A perspective on the impacts of microplastics on mosquito biology and their vectorial capacity

Microplastics (plastic particles <5 mm) permeate aquatic and terrestrial ecosystems and constitute a hazard to animal life. Although much research has been conducted on the effects of microplastics on marine and benthic organisms, less consideration has been given to insects, especially those adapted to urban environments. Here, we provide a perspective on the potential consequences of exposure to microplastics within typical larval habitat on mosquito biology. Mosquitoes represent an ideal organism in which to explore the biological effects of microplastics on terrestrial insects, not least because of their importance as an infectious disease vector. Drawing on evidence from other organisms and knowledge of the mosquito life cycle, we summarise some of the more plausible impacts of microplastics including physiological, ecotoxicological and immunological responses. We conclude that although there remains little experimental evidence demonstrating any adverse effect on mosquito biology or pathogen transmission, significant knowledge gaps remain, and there is now a need to quantify the effects that microplastic pollution could have on such an important disease vector.

A systematic review of circulating predictive and prognostic biomarkers to aid the personalised use of radiotherapy in the radical treatment of patients with oesophageal cancer

BACKGROUND

The availability of circulating biomarkers that are predictive of treatment response or prognostic of overall outcome could enable the personalised and adaptive use of radiotherapy (RT) in patients with oesophageal adenocarcinoma (OAC) and squamous cell carcinoma (OSCC).

METHODS

A systematic review was carried out following Preferred Reporting Items for Systematic Reviews guidance. Medline, EMBASE, PubMed, Cochrane Library, CINAHL, Scopus and the Web of Science databases were searched for studies published between January 2005-February 2023 relating to circulating biomarkers evaluated in the context of neoadjuvant or definitive RT delivered for OAC/OSCC. Study quality was assessed using predefined criteria.

RESULTS

A total of 3012 studies were screened and 57 subsequently included, across which 61 biomarkers were reported. A majority (43/57,75.4%) of studies were of Asian origin and retrospective (40/57, 70.2%), with most (52/57, 91.2%) biomarkers reported in the context of patients with OSCC. There was marked inter-study heterogeneity in patient populations, treatment characteristics, biomarker measurement and the cut points used to define biomarker positivity. Nevertheless, there is evidence for the prognostic and predictive value of circulating tumour DNA and numerous miRNAs in OAC and OSCC, as well as for the prognostic and predictive value of circulating levels of CYFRA21.1 in OSCC.

CONCLUSIONS

There is consistent evidence for the potential predictive and prognostic value of a small number of biomarkers in OSCC and OAC, though these data are insufficient for translation to current clinical practice. Well-designed prospective studies are now required to validate their role in stratified and personalised RT treatment approaches.

Estimated Number of Children Who Lost a Parent to Drug Overdose in the US From 2011 to 2021

Importance

Parents' overdose death can have a profound short- and long-term impact on their children, yet little is known about the number of children who have lost a parent to drug overdose in the US.

Objective

To estimate the number and rate of children who have lost a parent to drug overdose from 2011 to 2021 overall and by parental age, sex, and race and ethnicity.

Design, Setting, and Participants

This was a cross-sectional study of US community-dwelling persons using data from the National Survey on Drug Use and Health (2010-2014 and 2015-2019) and the National Vital Statistics System (2011-2021). Data were analyzed from January to June 2023.

Exposure

Parental drug overdose death, stratified by age group, sex, and race and ethnicity.

Main Outcomes and Measures

Numbers, rates, and average annual percentage change (AAPC) in rates of children losing a parent aged 18 to 64 years to drug overdose, overall and by age, sex, and race and ethnicity.

Results

From 2011 to 2021, 649 599 adults aged 18 to 64 years died from a drug overdose (mean [SD] age, 41.7 [12.0] years; 430 050 [66.2%] male and 219 549 [33.8%] female; 62 606 [9.6%] Hispanic, 6899 [1.1%] non-Hispanic American Indian or Alaska Native, 6133 [0.9%] non-Hispanic Asian or Pacific Islander, 82 313 [12.7%] non-Hispanic Black, 485 623 [74.8%] non-Hispanic White, and 6025 [0.9%] non-Hispanic with more than 1 race). Among these decedents, from 2011 to 2021, an estimated 321 566 (95% CI, 276 592-366 662) community-dwelling children lost a parent aged 18 to 64 years to drug overdose. The rate of community-dwelling children who lost a parent to drug overdose per 100 000 children increased from 27.0 per 100 000 in 2011 to 63.1 per 100 000 in 2021. The highest rates were found among children of non-Hispanic American Indian or Alaska Native individuals, who had a rate of 187.1 per 100 000 in 2021, more than double the rate among children of non-Hispanic White individuals (76.5 per 100 000) and non-Hispanic Black individuals (73.2 per 100 000). While rates increased consistently each year for all parental age, sex, and race and ethnicity groups, non-Hispanic Black parents aged 18 to 25 years had the largest AAPC (23.8%; 95% CI, 16.5-31.6). Rates increased for both fathers and mothers; however, more children overall lost fathers (estimated 192 459; 95% CI, 164 081-220 838) than mothers (estimated 129 107; 95% CI, 112 510-145 824).

Conclusions and Relevance

An estimated 321 566 children lost a parent to drug overdose in the US from 2011 to 2021, with significant disparities evident across racial and ethnic groups. Given the potential short- and long-term negative impact of parental loss, program and policy planning should ensure that responses to the overdose crisis account for the full burden of drug overdose on families and children, including addressing the economic, social, educational, and health care needs of children who have lost parents to overdose.

Impact of four years of annually repeated indoor residual spraying (IRS) with Actellic 300CS on routinely reported malaria cases in an agricultural setting in Malawi

Indoor residual spraying (IRS) is one of the main vector control tools used in malaria prevention. This study evaluates IRS in the context of a privately run campaign conducted across a low-lying, irrigated, sugarcane estate from Illovo Sugar, in the Chikwawa district of Malawi. The effect of Actellic 300CS annual spraying over four years (2015-2018) was assessed using a negative binomial mixed effects model, in an area where pyrethroid resistance has previously been identified. With an unadjusted incidence rate ratio (IRR) of 0.38 (95% CI: 0.32-0.45) and an adjusted IRR of 0.50 (95% CI: 0.42-0.59), IRS has significantly contributed to a reduction in case incidence rates at Illovo, as compared to control clinics and time points outside of the six month protective period. This study shows how the consistency of a privately run IRS campaign can improve the health of employees. More research is needed on the duration of protection and optimal timing of IRS programmes.

Different clinical characteristics and outcomes of adult hospitalized SARS-CoV-2 pneumonia patients complicated by cardiovascular events during the first, delta and omicron waves of COVID-19

Background

The effects of SARS-CoV-2 have varied between significant waves of hospitalization.

Research question

Are cardiovascular complications different among the first, delta and omicron waves of hospitalized COVID-19 pneumonia patients?

Study design and methods

This was a multi-centre retrospective study of patients hospitalized with SARS-CoV-2 pneumonia: 632 were hospitalized during the first wave (March-July 2020), 1013 during the delta wave (September 2020-March 2021), and 323 during the omicron wave (January 2022-July 2022). Patients were stratified by wave and occurrence of cardiovascular events.

Results

Among all hospitalized patients with cardiovascular events, patients in the omicron wave were younger (62.4 ± 14 years) than patients in the first wave (67.4 ± 7.8 years) and the delta wave (66.9 ± 12.6 years) and had a higher proportion of non-Hispanic White people than in the first wave (78.6% vs. 61.7%). For COVID-19 patients who suffered from cardiovascular events, the omicron wave patients had significantly higher neutrophil/lymphocyte ratio, white blood cell and platelet counts when compared to the first wave. Omicron wave patients had significantly lower albumin and B-type natriuretic peptide levels (only 5.8% of the first wave and 14.6% of the delta wave) when compared to either the first wave or delta wave patients. In COVID-19 patients who suffered cardiovascular events during hospitalization, mortality rate in the omicron wave (26.8%) was significantly lower than the first wave (48.3%), time to mortality for non-survivors of COVID-19 patients who suffered cardiovascular events was significantly longer in the omicron wave (median 16 days) than in the first wave (median 10 days).

Conclusions

Younger and white patients were affected with cardiovascular complications more often by the omicron variant. Despite higher neutrophil/lymphocyte ratio and WBC counts, the omicron patients with cardiovascular events showed lower heart injuries, lower mortality and longer time to mortality for non-survivors when compared to the first and delta waves.

Optimal Position of the Bone Anchor for the Internal Brace Suspensionplasty Technique for Thumb Basal Joint Arthroplasty

PURPOSE

Ligament reconstruction and tendon interposition is a common technique for thumb basal joint arthroplasty. Recently, a variation of this technique, a suture suspensionplasty, has been introduced. The goal of our study was to assess the optimal position of the bone anchor in the thumb metacarpal. We hypothesized that an anchor placed in the radial aspect of the thumb metacarpal base would provide improved stability and resist subsidence more effectively than an ulnar-based thumb anchor.

METHODS

Eight fresh-frozen cadaver arms were imaged fluoroscopically in anteroposterior and lateral views centered over the thumb carpometacarpal joint before and after trapeziectomy and after the placement of radial-based and ulnar-based bone anchors. The intermetacarpal angle between the thumb and index metacarpals was measured on all images after the application of a standard force. Radial abduction, opposition, subsidence, palmar abduction, and adduction were measured. Subsidence was calculated as the percentage loss of the trapezial space.

RESULTS

Both radially and ulnarly placed internal brace constructs allowed more radial abduction, opposition, and palmar abduction than the pretrapeziectomy constructs. They both also reduced subsidence by approximately 20% to 29% compared with the posttrapeziectomy constructs. Comparing radial to ulnar constructs, motion and subsidence were similar.

CONCLUSIONS

There was immediate stability of the thumb with respect to axial load and subsidence after anchor placement, and this was independent of the anchor position. The position of the bone anchor in the thumb metacarpal base did not affect the range of motion. Although the device can limit subsidence, it does not appear to restrict any range of motion of the thumb, irrespective of anchor position.

CLINICAL RELEVANCE

This cadaver study can help hand surgeons understand the effect of positioning of bone anchors when performing a specific suture suspensionplasty technique.

Systematic Review of Hypofractionated Radiation Therapy for the Treatment of Oesophageal Squamous Cell Carcinoma and Oesophageal Adenocarcinoma

BACKGROUND AND AIM

There has been limited progress made in improving the suboptimal outcomes delivered by conventionally fractionated radiotherapy (RT) for oesophageal adenocarcinoma (OAC) and squamous cell carcinoma (OSCC). A greater biological effect may be achieved using hypofractionated RT (HFRT), though the toxicity, tolerability and efficacy of this approach in OAC and OSCC is uncertain.

METHODS

A systematic literature review was carried out in accordance with Preferred Reporting Items for Systematic Reviews guidance. Medline, EMBASE, PubMed, Cochrane, CINAHL, Scopus and Web of Science databases were searched for terms relating to HFRT (>2.4Gy per fraction) for OAC or OSCC. All relevant clinical studies published between January 2000 and April 2023 were included. Study quality was assessed using predefined criteria.

RESULTS

Ninety-six studies were screened and 20 subsequently included, together incorporating 1208 patients. Fourteen studies focussed on neoadjuvant or definitive treatment. These were predominantly retrospective (n = 10, 71%) though two (n = 2, 14%) early phase trials were identified. Most focussed on OSCC (n = 7, 47%) or mixed OSCC/OAC (n = 6, 43%) populations. Four (28.6%) included a conventionally fractionated chemoradiotherapy (CRT) comparator, against which median overall (mOS) and progression free survival outcomes from HFRT did not differ. Reported mOS for HFRT ranged between 29-36 months at 2.5-3.125Gy per fraction (total dose 50-60Gy) for OAC and OSCC combined. Toxicity and tolerability with HFRT was comparable with conventionally fractionated CRT up to, but not exceeding, 5Gy. Three (50%) of the six palliative-intent studies were early phase trials and most (n = 4, 67%) focussed on OAC and OSCC. Response rates with HFRT in the palliative setting were 63.6-88.0%.

CONCLUSION

These data provide evidence in OAC/OSCC for promising efficacy and an acceptable toxicity profile for moderately HFRT, alone or with concurrent chemotherapy. These data should prompt prospective, randomised comparisons of HFRT and conventionally fractionated CRT and single-modality RT schedules.

REGISTRATION DETAILS

PROSPERO; CRD42023457791.

Goal pursuit increases more after dietary success than after dietary failure: examining conflicting theories of self-regulation using ecological momentary assessment

BACKGROUND

Maintaining a healthy body weight and reaching long-term dietary goals requires ongoing self-monitoring and behavioral adjustments. How individuals respond to successes and failures is described in models of self-regulation: while cybernetic models propose that failures lead to increased self-regulatory efforts and successes permit a reduction of such efforts, motivational models (e.g., social-cognitive theory) make opposite predictions. Here, we tested these conflicting models in an ecological momentary assessment (EMA) context and explored whether effort adjustments are related to inter-individual differences in perceived self-regulatory success in dieting (i.e., weight management).

METHODS

Using linear mixed effects models, we tested in 174 diet-interested individuals whether current day dietary success or failure (e.g., on Monday) was followed by self-regulatory effort adjustment for the next day (e.g., on Tuesday) across 14 days. Success vs. failure was operationalized with two EMA items: first, whether food intake was higher vs. lower than usual and second, whether food intake was perceived as more vs. less goal-congruent than usual. Trait-level perceived self-regulatory success in dieting was measured on a questionnaire.

RESULTS

Intended self-regulatory effort increased more strongly after days with dietary success (i.e., eating less than usual / rating intake as goal-congruent) than after days with dietary failure (i.e., eating more than usual / rating intake as goal-incongruent), especially in those individuals with lower scores on perceived self-regulatory success in dieting.

CONCLUSIONS

Findings support mechanisms proposed by social-cognitive theory, especially in unsuccessful dieters. Thus, future dietary interventions could focus on preventing the decrease in self-regulatory effort after instances of dietary failures and thereby mitigate the potential risk that a single dietary failure initiates a downward spiral into unhealthy eating.

Why we don't eat as intended: Moderators of the short-term intention-behaviour relation in food intake

OBJECTIVES

A healthy diet is essential for preventing chronic disease and promoting overall health. Translating one's intention to eat healthy into actual behaviour has, however, proven difficult with a range of internal and contextual factors identified as driving eating behaviour.

DESIGN

We leverage Temporal Self-Regulation Theory to examine these momentary determinants' direct and moderating effects on the intention-behaviour relation with Ecological Momentary Assessment (EMA).

METHODS

Eighty-seven healthy participants (mage  = 24.1 years; 59 women, 28 men) reported, 5 times daily for 10 weekdays, their intentions to stick to a self-set dietary restriction goal for the next 3 hr, the goal congruency of their eating behaviour in the past 3 hr, and a range of factors potentially influencing food intake, such as stress, emotions and environmental eating cues.

RESULTS

Two-part multilevel modelling revealed that craving, availability of goal-incongruent foods, social eating cues, giving in to other temptations and weaker momentary intentions directly increased the risk and severity of goal-incongruent intake within the next 3 hr. Social cues, stress and craving further influence behaviour through altering intention implementation.

CONCLUSIONS

Results imply that people regularly fail to implement intentions for 3-hr periods and that a range of factors influences this, both directly and by disrupting intentional processes. While for some barriers, fostering strong intentions throughout the day could be beneficial, others require different strategies for dietary adherence.

Posterior Interosseous Neuropathy Related to a Loose Distal Biceps Cortical Button: A Case Series

Posterior interosseous nerve (PIN) injury is an uncommon yet debilitating complication following distal bicep tendon repair. There are case reports of acute intraoperative PIN injury related to retractor placement, drill trajectory, and nerve incarceration. We report three cases of delayed PIN neuropathy in the setting of a loose cortical button. All patients had resolution of their pain with removal of the cortical button and decompression of the radial tunnel. The purpose of this case series is to: 1) highlight the possibility of a loose cortical bicep button as the cause of proximal forearm pain and PIN neuropathy in the early or late postoperative timeframe; and 2) emphasize the importance of proper surgical technique and use of intraoperative fluoroscopy to assure the cortical button is well-fixed and flush with the radial shaft. .

Outcomes Following Fully Threaded Intramedullary Nailing of Metacarpal Fractures

Purpose

Intramedullary screw fixation has emerged as a popular approach for the treatment of displaced metacarpal fractures. The purpose of this study was to investigate the functional and radiographic outcomes of a newly designed, headless noncompressive fully threaded intramedullary nail (TIMN) for the treatment of metacarpal fractures.

Methods

A retrospective chart review was performed on patients who were treated with the INnate TIMN (ExsoMed) at a single academic institution with a minimum of 1-year follow-up. Patient-reported functional outcomes included Quick Disabilities for the Arm, Shoulder, and Hand (QuickDASH) questionnaires, return to work and physical activity time, and overall satisfaction. Radiographs were retrospectively reviewed to determine radiographic union, change in angulation, and metacarpal shortening.

Results

A total of 49 patients (58 fractures) with a mean age of 36 years (range: 17-75 years) were included. The mean follow-up time was 2.7 years (range: 1.4-4.3 years). Overall, the mean patient satisfaction rating was 4.9 of 5 (range: 3-5). The mean return to work time was 7.2 weeks (range: 0.14-28 weeks), and the mean return to sport or activity was 8.3 weeks (range: 1-28 weeks). Average QuickDASH scores across all patients were 4 (range: 0-56.9). The median radiographic healing time was 6.1 weeks (range: 4.7-15.4 weeks). Mean postoperative shortening in the fifth metacarpal fracture was 3 mm (range: -4.2 to 8 mm) at the initial postoperative visit and 3.6 mm (range: -3.3 to 7.9 mm) at the final radiographic follow-up. Subgroup analysis showed that postoperative shortening was similar, regardless of the fracture pattern. The following four complications were reported: one case of persistent pain and stiffness, one case of carpal tunnel syndrome, one nonunion, and one fractured intramedullary nail.

Conclusions

Our findings suggest that the TIMN allows for a reliable return to work and physical activity, high patient satisfaction, low complication rate, and minimal shortening at the final radiographic follow-up.

Type of study/level of evidence

Therapeutic IV.

Phylogenetics and environmental distribution of nitric oxide-forming nitrite reductases reveal their distinct functional and ecological roles

The two evolutionarily unrelated nitric oxide-producing nitrite reductases, NirK and NirS, are best known for their redundant role in denitrification. They are also often found in organisms that do not perform denitrification. To assess the functional roles of the two enzymes and to address the sequence and structural variation within each, we reconstructed robust phylogenies of both proteins with sequences recovered from 6973 isolate and metagenome-assembled genomes and identified 32 well-supported clades of structurally distinct protein lineages. We then inferred the potential niche of each clade by considering other functional genes of the organisms carrying them as well as the relative abundances of each nir gene in 4082 environmental metagenomes across diverse aquatic, terrestrial, host-associated, and engineered biomes. We demonstrate that Nir phylogenies recapitulate ecology distinctly from the corresponding organismal phylogeny. While some clades of the nitrite reductase were equally prevalent across biomes, others had more restricted ranges. Nitrifiers make up a sizeable proportion of the nitrite-reducing community, especially for NirK in marine waters and dry soils. Furthermore, the two reductases showed distinct associations with genes involved in oxidizing and reducing other compounds, indicating that the NirS and NirK activities may be linked to different elemental cycles. Accordingly, the relative abundance and diversity of NirS versus NirK vary between biomes. Our results show the divergent ecological roles NirK and NirS-encoding organisms may play in the environment and provide a phylogenetic framework to distinguish the traits associated with organisms encoding the different lineages of nitrite reductases.

Curb the spread: Leveraging intensive longitudinal data to unravel within- and between-person processes in adherence to nonpharmaceutical interventions during COVID-19

OBJECTIVES

Adhering to behavioral recommendations and nonpharmaceutical interventions (NPIs) is a key to control COVID-19 infection rates. However, rates have decreased globally, and potentially modifiable determinants of ongoing adherence and their interaction with social and physical momentary environments are still poorly understood. Here, we comprehensively examine within-person variations and between-person differences in known behavioral determinants (capability and motivation), as well as the moderating role of situational variable environmental factors (opportunity) in predicting adherence to hygiene and social distancing behaviors.

METHOD

Ecological momentary assessment study over 6 months with monthly assessment bouts (4 days each and five daily assessments) in 623 German adults. Repeated daily assessments of capability, opportunity, motivation, and behavior (COM-B) model factors. Bayesian multilevel logistic regression models were estimated to examine main effects of COM-B factors and moderating effects of momentary environmental factors.

RESULTS

Momentary adherence to NPIs was predicted by within-person changes in COM-B factors (motivation: intentions, goal conflict, and control beliefs; opportunities: regulations and norms). Between-person differences in capabilities (habit strength) and motivation (intentions and control beliefs) predicted adherence across situations. Situation-specific environmental factors moderated the motivation-behavior association (regulation measures increased; goal conflict and nonadherent others decreased the association).

CONCLUSIONS

Individual momentary (within-person) and stable (between-person) motivation indicators predicted adherence. However, situational environmental factors such as regulations or norms have strong main effects and moderate the motivation-behavior translation. These findings have policy implications, supporting recent claims to not rely on the narrative of "personal responsibility," but instead combine health education measures to increase individual motivation with consistent regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Multimodal Pain Management After Outpatient Orthopedic Hand Surgery: A Prospective Randomized Trial

Purpose

Opioid stewardship ensures effective pain management while avoiding overprescribing of opioids after surgery. This prospective randomized study investigates the efficacy of a multimodal postoperative pain regimen compared to a traditional opioid-only pain regimen following elective outpatient orthopedic hand surgery. We hypothesized that patients receiving multimodal pain management would consume fewer opioids and report greater satisfaction than patients receiving only opioids.

Methods

Consecutive patients undergoing outpatient hand and upper extremity surgery performed by two board-certified fellowship-trained orthopedic hand surgeons at one institution were recruited and randomized into either a study or control group. The study group received a standing multimodal postoperative regimen consisting of scheduled oral acetaminophen and naproxen as well as oxycodone to be taken as needed. The control group received only oxycodone to be taken as needed. Postoperatively, daily pain levels, medication usage, refills, satisfaction, and adverse events were recorded. Descriptive statistics were performed.

Results

Of the 112 patients enrolled, 54 were randomized to the control group, and 58 were randomized to the study group. Study and control group patients did not differ significantly based on daily average pain scores or daily worst pain scores. However, study group patients reported fewer average daily oxycodone intake and total oxycodone pill count (7.0 vs 2.4 total pills, P <.005). In addition, the study group patients were more likely to report satisfaction with their postoperative pain control than control regimen patient's and were more likely to use the same pain regimen again if required.

Conclusion

A multimodal postoperative pain regimen reduces opioid usage and has higher patient satisfaction rates in comparison to traditional opioid-only regimens. Use of multimodal pain regimens that use nonopioids, such as acetaminophen and naproxen, over an opioid should be considered for postoperative pain after orthopedic hand surgery.

Level of Evidence

Therapeutic II.

COVID Protection Behaviors, Mental Health, Risk Perceptions, and Control Beliefs: A Dynamic Temporal Network Analysis of Daily Diary Data

BACKGROUND

To control infections, behavioral non-pharmaceutical interventions (NPIs) such as social distancing and hygiene measures (masking, hand hygiene) were implemented widely during the COVID-19 pandemic. At the same time, adherence to NPIs has also been implied in an increase in mental health problems. However, the designs of many existing studies are often poorly suited to disentangle complex relationships between NPI adherence, mental health symptoms, and health-related cognitions (risk perceptions, control beliefs).

PURPOSE

To separate between- and temporal within-person associations between mental health, health-related cognitions, and NPI adherence.

METHODS

Six-month ecological momentary assessment (EMA) study with six 4-day assessment bouts in 397 German adults. Daily measurement of adherence, mental health symptoms, and cognitions during bouts. We used dynamic temporal network analysis to estimate between-person, as well as contemporaneous and lagged within-person effects for distancing and hygiene NPIs.

RESULTS

Distinct network clusters of mental health, health cognitions, and adherence emerged. Participants with higher control beliefs and higher susceptibility were also more adherent (between-person perspective). Within-person, similar findings emerged, additionally, distancing and loneliness were associated. Lagged findings suggest that better adherence to NPIs was associated with better mental health on subsequent days, whereas higher loneliness was associated with better subsequent hygiene adherence.

CONCLUSIONS

Findings suggest no negative impact of NPI adherence on mental health or vice versa, but instead suggest that adherence might improve mental health symptoms. Control beliefs and risk perceptions are important covariates of adherence-both on between-person and within-person level.

Online Oncology Careers Events to Attract the Future Oncology Medical Workforce: An Exemplar Event and Review of the Literature

AIMS

There are too few oncologists to meet the increasing burden imposed by the rising incidence of cancer. This results from issues with the retention of established oncologists and longstanding challenges to the recruitment of adequate numbers of trainees. To counter this, the British Oncology Network for Undergraduate Societies (BONUS) devised an online oncology careers event for medical students and junior doctors who are yet to select a specialty.

MATERIALS AND METHODS

An online careers event was devised with a focus on oncology practice and related subspecialties, as well as research. Event attendees were asked to respond to piloted pre- and post-event surveys. Knowledge and attitudes towards a career in oncology were evaluated using Likert scale and multiple-choice questions. A systematic literature search was carried out to contextualise these data.

RESULTS

Of the 73 attendees, 44 (60%) participants completed both the pre- and post-event surveys; 79.5% of attendees believed that information on a career in oncology is lacking in medical training. This viewpoint was supported by the systematic review, which highlighted a need for relevant focussed interventions targeted at medical students and fledgling doctors. The education event led to an increase in the median reported understanding of the oncology career pathway from 6.0 to 8.0 (P < 0.05 and P < 0.001), as well as the likelihood of pursuing a career in oncology (8.0-9.0; P < 0.05). It was also associated with a proportional increase in medical and surgical oncology interest, albeit with a fall in interest in clinical and interventional oncology as well as academia.

CONCLUSION

A targeted online careers event increases knowledge of and interest in a career in oncology, albeit predominantly for medical and surgical subspecialties. Broader initiatives based on our model should be developed and careers in academia as well as clinical and interventional oncology emphasised.

Phyloecology of nitrate ammonifiers and their importance relative to denitrifiers in global terrestrial biomes

Nitrate ammonification is important for soil nitrogen retention. However, the ecology of ammonifiers and their prevalence compared with denitrifiers, being competitors for nitrate, are overlooked. Here, we screen 1 million genomes for nrfA and onr, encoding ammonifier nitrite reductases. About 40% of ammonifier assemblies carry at least one denitrification gene and show higher potential for nitrous oxide production than consumption. We then use a phylogeny-based approach to recruit gene fragments of nrfA, onr and denitrification nitrite reductase genes (nirK, nirS) in 1861 global terrestrial metagenomes. nrfA outnumbers the nearly negligible onr counts in all biomes, but denitrification genes dominate, except in tundra. Random forest modelling teases apart the influence of the soil C/N on nrfA-ammonifier vs denitrifier abundance, showing an effect of nitrate rather than carbon content. This study demonstrates the multiple roles nitrate ammonifiers play in nitrogen cycling and identifies factors ultimately controlling the fate of soil nitrate.

Radiographic Comparison of Forearm Symmetry in Healthy Individuals and its Importance in the Diagnosis of Longitudinal Radioulnar Dissociation

PURPOSE

Longitudinal radioulnar dissociation (LRD) is an injury often missed upon initial presentation. A recent study examined a radiographic screening test in cadavers that showed increased interosseous distance when the interosseous ligament (IOL) was divided. For this test to be clinically useful, it is necessary for uninjured forearms to have similar interosseous spaces. The purpose of this study was to determine the typical differences between right and left interosseous spaces of healthy individuals.

METHODS

Anterior-posterior x-rays of bilateral forearms in maximum supination of 28 surgical residents with no history of injury were obtained. These images were uploaded into a picture archiving and communication system and then digitized. The length of the radius was measured (Xr). The maximum interosseous distance (Dmax) between the radius and ulna as well as the interosseous distance at a location 0.3 Xr from the distal radioulnar joint was measured. The right and left arm distances were compared. Also, an outlier analysis was used to evaluate forearm rotational asymmetry between right and left arms.

RESULTS

The outlier analysis revealed two sets of forearm x-rays were rotationally different compared to the rest of the group due to asymmetric arm positioning; these data were excluded from the analysis. The average difference in Dmax was 1.7 mm (standard deviation [SD] 1.5) between right and left arms, and this was found at a position of 0.28 Xr on average. The difference in interosseous distance measured at a fixed location 0.3 Xr was 1.6 mm (SD 1.5). No significant difference was found between the paired right and left arms for Dmax or at 0.3 Xr.

CONCLUSIONS

There does not appear to be any significant difference between the maximum interosseous distance of right and left arms in healthy individuals. Therefore, analyzing bilateral forearm x-rays may be a simple LRD screening test.

CLINICAL RELEVANCE

Understanding the degree of normal variation in the forearm bone spacing might inform evaluation of abnormal forearm bone alignment resulting from LRD.

Conformal 3D computed tomography planned endoluminal brachytherapy for the local control of esophageal cancer

PURPOSE

To outline the toxicity, tolerability, and efficacy of a 3D conformal computed tomography planned endoluminal brachytherapy (ELBT) treatment for esophageal adenocarcinoma (OAC) or squamous cell carcinoma (OSCC).

METHODS AND MATERIALS

A retrospective single-center analysis of toxicity, tolerability, and outcomes for 65 consecutive patients with OAC/OSCC who received 6-8Gy in one fraction or 12-16Gy in two fractions of high-dose-rate ELBT as salvage postchemoradiotherapy (n = 7 and n = 14 respectively), or as a boost to external beam radiotherapy (n = 14 and n = 30, respectively).

RESULTS

Median overall survival from the first brachytherapy application was 7.4 (IQR 5.0-14.7) months for the boost cohort and 9.2 (IQR 5.8-20.1) months for the salvage cohort. In a univariate analysis, use of a higher, fractionated dose of radiotherapy was associated with longer overall survival. At least one-third (33%; n = 7) of the salvage cohort and 28% (n = 12) of the boost cohort exhibited a local recurrence prior to death. Overall, 66.7% of the salvage and 56.8% of the boost cohort experienced odynophagia. Swallow function stabilized or improved early after treatment, with only 11.6% of the boost and 14.3% of the salvage cohort demonstrating a long-term decline in dysphagia score.

CONCLUSIONS

3D conformal planned ELBT is safe and tolerable. Most patients exhibit an early and sustained stabilization or improvement in their swallow function and greater survival is seen with higher brachytherapy doses. Further research is required to determine the place of brachytherapy in the management of esophageal cancer, particularly when planned using contemporary conformal approaches.

Monitoring and simulating landscape changes: how do long-term changes in land use and long-term average climate affect regional biophysical conditions in southern Malawi?

We set out to reveal the effects of long-term changes in land use and long-term average climate on the regional biophysical environment in southern Malawi. Object-oriented supervised image classification was performed on Landsat 5 and 8 satellite images from 1990 to 2020 to identify and quantify past and present land use-land cover changes using a support vector machine classifier. Subsequently, using 2000 and 2010 land use-land cover in an artificial neural network, land use-land cover for 2020 driven by elevation, slope, precipitation and temperature, population density, poverty, distance to major roads, and distance to villages data was simulated. Between 1990 and 2020, area of land cover increased in built-up (209%), bare land (10%), and cropland (10%) and decreased in forest (30%), herbaceous (4%), shrubland (20%), and water area (20%). Overall, the findings reveal that southern Malawi is dominantly an agro-mosaic landscape shaped by the combined effects of urban and agricultural expansions and climate. The findings also suggest the need to enhance the machine learning algorithms to improve capacity for landscape modelling and, ultimately, prevention, preparedness, and response to environmental risks.

Impact of Social Reference Cues on Misinformation Sharing on Social Media: Series of Experimental Studies

BACKGROUND

Health-related misinformation on social media is a key challenge to effective and timely public health responses. Existing mitigation measures include flagging misinformation or providing links to correct information, but they have not yet targeted social processes. Current approaches focus on increasing scrutiny, providing corrections to misinformation (debunking), or alerting users prospectively about future misinformation (prebunking and inoculation). Here, we provide a test of a complementary strategy that focuses on the social processes inherent in social media use, in particular, social reinforcement, social identity, and injunctive norms.

OBJECTIVE

This study aimed to examine whether providing balanced social reference cues (ie, cues that provide information on users sharing and, more importantly, not sharing specific content) in addition to flagging COVID-19-related misinformation leads to reductions in sharing behavior and improvement in overall sharing quality.

METHODS

A total of 3 field experiments were conducted on Twitter's native social media feed (via a newly developed browser extension). Participants' feed was augmented to include misleading and control information, resulting in 4 groups: no-information control, Twitter's own misinformation warning (misinformation flag), social cue only, and combined misinformation flag and social cue. We tracked the content shared or liked by participants. Participants were provided with social information by referencing either their personal network on Twitter or all Twitter users.

RESULTS

A total of 1424 Twitter users participated in 3 studies (n=824, n=322, and n=278). Across all 3 studies, we found that social cues that reference users' personal network combined with a misinformation flag reduced the sharing of misleading but not control information and improved overall sharing quality. We show that this improvement could be driven by a change in injunctive social norms (study 2) but not social identity (study 3).

CONCLUSIONS

Social reference cues combined with misinformation flags can significantly and meaningfully reduce the amount of COVID-19-related misinformation shared and improve overall sharing quality. They are a feasible and scalable way to effectively curb the sharing of COVID-19-related misinformation on social media.

Proximity of the Ulnar Neurovascular Structures in Endoscopic Carpal Tunnel Release Surgery: A Cadaveric Study

PURPOSE

To evaluate the proximity of the ulnar neurovascular structures to the endoscopic blade during endoscopic carpal tunnel release (CTR).

METHODS

Ten fresh-frozen cadaver hands were used to perform endoscopic CTR using devices from two manufacturers. The skin was excised from the palm, and the endoscopic carpal tunnel blade was deployed at the distal edge of the transverse carpal ligament (TCL). The blade's proximity to the ulnar neurovascular bundle, deep ulnar motor branch, superficial palmar arch, and median nerve was recorded. Following release of the TCL, the device was turned ulnar to the maximal extent to determine if direct injury to the ulnar neurovascular bundle was possible.

RESULTS

The average longitudinal distance from the end of the TCL to the superficial palmar arch was 13.3 mm (range, 8.4-20.9) and to the ulnar motor branch was 10.8 mm (range, 4.0-15.0). The average transverse distance from the end of the TCL to the ulnar neurovascular bundle was 5.9 mm (range, 3.1-7.8) and to the median nerve was 3.3 mm (range, 0-6.5). In two of our specimens, the median nerve subluxated volarly over the cutting device. When placing the blade at the distal edge of the TCL, injury to the deep motor branch of the ulnar nerve, ulnar neurovascular bundle, or superficial palmar arch was not possible in any specimens using the tested devices, even when turning the blade directly toward these structures.

CONCLUSIONS

There is a low likelihood of direct injury to the ulnar neurovascular bundle during endoscopic CTR.

CLINICAL RELEVANCE

These results suggest that injury to the ulnar neurovascular bundle is unlikely during endoscopic CTR if the distal aspect of the transverse carpal ligament can be clearly identified prior to release. Control of the median nerve is also important to prevent subluxation over the cutting device.

Use of Medication for Opioid Use Disorder Among Adults With Past-Year Opioid Use Disorder in the US, 2021

This cross-sectional study uses data from the 2021 National Survey on Drug Use and Health to estimate the receipt of medication for opioid use disorder among US adults with past-year opioid use disorder.

Donor-derived Transmission of Hepatitis A Virus Following Kidney Transplantation: Clinical Course of Two Cases From One Donor

Donor-derived transmission of infections is a rare complication of kidney transplant. Hepatitis A virus (HAV) is a common cause of acute viral hepatitis worldwide, but donor-derived transmission to organ recipients has been reported in the literature only twice previously. The timeline for HAV incubation and clearance in transplant recipients is not well understood.

Methods

In 2018, 2 kidneys and a liver were procured from a deceased donor resident of Kentucky, one of many states that was experiencing an HAV outbreak associated with person-to-person transmission through close contact, primarily among people who reported drug use. Both kidney recipients, residents of Virginia, subsequently developed acute HAV infections. We report the results of an investigation to determine the source of transmission and describe the clinical course of HAV infection in the infected kidney recipients.

Results

The liver recipient had evidence of immunity to HAV and did not become infected. The donor and both kidney recipients were found to have a genetically identical strain of HAV using a next-generation sequencing-based cyber molecular assay (Global Hepatitis Outbreak Surveillance Technology), confirming donor-derived HAV infections in kidney recipients. At least 1 kidney recipient experienced delayed development of detectable hepatitis A anti-IgM antibodies. By 383 and 198 d posttransplant, HAV RNA was no longer detectable in stool specimens from the left and right kidney recipients, respectively.

Conclusions

Adherence to current guidance for hepatitis A vaccination may prevent future morbidity due to HAV among organ recipients. http://links.lww.com/TXD/A548.

Anatomic Relationship of Hand Intrinsic Tendons at the Metacarpal Head as It Relates to the Diagnosis of Saddle Syndrome: A Cadaveric Study

PURPOSE

The purpose of this cadaveric study was to investigate the intrinsic anatomy surrounding the metacarpal head and the relationship between the interosseous-lumbrical junction (ILJ) and transverse metacarpal ligament (TML) as it pertains to saddle deformity-posttraumatic adhesions at the ILJ that cause impingement during intrinsic activation.

METHODS

Ten fresh frozen cadaveric arms underwent dissections, identifying the intrinsic musculature within the second through fourth webspaces. The TML and ILJ, or "true tendon," were identified. A separate area of nontendinous fibrous tissue identified proximal to the ILJ was referred to as "pseudotendon." Measurements were made within each webspace to identify distances between these structures in full finger extension and intrinsic plus position to assess for changes during simulated motion.

RESULTS

The true tendon to TML distance progressively decreased toward the ulnar digits. In the intrinsic plus position, the pseudotendon to TML distance was 0 mm at all webspaces for each specimen. When moving from neutral to intrinsic plus, the true tendon to TML distance decreased the most in the third and fourth webspaces compared with the second, consistent with the trend toward a smaller ILJ to TML gap in the ulnar digits.

CONCLUSIONS

There is a fibrous pseudotendinous region proximal to the ILJ that abuts the TML in the intrinsic plus position, which may cause impingement when inflamed in the setting of saddle syndrome. Furthermore, a decreased ILJ to TML gap in the ulnar digits may be related to an increased predilection for saddle deformity in those areas.

CLINICAL RELEVANCE

These results suggest that there is a fibrous region present proximal to the ILJ that may be implicated in the pathology of saddle deformity. Furthermore, decreased distances found between the ILJ and TML in vivo may be an explanation for increased occurrence of saddle syndrome in the third and fourth webspaces in clinical practice.

Integrating vector control within an emerging agricultural system in a region of climate vulnerability in southern Malawi: A focus on malaria, schistosomiasis, and arboviral diseases

Infectious diseases are emerging at an unprecedented rate while food production intensifies to keep pace with population growth. Large-scale irrigation schemes have the potential to permanently transform the landscape with health, nutritional and socio-economic benefits; yet, this also leads to a shift in land-use patterns that can promote endemic and invasive insect vectors and pathogens. The balance between ensuring food security and preventing emerging infectious disease is a necessity; yet the impact of irrigation on vector-borne diseases at the epidemiological, entomological and economic level is uncertain and depends on the geographical and climatological context. Here, we highlight the risk factors and challenges facing vector-borne disease surveillance and control in an emerging agricultural ecosystem in the lower Shire Valley region of southern Malawi. A phased large scale irrigation programme (The Shire Valley Transformation Project, SVTP) promises to transform over 40,000 ha into viable and resilient farmland, yet the valley is endemic for malaria and schistosomiasis and experiences frequent extreme flooding events following tropical cyclones. The latter exacerbate vector-borne disease risk while simultaneously making any empirical assessment of that risk a significant hurdle. We propose that the SVTP provides a unique opportunity to take a One Health approach at mitigating vector-borne disease risk while maintaining agricultural output. A long-term and multi-disciplinary approach with buy-in from multiple stakeholders will be needed to achieve this goal.

Characteristics and Prescribing Patterns of Clinicians Waivered to Prescribe Buprenorphine for Opioid Use Disorder Before and After Release of New Practice Guidelines

Importance

In April 2021, the US Department of Health and Human Services (HHS) released practice guidelines exempting educational requirements to obtain a Drug Addiction Treatment Act (DATA) waiver to treat up to 30 patients with opioid use disorder with buprenorphine.

Objective

To compare demographic and practice characteristics of clinicians who received traditional DATA waivers before and after release of the education-exempted HHS practice guidelines and those who were approved under the guidelines.

Design, Setting, and Participants

This survey study was conducted electronically from February 1 to March 1, 2022. Eligible survey recipients were US clinicians who obtained an initial DATA waiver between April 2020 and November 2021.

Exposure

DATA waiver approval pathway.

Main Outcome and Measures

The outcomes were clinician demographic and practice characteristics, buprenorphine prescribing barriers, and strategies to treat patients with opioid use disorder, measured using χ2 tests and z tests to assess for differences among the waivered groups.

Results

Of 23 218 eligible clinicians, 4519 (19.5%) responded to the survey. This analysis was limited to 2736 respondents with a 30-patient limit at the time of survey administration who identified their DATA waiver approval pathway. Among these respondents, 1365 (49.9%; female, 831 [61.9%]; male, 512 [38.1%]) received their DATA waiver prior to the education-exempted practice guidelines (prior DATA waiver), 550 (20.1%; female, 343 [63.4%]; male, 198 [36.6%]) received their waiver after guidelines were released but met education requirements (concurrent DATA waiver), and 821 (30.0%; female, 396 [49.2%]; male, 409 [50.8%]) received the waiver under the education-exempted guidelines (practice guidelines). Among practice guidelines clinicians, 500 (60.9%) reported that traditional DATA waiver educational requirements were a reason for not previously obtaining a waiver. Demographic and practice characteristics differed by waiver approval type. Across all groups, a large minority had not prescribed buprenorphine since obtaining a waiver (prior DATA waiver, 483 [35.7%]; concurrent DATA waiver, 226 [41.2%]; practice guidelines, 359 [44.3%]; P < .001). Clinicians who prescribed buprenorphine in the past 6 months reported treating few patients in an average month: 27 practice guidelines clinicians (6.0%) prescribed to 0 patients and 338 (75.1%) to 1 to 4 patients compared with 16 (2.2%) and 435 (59.9%) for prior and 11 (3.6%) and 166 (55.0%) for concurrent DATA waiver clinicians, respectively (P < .001). Across waiver types, clinicians reported multiple challenges to buprenorphine prescribing.

Conclusions and Relevance

In this survey of DATA-waivered clinicians, clinician- and systems-level challenges that limit buprenorphine prescribing were observed, even among clinicians approved under the education-exempted guidelines pathway. The findings suggest that as implementation of legislation removing the DATA waiver begins, addressing these barriers could be essential to increasing buprenorphine access.

Efficacy of early PET-CT directed switch to carboplatin and paclitaxel based definitive chemoradiotherapy in patients with oesophageal cancer who have a poor early response to induction cisplatin and capecitabine in the UK: a multi-centre randomised controlled phase II trial

Background

The utility of early metabolic response assessment to guide selection of the systemic component of definitive chemoradiotherapy (dCRT) for oesophageal cancer is uncertain.

Methods

In this multi-centre, randomised, open-label, phase II substudy of the radiotherapy dose-escalation SCOPE2 trial we evaluated the role of ¹⁸F-Fluorodeoxyglucose positron emission tomography (PET) at day 14 of cycle 1 of three-weekly induction cis/cap (cisplatin (60 mg/m²)/capecitabine (625 mg/m² days 1-21)) in patients with oesophageal squamous cell carcinoma (OSCC) or adenocarcinoma (OAC). Non-responders, who had a less than 35% reduction in maximum standardised uptake value (SUV_max) from pre-treatment baseline, were randomly assigned to continue cis/cap or switch to car/pac (carboplatin AUC 5/paclitaxel 175 mg/m²) for a further induction cycle, then concurrently with radiotherapy over 25 fractions. Responders continued cis/cap for the duration of treatment. All patients (including responders) were randomised to standard (50Gy) or high (60Gy) dose radiation as part of the main study. Primary endpoint for the substudy was treatment failure-free survival (TFFS) at week 24. The trial was registered with International Standard Randomized Controlled Trial Number 97125464 and ClinicalTrials.govNCT02741856.

Findings

This substudy was closed on 1st August 2021 by the Independent Data Monitoring Committee on the grounds of futility and possible harm. To this point from 22nd November 2016, 103 patients from 16 UK centres had participated in the PET-CT substudy; 63 (61.2%; 52/83 OSCC, 11/20 OAC) of whom were non-responders. Of these, 31 were randomised to car/pac and 32 to remain on cis/cap. All patients were followed up until at least 24 weeks, at which point in OSCC both TFFS (25/27 (92.6%) vs 17/25 (68%); p = 0.028) and overall survival (42.5 vs. 20.4 months, adjusted HR 0.36; p = 0.018) favoured cis/cap over car/pac. There was a trend towards worse survival in OSCC + OAC cis/cap responders (33.6 months; 95%CI 23.1-nr) vs. non-responders (42.5 (95%CI 27.0-nr) months; HR = 1.43; 95%CI 0.67-3.08; p = 0.35).

Interpretation

In OSCC, early metabolic response assessment is not prognostic for TFFS or overall survival and should not be used to personalise systemic therapy in patients receiving dCRT.

Funding

Cancer Research UK.

Development and validation of a REcurrent Liver cAncer Prediction ScorE (RELAPSE) following liver transplantation in patients with hepatocellular carcinoma: Analysis of the US Multicenter HCC Transplant Consortium

HCC recurrence following liver transplantation (LT) is highly morbid and occurs despite strict patient selection criteria. Individualized prediction of post-LT HCC recurrence risk remains an important need. Clinico-radiologic and pathologic data of 4981 patients with HCC undergoing LT from the US Multicenter HCC Transplant Consortium (UMHTC) were analyzed to develop a REcurrent Liver cAncer Prediction ScorE (RELAPSE). Multivariable Fine and Gray competing risk analysis and machine learning algorithms (Random Survival Forest and Classification and Regression Tree models) identified variables to model HCC recurrence. RELAPSE was externally validated in 1160 HCC LT recipients from the European Hepatocellular Cancer Liver Transplant study group. Of 4981 UMHTC patients with HCC undergoing LT, 71.9% were within Milan criteria, 16.1% were initially beyond Milan criteria with 9.4% downstaged before LT, and 12.0% had incidental HCC on explant pathology. Overall and recurrence-free survival at 1, 3, and 5 years was 89.7%, 78.6%, and 69.8% and 86.8%, 74.9%, and 66.7%, respectively, with a 5-year incidence of HCC recurrence of 12.5% (median 16 months) and non-HCC mortality of 20.8%. A multivariable model identified maximum alpha-fetoprotein (HR = 1.35 per-log SD, 95% CI,1.22-1.50, p < 0.001), neutrophil-lymphocyte ratio (HR = 1.16 per-log SD, 95% CI,1.04-1.28, p < 0.006), pathologic maximum tumor diameter (HR = 1.53 per-log SD, 95% CI, 1.35-1.73, p < 0.001), microvascular (HR = 2.37, 95%-CI, 1.87-2.99, p < 0.001) and macrovascular (HR = 3.38, 95% CI, 2.41-4.75, p < 0.001) invasion, and tumor differentiation (moderate HR = 1.75, 95% CI, 1.29-2.37, p < 0.001; poor HR = 2.62, 95% CI, 1.54-3.32, p < 0.001) as independent variables predicting post-LT HCC recurrence (C-statistic = 0.78). Machine learning algorithms incorporating additional covariates improved prediction of recurrence (Random Survival Forest C-statistic = 0.81). Despite significant differences in European Hepatocellular Cancer Liver Transplant recipient radiologic, treatment, and pathologic characteristics, external validation of RELAPSE demonstrated consistent 2- and 5-year recurrence risk discrimination (AUCs 0.77 and 0.75, respectively). We developed and externally validated a RELAPSE score that accurately discriminates post-LT HCC recurrence risk and may allow for individualized post-LT surveillance, immunosuppression modification, and selection of high-risk patients for adjuvant therapies.

Distribution and Environmental Drivers of Fungal Denitrifiers in Global Soils

The microbial process of denitrification is the primary source of the greenhouse gas nitrous oxide (N2O) from terrestrial ecosystems. Fungal denitrifiers, unlike many bacteria, lack the N2O reductase, and thereby are sources of N2O. Still, their diversity, global distribution, and environmental determinants, as well as their relative importance, compared to bacterial and archaeal denitrifiers, remain unresolved. Employing a phylogenetically informed approach to analyze 1,980 global soil and rhizosphere metagenomes for the denitrification marker gene nirK, which codes for the copper dependent nitrite reductase in denitrification, we show that fungal denitrifiers are sparse, yet cosmopolitan and that they are dominated by saprotrophs and pathogens. Few showed biome-specific distribution patterns, although members of the Fusarium oxysporum species complex, which are known to produce substantial amounts of N2O, were proportionally more abundant and diverse in the rhizosphere than in other biomes. Fungal denitrifiers were most frequently detected in croplands, but they were most abundant in forest soils when normalized to metagenome size. Nevertheless, the overwhelming dominance of bacterial and archaeal denitrifiers suggests a much lower fungal contribution to N2O emissions than was previously estimated. In relative terms, they could play a role in soils that are characterized by a high carbon to nitrogen ratio and a low pH, especially in the tundra as well as in boreal and temperate coniferous forests. Because global warming predicts the proliferation of fungal pathogens, the prevalence of potential plant pathogens among fungal denitrifiers and the cosmopolitan distribution of these organisms suggest that fungal denitrifier abundance may increase in terrestrial ecosystems. IMPORTANCE Fungal denitrifiers, in contrast to their bacterial counterparts, are a poorly studied functional group within the nitrogen cycle, even though they produce the greenhouse gas N2O. To curb soil N2O emissions, a better understanding of their ecology and distribution in soils from different ecosystems is needed. Here, we probed a massive amount of DNA sequences and corresponding soil data from a large number of samples that represented the major soil environments for a broad understanding of fungal denitrifier diversity at the global scale. We show that fungal denitrifiers are predominantly cosmopolitan saprotrophs and opportunistic pathogens. Fungal denitrifiers constituted, on average, 1% of the total denitrifier community. This suggests that earlier estimations of fungal denitrifier abundance, and, thereby, it is also likely that the contributions of fungal denitrifiers to N2O emissions have been overestimated. Nevertheless, with many fungal denitrifiers being plant pathogens, they could become increasingly relevant, as soilborne pathogenic fungi are predicted to increase with ongoing climate change.

The occipital place area represents visual information about walking, not crawling

Recent work has shown that the occipital place area (OPA)-a scene-selective region in adult humans-supports "visually guided navigation" (i.e. moving about the local visual environment and avoiding boundaries/obstacles). But what is the precise role of OPA in visually guided navigation? Considering humans move about their local environments beginning with crawling followed by walking, 1 possibility is that OPA is involved in both modes of locomotion. Another possibility is that OPA is specialized for walking only, since walking and crawling are different kinds of locomotion. To test these possibilities, we measured the responses in OPA to first-person perspective videos from both "walking" and "crawling" perspectives as well as for 2 conditions by which humans do not navigate ("flying" and "scrambled"). We found that OPA responded more to walking videos than to any of the others, including crawling, and did not respond more to crawling videos than to flying or scrambled ones. These results (i) reveal that OPA represents visual information only from a walking (not crawling) perspective, (ii) suggest crawling is processed by a different neural system, and (iii) raise questions for how OPA develops; namely, OPA may have never supported crawling, which is consistent with the hypothesis that OPA undergoes protracted development.

Global funding for cancer research between 2016 and 2020: a content analysis of public and philanthropic investments

BACKGROUND

Cancer is a leading cause of disease burden globally, with more than 19·3 million cases and 10 million deaths recorded in 2020. Research is crucial to understanding the determinants of cancer and the effects of interventions, and to improving outcomes. We aimed to analyse global patterns of public and philanthropic investment in cancer research.

METHODS

In this content analysis, we searched the UberResearch Dimensions database and Cancer Research UK data for human cancer research funding awards from public and philanthropic funders between Jan 1, 2016, and Dec 31, 2020. Included award types were project and programme grants, fellowships, pump priming, and pilot projects. Awards focused on operational delivery of cancer care were excluded. Awards were categorised by cancer type, cross-cutting research theme, and research phase. Funding amount was compared with global burden of specific cancers, measured by disability-adjusted life-years, years lived with disability, and mortality using data from the Global Burden of Disease study.

FINDINGS

We identified 66 388 awards with total investment of about US$24·5 billion in 2016-20. Investment decreased year-on-year, with the largest drop observed between 2019 and 2020. Pre-clinical research received 73·5% of the funding across the 5 years ($18 billion), phase 1-4 clinical trials received 7·4% ($1·8 billion), public health research received 9·4% ($2·3 billion), and cross-disciplinary research received 5·0% ($1·2 billion). General cancer research received the largest investment ($7·1 billion, 29·2% of the total funding). The most highly funded cancer types were breast cancer ($2·7 billion [11·2%]), haematological cancer ($2·3 billion [9·4%]), and brain cancer ($1·3 billion [5·5%]). Analysis by cross-cutting theme revealed that 41·2% of investment ($9·6 billion) went to cancer biology research, 19·6% ($4·6 billion) to drug treatment research, and 12·1% ($2·8 billion) to immuno-oncology. 1·4% of the total funding ($0·3 billion) was spent on surgery research, 2·8% ($0·7 billion) was spent on radiotherapy research, and 0·5% ($0·1 billion) was spent on global health studies.

INTERPRETATION

Cancer research funding must be aligned with the global burden of cancer with more equitable funding for cancer research in low-income and middle-income countries (which account for 80% of cancer burden), both to support research relevant to these settings, and build research capacity within these countries. There is an urgent need to prioritise investment in surgery and radiotherapy research given their primacy in the treatment of many solid tumours.

FUNDING

None.

Associations between prescription stimulant use as prescribed, nonmedical use, and illicit stimulant use among adults evaluated for substance use treatment, 2017-2021

Background

Limited data exist on risk factors for illicit stimulant use, including associations between prescription stimulant use/nonmedical use (NMU) and illicit stimulant use.

Methods

We used 2017-2021 data from adults assessed for substance use disorder (SUD) treatment using the National Addictions Vigilance Intervention and Prevention Program Addiction Severity Index-Multimedia Version® tool. Multivariable Poisson regression models analyzed associations between past 30-day prescription stimulant use as prescribed or NMU and past 30-day illicit stimulant use. Separate models examined past 30-day illicit stimulant, methamphetamine, and cocaine use. We explored problem severity across seven biopsychosocial domains (e.g., drug, psychiatric, family) by past 30-day prescription stimulant use/NMU and illicit stimulant use.

Results

Among 218,981 assessments, 1.8% reported prescription stimulant NMU; 1.6% reported use as prescribed. Past 30-day prescription stimulant NMU (vs. no use) was associated with past 30-day illicit stimulant use (adjusted prevalence ratio [aPR] [95% CI]: 2.67 [2.59, 2.75]), methamphetamine use (aPR: 2.81 [2.71, 2.92]), and cocaine use (aPR: 3.53 [3.33, 3.74]). Prescription stimulant use as prescribed (vs. no use) was associated with lower prevalence of past 30-day illicit stimulant use. Assessments reporting prescription stimulant NMU (vs. no use, or use as prescribed) appeared more likely to have moderate-to-extreme problem scores across biopsychosocial domains, indicating greater need for treatment or assistance. Assessments reporting prescription stimulant use as prescribed or NMU frequently reported opioids, alcohol, or other substances as their primary substance problem.

Conclusions

Adults using illicit stimulants/nonmedically using prescription stimulants may benefit from care addressing polysubstance use, mental health, social, and recovery support services.

Change in opioid and buprenorphine prescribers and prescriptions by specialty, 2016-2021

BACKGROUND

Safer opioid analgesic prescribing and increasing use of medications for opioid use disorder, including buprenorphine, are strategies prioritized to reduce opioid overdose deaths in the United States. Specialty-specific trends in the number of prescribers and prescriptions for opioid analgesics and buprenorphine are not well characterized.

METHODS

We used data from the IQVIA Longitudinal Prescription database for January 1, 2016 through December 31, 2021. We identified opioid and buprenorphine prescriptions based on NDC codes. We classified prescribers into one of 14 mutually exclusive specialty groups. We calculated the number of prescribers and number of prescriptions for opioids and buprenorphine by specialty and year.

RESULTS

From 2016 to 2021, the total number of opioid analgesic prescriptions dispensed decreased by 32% to 121,693,308 and the number of unique opioid analgesic prescribers decreased 7% to 966,369. Over the same time period, the number of buprenorphine prescriptions dispensed increased 36% to 13,909,724 and unique number of buprenorphine prescribers increased 86% to 59,090. Across most specialties we identified a contraction in the number of opioid prescriptions dispensed and opioid prescribers and an expansion in the number of buprenorphine prescriptions dispensed. Among high-volume opioid prescribing specialties, the largest decrease in opioid prescribers was 32% among Pain Medicine clinicians. By 2021, Advanced Practice Practitioners overtook Primary Care clinicians as the highest volume buprenorphine prescribers.

CONCLUSIONS

More work is needed to understand the impact of clinicians who stop prescribing opioids. While the trend in buprenorphine prescribing is encouraging, further expansion is warranted to meet the underlying need.

Emergency Department Visits Involving Mental Health Conditions, Suicide-Related Behaviors, and Drug Overdoses Among Adolescents - United States, January 2019-February 2023

The U.S. adolescent mental and behavioral health crisis is ongoing,* with high pre-COVID-19 pandemic baseline rates^† (1) and further increases in poor mental health (2), suicide-related behaviors (3), and drug overdose deaths (4) reported during 2020-2021. CDC examined changes in U.S. emergency department (ED) visits for mental health conditions (MHCs) overall and for nine specific MHCs,^§ suicide-related behaviors (including suspected suicide attempts), and drug-involved overdoses (including opioids) among children and adolescents aged 12-17 years (adolescents) during January 2019-February 2023, overall and by sex. Compared with fall 2021, by fall 2022, decreases in weekly ED visits were reported among all adolescents, and females specifically, for MHCs overall, suicide-related behaviors, and drug overdoses; weekly ED visits among males were stable. During this same period, increases in weekly ED visits for opioid-involved overdoses were detected. Mean weekly ED visits in fall 2022 for suicide-related behaviors and MHCs overall were at or lower than the 2019 prepandemic baseline, respectively, and drug overdose visits were higher. Differences by sex were observed; levels among females were at or higher than prepandemic baselines for these conditions. These findings suggest some improvements as of fall 2022 in the trajectory of adolescent mental and behavioral health, as measured by ED visits; however, poor mental and behavioral health remains a substantial public health problem, particularly among adolescent females. Early identification and trauma-informed interventions, coupled with expanded evidence-based, comprehensive prevention efforts, are needed to support adolescents' mental and behavioral health.

Alcohol and Other Substance Use Before and During the COVID-19 Pandemic Among High School Students - Youth Risk Behavior Survey, United States, 2021

Adolescence is a critical phase of development and is frequently a period of initiating and engaging in risky behaviors, including alcohol and other substance use. The COVID-19 pandemic and associated stressors might have affected adolescent involvement in these behaviors. To examine substance use patterns and understand how substance use among high school students changed before and during the COVID-19 pandemic, CDC analyzed data from the nationally representative Youth Risk Behavior Survey. This report presents estimated prevalences among high school students of current (i.e., previous 30 days) alcohol use, marijuana use, binge drinking, and prescription opioid misuse and lifetime alcohol, marijuana, synthetic marijuana, inhalants, ecstasy, cocaine, methamphetamine, heroin, and injection drug use and prescription opioid misuse. Trends during 2009-2021 were assessed using logistic regression and joinpoint regression analyses. Changes in substance use from 2019 to 2021 were assessed using prevalence differences and prevalence ratios, stratified by demographic characteristics. Prevalence of substance use measures by sexual identity and current co-occurring substance use were estimated using 2021 data. Substance use prevalence declined during 2009-2021. From 2019 to 2021, the prevalence of current alcohol use, marijuana use, and binge drinking and lifetime use of alcohol, marijuana, and cocaine and prescription opioid misuse decreased; lifetime inhalant use increased. In 2021, substance use varied by sex, race and ethnicity, and sexual identity. Approximately one third of students (29%) reported current use of alcohol or marijuana or prescription opioid misuse; among those reporting current substance use, approximately 34% used two or more substances. Widespread implementation of tailored evidence-based policies, programs, and practices likely to reduce risk factors for adolescent substance use and promote protective factors might further decrease substance use among U.S. high school students and is urgently needed in the context of the changing marketplaces for alcohol beverage products and other drugs (e.g., release of high-alcohol beverage products and increased availability of counterfeit pills containing fentanyl).

Trends in stigmatizing language about addiction: A longitudinal analysis of multiple public communication channels

INTRODUCTION

Stigma associated with substance use and addiction is a major barrier to overdose prevention. Although stigma reduction is a key goal of federal strategies to prevent overdose, there is limited data to assess progress made in reducing use of stigmatizing language about addiction.

METHODS

Using language guidelines published by the federal National Institute on Drug Abuse (NIDA), we examined trends in use of stigmatizing terms about addiction across four popular public communication modalities: news articles, blogs, Twitter, and Reddit. We calculate percent changes in the rates of articles/posts using stigmatizing terms over a five-year period (2017-2021) by fitting a linear trendline and assess statistically significant trends using the Mann-Kendall test.

RESULTS

The rate of articles containing stigmatizing language decreased over the past five years for news articles (-68.2 %, p < 0.001) and blogs (-33.6 %, p < 0.001). Among social media platforms, the rate of posts using stigmatizing language increased (Twitter [43.5 %, p = 0.01]) or remained stable (Reddit [3.1 %, p = 0.29]). In absolute terms, news articles had the highest rate of articles containing stigmatizing terms over the five-year period (324.9 articles per million) compared to 132.3, 18.3, and 138.6 posts per million for blogs, Twitter, and Reddit, respectively.

CONCLUSIONS

Use of stigmatizing language about addiction appears to have decreased across more traditional, longer-format communication modalities such as news articles. Additional work is needed to reduce use of stigmatizing language on social media.

Correlation of Carpal Tunnel Syndrome 6 Score and Physical Exam Maneuvers With Electrodiagnostic Test Severity in Carpal Tunnel Syndrome: A Blinded Prospective Cohort Study

PURPOSE

Although carpal tunnel syndrome (CTS) can be diagnosed clinically with the Carpal Tunnel Syndrome 6 (CTS-6) evaluation tool, the relationship between disease severity and CTS-6 score has not been elucidated. The purpose of our study was to determine the correlation of the CTS-6 score and other physical examination maneuvers with the carpal tunnel severity grade by electrodiagnostic testing (EDT). We hypothesized that the CTS-6 score, Durkan test, and Semmes Weinstein Monofilament Testing (SWMT) positively correlate with EDT severity.

METHODS

We prospectively enrolled 105 consecutive patients who presented to the office with suspected CTS, excluding those with previous surgery, previous EDT from an outside facility, or concomitant neuropathy. Four fellowship-trained hand surgeons obtained the CTS-6 score, time to obtain a positive Durkan compression test, and SWMT of the thumb, index, and middle fingers. All patients were sent for EDT. Hand surgeons were blinded to the results of the EDT, and the electrodiagnosticians were blinded to the clinical data. We used the Bland criteria (0-6) to grade CTS severity on EDT. This grade was compared with the CTS-6 score, Durkan time, and SWMT results.

RESULTS

Using Spearman correlation coefficients, we found a weakly positive correlation between a higher CTS-6 score and a higher severity grade on EDT. The mean CTS-6 score based on EDT grading were the following: (1) 14.8 (grade 0), (2) 16.0 (grade 1), (3) 14.8 (grade 2), (4) 16.7 (grade 3), (5) 18.7 (grade 4), (6) 18.3 (grade 5), and (7) 22.4 (grade 6). We also found a statistically significant association between the SWMT and a higher CTS-6 score as well as a higher severity grade on EDT. Durkan compression test did not appear to correlate with the EDT grade.

CONCLUSIONS

The CTS-6 and SWMT show a positive correlation with EDT severity in CTS on the basis of the Bland criteria. The time to a positive Durkan test did not show any correlation.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Association of Receipt of Opioid Use Disorder-Related Telehealth Services and Medications for Opioid Use Disorder With Fatal Drug Overdoses Among Medicare Beneficiaries Before and During the COVID-19 Pandemic

Importance

Federal emergency authorities were invoked during the COVID-19 pandemic to expand clinical telehealth for opioid use disorder (OUD).

Objective

To examine the association of the receipt of telehealth services and medications for OUD (MOUD) with fatal drug overdoses before and during the pandemic.

Design, Setting, and Participants

This cohort study used exploratory longitudinal data from 2 cohorts (prepandemic cohort: September 1, 2018, to February 29, 2020; pandemic cohort: September 1, 2019, to February 28, 2021) of Medicare Fee-for-Service beneficiaries aged 18 years or older initiating an episode of OUD-related care using Medicare Fee-for-Service data from the Centers for Medicare & Medicaid Services and National Death Index data from the Centers for Disease Control and Prevention. Data analysis was performed from September 19 to October 17, 2022.

Exposures

Prepandemic vs pandemic cohort demographic, medical, substance use, and psychiatric characteristics.

Main Outcomes and Measures

Receipt of OUD-related telehealth services, receipt of MOUD, and fatal drug overdose.

Results

The prepandemic cohort comprised 105 162 beneficiaries (58.1% female; 67.6% aged 45-74 years). The pandemic cohort comprised 70 479 beneficiaries (57.1% female; 66.3% aged 45-74 years). The rate of all-cause mortality was higher in the pandemic cohort (99.9 per 1000 beneficiaries; 7041 deaths) than in the prepandemic cohort (76.8 per 1000; 8076 deaths) (P < .001). The rate of fatal drug overdoses was higher in the pandemic cohort (5.1 per 1000 beneficiaries; n = 358) than in the prepandemic cohort (3.7 per 1000; n = 391) (P < .001). The percentage of deaths due to a fatal drug overdose was similar in the prepandemic (4.8%) and pandemic (5.1%) cohorts (P = .49). In multivariable analysis of the pandemic cohort, receipt of OUD-related telehealth was associated with a significantly lower adjusted odds ratio (aOR) for fatal drug overdose (aOR, 0.67; 95% CI, 0.48-0.92) as was receipt of MOUD from opioid treatment programs (aOR, 0.41; 95% CI, 0.25-0.68) and receipt of buprenorphine in office-based settings (aOR, 0.62; 95% CI, 0.43-0.91) compared with those not receiving MOUD; receipt of extended-release naltrexone in office-based settings was not associated with lower odds for fatal drug overdose (aOR, 1.16; 95% CI, 0.41-3.26).

Conclusions and Relevance

This cohort study found that, among Medicare beneficiaries initiating OUD-related care during the COVID-19 pandemic, receipt of OUD-related telehealth services was associated with reduced risk for fatal drug overdose, as was receipt of MOUD from opioid treatment programs and receipt of buprenorphine in office-based settings. Strategies to expand provision of MOUD, increase retention in care, and address co-occurring physical and behavioral health conditions are needed.

Complications Following Intramedullary Screw Fixation for Metacarpal Fractures: A Systematic Review

PURPOSE

There has been a recent increase in the use of intramedullary screws (IMS) for the surgical treatment of metacarpal fractures. While IMS fixation has been shown to produce excellent functional outcomes, postoperative complications have yet to be fully explored in a comprehensive way. This systematic review quantified the incidence, treatment, and results of complications following IMS fixation for metacarpal fractures.

METHODS

A systematic review was performed using PubMed, Cochrane Central, EBSCO, and EMBASE databases. All clinical studies that documented IMS complications following metacarpal fracture fixation were included. Descriptive statistics were analyzed for all available data.

RESULTS

Twenty-six studies were included: 2 randomized trials, 4 cohort studies, 19 case series, and 1 case report. Among the 1,014 fractures studied, 47 complications were reported across all studies (4.6%). Stiffness was the most common, followed by extension lag, loss of reduction, shortening, and complex regional pain syndrome. Other complications included screw fracture, bending, and migration; early-onset arthrosis; infection; tendon adhesion; hypertrophic scar; hematoma; and nickel allergy. Eighteen of the 47 (38%) patients with complications underwent revision surgery.

CONCLUSIONS

Complications following IMS fixation of metacarpal fractures are relatively uncommon.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Estimated Number of People Who Inject Drugs in the United States

BACKGROUND

Public health data signal increases in the number of people who inject drugs (PWID) in the United States during the past decade. An updated PWID population size estimate is critical for informing interventions and policies aiming to reduce injection-associated infections and overdose, as well as to provide a baseline for assessments of pandemic-related changes in injection drug use.

METHODS

We used a modified multiplier approach to estimate the number of adults who injected drugs in the United States in 2018. We deduced the estimated number of nonfatal overdose events among PWID from 2 of our previously published estimates: the number of injection-involved overdose deaths and the meta-analyzed ratio of nonfatal to fatal overdose. The number of nonfatal overdose events was divided by prevalence of nonfatal overdose among current PWID for a population size estimate.

RESULTS

There were an estimated 3 694 500 (95% confidence interval [CI], 1 872 700-7 273 300) PWID in the United States in 2018, representing 1.46% (95% CI, .74-2.87) of the adult population. The estimated prevalence of injection drug use was highest among males (2.1%; 95% CI, 1.1-4.2), non-Hispanic Whites (1.8%; 95% CI, .9-3.6), and adults aged 18-39 years (1.8%; 95% CI, .9-3.6).

CONCLUSIONS

Using transparent, replicable methods and largely publicly available data, we provide the first update to the number of people who inject drugs in the United States in nearly 10 years. Findings suggest the population size of PWID has substantially grown in the past decade and that prevention services for PWID should be proportionally increased.

Trends and Characteristics of Buprenorphine-Involved Overdose Deaths Prior to and During the COVID-19 Pandemic

Importance

Buprenorphine remains underused in treating opioid use disorder, despite its effectiveness. During the onset of the COVID-19 pandemic, the US government implemented prescribing flexibilities to support continued access.

Objective

To determine whether buprenorphine-involved overdose deaths changed after implementing these policy changes and highlight characteristics and circumstances of these deaths.

Design, Setting, and Participants

This cross-sectional study used data from the State Unintentional Drug Overdose Reporting System (SUDORS) to assess overdose deaths in 46 states and the District of Columbia occurring July 2019 to June 2021. Data were analyzed from March 7, 2022, to June 30, 2022.

Main Outcomes and Measures

Buprenorphine-involved and other opioid-involved overdose deaths were examined. Monthly opioid-involved overdose deaths and the percentage involving buprenorphine were computed to assess trends. Proportions and exact 95% CIs of drug coinvolvement, demographics, and circumstances were calculated by group.

Results

During July 2019 to June 2021, 32 jurisdictions reported 89 111 total overdose deaths and 74 474 opioid-involved overdose deaths, including 1955 buprenorphine-involved overdose deaths, accounting for 2.2% of all drug overdose deaths and 2.6% of opioid-involved overdose deaths. Median (IQR) age was similar for buprenorphine-involved overdose deaths (41 [34-55] years) and other opioid-involved overdose deaths (40 [31-52] years). A higher proportion of buprenorphine-involved overdose decedents, compared with other opioid-involved decedents, were female (36.1% [95% CI, 34.2%-38.2%] vs 29.1% [95% CI, 28.8%-29.4%]), non-Hispanic White (86.1% [95% CI, 84.6%-87.6%] vs 69.4% [95% CI, 69.1%-69.7%]), and residing in rural areas (20.8% [95% CI, 19.1%-22.5%] vs 11.4% [95% CI, 11.2%-11.7%]). Although monthly opioid-involved overdose deaths increased, the proportion involving buprenorphine fluctuated but did not increase during July 2019 to June 2021. Nearly all (92.7% [95% CI, 91.5%-93.7%]) buprenorphine-involved overdose deaths involved at least 1 other drug; higher proportions involved other prescription medications compared with other opioid-involved overdose deaths (eg, anticonvulsants: 18.6% [95% CI, 17.0%-20.3%] vs 5.4% [95% CI, 5.2%-5.5%]) and a lower proportion involved illicitly manufactured fentanyls (50.2% [95% CI, 48.1%-52.3%] vs 85.3% [95% CI, 85.1%-85.5%]). Buprenorphine decedents were more likely to be receiving mental health treatment than other opioid-involved overdose decedents (31.4% [95% CI, 29.3%-33.5%] vs 13.3% [95% CI, 13.1%-13.6%]).

Conclusions and Relevance

The findings of this cross-sectional study suggest that actions to facilitate access to buprenorphine-based treatment for opioid use disorder during the COVID-19 pandemic were not associated with an increased proportion of overdose deaths involving buprenorphine. Efforts are needed to expand more equitable and culturally competent access to and provision of buprenorphine-based treatment.

Comparative Bending Strength of Metacarpal Neck Fractures Fixed with Two Types of Intramedullary Screws

Objectives

Intramedullary (IM) screw fixation of metacarpal fractures is a technique, which has gained in popularity owing to its simplicity, speedy rehabilitation, and good functional outcomes. A new, larger diameter, non-compression screw designed specifically for IM metacarpal fixation was recently introduced which could provide better fracture stability and reduce the risk of hardware failure. Our goal was to evaluate the strength of this screw compared to a first-generation screw.

Methods

This mechanical study was designed to compare a 4.5 mm metacarpal headless screw (MCHS) to data from our prior research evaluating a 3.0 mm headless screw (HS). Accordingly, we used identical bone models, testing constructs, equipment, and protocols. A metacarpal neck osteotomy was created in 10 Sawbones models. A 4.5 mm x 50 mm MCHS was inserted retrograde to stabilize the fracture. Flexion bending strength was measured through a cable tension construct on a materials testing machine. Failure mechanism and strength was recorded and compared to data with a 3.0 mm screw construct.

Results

Eight models failed by bending of the intramedullary screw. Two models failed by rotation of the metacarpal head. Failure occurred at an average of 539 N (Range 315 - 735 N). The MCHS demonstrated a significantly greater load to failure compared to the previously studied 3.0 mm HS at 215 N (P<0.05).

Conclusion

A larger, 4.5 mm metacarpal-specific headless screw is more than twice as strong as a 3.0 mm diameter screw in a metacarpal neck fracture model.

Retrograde Intramedullary Screw Fixation for Metacarpal Fractures: A Systematic Review

Common forms of fixation of metacarpal fractures have historically included percutaneous Kirschner wire fixation, plates and screws, and, more recently, intramedullary screw fixation. Retrograde intramedullary screws (RISs) are a novel modality first described 10 years ago. The purpose of this review is to critically evaluate the published literature assessing outcomes of RIS fixation for metacarpal fractures and create a complication profile for this novel technique. A comprehensive literature search was performed using electronic databases for both clinical and biomechanical studies in relation to RIS fixation published from 2000 to 2020. A total of 19 studies (13 clinical and 6 biomechanical) met the inclusion criteria. The clinical studies examined 603 metacarpal fractures and demonstrated adequate functional outcomes in terms of grip strength, total active motion, and time to return to work. The biomechanical studies examined 80 metacarpal fractures, finding that load to failure in RISs was often equal to or higher than Kirschner wires but less than plate and screws. The complication rate in reviewed studies was 2.8%, with the most prevalent complications being stiffness and extension lag. RIS use in metacarpal fractures appears to provide adequate stability with satisfactory clinical outcomes and minimal complications, although more high-quality studies are needed to fully examine this modality.