Revisiting Loré's retrograde thyroidectomy from the perspective of preserving the external branch of the superior laryngeal nerve.

Background: Injury to the external branches of the superior laryngeal nerve (EBSLN) is the main reported cause of inexplicable post-thyroidectomy dysphonia (PTD) without recurrent laryngeal nerve (RLN) injury. Loré proposed a retrograde thyroidectomy (RT) technique in which the superior pole is dissected as a final step after the Berry ligament division, making this approach advantageous for protecting the EBSLN. However, evidence of this protective effect remains insufficient. We aimed to evaluate EBSLN function following RT and conventional thyroidectomy (CT) using postoperative electromyography (EMG). Methods: This is a retrospective cohort study conducted at a single tertiary center. Consecutive patients who had undergone CT or RT were included. Bilateral EMG of the cricothyroid muscle was performed 2-3 months postoperatively in all patients. Patient characteristics, postoperative findings of bleeding events, drain amount, hypocalcemia, calcium replacement, RLN function, and EBSLN function were thoroughly reviewed and compared between the two surgical approaches. Abnormalities in the EMG findings were reported based on the wave configuration, and the results were graded into four categories. Results: Seven hundred and thirty-one consecutive patients who underwent CT (n=341), or RT (n=390) were included, and a total of 1,179 RLNs and EBSLNs were at risk in CT (n=601) and RT (n=578). The CT and RT groups had similar clinical characteristics and surgical data. Two groups presented similar postoperative results for bleeding incidence, drain amount, and hypocalcemia. All RLNs were identified in both groups and their permanent function was preserved. EBSLN was significantly less frequently identified in the surgical field during RT than it was during CT (0.3% vs. 4.2%, respectively; P<0.001). Abnormal rates of postoperative EMG on the EBSLN were significantly lower in the RT group than in the CT group (1.7% vs. 7.8%, respectively; P<0.001), while the CT group presented with a higher grade of abnormal EMG (P<0.001). Conclusions: The RT technique may be beneficial for preserving EBSLN function. Meticulous capsular dissection and appropriate traction of the upper pole facilitated by RT are crucial for decreasing the risk of EBSLN injury, which can be achieved without directly identifying the nerve.

Real-time light-guided vocal fold injection as a simulation-based training tool.

OBJECTIVE: Cricothyroid (CT) approach for vocal fold injection (VFI) has advantages of a low complication rate, suitability for in-office practice, and good patient compliance. However, it requires a high level of experience and a steep learning curve due to invisibility of needle. Recently, real-time light-guided VFI (RL-VFI) was developed for safe and precise injection into laryngeal structures under light guidance. Herein, we describe the development of a simulation-based training (SBT) program using RL-VFI for CT approach and report its preliminary application with in-training otolaryngologists. METHODS: The workshop comprised 3 sessions: mini-lectures, and two hands-on training courses of conventional VFI and RL-VFI. Excised canine larynges and the device for RL-VFI were prepared for hands-on courses. Comfort levels for VFI was evaluated using visual analogue scale after each session. Trainees were requested to identify the needle tip on the target point lateral to vocal process. The time (s) to reach the target point was measured in all procedures. After workshop, all participants filled out questionnaires regarding their future preference for conventional VFI and RL-VFI. RESULTS: Eleven otolaryngology residents participated in the study. The mean comfort levels were 1.7 ±â€¯1.6, 5.5 ±â€¯2.6, 4.8 ±â€¯1.7, and 7.5 ±â€¯1.6 for pre-workshop, post-lecture, post-conventional VFI, and post-RL-VFI (P < .001). The mean time (s) to reach the target point were 146.4 ±â€¯90.1 and 42.7 ±â€¯40.5 for conventional VFI and RL-VFI (P = .004). The mean preference scores were 4.2 ±â€¯1.3 and 8.7 ±â€¯1.3 for conventional VFI and RL-VFI (P = .004). CONCLUSION: SBT program using RL-VFI might improve the comfort levels of trainees for VFI with CT approach. It would be helpful for trainees to practice VFI before trying it on actual patients. LEVEL OF EVIDENCE: N/A.

Septal Cartilage Traction Suture Technique for Correction of Caudal Septal Deviation.

OBJECTIVE: Correction of the caudal septum deviation is the most difficult part of the septoplasty and a common cause of revision septoplasty. The purpose of this study was to present authors' preliminary results in the treatment of patients with caudal septal deviation using the septal cartilage traction suture technique. STUDY DESIGN: Prospective, single center, observational study. MATERIALS AND METHODS: Sixty-seven patients with a caudal septal deviation underwent septal cartilage traction suture technique with endonasal septoplasty. After removal of excessive caudal cartilage, the caudal L-strut was sutured at two or more points using 5-0 Vicryl on the modified Killian incision site. Subjective outcomes using visual analog scales (VAS) and Nasal Obstruction Symptom Evaluation (NOSE) scale, objective endoscopic examination, and acoustic rhinometry data were assessed. RESULTS: There was significant symptomatic improvement in the VAS and NOSE scale at 1, 3, and 6 months postsurgery. Complete correction in the endoscopy was observed in the 91.0% of patients at 3 months postsurgery. The results of acoustic rhinometry increased from 0.3 and 4.3 preoperatively to 0.7 and 7.7 at 3 months postoperatively. Furthermore, no patient experienced septal hematoma, septal perforation, and loss of nasal tip support at 6 months follow-up. CONCLUSIONS: The septal cartilage traction suture technique obtained significant improvement in subjective and objective outcomes in patients with caudal septal deviation. This technique is a simple, safe, and effective method to treat caudal septal deviation. LEVEL OF EVIDENCE: 4 Laryngoscope, 2020.

Real-Time Light-Guided Vocal Fold Injection: Ex Vivo Feasibility Study in a Canine Model.

OBJECTIVE: The transcricothyroid (CT) membrane approach is a good option for office-based vocal fold injection (VFI). However, because the needle tip is invisible during injection using the CT approach, precise localization requires a high level of experience, and mastering this approach involves a steep learning curve. To overcome current limitations, we conceptualized a novel technique: real-time light-guided VFI (RL-VFI), which enables simultaneous VFI under direct visualization of the lighted needle tip. Herein, we aimed to verify the feasibility of RL-VFI in cadaveric canine model, simulating the setting of office-based VFI, as well as to explore its clinical usefulness. STUDY DESIGN: Animal study. METHODS: A customized prototype device was developed. It consisted of three parts: light source, controller, and injector. Light source comprised laser diodes of two wavelengths (635 nanometers [nm], red; 532 nm, green). Four types of injector were developed using 40-mm needles of 23- and 25-gauge and optic fibers of 50 and 100 µm. ex vivo canine larynx was prepared for the experiment. Flexible laryngoscopy system was used to examine canine vocal folds. RESULTS: Various routes from three insertion points (3 mm, 10 mm, and 17 mm from the midline) were validated using the device. Regardless of the injection routes, the location of the needle tip was accurately indicated by light. RL-VFI was feasible under light guidance without difficulties. Moreover, precise and simultaneous re-injection could be performed at the intended point using the device. CONCLUSION: We introduced RL-VFI using our customized prototype device in an ex vivo canine larynx, simulating the setting of office-based VFI. Clinical application of RL-VFI will improve safety and precision of CT approach, as well as expand its applications in laryngology. LEVEL OF EVIDENCE: NA. Laryngoscope, 129:935-942, 2019.

Luteolin inhibited the gene expression, production and secretion of MUC5AC mucin via regulation of nuclear factor kappa B signaling pathway in human airway epithelial cells.

Luteolin, a flavonoidal compound derived from Lonicera japonica Thunb. and Chrysanthemum indicum L., has been reported to show anti-inflammatory, anti-oxidative and anti-carcinogenic effects. In this study, we investigated whether luteolin significantly affects the secretion, production and gene expression of airway mucin. Confluent NCI-H292 cells were pretreated with luteolin for 30 min and then stimulated with EGF (epidermal growth factor) or PMA (phorbol 12-myristate 13-acetate) for 24 h or the indicated periods. The MUC5AC mucin gene expression was measured by RT-PCR. Production and secretion of MUC5AC mucin protein were measured by ELISA. To elucidate the action mechanism of luteolin, effect of luteolin on PMA-induced NF-κB signaling pathway was investigated by western blot analysis. The results were as follows: (1) Luteolin inhibited the secretion of MUC5AC mucin protein induced by EGF or PMA; (2) Luteolin inhibited the production of MUC5AC mucin protein and the expression of MUC5AC mucin gene induced by EGF or PMA; (3) Luteolin inhibited PMA-induced phosphorylation and degradation of inhibitory kappa Bα (IκBα); (4) Luteolin inhibited PMA-induced phosphorylation and nuclear translocation of nuclear factor kappa B (NF-κB) p65. This result suggests that luteolin can regulate the secretion, production and gene expression of mucin by acting on airway epithelial cells via regulation of NF-kB signaling pathway.

Apigenin Inhibits Tumor Necrosis Factor-α-Induced Production and Gene Expression of Mucin through Regulating Nuclear Factor-Kappa B Signaling Pathway in Airway Epithelial Cells.

In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-α (TNF-α)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-α for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription - polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-κB activation induced by TNF-α. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha (IκBα) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-κB signaling pathway in airway epithelial cells.

Simple sequence repeat (SSR)-based gene diversity in Burkholderia pseudomallei and Burkholderia mallei.

Pathogens Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) contain a large number (> 12,000) of Simple Sequence Repeats (SSRs). To study the extent to which these features have contributed to the diversification of genes, we have conducted comparative studies with nineteen genomes of these bacteria. We found 210 genes with characteristic types of SSR variations. SSRs with nonamer repeat units were the most abundant, followed by hexamers and trimers. Amino acids with smaller and nonpolar R-groups are preferred to be encoded by the variant SSRs, perhaps due to their minimal impacts to protein functionality. A majority of these genes appears to code for surface or secreted proteins that may directly interact with the host factors during pathogenesis or other environmental factors. There also are others that encode diverse functions in the cytoplasm, and this protein variability may reflect an extensive involvement of phase variation in survival and adaptation of these pathogens.