Wen Xu

Adipose-Derived Mesenchymal Stem Cells in Collagen—Hyaluronic Acid Gel Composite Scaffolds for Vocal Fold Regeneration

Objectives: We sought to characterize the changes in the extracellular matrix (ECM) of the lamina propria following the implantation of autologous adipose-derived mesenchymal stem cells (ADSCs) in composite scaffolds in a rabbit vocal fold wound model. Methods: The ADSCs were co-cultured with collagen or hyaluronic acid gel. Each vocal fold was injured by localized resection and injected with ADSC complexes, ADSCs, or scaffolds or left untreated. From 15 days to 12 months, the vocal fold shape and the characteristics of the ECM components were analyzed. Results: With implantation of the ADSC complexes, the collagen content was significantly increased and had a disorderly distribution at 3 months. Subsequently, it began to decrease and reached close to normal by 12 months. The hyaluronic acid content was increased at 40 days, but it was reduced to normal levels and was limited to the superficial and middle layers of the lamina propria over the following 12 months. Fibronectin continued to be scattered in the lamina propria, at peak levels at 40 days, and then decreased over the following 12 months to reach near-normal levels. At 12 months, the vocal folds had a normal surface. Conclusions: ADSC complexes can play a facilitatory role in vocal fold regeneration, regulating the generation and orderly distribution of ECM.

Value of Laryngeal Electromyography in Diagnosis of Vocal Fold Immobility

Objectives: We sought to determine the value of laryngeal electromyography (LEMG) and evoked LEMG in the diagnosis of vocal fold immobility. Methods: We analyzed 110 cases of vocal fold immobility by their clinical manifestations and LEMG characteristics, including spontaneous potential activity, motor unit potential measurement, recruitment pattern analysis, and evoked LEMG signals. Results: With LEMG, we identified 87 patients with neuropathic laryngeal injuries. Neurogenic vocal fold immobility showed a wide variety of abnormal activity. Fibrillation potentials and positive sharp waves were found in patients with laryngeal nerve injuries. For laryngeal paralysis, there was no reaction with LEMG and evoked LEMG. For incomplete laryngeal paralysis, decreased evoked LEMG signals were also seen with delayed latency (thyroarytenoid muscle, 2.2 ± 1.0 ms, p < 01; posterior cricoarytenoid muscle, 2.4 ± 1.0 ms, p < .05) and lower amplitude (thyroarytenoid muscle, 0.9 ± 0.7 mV, p < .05; posterior cricoarytenoid muscle, 1.2 ± 1.0 mV, p < .01). Nineteen patients with vocal fold mechanical limitations generally had normal LEMG and evoked LEMG signals. Four patients with neoplastic infiltration of the laryngeal muscles demonstrated abnormal LEMG signals but nearly normal evoked LEMG signals. Conclusions: We conclude that LEMG and evoked LEMG behavior plays a crucial role in the diagnosis of vocal fold immobility. The decreased recruitment activities on LEMG and the decreased evoked LEMG signals with longer latency and lower amplitude reflect the severity of neuropathic laryngeal injury.

Voice function following CO2 laser microsurgery for precancerous and early-stage glottic carcinoma.

Conclusions. With the cover layer injured, vocal function of mucosal ablation could be protected and even return to normal after surgery and vocal function of mucosal stripping was slightly affected with extensive mucosal injury. Once the body layer was injured, the compensatory mechanism would play an important role in phonation. Objectives. To investigate voice function following CO2 laser microsurgery for precancerous and early-stage glottic carcinoma. Patients and methods. Vocal function was examined by acoustic analysis, aerodynamic analysis and videostroboscopic examination. Results. For mucosal ablation, vocal quality recovered 1 month after surgery. For mucosal stripping, although vocal quality was steady 3 months after surgery, slight hoarseness persisted in this group. The contour of the treated fold recovered postoperatively. There were no complications in recovery. For cordectomies, vocal quality became steady 6 months after the surgery. The supraglottal hyperfunction with supraglottal structure squeezing played an important role in phonation. The affected vocal fold mucosal wave was absent instead of a regular ventricular fold wave or mucosal wave of the vocal process during phonation. In comparison with the type III–IV cordectomy, the results of extended cordectomies (type Va and Vc) were worse; however, the difference was not statistically significant. Granulomas and anterior commissure webs were present. All granulomas resolved spontaneously 3 months postoperatively.

Characteristics of Vocal Fold Immobility following Endotracheal Intubation

Objectives: We investigated the clinical and laryngeal electromyography (LEMG) characteristics and the outcome of closed reduction of arytenoid cartilage dislocation in patients with vocal fold immobility (VFI) following endotracheal intubation. Methods: Sixty patients with VFI following endotracheal intubation were included. Closed reduction was performed under local anesthesia in 54 cases. Another 6 patients did not undergo an intervention. Laryngeal behaviors and voice function were evaluated. Forty-five patients underwent LEMG testing. Results: All patients complained of persistent hoarseness immediately following surgery. The LEMG results for 29 of 45 patients showed normal patterns (15 cases) or mildly abnormal patterns (14 cases) on the affected side. Sixteen cases displayed apparent abnormal LEMG patterns on the affected side. The voices of all 54 patients improved after reduction. The movement of the affected vocal folds recovered to normal in 51 cases. One month after reduction, neuromuscular function had improved in 29 of 30 cases. Among the 6 patients who did not undergo intervention, 3 had normal or slightly hoarse voices, and 3 experienced moderate hoarseness. Conclusions: Vocal fold immobility following endotracheal intubation is typically caused by arytenoid dislocation. Some instances were accompanied by an abnormality of the recurrent laryngeal nerve. A timely closed arytenoid reduction should be performed to restore patients normal voices and vocal fold mobility. Our reduction technique under local anesthesia can be performed easily and obtains satisfactory outcomes within 6 weeks after endotracheal intubation.

Clinical and electrophysiological characteristics of larynx in myasthenia gravis.

Objectives: We investigated the clinical and electrophysiological characteristics of the larynx in patients with myasthenia gravis (MG). Methods: Thirty-two cases of MG were analyzed. The laryngeal behaviors and characteristics of laryngeal electromyography were evaluated, and voice assessment and repetitive nerve stimulation (RNS) tests were conducted. Results: The initial symptoms of patients were ptosis and/or diplopia in 28, dysphagia and slurred speech in 3, and limb weakness in 1. Only 8 patients had slight hoarseness and vocal fatigue, and 4 patients had positive laryngeal signs. When compared with normal subjects, the patients with MG had worse results on the acoustic analysis of shimmer, their normalized noise energy was greater, and the harmonics-to-noise ratio and maximum phonation time were significantly lower. The RNS findings were positive in 28 patients and negative in 4 patients. The average (±SD) amplitude decrement was 31.9% ± 19.1%. The mean number of involved laryngeal muscles was 2.22 ± 1.35. Cricothyroid muscles were involved in 26 cases, thyroarytenoid muscles were involved in 14 cases, posterior cricoarytenoid muscles were involved in 6 cases, and lateral cricoarytenoid muscles were involved in 2 cases. Conclusions: Although few patients presented with laryngeal symptoms as their initial symptoms, most patients with MG exhibited asymmetry and abnormal findings on laryngeal electromyography. The RNS test for laryngeal muscles is a more sensitive indicator for the diagnosis of MG, especially in the cricothyroid muscle

ENDOSCOPIC MUCOSAL SUTURING OF VOCAL FOLD WITH PLACEMENT OF STENT FOR THE TREATMENT OF GLOTTIC STENOSES

Stenosis of the glottis can influence both phonation and respiration. The management of laryngeal web is difficult because of the tendency of readhesion to recur locally.

Characteristics of Experimental Recurrent Laryngeal Nerve Surgical Injury in Dogs

Objectives We characterized various recurrent laryngeal nerve (RLN) injuries in dogs. Methods Sixteen dogs were classified as having complete injuries (transection) or incomplete injuries (ligation, half-section, and crush). The characteristics of nerve injuries were evaluated by endoscopic examination, laryngeal electromyography (LEMG), and histopathologic examination at 0 to 12 months after the injury. Results After the RLN injury, the average muscle fiber diameter and the average muscle bundle diameter of the affected muscles were decreased, and the average number of muscular cell nuclei per square inch increased. Fibrillation potentials were found 1 to 3 months after injury, and reinnervation potentials appeared 3 to 6 months after incomplete injury. For nerve transection and ligation, there was no reaction with LEMG instantly after injury involving vocal fold fixation. Vocal fold motion did not improve in members of the complete injury group, whereas all of the vocal folds in the members of the nerve ligation subgroup had limited activity in the later period. Various forms of vocal fold mobility were observed after injury in the half-section subgroup. Animals in the crush subgroup had normal EMG signals combined with abnormal LEMG signals with lower amplitudes after injury. Vocal fold fixation was not observed in this subgroup. Conclusions We found the causes of nerve injury, in order of decreasing severity, to be transection, ligation, half-section, and crush.

The value of narrow band imaging combined with stroboscopy for the detection of applanate indiscernible early-stage vocal cord cancer

Abstract Background: Narrow band imaging (NBI) and stroboscopy are non-invasive techniques to detect the malignant lesions of the vocal cord. This study was to assess the diagnostic value of combined endoscopic analysis in the applanate indiscernible early-stage vocal cord cancer. Methods: A total of 110 patients with 160 suspicious vocal cord malignant lesions were included in this retrospective study. Stroboscopy was immediately performed after NBI and white light endoscopy (WLE) were performed in all patients. Excisional biopsy was performed to examine histopathology examination. Results: We found that the diagnostic specificity and PPV were higher in the NBI and WLE combined with stroboscopy group than in the NBI and WLE group without stroboscopy (88.9% vs 72.5%, 88.4% vs 60.9%). However, the diagnostic sensitivity was not significantly different in those two groups (69.3% vs 67.7%). Conclusion: NBI and WLE combined with stroboscopy is a promising method to detect early-stage vocal cord cancer with the advantage of clinical feasibility and diagnostic specificity.