiratory flow rate (PEFR) in the AA group, and PEFR in the three groups (type I, AA, and AA with NMP). Forty-six patients associated with AA were combined for statistical analysis. The differences were statistically significant for FEV(1%), PEFR, and FEV(1)/PEFR. Changes in maximum phonation time (MPT) were found to have a significant correlation with changes in FEV(1)/PEFR. All the patients denied episodes of dyspnea during their normal daily activities.