Effect of intranasal administration of concentrated growth factors on regeneration of the olfactory epithelium in an olfactory dysfunction-induced rat model.

OBJECTIVE: The development of treatments that promote the regenerative capacity of the olfactory epithelium (OE) is desirable. This study aimed to evaluate the effects of intranasal administration of concentrated growth factors (CGFs) in a rat model of olfactory dysfunction. STUDY DESIGN: Animal study. METHODS: Nineteen male rats were used. Fourteen olfactory dysfunction models were created by intraperitoneal administration of 3-methylindole. We randomly divided the rats from the olfactory dysfunction model after 1 week into the CGF or saline group; CGFs were administered to seven animals and saline to seven animals. Behavioral assessments using the avoidance test were conducted until day 28 after CGF/saline administration. On day 28, histological evaluation was conducted to determine olfactory epithelial thickness and the olfactory marker protein (OMP)-positive cell count. Five animals were intraperitoneally injected with saline as the control group. RESULTS: The avoidance rate remained decreased until 28 days after CGF/saline administration, and there was no significant difference between the two groups. Olfactory epithelial thicknesses on day 28 were 38.64 ± 3.17 µm and 32.84 ± 4.50 µm in the CGF and saline groups, respectively. OE thickness was significantly thicker in the CGF group than in the saline group (P = 0.013). The numbers of OMP-positive cells were 40.29 ± 9.77/1.0 × 104 µm2 and 31.00 ± 3.69/1.0 × 104 µm2 in the CGF and saline groups, respectively. The number of OMP+ cells in the CGF group was significantly increased compared with that in the saline group (P = 0.009). Both groups showed no improvement compared with the control group (OE thickness: 54.08 ± 3.36 µm; OMP+ cell count: 56.90 ± 9.91/1.0 × 104 µm2). CONCLUSIONS: The CGF group showed improved olfactory epithelial thickness and OMP-positive cell numbers compared with that in the saline group.

Development of a proficiency-based training curriculum for beginners in endoscopic endonasal surgery.

OBJECTIVE: Precise endoscopic skills are critical for endoscopic endonasal surgery (EES) to ensure patient safety, as well as to succeed as a surgeon. Among these skills, basic skills such as hand-eye coordination and bimanual dexterity are the most important skills for novice surgeons. However, there is no proficiency-based training for the basic skills in EES. In this study, we aimed to develop a proficiency-based training curriculum for beginners in EES using tractable tasks and to assess the curriculum's validity and educational benefits. METHODS: Training tasks for basic surgical skills of EES were created by experts, using a low-cost and simple simulator. Subsequently, a proficiency-based training curriculum was developed through a preliminary study. The face and content validity of the curriculum was evaluated by expert surgeons. The construct validity was confirmed by comparing the scores of the medical students with those of the experts. In addition, the educational benefits of the curriculum were assessed by comparing the scores of the medical students before and after the implementation of the curriculum. RESULTS: A proficiency-based training curriculum using six tractable tasks was developed in the preliminary study. Replication of real surgical situation, camera navigation, and instrument operability under endoscopy were all highly appreciated (4.6, 4.6, and 4.8 out of 5 points, respectively), which indicates face validity. The content validity of the curriculum was demonstrated by the results of the questionnaire (4.4 out of 5 points). The curriculum was implemented by 12 medical students. The initial student scores were significantly lower than the expert scores (mean score: 61.9 vs. 100.0, p < 0.001), and each coefficient of variation of the student scores was higher than that of the expert scores (p < 0.01), supporting the construct validity of the curriculum. The mean student composite scores were statistically improved after the training (61.9 vs. 93.3, p < 0.0001). In addition, improvement of five other medical students' EES skills through this training curriculum was confirmed in cadaver dissection (1.7 vs. 3.7, p < 0.0001). CONCLUSION: The validity of the proficiency-based training curriculum developed through the preliminary study was established based on the questionnaire of experts and the difference between student and expert scores. In addition, the educational benefits were demonstrated by the students' learning curves. The low-cost and simple simulator seems appropriate as an entry model for beginners in EES, and this curriculum can provide rapid intervention and objective assessment of basic skills in EES.

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.

Efficacy of chlorophyll c2 for seasonal allergic rhinitis: single-center double-blind randomized control trial.

Chlorophyll c2 extracted from Sargassum horneri improved allergic symptoms in an animal model of allergic rhinitis. In the present study, we explored the efficacy of chlorophyll c2 in patients with seasonal allergic rhinitis. This was a single-center, randomized, double-blind placebo-controlled trial. Sixty-six patients aged 20-43 years, each with a 2-year history of seasonal allergic rhinitis, were randomly assigned to receive either a single daily dose (0.7 mg) of chlorophyll c2 or placebo for 12 weeks. The use of medications including H1-antihistamines and topical nasal steroids was recorded by rescue medication scores (RMSs) noted after 4, 8, and 12 weeks of treatment. Disease-specific quality of life was measured using the Japan Rhinitis Quality of Life Questionnaire (JRQLQ) both before and after 4, 8, and 12 weeks of treatment. The RMS at 8 weeks was significantly better in the chlorophyll c2 than the placebo group (mean RMS difference = -3.09; 95 % confidence interval = -5.96 to -0.22); the mean RMS at 4 weeks was only slightly better in the chlorophyll c2 group. The JRQLQ scores did not differ significantly between the two groups. Chlorophyll c2 would have a potential to be an alternative treatment for allergic rhinitis.

Treatment of allergic rhinitis with intranasal infusion of botulinum toxin type A in mice.

AIMS: To determine whether intranasal infusion of botulinum toxin type A (BTX-A) relieves symptoms of ovalbumin (OVA)-induced allergic rhinitis (AR) and reduces nasal inflammation in mice. MAIN METHODS: AR was induced via intraperitoneal injection of OVA followed by daily intranasal challenge with OVA. Five weeks after the initiation of OVA sensitization, nasal cavities were exposed to a single intranasal infusion of BTX-A. The behavior of mice was observed before and 1, 3, 5, 7, 14, 21, and 28days after infusion. Mice were sacrificed after 28days and late histological findings were examined. PBS was administered to control mice. RESULTS: On Day 3, the frequency of typical AR symptoms, including sneezing and nose scratching, significantly decreased in the BTX-A-treated group (n=6) compared to the control group (n=6). Although the AR-inhibiting effects of BTX-A persisted until Day 21, AR symptoms re-appeared in response to daily OVA stimulation. Histological findings of the nasal mucosa also improved following BTX-A administration. Although capillary dilatation and eosinophil infiltration decreased by Day 3, these effects disappeared by Day 28. In contrast, the number and size of the secretary glands in the nasal mucosa did not change following BTX-A administration. PBS had no effect on nasal symptoms or histology. CONCLUSIONS: Topical treatment with BTX-A efficiently and temporarily ameliorates AR symptoms. Intranasal infusion does not cause pain or bleeding, and the effects of a single infusion of BTX-A last for at least three weeks. This treatment might be a promising therapeutic strategy for the treatment of AR.