The impact of SARS-Cov-2 infection on the periocular injection pain and hypersensitive reaction to botulinum toxin type A: results from clinical questionnaires.

Background: The COVID-19 pandemic has brought about significant changes in the medical field, yet the use of botulinum toxin type A has remained uninterrupted. Plastic surgeons must carefully consider the timing of administering botulinum toxin type A to patients who have recovered from COVID-19. Methods: A questionnaire survey was conducted among patients who had contracted and recovered from SARS-CoV-2 within a month. The survey aimed to investigate various indicators in patients who had received botulinum toxin A injections at the same site before and after their infection, including pain scores and allergic reactions and the occurrence of complications. Results: The pain scores of patients who contracted SARS-CoV-2 infection between 14-21 days post-infection exhibited significant variation from previous injections. However, patients who contracted the infection between 22-28 days post-infection did not exhibit significant variation from previous injections. Furthermore, the incidence of allergic reactions and complications following botulinum toxin injection within one month after contracting the infection did not significantly differ from that observed prior to infection. Conclusion: Administering botulinum toxin type A three weeks after COVID-19 recovery is a justifiable and comparatively secure approach.

Anthropometric assessment of microtia patients' normal ears and discussion on expander selection in auricular reconstruction surgery.

The tissue expansion technique is the most suitable procedure for Chinese patients with microtia. However, it is difficult to determine whether the expanded flap is sufficient, and there are no clear or objective guidelines for determining the volume of the expander for different sizes of auricles. One hundred patients with unilateral microtia who visited our department in 2021 were randomly selected for auricular data collection using 3D scanning. The auricle length, width, projection, perimeter, and surface area were measured. Eight different volumes of expanders underwent CT and the surface areas of these expanders were measured. The surface areas of the auricles and expanders were compared and the correlation between them was explored. The average auricle parameters were calculated. The scatter plot showed a linear relationship between auricle length and auricle surface area (R2 = 0.9913), which demonstrated that the auricle area was approximately equal to the auricle length multiplied by 76.921. Additionally, the surface area of the expanders was measured and made into a table for selection against the surface area of the auricles. Using our equation, the auricle surface could be estimated by simply measuring the non-defective auricle length; therefore, the suitable volume of the expander could be determined.

Differences between Bilateral Costal Cartilage in Patients with Microtia: A Retrospective Study Using Three-Dimensional Imaging.

SUMMARY: Costal cartilage is the ideal medium for auricular framework fabrication in auricular reconstruction surgery. Well-developed cartilage is closely associated with surgical outcomes; however, which costal cartilage is better developed and more suitable for framework fabrication is controversial. This study aimed to examine the laterality differences in costal cartilage development in pediatric patients who have undergone auricular reconstruction surgery for microtia. Preoperative thoracic computed tomography data of 101 microtia patients (age range, 6 to 10 years) were retrospectively analyzed. Computer software was used to create three-dimensional costal cartilage images. The length and volume of the costal cartilage of the sixth, seventh, and eighth ribs were measured from these images. Results indicate that the cartilage of the sixth rib on the left side was significantly longer and had a greater volume than that on the right side. Further, the cartilage of the seventh rib on the left side was significantly longer than that on the right side; however, there was no significant difference in volume. No significant differences were found between the cartilage of the eighth rib on the right and left sides. In general, the costal cartilage of ribs on the left side of the thorax was more developed than that on the right. These results may help clinicians in selecting appropriate donor sites before auricular reconstruction surgery in microtia patients.

Contribution of perichondrium to the mechanical properties of auricular cartilage.

The poor mechanical strength of tissue-engineered auricular cartilage which is possibly due to the lack of perichondrium limits its application in auricular reconstruction surgery. However, there is insufficient research and no reliable data to support this. This study aims to investigate the contribution of perichondrium to the mechanical strength of auricular cartilage under loading. Rabbit auricular cartilage was harvested and classified into two groups. The perichondrium was removed in Group A and was left intact in Group B. Young's modulus, stress relaxation slope, and relaxation amout were analyzed through tensile and compressive tests using a material testing machine. Group B exhibited significantly higher Young's modulus in both the tensile and compressive tests (p < 0.05), lower relaxation slope (p < 0.05 in tensile test, p = 0.65 in compressive test), and lower relaxation amout (p < 0.05 in tensile test, p < 0.01 in compressive test). Our results showed that the perichondrium has a definite contribution to the mechanical properties of ear cartilage. This study may provide new insights to researchers focusing on improving the mechanical strength of tissue-engineered auricular cartilage.

Dispersive solid-phase extraction for the determination of trace organochlorine pesticides in apple juices using reduced graphene oxide coated with ZnO nanocomposites as sorbent.

In this work, reduced graphene oxide coated with ZnO nanocomposites was used as an efficient sorbent of dispersive solid-phase extraction and successfully applied for the extraction of organochlorine pesticides from apple juice followed by gas chromatography with mass spectrometry. Several experimental parameters affecting the extraction efficiencies, including the amount of adsorbent, extraction time, and the pH of the sample solution, as well as the type and volume of eluent solvent, were investigated and optimized. Under the optimal experimental conditions, good linearity existed in the range of 1.0-200.0 ng/mL for all the analytes with the correlation coefficients (R2 ) ranging from 0.9964 to 0.9994. The limits of detection of the method for the compounds were 0.011-0.053 ng/mL. Good reproducibilities were acquired with relative standard deviations below 8.7% for both intraday and interday precision. The recoveries of the method were in the range of 78.1-105.8% with relative standard deviations of 3.3-6.9%.