Post-peak Period Research Articles

Spatio-temporal evolution law of anisotropic shear damage on rock mass joint surface affected by joint morphology

The spatial–temporal evolution law of shear damage on the joint surface is closely related to its morphological characteristics. Understanding the heterogeneous failure behavior of the joint surface is essential for revealing the controlling role of the joint morphology. The diorite from the Guanshan Tunnel is investigated through anisotropic direct shear tests in this study. Based on shear damage quantification and acoustic emission (AE) localization techniques, the heterogeneous damage evolution law of joint surfaces under different joint compression strength (JCS), normal stress (σn), and morphology parameter (M) is studied. The results indicate that the joint surface morphology, shear damage, and AE parameters exhibit similar anisotropic characteristics in different shear directions. An increase in the morphology parameter leads to an increase in shear failure, with shear fracture energy and the number of fracture events showing an increasing trend. Meanwhile, the occurrence of a large number of fracture points shifts from the pre-peak nonlinear period to the post-peak period. However, the evolution process of fracture events exhibits certain similarities, though the morphology parameters are different in two opposite shear directions. Additionally, shear damage volume and fracture energy demonstrate consistency in spatial distribution and quantitative characteristics, while the linear scale factor between cumulative shear fracture energy and damage volume decreases with increasing joint surface strength. These findings assist in a better understanding of the anti-sliding property of joint surfaces and provide crucial clues for further exploration of joint surface failure mechanisms.

An incentive strategy for the retention of impatient passengers in ride-sourcing markets

A prominent problem plagued the ride-sourcing service providers is the instantaneous real-time demand–supply imbalance. This entails a terrible user experience and causes adverse sustainable results such as customer churn for the platform, which will damage both drivers’ income and the platform revenue. To reduce passenger cancellation caused by extended wait times, we propose an incentive-based queue management strategy —a discount method— to enhance the waiting experience and encourage passengers to stay in a post-peak period . We formulate the waiting process for a ride-sourcing service as an M/M/c+M queue system with impatient passengers, and model passengers’ reneging behaviors by characterizing the impact of discounted trip fare and updated queue information on their travel utilities. Based on such a behavior model, we can analyze the effect of the discount strategy on the queueing process, which allows us to maximize the platform’s profit growth by tailoring the discount strategy. Our result shows that the discount strategy can effectively increase the platform’s profit. Under the specific condition of the discount strategy, the earlier the strategy is implemented in the post-peak period, the higher platform profit can be achieved. Moreover, we explore the impact of queueing system parameters on the performance of the discount strategy and gain some interesting insights.

Age validation of yellowfin tuna Thunnus albacares in the Indian Ocean using post-peak bomb radiocarbon chronologies

Yellowfin tuna Thunnus albacares stock assessments use age-structured models; therefore, accurate methods for ageing the catch are required. Age estimation techniques need to be validated at the population level to ensure accuracy. However, otolith-based age estimates of yellowfin tuna have never been validated in the Indian Ocean. The current study provides the first age validation for Indian Ocean yellowfin tuna using the post-peak decline period of the bomb radiocarbon (14C) chronometer. A 14C reference chronology based on accelerator mass spectrometry assays of known-age yellowfin tuna otoliths was consistent with published regional coral records, with all showing similar rates of decline during the 2000 to 2019 study period. After back-calculating the birth years of sub-adult and adult yellowfin tuna from otolith increment counts, Δ14C values measured in the early growth portion of the otolith were compared with the observed decline slope of the reference chronology. There were no significant differences between the birth years of validation and reference samples, supporting the otolith increment age determination methodology between the ages of 2.2 and 10.5 yr. The validation of age and growth estimates is expected to benefit assessment models for Indian Ocean yellowfin tuna. We recommend that otoliths from large fish continue to be collected to expand the validation to older fish. Greater precision in the validation results will also require a larger reference chronology.

The response of laying hen production, performance, bone health, and inositol levels to limestone particle size ratios and phytase levels supplemented during the post-peak period (40–60 wk of age)

The response of laying hen production, performance, bone health, and inositol levels to limestone particle size ratios and phytase levels supplemented during the post-peak period (40–60 wk of age)

Have consumption-based CO2 emissions in developed countries peaked?

This study innovatively divided consumption-based CO2 emissions of developed countries into domestic and foreign components using an environmentally extended multi-regional input–output model, and revealed their different driving factors using the structural decomposition analysis method. The results showed that the consumption-based emission peaked in 16 developed countries, with 14 countries peaking around 2008. Domestic emissions in all 16 developed countries had peaked, most of which accounted for 40–70% of the total consumption-based emissions. However, the foreign emissions driven by 9 peaking countries still kept increasing. Regarding domestic emissions, the decline of domestic carbon intensity was the main driving factor across 16 peaking countries. In terms of foreign emissions, carbon intensity decline, especially in main medium- and low-income countries, was the dominant factor in the CO2 emissions decrease. Significant improvements in production technology levels of medium-income countries played a key role in weakening the carbon-increasing effects of foreign emissions during the post-peak period. Thus, to further promote global carbon emissions to peak as soon as possible, peaking developed countries should provide more emission reduction funds and technologies to support the decline in carbon intensity and the improvement of production technology in medium- and low-income countries.

Differences in medical education before, during, and in the post-peak period of the COVID-19 pandemic—exploring senior medical students’ attitudes

BackgroundThe burden that COVID-19 has brought to the economy, healthcare systems, and education is unmatched. Public health and social measures were implemented to halt transmission. Thus, social gathering and in-person learning, core aspects of medical education, were interrupted. Studies have documented the detrimental impact students graduating during the pandemic have had on their confidence and skills. However, data comparing pre-pandemic, pandemic, and post-peak students still lack. This study aimed to identify senior medical students' attitudes regarding their education and compare them according to the three previously described periods.MethodsIn this cross-sectional study, the survey employed was designed based on a previous questionnaire and applied to senior medical students before graduating between January 2018 and June 2022. Answers were collected using a three-point Likert scale and Yes/No questions. Associations between variables were examined using Chi-squared, Fisher’s Exact tests, and ANOVA, employing logistic regression to calculate odds ratio (OR) when appropriate.ResultsA total of 679 responses were analyzed. Most students (59%) were women. Up to 383, 241, and 55 senior medical students answered the survey before, during, and in the post-peak period of the COVID-19 pandemic, respectively. There was a staggering decrease in the percentage of students in the post-peak compared to the pre-pandemic period that considered certain factors such as being taught about the doctor-patient relationship (62% vs 75%), practicing teamwork (33% vs 54%), preclinical & clinical subjects (44% vs 63%), and being taught to conduct research (22% vs 32%) as “very useful” to their professional traineeship. There was a significant difference between pre-pandemic, pandemic, and post-peak students when asked if the study curriculum accomplished the goal of training a professional with integrity (89% vs 66% vs 64%, p < 0.001), respectively. In a multivariate analysis graduating during the pandemic (OR 3.92; 95% CI, 2.58–5.94) and in the post-peak period (OR 4.24; 95% CI, 2.23–8.07) were independent factors for the appreciation that the study curriculum did not meet its objective.ConclusionsThe pandemic has hindered medical education. Students’ appreciation of their instruction has deteriorated. Urgent interventions that halt the negative impact on training, ensure readiness for future problems and improve schooling worldwide are needed.

Dietary L-Glutamine affects Eggshell Quality in the Post-Peak Laying Period

Abstract In the current study the hypothesis that 1.0% dietary inclusion of glutamine (Gln), a conditionally essential amino acid that influences protein synthesis and shows anti-osteoporotic effect, can influence eggshell quality was tested on laying hens in the post-peak laying period. Thirty-week-old Bovans Brown hens were randomly assigned to control group or group supplemented with Gln in the form of alphaketoglutarate (10 g/kg) with 12 replicate cages (2 hens/cage) in each group. The experimental period lasted for 30 weeks, from the 31st to the 60th week of age of hens, when eggs were collected and selected eggshell quality indices were determined. While Gln supplementation had no effect on egg geometry and eggshell cracking force, the analysis of eggshell quality showed an increase of the eggshell thickness (P&lt;0.01), porosity (P&lt;0.01), eggshell specific surface (P&lt;0.001) and positive changes in other mechanical parameters (decrease of eggshell stiffness and Young’s modulus, P&lt;0.05 and P&lt;0.01, respectively; increase of work needed to crack the eggshell, P&lt;0.05). Changes in eggshell mineral composition, including an increase of Ca content (P&lt;0.001), were also observed. In conclusion, the current study showed a beneficial effect of Gln on the eggshell thickness, calcification, and some mechanical parameters.

Social media use, uncertainty, and negative affect in times of pandemic crisis.

A common assertion in the social media literature is that passive media use undermines affective wellbeing, and active media use enhances it. The present study investigated the effects of social media use on negative affective wellbeing during pandemic crises and examined the mechanism underlying these effects through perceived uncertainty. Three studies were conducted during the Delta variant phase in the post-peak period of the COVID-19 pandemic in China. Participants were recruited from the medium-high-risk infection areas in late August 2022. Study 1 used a cross-sectional survey to explore the relationships between social media use, uncertainty, and negative affect during the pandemic crisis. Study 2 employed a repeated-measures experiment to demonstrate how social media use and (un)certainty impact negative affect. Study 3 utilized a one-week experience sampling design to examine the role of uncertainty in the relationship between social media use and negative affect in real life. Despite some inconsistencies regarding social media use's direct effect on negative affect, across the three studies, perceived uncertainty was critical in linking pandemic-related social media use to individuals' negative affect, particularly for passive use. The relationships between social media use and affective wellbeing are complex and dynamic. While the perception of uncertainty provided an underlying mechanism that links social media use to individuals' affective wellbeing, this mechanism may be further moderated by individual-level factors. More research is needed as we seek to understand how social media use impacts affective wellbeing in uncertain contexts.

Influence of COVID-19 pandemic and vaccination on the menstrual cycle: A retrospective study in Hungary.

Observations of women and clinicians indicated that the prevalence of menstrual cycle problems has escalated during the COVID-19 pandemic. However, it was not clear whether the observed menstrual cycle changes were related to vaccination, the disease itself or the COVID-19 pandemic-induced psychological alterations. To systematically analyze this question, we conducted a human online survey in women aged between 18 and 65 in Hungary. The menstrual cycle of 1563 individuals were analyzed in our study in relation to the COVID-19 vaccination, the COVID-19 infection, the pandemic itself and the mental health. We found no association between the COVID-19 vaccination, the vaccine types or the COVID-19 infection and the menstrual cycle changes. We also evaluated the menstrual cycle alterations focusing on three parameters of the menstrual cycle including the cycle length, the menses length and the cycle regularity in three pandemic phases: the pre-peak, the peak and the post-peak period in Hungary. Our finding was that the length of the menstrual cycle did not change in any of the periods. However, the menses length increased, while the regularity of the menstrual cycle decreased significantly during the peak of the COVID-19 pandemic when comparing to the pre- and post-peak periods. In addition, we exhibited that the length and the regularity of the menstrual cycle both correlated with the severity of depression during the post-peak period, therefore we concluded that the reported menstrual cycle abnormalities during the peak of COVID-19 in Hungary might be the result of elevated depressive symptoms.

Numerical study on triaxial compressive behavior of engineered cementitious composites confined by circular steel tubes

The mechanism of engineered cementitious composites (ECC) in triaxial compression is still unclear, and the existing method cannot accurately predict its compressive capacity due to the lower elastic modulus and the effect of fiber bridging. In this paper, the compressive behavior of ECC confined by circular steel tubes was studied by performing a series of nonlinear finite element (FE) analysis. The non-linear material properties of ECC and steel and composite actions were considered in developing the FE models. The accuracy of the models was verified by comparison with the test results, such as load–displacement histories, failure modes and ultimate strengths. The verified model was utilized to explore contact pressure, the contribution of ECC to compressive capacity, ductility, energy absorption, and the influence of important parameters. Additionally, the effective confining stress (fr) was modified by average contact pressure, and a constitutive model of ECC under triaxial compression was developed by stress–strain relationships. It is shown that the effect of boundary confinement effect coefficient on the post-peak period of load–displacement history is classified and discussed. Meanwhile, the results of Richart’s model achieve a good accuracy by modifying the effective confining stress. Finally, a constitutive model of ECC under triaxial compression is proposed, of which the prediction results can describe the variation law of stress–strain relationship.

Preventive and control system for the life cycle of a pandemic

Herein, a matching method for varied epidemic phase characteristics and appropriate strategies is presented, aiming at the complexities of the novel coronavirus disease 2019 pandemic and the hysteresis of strategies. The classical diffusion dynamic models of the epidemic spread are compared. Furthermore, the Bass diffusion model is selected to study more characteristics of an epidemic, such as the diversities in regional internal and external infection rates. Thereafter, the classical division method vis-à-vis a pandemic life cycle is improved. A specific approach is proposed to portray more detailed characteristics of the pandemic by dividing it into more phases. Next, a four-level epidemic prevention and control measure system is concretized. The applicable phases and strategic effectiveness of each measure are integrated into the different phases of the pandemic life cycle. Finally, the matching method is applied to analyze two cases of the spread of the outbreak in cities and significant events. The findings provide a certain reference for the effectiveness of the matching method in the post-peak epidemic period.

A novel approach to radiographic detection of growth development period with hand-wrist radiographs: Apreliminary study with ImageJ imaging software.

The purpose of this study is to determine whether or not the ImageJ program can be used to automatically determine the growth period of the hand and wrist which have different growth-development periods according to the density values in the phalanges in radiographs. Our study included hands-wrist radiographs of 270 individuals aged 8-17 years. The study's participants were classified into 7 groups according to their skeletal maturation stage (PP2=, MP3=, MP3cap, DP3u, PP3u, MP3u, and Ru) which included pre-peak, peak, and post-peak periods. The total density values (TDV) and pure density values (PDV) in the distal, medial, and proximal phalanges were calculated using each radiograph in the ImageJ program. Analysis of variance (ANOVA) was used to evaluate the density values and chronological age, and pairwise comparisons were made using the post-hoc LSD test. The total density value was graphically zigzagged in the mesial, distal, and proximal phalanges. However, the pure density value increased continuously until the post-peak period and decreased after the DP3u period until the Ru period. While no significant difference in total density values was observed between the growth periods for all three phalanges, a significant difference in pure density values was observed. It has been demonstrated in the ImageJ program that the peak growth period can be distinguished using the pure density values obtained from all phalanges of the third finger and that this method can be used as an alternative to the growth period detection through artificial intelligence.

A Dynamic Nexus Between COVID-19 Sentiment, Clean Energy Stocks, Technology Stocks, and Oil Prices: Global Evidence

This study examines time-varying correlations between clean energy stocks, technology stocks, oil prices, and COVID-19 sentiment. The results confirm a weaker positive relation between oil prices and clean energy stocks. Correlations between COVID-19 sentiment and clean energy and technology stocks vary from low and negative during the peak period to positive and relatively high during the post-peak period. The results show the relatively better position of clean and technology stocks during the post-peak period.

Exit strategies from lockdowns due to COVID-19: a scoping review

IntroductionIn response to the ongoing COVID-19 pandemic, countries have adopted various degrees of restrictive measures on people to reduce COVID-19 transmission. These measures have had significant social and economic costs. In the absence of therapeutics, and low vaccination coverage, strategies for a safe exit plan from a lockdown are required to mitigate the transmission and simultaneously re-open societies. Most countries have outlined or have implemented lockdown exit plans. The objective of this scoping review is to (a) identify and map the different strategies for exit from lockdowns, (b) document the effects of these exit strategies, and (c) discuss features of successful exit strategies based on the evidence.MethodsA five-step approach was used in this scoping review: (a) identifying the research question and inclusion/exclusion criteria; (b) searching the literature using keywords within PubMed and WHO databases; (c) study selection; (d) data extraction; (e) collating results and qualitative synthesis of findings.ResultsOf the 406 unique studies found, 107 were kept for full-text review. Studies suggest the post-peak period as optimal timing for an exit, supplemented by other triggers such as sufficient health system capacity, and increased testing rate. A controlled and step-wise exit plan which is flexible and guided by information from surveillance systems is optimal. Studies recommend continued use of non-pharmaceutical interventions such as physical distancing, use of facemasks, and hygiene measures, in different combinations when exiting from a lockdown, even after optimal vaccination coverage has been attained.ConclusionReviewed studies have suggested adopting a multi-pronged strategy consisting of different approaches depending on the context. Among the different exit strategies reviewed (phase-wise exit, hard exit, and constant cyclic patterns of lockdown), phase-wise exit appears to be the optimal exit strategy.

Abstract P3-01-12: The impact of COVID-19 on diagnosis of recurrent breast cancer

Abstract Background - Physical distancing for COVID-19 led to decreased in-person patient follow up assessments and delayed imaging appointments. Herein we describe for the first time the impact of delays in diagnostic investigations of patients with an history of early-stage breast cancer (BC) in the largest public cancer center of Lombardy, the Italian region most affected by the pandemic. Methods - This single-institution retrospective study included three observational periods. The first pandemic peak period (March-April 2020) corresponding to the interruption of follow up imaging; the post-peak period (May-December 2020); the pre-pandemic period represented by the five previous years (January 2015- December 2019) as control. The flow of diagnostic activities was compared among the different years. Moreover, the number and characteristics of recurrent BC cases (rBC) diagnosed in the post-peak period were compared to the figures observed in pre-pandemic years, when imaging was regularly carried out, using descriptive statistics. A further comparison was performed between the characteristics of scheduled and delayed rBC diagnosed after the first peak. Results - During the first pandemic peak, diagnostic investigations declined by 81.2% (from 1032 in January-February to 194 in March-April), a drop which was not identified in the same period of the pre-pandemic years, before rebounding to 1065 in May-June, 832 July-August (reflecting the summer physiological drop), 1334 September-October, and 879 November-December. The average number of rBC cases of 16 (range 12-25) in March-April of the pre-pandemic period declined to a value as low as 4 during the first pandemic peak. Thereafter, the number of rBC cases began a steady increase, until reaching a total of 27 in September-October 2020, almost doubling the mean of 14.8 (range 11-21) achieved in the corresponding months of 2015-2019. As a result, the absolute number of rBC cases was 76 in 2020 and on average 78.4 (range 70 - 95) in pre-pandemic years, and the rBC proportion of 1.42% (76/5336; 95% exact confidence interval, CI: 1.12-1.78%) in 2020 was slightly higher than the average proportion of 1.26% of the five previous years, though the latter being well included in the CI of the 2020 proportion. No difference in primary tumor presentation and age at initial diagnosis was found among recurrent patients before and after the pandemic. Of the rBC cases reported during 2020, 10 were from 513 patients with postponed follow up who were finally diagnosed between September-December. As compared to patients on schedule, delayed rBC cases did not present with ductal carcinoma in situ, and reported a median tumor size of 18 mm (range 4.3-90 mm), which was 20% higher than the median of 15 mm (3.1-34) observed for scheduled patients. Distribution of luminal-like, triple negative and HER2-overexpressing BC subtypes among evaluable rBC cases was 75%, 12.5%, 12.5% in scheduled and 66%, 11% and 22% in delayed cases, respectively. Conclusions - Our data showed a slight decrease in the absolute number of rBC during 2020 despite a rebound of examinations, and an increased size of invasive recurrence following the 2-month stop of the first pandemic peak. The full impact of the COVID-19 pandemic on recurrent cancer diagnosis will be known when national population-based data become available in the coming years. Citation Format: Serena Di Cosimo, Catherine Depretto, Rosalba Miceli, Paolo Baili, Silva Ljevar, Milena Sant, Claudio Ferranti, Secondo Folli, Massimiliano Gennaro, Filippo G de Braud, Claudio Vernieri, Maria Carmen De Santis, Laura Lozza, Andrea Vingiani, Giancarlo Pruneri, Giovanni Apolone, Alfonso Marchianò, Gianfranco P Scaperrotta. The impact of COVID-19 on diagnosis of recurrent breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-01-12.

Weight of risk factors for mortality and short-term mortality displacement during the COVID-19 pandemic

SummaryBackgroundWe conducted a population-based cohort study to estimate mortality before, during and after the COVID-19 peak and to compare mortality in 2020 with rates reported in previous years, with a view to helping decision makers to apply containment measures for high-risk groups.MethodsAll deaths were collected between 2015 and 2020 from municipal registry database. In 2020, weeks 1-26 were stratified in three periods: before, during and after the COVID mortality peak. The Poisson Generalized Linear regression Model showed the “harvesting effect”. Three logistic regressions for 8 dependent variables (age and comorbidities) and a t-test of differences described all-cause mortality risk factors in 2019 and 2020 and differences between COVID and non-COVID patients.ResultsA total of 47,876 deaths were collected. All-cause deaths increased by 38.5% during the COVID peak and decreased by 18% during the post-peak period in comparison with the average registered during the control period (2015-19), with significant mortality displacement in 2020. Except for chronic renal injuries in subjects aged 45-64 years, diabetes and chronic cardiovascular diseases in those aged 65-84 years, and neuropathies in those aged > 84 years, the weight of comorbidities in deaths was similar or lower in COVID subjects than in non-COVID subjects.DiscussionsSurprisingly, the weight of comorbidities in death, compared to weight in non-COVID subjects allows you to highlight some surprising results such as COPD, IBD and Cancer. The excess mortality that we observed in the entire period were modest in comparison with initial estimates during the peak, owing to the mild influenza season and the harvesting effect starting from the second half of May.

“We Look Forward to Seeing You”: Air Travel Digital Discourse in the Post-peak Pandemic Period

“We Look Forward to Seeing You”: Air Travel Digital Discourse in the Post-peak Pandemic Period

How has the COVID Pandemic Impacted the Clinical Volume and Variety of an Academic Oral and Maxillofacial Surgery Program?

PurposeAttempts to mitigate the coronavirus disease of 2019 (COVID) have disrupted the delivery of non–pandemic care. The purpose of this study was to evaluate the effects of the COVID pandemic on surgical volume and variety at an academic oral and maxillofacial surgery program.Materials and MethodsA retrospective cohort study was conducted using the surgical logs of the University of Pennsylvania, Department of Oral and Maxillofacial Surgery from January 2012 through January 2021. Each record identified patient demographics and case classifications. The study predictor was timing of care, which was divided into pre-pandemic, peak pandemic, or post-peak pandemic. The primary study outcomes were the monthly procedure count and the procedure categories. The secondary dependent variables were patient age and race. Multivariate and univariate analyses of variance were used to determine whether pandemic effects existed within outcome groups.ResultsThe final sample included 64,709 surgical procedures. Before, during, and after the pandemic peak, there were means of 691.0, 209.0, and 789.4 procedures per time period, respectively (P < .01). There was significantly more infection (baseline 2.2%, peak 6.0%, post-peak 2.0%, P < .01) and trauma (baseline 5.3%, peak 26.7%, post-peak 3.9%, P < .01) cases during the pandemic peak. The mean percentage of pediatric patients increased during the peak and post-peak periods (baseline 2.4%, peak 12.9%, post-peak 10.2%, P < .01). No differences were observed among the mean percentage of White (P = .12), Black (P = .21), and Hispanic (P = .25) patients treated.ConclusionsAlong with a predictable decline in surgical numbers, a greater proportion of infection and trauma procedures were performed at the pandemic's peak. Despite these changes, surgery volume normalized and case variety returned to pre-pandemic levels in the post-peak period. Our study suggests that the addition of COVID restrictions did not change the case volume or variety in the months’ after the initial crisis.

Shear strength prediction for concrete encased steel short columns: Calibration based on current design codes

Due to the brittle failure process of shear failure, the accurate strength prediction of concrete encased steel (CES) short columns significantly influences the seismic assessment. In current design codes, the superposition method is widely employed, namely that the shear strength of a CES short column can be regarded as the sum of the shear strength of the RC part and that of the steel shape. However, the existing test results indicated that the RC part suffered a significant loss in shear strength during its post-peak period, and the steel shape could exhibit outstanding toughness, namely that these two parts cannot reach the corresponding shear strength simultaneously, which may lead to a deviation in the shear strength prediction. This paper reviews and assesses the calculation methods in current design codes using existing test results. Then, the traditional superposition method is calibrated in terms of the interaction between the RC part and the steel shape, and the shear contribution of these two parts can be decoupled by evaluating the corresponding peak strength point and the strength loss during the post-peak period. Finally, a comparison with a database consisting of the test results of 43 CES short columns is reported to verify the applicability of the proposed calibration. It can be concluded that the calibrated method can produce reasonable predictions, and the strength overestimation caused by the negligence of the interaction between the RC part and the steel shape in current design codes can be effectively captured to facilitate the practical design.

How has the COVID-19 Pandemic Impacted the Clinical Volume and Variety of an Academic Oral and Maxillofacial Surgery Program?

PurposeAttempts to mitigate the coronavirus disease of 2019 (COVID) have disrupted the delivery of non-pandemic care. The purpose of this study was to evaluate the effects of the COVID pandemic on surgical volume and variety at an academic oral and maxillofacial surgery program. Materials and methodsA retrospective cohort study was conducted using the surgical logs of the University of Pennsylvania, Department of Oral and Maxillofacial Surgery from January 2012 through January 2021. Each record identified patient demographics and case classifications. Of note, the surgical logs analyzed were only those which were performed in the operating room and not the outpatient clinic nor emergency department. The study predictor was timing of care, which was divided into pre-pandemic, peak pandemic, or post-peak pandemic. The primary study outcomes were the monthly procedure count and the procedure categories. The secondary dependent variables were patient age and race. Multivariate and univariate analyses of variance were used to determine whether pandemic effects existed within outcome groups. ResultsThe final sample included 64,709 surgical procedures (Table 1). Before, during, and after the pandemic peak, there were means of 691.0, 209.0, and 789.4 procedures per time period, respectively (p < 0.01) (Table 2). There were significantly more infection (baseline 2.2%, peak 6.0%, post-peak 2.0%, p<0.01) and trauma (baseline 5.3%, peak 26.7%, post-peak 3.9%, p<0.01) cases during the pandemic peak (Table 3). The mean percentage of pediatric patients increased during the peak and post-peak periods (baseline 2.4%, peak 12.9%, post-peak 10.2%, p<0.01) (Table 3). No differences were observed among the mean percentage of white (p=0.12), black (p=0.21), and Hispanic (p=0.25) patients treated (Table 3). ConclusionAlong with a predictable decline in surgical numbers, a greater proportion of infection and trauma procedures were performed at the pandemic's peak; trauma accounted for over a quarter of surgical cases during this peak. One potential reason for this could be due to an increase in at-home domestic violence. Pennsylvania issued a stay-at-home order for Philadelphia County from March 23 until May 8, 2020. A recent study highlighted that there was a regional decrease in the overall volume of trauma at the University of Pennsylvania [1]. This was largely driven by parallel decreases in the number of unintentional injury mechanisms, such as motor vehicle collisions. Interestingly, there was a paradoxical increase in the number of intentional interpersonal injuries [1]. In fact, the number of domestic assault cases grew by at least 5% during this time at the national level [2].The increase in infections may be due to outpatient dental services being inaccessible during the pandemic's peak, causing patients with odontogenic infections to have limited care options. Furthermore, because most patients were avoiding local emergency departments that were overwhelmed with COVID, it is probable that certain mild infections that otherwise could be treated in-office may have transformed into more severe airway threatening conditions that required operating room drainage. Despite all these changes, surgery volume normalized, and case variety returned to pre-pandemic levels in the post-peak period. Our study suggests that the addition of COVID restrictions did not change the case volume or variety in the months after the initial crisis.