The dynamics of deglutition during head rotation using dynamic 320-row area detector computed tomography.

Objective: We aimed to elucidate the dynamics of deglutition during head rotation by acquiring 320-row area detector computed tomography (320-ADCT) images and analyzing deglutition during head rotation. Methods: This study included 11 patients experiencing globus pharyngeus. A 320-ADCT was used to acquire images in two types of viscosity (thin and thick), with the head rotated to the left. We measured the movement time of deglutition-related organs (soft palate, epiglottis, upper esophageal sphincter [UES], and true vocal cords) and pharyngeal volume (bolus ratio at the start of UES opening [Bolus ratio], pharyngeal volume contraction ratio [PVCR], and pharyngeal volume before swallowing [PVBS]). A two-way analysis of variance was performed for statistical analysis, and all items were compared for significant differences in terms of head rotation and viscosity. EZR was used for all statistical analyses (p-value <.05). Results: Head rotation significantly accelerated the onset of epiglottis inversion and UES opening compared with no head rotation. The duration of epiglottis inversion with the thin viscosity fluid was significantly longer. The bolus ratio increased significantly with thick viscosity. There was no significant difference in viscosity and head rotation in terms of PVCR. PVBS increased significantly with head rotation. Conclusion: The significantly earlier start of epiglottis inversion and UES opening due to head rotation could be caused by: (1) swallowing center; (2) pharyngeal volume; and (3) pharyngeal contraction force. Thus, we plan to further analyze swallowing with head rotation by combining swallowing CT with manometry and examine its relationship with pharyngeal contraction force. Level of Evidence: 3b.

Cricotracheostomy for patients with severe COVID-19: A case control study.

Background: Tracheostomy is an important procedure for the treatment of severe coronavirus disease-2019 (COVID-19). Older age and obesity have been reported to be associated with the risk of severe COVID-19 and prolonged intubation, and anticoagulants are often administered in patients with severe COVID-19; these factors are also related to a higher risk of tracheostomy. Cricotracheostomy, a modified procedure for opening the airway through intentional partial cricoid cartilage resection, was recently reported to be useful in cases with low-lying larynx, obesity, stiff neck, and bleeding tendency. Here, we investigated the usefulness and safety of cricotracheostomy for severe COVID-19 patients. Materials and methods: Fifteen patients with severe COVID-19 who underwent cricotracheostomy between January 2021 and April 2022 with a follow-up period of ≥ 14 days were included in this study. Forty patients with respiratory failure not related to COVID-19 who underwent traditional tracheostomy between January 2015 and April 2022 comprised the control group. Data were collected from medical records and comprised age, sex, body mass index, interval from intubation to tracheostomy, use of anticoagulants, complications of tracheostomy, and decannulation. Results: Age, sex, and days from intubation to tracheostomy were not significantly different between the COVID-19/cricotracheostomy and control/traditional tracheostomy groups. Body mass index was significantly higher in the COVID-19 group than that in the control group (P = 0.02). The rate of use of anticoagulants was significantly higher in the COVID-19 group compared with the control group (P < 0.01). Peri-operative bleeding, subcutaneous emphysema, and stomal infection rates were not different between the groups, while stomal granulation was significantly less in the COVID-19 group (P = 0.04). Conclusions: These results suggest that cricotracheostomy is a safe procedure in patients with severe COVID-19.

Laryngeal complications after endotracheal intubation and prone positioning in patients with coronavirus disease 2019.

Objectives: Laryngeal complications have been reported after endotracheal intubation and prone positioning in patients with critical coronavirus disease 2019 (COVID-19), but their association is unclear. In this study, we investigated the rate of laryngeal complications in patients with COVID-19 compared to an alternative condition (control group). Methods: We retrospectively analyzed the data of 40 patients who underwent endotracheal intubation for either COVID-19 or an alternative condition (control group). Data on age, sex, body mass index (BMI), cardiovascular disease (CVD) risk factors, use of prone therapy, duration of endotracheal intubation, and duration from extubation/tracheostomy to laryngeal evaluation were collected from medical records. Results: There were no significant differences in BMI, frequency of CVD risk factors, duration of endotracheal intubation, or duration from extubation/tracheostomy to laryngeal evaluation between the two groups. In the COVID-19 group, all patients adopted the prone position. In comparison, only one patient in the control group adopted the prone position. Significant differences were observed between the two groups regarding the incidence of vocal fold immobility and laryngeal granuloma. Conclusion: Laryngeal complications were more common in the COVID-19 group than in the control group. Prone positioning may be a risk factor for these complications. Level of Evidence: 4.

Development of a simple evaluation instrument for liquid thickness measurement.

Simple methods, such as the line spread test (LST), are often used to evaluate thickened liquids in clinical settings. Although it is desirable for these simple methods to be rapid, even the LST requires approximately 1 min to complete the evaluation. Herein, we aimed to shorten this time by developing a new simple instrument for evaluating thickened liquids considering the fluid engineering perspective with improved funnel design and evaluation methods. A thickened liquid was prepared with a xanthan gum-based thickening agent and water. Samples with viscosities of approximately 50, 150, 300, and 500 mPa∙s were prepared. For evaluation, 30 ml of the sample was injected manually with the outlet closed. The outlet was then opened to allow the liquid to fall as soon as the evaluation began. The time taken for the water surface of the liquid to move 50 mm from the starting point to the target point was measured eight times using a stopwatch, and the average was taken as the evaluation time. The instrument took 2.22-3.29 s, 3.29-9.16 s, and 9.16-23.14 s to classify mildly thick, moderately thick, and extremely thick samples, respectively. This method enabled extremely thick samples to be evaluated in 23 s, which is 27 s less than the time taken by the conventional funnel method. Verification results showed that this developed evaluation instrument for thickened liquids could perform classification according to the criteria of the Japanese Dysphagia Diet 2013. We aim to improve its design for clinical use in the future.

Post-transplantation laryngeal actinomycosis.

A case of laryngeal actinomycosis occurred after bone marrow transplantation was reported. The patient was a 14-year-old girl who had a history of bone marrow transplantation for the treatment of acute lymphocytic leukemia 4month before the onset of the disease. She was referred to our hospital complaining persistent sore throat since 2weeks ago. Fiberscopic observation proved the presence of white tumor-like mass on her right arytenoid of the larynx. As CT image demonstrated that the mass was localized at the arytenoid region with central low-density area surrounded by granulation tissue, we underwent biopsy under local anesthesia. Excision of the mass proved it to be a soft granulation including sulfur granules. Oral administration of amoxicillin 750mg per day was initiated as a postoperative medication. On day 17, histological study confirmed that the tumor-like mass was Actinomyces granuloma, and therefore amoxicillin administration continued. The medication was effective to subside the disease and the arytenoid lesion healed on day 31. Amoxicillin was further administered until day 70 to prevent recurrence. At 6month after the biopsy, she was free from the disease.

Preventive effects of bortezomib on denervation-induced atrophy of the intrinsic laryngeal muscles: an experimental study in the rat.

CONCLUSION: Bortezomib was effective in attenuating atrophy of the posterior cricoarytenoid (PCA) muscle, but not the thyroarytenoid (TA) muscle. This was probably due to differences in the fiber composition of the two muscles. The PCA muscle is composed of a combination of fast- and slow-twitch fibers, and therefore is more resistant to atrophy than the TA muscle, which is composed solely of fast-twitch fibers. OBJECTIVES: To investigate the preventive effects of bortezomib on denervation-induced atrophy of the TA and PCA muscles in the rat. METHODS: Following transection of the left recurrent laryngeal nerve, bortezomib (100 µg/kg) was administered subcutaneously on post-denervation days 1 and 4, followed by a 10-day rest period every 14 days; each 2-week period constituted a single treatment cycle. In controls, saline was administered instead. Animals were killed for histological examination at 4 (n = 6), 8 (n = 7), and 12 (n = 7) weeks post-denervation. Muscle atrophy was assessed using three indices: wet muscle weight, muscle fiber cross-sectional area, and the number of muscle fibers/mm(2). The effects of bortezomib were evaluated by comparing the left (L) and right (R) muscles, with sequential changes in the L/R ratio assessed. RESULTS: In saline-administered animals, atrophy of the left-sided TA and PCA muscles progressed rapidly during the first 4 weeks post-denervation, following which progression slowed. Atrophy was greater in the TA compared with the PCA muscle, although this difference was not statistically significant. In bortezomib-administered animals, atrophy of the PCA muscle was attenuated significantly at post-denervation weeks 8 and 12; no such reduction in atrophy was observed for the TA muscle.

Expression of atrophy-related transcription factors in the process of intrinsic laryngeal muscle atrophy after denervation.

We examined changes in the expressions of three atrophy-related transcription factors (FOXO3a, P-FOXO3a, and PGC-1α) in the process of intrinsic laryngeal muscle atrophy after denervation. In total, 51 Wistar rats were used. After transection of the unilateral recurrent laryngeal nerve, the thyroarytenoid (TA) muscle and the posterior cricoarytenoid (PCA) muscle were excised and subjected to histological and Western blot studies. Relationships between the expressions of transcription factors during atrophy of the intrinsic laryngeal muscles were investigated by comparing the results of the treated side (T) with those of the untreated side (U), and sequential changes in the T/U ratio after denervation were assessed. Loss of wet muscle weight, together with a decrease in muscle fiber cross-sectional area and increase in the number of muscle fibers/mm(2), occurred more quickly in TA muscle than in PCA muscle. Muscle atrophy progressed rapidly between 7 and 28 days after denervation, while expression of FOXO3a was maximal on day 7, in both TA and PCA muscles. By contrast, P-FOXO3a expression decreased gradually after denervation. Expression of PGC-1α increased slowly until day 7, and then it declined. Denervation-induced atrophy of the intrinsic laryngeal muscles was closely linked with the expression of FOXO3a and PGC-1α, suggesting that atrophy of these muscles may involve the actions of these transcription factors. In addition, muscle atrophy progressed faster in TA muscle than in PCA muscle, due mainly to differences in muscle fiber composition.