Exploring Barriers and Facilitators to Reducing the Environmental Impact of the Operating Room

INTRODUCTION

The operating room (OR) is a major contributor to greenhouse gas emissions both nationally and globally. Successful implementation of quality improvement initiatives requires understanding of key stakeholders' perspectives of the issues at hand. Our aim was to explore surgical, anesthesia, and OR staff member perspectives on barriers and facilitators to reducing OR waste.

MATERIALS AND METHODS

Identified stakeholders from a single academic medical center were interviewed to identify important barriers and facilitators to reducing surgical waste. Two team members with qualitative research experience used deductive logic guided by the Theoretical Domains Framework of behavior change to identify themes within transcripts.

RESULTS

Nineteen participants including surgeons (n = 3, 15.8%), surgical residents (n = 5, 26.3%), an anesthesiologist (n = 1, 5.3%), anesthesia residents (n = 2, 10.5%), nurse anesthetists (n = 2, 10.5%), nurses (n = 5, 26.3%), and a surgical technologist (n = 1, 5.3%) were interviewed. Twelve of the 14 themes within the Theoretical Domains Framework were discovered in transcripts. Barriers within these themes included lack of resources to pursue environmental sustainability in the OR and the necessity of maintaining sterility for patient safety. Facilitators included emphasizing surgeon leadership within the OR to reduce unused supplies and spreading awareness of the environmental and economic impact of surgical waste.

CONCLUSIONS

Interviewed stakeholders were able to identify areas where improvements around surgical waste reduction and management could be made at the institution by describing barriers and facilitators to sustainability-driven interventions. Future surgical waste reduction initiatives at this institution will be guided by these important perspectives.

Mycorrhizal feedbacks influence global forest structure and diversity

One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles in proximity to conspecific adult plants. Although evidence shows that plant-specific soil pathogens can drive negative CDD, trees also form key mutualisms with mycorrhizal fungi, which may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree species exhibit weaker negative CDD than arbuscular mycorrhizal tree species. We further tested for conmycorrhizal density dependence (CMDD) to test for benefit from shared mutualists. We found that the strength of CDD varies systematically with mycorrhizal type, with ectomycorrhizal tree species exhibiting higher sapling densities with increasing adult densities than arbuscular mycorrhizal tree species. Moreover, we found evidence of positive CMDD for tree species of both mycorrhizal types. Collectively, these findings indicate that mycorrhizal interactions likely play a foundational role in global forest diversity patterns and structure.

Historical Assembly of Andean Tree Communities

Patterns of species diversity have been associated with changes in climate across latitude and elevation. However, the ecological and evolutionary mechanisms underlying these relationships are still actively debated. Here, we present a complementary view of the well-known tropical niche conservatism (TNC) hypothesis, termed the multiple zones of origin (MZO) hypothesis, to explore mechanisms underlying latitudinal and elevational gradients of phylogenetic diversity in tree communities. The TNC hypothesis posits that most lineages originate in warmer, wetter, and less seasonal environments in the tropics and rarely colonize colder, drier, and more seasonal environments outside of the tropical lowlands, leading to higher phylogenetic diversity at lower latitudes and elevations. In contrast, the MZO hypothesis posits that lineages also originate in temperate environments and readily colonize similar environments in the tropical highlands, leading to lower phylogenetic diversity at lower latitudes and elevations. We tested these phylogenetic predictions using a combination of computer simulations and empirical analyses of tree communities in 245 forest plots located in six countries across the tropical and subtropical Andes. We estimated the phylogenetic diversity for each plot and regressed it against elevation and latitude. Our simulated and empirical results provide strong support for the MZO hypothesis. Phylogenetic diversity among co-occurring tree species increased with both latitude and elevation, suggesting an important influence on the historical dispersal of lineages with temperate origins into the tropical highlands. The mixing of different floras was likely favored by the formation of climatically suitable corridors for plant migration due to the Andean uplift. Accounting for the evolutionary history of plant communities helps to advance our knowledge of the drivers of tree community assembly along complex climatic gradients, and thus their likely responses to modern anthropogenic climate change.

Masting is uncommon in trees that depend on mutualist dispersers in the context of global climate and fertility gradients

The benefits of masting (volatile, quasi-synchronous seed production at lagged intervals) include satiation of seed predators, but these benefits come with a cost to mutualist pollen and seed dispersers. If the evolution of masting represents a balance between these benefits and costs, we expect mast avoidance in species that are heavily reliant on mutualist dispersers. These effects play out in the context of variable climate and site fertility among species that vary widely in nutrient demand. Meta-analyses of published data have focused on variation at the population scale, thus omitting periodicity within trees and synchronicity between trees. From raw data on 12 million tree-years worldwide, we quantified three components of masting that have not previously been analysed together: (i) volatility, defined as the frequency-weighted year-to-year variation; (ii) periodicity, representing the lag between high-seed years; and (iii) synchronicity, indicating the tree-to-tree correlation. Results show that mast avoidance (low volatility and low synchronicity) by species dependent on mutualist dispersers explains more variation than any other effect. Nutrient-demanding species have low volatility, and species that are most common on nutrient-rich and warm/wet sites exhibit short periods. The prevalence of masting in cold/dry sites coincides with climatic conditions where dependence on vertebrate dispersers is less common than in the wet tropics. Mutualist dispersers neutralize the benefits of masting for predator satiation, further balancing the effects of climate, site fertility and nutrient demands.

Beta diversity as a driver of forest biomass across spatial scales

Despite the importance of biodiversity-ecosystem functioning (BEF) relationships in ecology and conservation, relatively little is known about how BEF relationships change across spatial scales. Theory predicts that change in BEF relationships with increasing spatial scale will depend on variation in species composition across space (β-diversity), but empirical evidence for this is limited. Moreover, studies have not quantified the direct and indirect role the environment plays in costructuring ecosystem functioning across spatial scales. We used 14 temperate-forest plots 1.4 ha in size containing 18,323 trees to quantify scale-dependence between aboveground tree biomass and three components of tree-species diversity-α-diversity (average local diversity), γ-diversity (total diversity), and β-diversity. Using structural-equation models, we quantified the direct effects of each diversity component and the environment (soil nutrients and topography), as well as indirect effects of the environment, on tree biomass across 11 spatial extents ranging from 400 to 14,400 m² . Our results show that the relationship between β-diversity and tree biomass strengthened with increasing spatial extent. Moreover, β-diversity appeared to be a stronger predictor of biomass than α-diversity and γ-diversity at intermediate to large spatial extents. The environment had strong direct and indirect effects on biomass, but, in contrast to diversity, these effects did not strengthen with increasing spatial extent. This study provides some of the first empirical evidence that β-diversity underpins the scaling of BEF relationships in naturally complex ecosystems.

Management of lymphocele following anterior lumbar interbody fusion, case report and review of literature

While anterior lumbar interbody fusion (ALIF) is known as an established and safe procedure for treatment of degenerative disc disease, albeit rare, the development of postoperative intra-abdominal or retroperitoneal collection of lymph warrants timely diagnosis and management. This study presents the case of a 62-year-old male who underwent L4-L5 and L5-S1 ALIF and developed a persistent left-sided fluid collection, resulting in a symptomatic retroperitoneal lymphocele confirmed by computed tomography (CT). After percutaneous drainage by interventional radiology (IR), output remained high at 1 liter (L) per day, necessitating sclerotherapy with doxycycline and ethanol. In the absence of improvement, a lymphangiogram demonstrating a persistent lymph leak and glue embolization was performed. Due to refractory symptoms, retroperitoneal exploration with methylene blue dye was utilized for lymphatic mapping, and a lymphatic capillary leak in proximity to the left iliac artery was identified and successfully ligated with resolution of symptoms. With suspected fluid collections following ALIF, confirmation with CT or ultrasound (US) imaging followed by percutaneous drainage and testing of fluid is necessary. In mild cases, drainage alone or nonsurgical chemical sclerotherapy may suffice. In symptomatic refractory cases, localization of the site with lymphangiogram or US-guided injection of methylene blue dye allows for easier identification and definitive management with either transabdominal laparoscopic fenestration or retroperitoneal surgical exploration and ligation.

FunAndes – A functional trait database of Andean plants

We introduce the FunAndes database, a compilation of functional trait data for the Andean flora spanning six countries. FunAndes contains data on 24 traits across 2,694 taxa, for a total of 105,466 entries. The database features plant-morphological attributes including growth form, and leaf, stem, and wood traits measured at the species or individual level, together with geographic metadata (i.e., coordinates and elevation). FunAndes follows the field names, trait descriptions and units of measurement of the TRY database. It is currently available in open access in the FIGSHARE data repository, and will be part of TRY’s next release. Open access trait data from Andean plants will contribute to ecological research in the region, the most species rich terrestrial biodiversity hotspot.

Measurement(s)	Bark thickness • Leaf area • Leaf aluminium (Al) content per leaf dry mass • Specific leaf area • Leaf calcium (Ca) content per leaf dry mass • Leaf carbon (C) content per leaf dry mass • Leaf carbon (C) isotope signature (delta 13 C) • Leaf compoundness • Leaf dry mass per leaf fresh mass (leaf dry matter content, LDMC) • Leaf magnesium (Mg) content per leaf dry mass • Leaf nitrogen (N) content per leaf dry mass • Leaf nitrogen (N) isotope signature (delta 15 N) • Leaf phosphorus (P) content per leaf dry mass • Leaf potassium (K) content per leaf dry mass • Leaf texture (sclerophylly, physical strength, toughness) • leaf thickness • Plant growth form • Stem conduit cross-sectional area (vessels and tracheids) • Stem conduit density (vessels and tracheids) • Sapwood specific conductivity
Technology Type(s)	bark gauge • Scanner Device • inductively-coupled plasma atomic emission spectroscopy • Calculated from area and mass • CN analyzer • Isotope analyzer • in vivo visual assessment • Ratio of fresh to dry mass • punch tester • micrometer • optical analysis of cross sections with specific software • weight and volume measurement • estimated with equations from wood anatomy
Factor Type(s)	Country • Lat • Long • Elevation • Collection_year
Sample Characteristic - Organism	Tracheophyta
Sample Characteristic - Environment	Andean ecosystems • cloud forest • tropical upper montane forest • tropical lower montane forest • Paramo • Andes
Sample Characteristic - Location	South America • Venezuela • Colombia • Ecuador • Peru • Bolivia • Argentina

Risk Assessment of Anterior Lumbar Interbody Fusion Access in Degenerative Spinal Conditions

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

Develop an evidence-based preoperative risk assessment scoring system for patients undergoing anterior lumbar interbody fusion (ALIF).

SUMMARY OF BACKGROUND DATA

ALIF may hold advantages over other fusion techniques in sagittal restoration and fusion rates, though it introduces unique risks to vascular and abdominal structures and thus possibly increased risk of operative morbidity.

METHODS

Primary, 1 or 2-level ALIFs were identified in a surgical registry. Baseline characteristics were recorded. Axial magnetic resonance imagings at L4-L5 and L5-S1 were reviewed for vascular confluence/bifurcation or anomalous structures, and measured for operative window size/slope. To assess favorable outcomes, a clinical grade was calculated: (clinical grade=blood loss×operative duration), higher value indicating poorer outcome. To establish a risk scoring system, a base risk score algorithm was established and stratified into 5 categories: high, high to intermediate, intermediate, intermediate to low, and low. Modifiers to base risk score included age, body mass index, operative level, history of bone morphogenic protein use, calcified vasculature, spondylolisthesis grade, working window size and slope, and abnormal vasculature. Modifiers were weighted for contribution to surgical risk. A total risk score was calculated and evaluated for strength of association with clinical outcome grades by Pearson correlation coefficient.

RESULTS

A total of 65 patients were included. Mean clinical outcome grade was 5.6, mean total risk score 21.3±21.5. Multilevel procedures (L4-S1) mean total risk score was 57.3±7.8. L4-L5 mean total risk score was 23.6±5.2; L5-S1 mean total risk score 8.3±6.6. Correlation analysis demonstrated a significant and strong relationship (| r |=0.753; P <0.001) between total risk scores and clinical outcome grades.

CONCLUSION

Calculated ALIF risk scores significantly correlated with operative duration and blood loss. This scoring system represents a potential framework to facilitate clinical decision-making and risk assessment for potential ALIF candidates with degenerative spinal pathologies.

Limits to reproduction and seed size-number trade-offs that shape forest dominance and future recovery

The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential.

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.

Globally, tree fecundity exceeds productivity gradients

Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250-fold increase in seed abundance from cold-dry to warm-wet climates, driven primarily by a 100-fold increase in seed production for a given tree size. The modest (threefold) increase in forest productivity across the same climate gradient cannot explain the magnitudes of these trends. The increase in seeds per tree can arise from adaptive evolution driven by intense species interactions or from the direct effects of a warm, moist climate on tree fecundity. Either way, the massive differences in seed supply ramify through food webs potentially explaining a disproportionate role for species interactions in the wet tropics.

Understanding Opioid Prescribing Practices of Resident Physicians

BACKGROUND

To compare opioid prescribing practices of resident physicians across a variety of surgical and nonsurgical specialties; to identify factors which influence prescribing practices; and to examine resident utilization of best practice supplemental resources.

METHODS

An anonymous survey which assessed prescribing practices was completed by residents from one of several different subspecialties, including internal medicine, obstetrics and gynecology, general surgery, neurosurgery, orthopedic surgery, and urology. Fisher's exact test assessed differences in prescribing practices between specialties.

RESULTS

Only 35% of residents reported receiving formal training in safe opioid prescribing. Overall, the most frequently reported influences on prescribing practices were the use of standardized order sets for specific procedures, attending preference, and patient's history of prescribed opioids. Resident physicians significantly underutilize best practice supplemental resources, such as counseling patients on pain expectations prior to prescribing opioid medication; contacting established pain specialists; screening patients for opioid abuse; referring to the Prescription Monitoring Program; and counseling patients on safe disposal of unused pills (P < .001).

DISCUSSION

The incorporation of comprehensive prescribing education into resident training and the utilization of standardized order sets can promote safe opioid prescribing.

The evolutionary assembly of forest communities along environmental gradients: recent diversification or sorting of pre-adapted clades?

Recent studies have demonstrated that ecological processes that shape community structure and dynamics change along environmental gradients. However, much less is known about how the emergence of the gradients themselves shape the evolution of species that underlie community assembly. In this study, we address how the creation of novel environments leads to community assembly via two nonmutually exclusive processes: immigration and ecological sorting of pre-adapted clades (ISPC), and recent adaptive diversification (RAD). We study these processes in the context of the elevational gradient created by the uplift of the Central Andes. We develop a novel approach and method based on the decomposition of species turnover into within- and among-clade components, where clades correspond to lineages that originated before mountain uplift. Effects of ISPC and RAD can be inferred from how components of turnover change with elevation. We test our approach using data from over 500 Andean forest plots. We found that species turnover between communities at different elevations is dominated by the replacement of clades that originated before the uplift of the Central Andes. Our results suggest that immigration and sorting of clades pre-adapted to montane habitats is the primary mechanism shaping tree communities across elevations.

Is there tree senescence? The fecundity evidence

Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size-fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models.

Chemical Similarity of Co-occurring Trees Decreases With Precipitation and Temperature in North American Forests

Plant diversity varies immensely over large-scale gradients in temperature, precipitation, and seasonality at global and regional scales. This relationship may be driven in part by climatic variation in the relative importance of abiotic and biotic interactions to the diversity and composition of plant communities. In particular, biotic interactions may become stronger and more host specific with increasing precipitation and temperature, resulting in greater plant species richness in wetter and warmer environments. This hypothesis predicts that the many defensive compounds found in plants’ metabolomes should increase in richness and decrease in interspecific similarity with precipitation, temperature, and plant diversity. To test this prediction, we compared patterns of chemical and morphological trait diversity of 140 woody plant species among seven temperate forests in North America representing 16.2°C variation in mean annual temperature (MAT), 2,115 mm variation in mean annual precipitation (MAP), and from 10 to 68 co-occurring species. We used untargeted metabolomics methods based on data generated with liquid chromatography-tandem mass spectrometry to identify, classify, and compare 13,480 unique foliar metabolites and to quantify the metabolomic similarity of species in each community with respect to the whole metabolome and each of five broad classes of metabolites. In addition, we compiled morphological trait data from existing databases and field surveys for three commonly measured traits (specific leaf area [SLA], wood density, and seed mass) for comparison with foliar metabolomes. We found that chemical defense strategies and growth and allocation strategies reflected by these traits largely represented orthogonal axes of variation. In addition, functional dispersion of SLA increased with MAP, whereas functional richness of wood density and seed mass increased with MAT. In contrast, chemical similarity of co-occurring species decreased with both MAT and MAP, and metabolite richness increased with MAT. Variation in metabolite richness among communities was positively correlated with species richness, but variation in mean chemical similarity was not. Our results are consistent with the hypothesis that plant metabolomes play a more important role in community assembly in wetter and warmer climates, even at temperate latitudes, and suggest that metabolomic traits can provide unique insight to studies of trait-based community assembly.

Arbuscular mycorrhizal trees influence the latitudinal beta-diversity gradient of tree communities in forests worldwide

Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) associations are critical for host-tree performance. However, how mycorrhizal associations correlate with the latitudinal tree beta-diversity remains untested. Using a global dataset of 45 forest plots representing 2,804,270 trees across 3840 species, we test how AM and EcM trees contribute to total beta-diversity and its components (turnover and nestedness) of all trees. We find AM rather than EcM trees predominantly contribute to decreasing total beta-diversity and turnover and increasing nestedness with increasing latitude, probably because wide distributions of EcM trees do not generate strong compositional differences among localities. Environmental variables, especially temperature and precipitation, are strongly correlated with beta-diversity patterns for both AM trees and all trees rather than EcM trees. Results support our hypotheses that latitudinal beta-diversity patterns and environmental effects on these patterns are highly dependent on mycorrhizal types. Our findings highlight the importance of AM-dominated forests for conserving global forest biodiversity.

Author Correction: Continent-wide tree fecundity driven by indirect climate effects

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-22025-2

Continent-wide tree fecundity driven by indirect climate effects

Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in North America that climate-condition interactions dominate responses through two pathways, i) effects of growth that depend on climate, and ii) effects of climate that depend on tree size. Because tree fecundity first increases and then declines with size, climate change that stimulates growth promotes a shift of small trees to more fecund sizes, but the opposite can be true for large sizes. Change the depresses growth also affects fecundity. We find a biogeographic divide, with these interactions reducing fecundity in the West and increasing it in the East. Continental-scale responses of these forests are thus driven largely by indirect effects, recommending management for climate change that considers multiple demographic rates.

Oral Microbiota Composition Predicts Early Childhood Caries Onset

As the most common chronic disease in preschool children in the United States, early childhood caries (ECC) has a profound impact on a child's quality of life, represents a tremendous human and economic burden to society, and disproportionately affects those living in poverty. Caries risk assessment (CRA) is a critical component of ECC management, yet the accuracy, consistency, reproducibility, and longitudinal validation of the available risk assessment techniques are lacking. Molecular and microbial biomarkers represent a potential source for accurate and reliable dental caries risk and onset. Next-generation nucleotide-sequencing technology has made it feasible to profile the composition of the oral microbiota. In the present study, 16S ribosomal RNA (rRNA) gene sequencing was applied to saliva samples that were collected at 6-mo intervals for 24 mo from a subset of 56 initially caries-free children from an ongoing cohort of 189 children, aged 1 to 3 y, over the 2-y study period; 36 children developed ECC and 20 remained caries free. Analyses from machine learning models of microbiota composition, across the study period, distinguished between affected and nonaffected groups at the time of their initial study visits with an area under the receiver operating characteristic curve (AUC) of 0.71 and discriminated ECC-converted from healthy controls at the visit immediately preceding ECC diagnosis with an AUC of 0.89, as assessed by nested cross-validation. Rothia mucilaginosa, Streptococcus sp., and Veillonella parvula were selected as important discriminatory features in all models and represent biomarkers of risk for ECC onset. These findings indicate that oral microbiota as profiled by high-throughput 16S rRNA gene sequencing is predictive of ECC onset.

Prairie plants harbor distinct and beneficial root-endophytic bacterial communities

Plant-soil feedback studies attempt to understand the interplay between composition of plant and soil microbial communities. A growing body of literature suggests that plant species can coexist when they interact with a subset of the soil microbial community that impacts plant performance. Most studies focus on the microbial community in the soil rhizosphere; therefore, the degree to which the bacterial community within plant roots (root-endophytic compartment) influences plant-microbe interactions remains relatively unknown. To determine if there is an interaction between conspecific vs heterospecific soil microbes and plant performance, we sequenced root-endophytic bacterial communities of five tallgrass-prairie plant species, each reciprocally grown with soil microbes from each hosts' soil rhizosphere. We found evidence of plant-soil feedbacks for some pairs of plant hosts; however, the strength and direction of feedbacks varied substantially across plant species pairs-from positive to negative feedbacks. Additionally, each plant species harbored a unique subset of root-endophytic bacteria. Conspecifics that hosted similar bacterial communities were more similar in biomass than individuals that hosted different bacterial communities, suggesting an important functional link between root-endophytic bacterial community composition and plant fitness. Our findings suggest a connection between an understudied component of the root-endophytic microbiome and plant performance, which may have important implications in understanding plant community composition and coexistence.

Predictors of inpatient admission in the setting of anterior lumbar interbody fusion: a Minimally Invasive Spine Study Group (MISSG) investigation

OBJECTIVE

While the anterior lumbar interbody fusion (ALIF) procedure may be amenable to ambulatory surgery, it has been hypothesized that limitations such as the risk of postoperative ileus and vascular complications have hindered transition of this procedure to the outpatient setting. Identification of independent risk factors predisposing patients to inpatient stays of ≥ 24 hours after ALIF may facilitate better postsurgical outcomes, target modifiable risk factors, and assist in the development of screening tools to transition appropriate patients to the ambulatory surgery center (ASC) setting for this procedure. The purpose of this study was to identify the most relevant risk factors that predispose patients to ≥ 24-hour admission following ALIF.

METHODS

A prospectively maintained surgical registry was reviewed for patients undergoing single ALIF between May 2006 and December 2019. Demographics, preoperative diagnosis, perioperative variables, and postoperative complications were evaluated according to their relative risk (RR) elevation for an inpatient stay of ≥ 24 hours. A Poisson regression model was used to evaluate predictors of inpatient stays of ≥ 24 hours. Risk factors for inpatient admission of ≥ 24 hours were identified with a stepwise backward regression model.

RESULTS

A total of 111 patients underwent single-level ALIF (50.9% female and 52.6% male, ≤ 50 years old). Eleven (9.5%) patients were discharged in < 24 hours and 116 remained admitted for ≥ 24 hours. The average inpatient stay was > 2 days (53.7 hours). The most common postoperative complications were fever (body temperature ≥ 100.4°F; n = 4, 3.5%) and blood transfusions (n = 4, 3.5%). Bivariate analysis revealed a preoperative diagnosis of retrolisthesis or lateral listhesis to elevate the RR for an inpatient stay of ≥ 24 hours (RR 1.11, p = 0.001, both diagnoses). Stepwise multivariate analysis demonstrated significant predictors for inpatient stays of ≥ 24 hours to be an operation on L4-5, coexisting degenerative disc disease (DDD) with foraminal stenosis, and herniated nucleus pulposus (RR 1.11, 95% CI 1.03-1.20, p = 0.009, all covariates).

CONCLUSIONS

This study provides data regarding the incidence of demographic and perioperative characteristics and postoperative complications as they pertain to patients undergoing single-level ALIF. This preliminary investigation identified the most relevant risk factors to be considered before appropriately transitioning ALIF procedures to the ASC. Further studies of preoperative characteristics are needed to elucidate ideal ASC ALIF patients.

Local species diversity, β-diversity and climate influence the regional stability of bird biomass across North America

Biodiversity often stabilizes aggregate ecosystem properties (e.g. biomass) at small spatial scales. However, the importance of species diversity within communities and variation in species composition among communities (β-diversity) for stability at larger scales remains unclear. Using a continental-scale analysis of 1657 North American breeding-bird communities spanning 20-years and 35 ecoregions, we show local species diversity and β-diversity influence two components of regional stability: local stability (stability of bird biomass within sites) and spatial asynchrony (asynchronous fluctuations in biomass among sites). We found spatial asynchrony explained three times more variation in regional stability of bird biomass than did local stability. This result contrasts with studies at smaller spatial scales-typically plant metacommunities under 1 ha-that find local stability to be more important than spatial asynchrony. Moreover, spatial asynchrony of bird biomass increased with bird β-diversity and climate heterogeneity (temperature and precipitation), while local stability increased with species diversity. Our study reveals new insights into the scale-dependent processes regulating ecosystem stability, providing evidence that both local biodiversity loss and homogenization can destabilize ecosystem processes at biogeographic scales.

Accurate forest projections require long-term wood decay experiments because plant trait effects change through time

Whether global change will drive changing forests from net carbon (C) sinks to sources relates to how quickly deadwood decomposes. Because complete wood mineralization takes years, most experiments focus on how traits, environments and decomposer communities interact as wood decay begins. Few experiments last long enough to test whether drivers change with decay rates through time, with unknown consequences for scaling short-term results up to long-term forest ecosystem projections. Using a 7 year experiment that captured complete mineralization among 21 temperate tree species, we demonstrate that trait effects fade with advancing decay. However, wood density and vessel diameter, which may influence permeability, control how decay rates change through time. Denser wood loses mass more slowly at first but more quickly with advancing decay, which resolves ambiguity about the after-life consequences of this key plant functional trait by demonstrating that its effect on decay depends on experiment duration and sampling frequency. Only long-term data and a time-varying model yielded accurate predictions of both mass loss in a concurrent experiment and naturally recruited deadwood structure in a 32-year-old forest plot. Given the importance of forests in the carbon cycle, and the pivotal role for wood decay, accurate ecosystem projections are critical and they require experiments that go beyond enumerating potential mechanisms by identifying the temporal scale for their effects.

Longer Operative Time and Intraoperative Blood Transfusion are Associated with Postoperative Anastomotic Leak after Lower Gastrointestinal Surgery

Anastomotic leak after lower gastrointestinal surgery is a complication with potential for high morbidity, mortality, and increased costs. A single-institution retrospective chart review was performed on all patients who underwent lower gastrointestinal surgery between June 2009 and June 2013. Fifty-seven variables were included in our analysis and their association with postoperative anastomotic leak was examined. Nine hundred fifty-two patients underwent 983 lower gastrointestinal anastomoses with an overall leak rate in this series of 6 per cent. Type of intestinal anastomosis created (P < 0.00005), operative indication (P < 0.015), operation performed (P < 0.014), intraoperative blood transfusion (P < 0.017), and intraoperative surgical drain placement (P < 0.022) were all predictive of anastomotic leak. Anastomotic leak rate increased by 1.3 times for every additional hour in the operating room after three hours. Both increasing operation time and intraoperative blood transfusions were associated with an increased rate of anastomotic leak. When operative time extends beyond three hours or in those cases were blood transfusions are given, surgeons should consider taking steps to minimize the risks of a potential anastomotic leak.

Longer Operative Time and Intraoperative Blood Transfusion Are Associated with Postoperative Anastomotic Leak after Lower Gastrointestinal Surgery

Anastomotic leak after lower gastrointestinal surgery is a complication with potential for high morbidity, mortality, and increased costs. A single-institution retrospective chart review was performed on all patients who underwent lower gastrointestinal surgery between June 2009 and June 2013. Fifty-seven variables were included in our analysis and their association with postoperative anastomotic leak was examined. Nine hundred fifty-two patients underwent 983 lower gastrointestinal anastomoses with an overall leak rate in this series of 6 per cent. Type of intestinal anastomosis created (P < 0.00005), operative indication (P < 0.015), operation performed (P < 0.014), intraoperative blood transfusion (P < 0.017), and intraoperative surgical drain placement (P < 0.022) were all predictive of anastomotic leak. Anastomotic leak rate increased by 1.3 times for every additional hour in the operating room after three hours. Both increasing operation time and intraoperative blood transfusions were associated with an increased rate of anastomotic leak. When operative time extends beyond three hours or in those cases were blood transfusions are given, surgeons should consider taking steps to minimize the risks of a potential anastomotic leak.

Direct and indirect effects of climate on richness drive the latitudinal diversity gradient in forest trees

Climate is widely recognised as an important determinant of the latitudinal diversity gradient. However, most existing studies make no distinction between direct and indirect effects of climate, which substantially hinders our understanding of how climate constrains biodiversity globally. Using data from 35 large forest plots, we test hypothesised relationships amongst climate, topography, forest structural attributes (stem abundance, tree size variation and stand basal area) and tree species richness to better understand drivers of latitudinal tree diversity patterns. Climate influences tree richness both directly, with more species in warm, moist, aseasonal climates and indirectly, with more species at higher stem abundance. These results imply direct limitation of species diversity by climatic stress and more rapid (co-)evolution and narrower niche partitioning in warm climates. They also support the idea that increased numbers of individuals associated with high primary productivity are partitioned to support a greater number of species.

Image-Guided Navigation in Lymph Node Biopsy

Background and Objectives:

Image-guided navigation is an effective intra-operative technology in select surgical sub-specialties. Laparoscopic and open lymph node biopsy are frequently undertaken to obtain adequate tissue of difficult lesions. Image-guided navigation may positively augment the precision and success of surgical lymph node biopsies.

Methods:

In this prospective pilot study, pre-operative imaging was uploaded into the navigation platform software, which superimposed the imaging and the subject's real-time anatomy. This required anatomical landmarks on the subject's body to be spatially registered with the platform using an infrared camera. This was then used to guide dissection and biopsy in laparoscopic and subcutaneous biopsies.

Results:

Image-guided lymph node biopsy was undertaken in 15 cases. Successful biopsy locations included: retroperitoneum, porta hepatis, mesentery, iliac region, para-aortic, axilla, and inguinal region. There was an 87% total absolute success rate in biopsies (89% in laparoscopic image-guided navigation [LIGN] and 83% in subcutaneous image-guided navigation [SIGN]). There was a 92% absolute success rate in lesions with fixed locations. There was a 67% absolute success rate in lesions with mobile locations.

Conclusion:

The investigators successfully incorporated image-guidance into surgical biopsy of lymph nodes in a diverse variety of locations. This image-guided technique for surgical biopsy can accurately and safely localize target lesions minimizing unnecessary dissection, conversion to open procedure, and re-operation for further tissue characterization. This technique was useful in the morbidly obese, instances of limited foci of disease, PET-active lesions, identifying areas of highest PET-avidity, and lesions with critical surrounding anatomy.

Landscape Physiognomy Influences Abundance of the Lone Star Tick, Amblyomma americanum (Ixodida: Ixodidae), in Ozark Forests

The lone star tick, Amblyomma americanum Linnaeus (Ixodida: Ixodidae), is emerging as an important human disease vector in the United States. While some recent studies have modeled broad-scale (regional or county-level) distribution patterns of A. americanum, less is known about how local-scale habitat characteristics drive A. americanum abundance. Such local-scale information is vital to identify targets for tick population control measures within land management units. We investigated how habitat features predict host-seeking A. americanum adult and nymph abundance within a 12-ha oak-hickory forest plot in the Missouri Ozarks. We trapped ticks using CO2-baited traps at 40 evenly spaced locations for three 24-h periods during the summer of 2015, and we measured biotic and abiotic variables surrounding each location. Of 2,008 A. americanum captured, 1,009 were nymphs, and 999 were adults. We observed spatial heterogeneity in local tick abundance (min = 0 ticks, max = 112 ticks, mean = 16.7 ticks per trap night). Using generalized linear mixed models, we found that both nymphs and adults had greater abundance in valleys as well as on northern-facing aspects. Moreover, nymph abundance was negatively related to temperature variance, while adult abundance had a negative relationship with elevation. These results demonstrate that managers in this region may be able to predict local tick abundance through simple physiognomic factors and use these parameters for targeted management action.

Response to Comment on "Plant diversity increases with the strength of negative density dependence at the global scale"

Hülsmann and Hartig suggest that ecological mechanisms other than specialized natural enemies or intraspecific competition contribute to our estimates of conspecific negative density dependence (CNDD). To address their concern, we show that our results are not the result of a methodological artifact and present a null-model analysis that demonstrates that our original findings-(i) stronger CNDD at tropical relative to temperate latitudes and (ii) a latitudinal shift in the relationship between CNDD and species abundance-persist even after controlling for other processes that might influence spatial relationships between adults and recruits.

Overdispersed Spatial Patterning of Dominant Bunchgrasses in Southeastern Pine Savannas

Spatial patterning is a key natural history attribute of sessile organisms that frequently emerges from and dictates potential for interactions among organisms. We tested whether bunchgrasses, the dominant plant functional group in longleaf pine savanna groundcover communities, are nonrandomly patterned by characterizing the spatial dispersion of three bunchgrass species across six sites in Louisiana and Florida. We mapped bunchgrass tussocks of >5.0 cm basal diameter in three [Formula: see text] plots at each site. We modeled tussocks as two-dimensional objects to analyze their spatial relationships while preserving sizes and shapes of individual tussocks. Tussocks were overdispersed (more regularly spaced than random) for all species and sites at the local interaction scale (<0.3 m). This general pattern likely arises from a tussock-centered, distance-dependent mechanism, for example, intertussock competition. Nonrandom spatial patterns of dominant species have implications for community assembly and ecosystem function in tussock-dominated grasslands and savannas, including those characterized by extreme biodiversity.

Plant diversity increases with the strength of negative density dependence at the global scale

Theory predicts that higher biodiversity in the tropics is maintained by specialized interactions among plants and their natural enemies that result in conspecific negative density dependence (CNDD). By using more than 3000 species and nearly 2.4 million trees across 24 forest plots worldwide, we show that global patterns in tree species diversity reflect not only stronger CNDD at tropical versus temperate latitudes but also a latitudinal shift in the relationship between CNDD and species abundance. CNDD was stronger for rare species at tropical versus temperate latitudes, potentially causing the persistence of greater numbers of rare species in the tropics. Our study reveals fundamental differences in the nature of local-scale biotic interactions that contribute to the maintenance of species diversity across temperate and tropical communities.

Negative density dependence mediates biodiversity-productivity relationships across scales

Regional species diversity generally increases with primary productivity whereas local diversity-productivity relationships are highly variable. This scale-dependence of the biodiversity-productivity relationship highlights the importance of understanding the mechanisms that govern variation in species composition among local communities, which is known as β-diversity. Hypotheses to explain changes in β-diversity with productivity invoke multiple mechanisms operating at local and regional scales, but the relative importance of these mechanisms is unknown. Here we show that changes in the strength of local density-dependent interactions within and among tree species explain changes in β-diversity across a subcontinental-productivity gradient. Stronger conspecific relative to heterospecific negative density dependence in more productive regions was associated with higher local diversity, weaker habitat partitioning (less species sorting), and homogenization of community composition among sites (lower β-diversity). Regional processes associated with changes in species pools had limited effects on β-diversity. Our study suggests that systematic shifts in the strength of local interactions within and among species might generally contribute to some of the most prominent but poorly understood gradients in global biodiversity.

Quantification of risk factors in 500 patients with postoperative urinary retention

INTRODUCTION

An Institutional Quality and Safety Initiative to reduce postoperative urinary retention (POUR) and improve patient safety indicators (PSIs) was undertaken after a nurse driven protocol for catheter removal lead to an increase in POUR. The aim of this study was to identify the number of risk factors present in patients with POUR while examining the prevalence of those risk factors individually.

MATERIALS AND METHODS

A retrospective review of our institution's surgical database was performed to identify 500 consecutive cases of POUR between July 1, 2013 and July 1, 2014. POUR was defined as the inability to void postoperatively with bladder scan volumes greater than 450 mL and subsequent need for catheterization with an output greater than 450 mL. These records were individually reviewed for 15 known independent risk factors for urinary retention. Patients with incomplete records or preoperative baseline urinary retention requiring catheterization were excluded.

RESULTS

Of the 500 consecutive patients with POUR, 288 (57.6%) were male and 212 (42.4%) were female. At the time of voiding trial, all 500 patients with POUR (100%) had at least one perioperative risk factor identified and over 75% had six or more (mean 6.88, median 7, range 1-12).

CONCLUSIONS

Multiple perioperative risk factors are present in the vast majority of patients with POUR. Many of the risk factors are modifiable and represent an opportunity for intervention. This could ultimately lead to a risk profile which could be used to optimize timing of postoperative voiding trials, thus improving patient care (improve PSIs and patient comfort, reduce trauma) while maintaining low rates of CAUTI.

Dispersal and neutral sampling mediate contingent effects of disturbance on plant beta-diversity: a meta-analysis

A major challenge in ecology, conservation and global-change biology is to understand why biodiversity responds differently to similar environmental changes. Contingent biodiversity responses may depend on how disturbance and dispersal interact to alter variation in community composition (β-diversity) and assembly mechanisms. However, quantitative syntheses of these patterns and processes across studies are lacking. Using null-models and meta-analyses of 22 factorial experiments in herbaceous plant communities across Europe and North America, we show that disturbance diversifies communities when dispersal is limited, but homogenises communities when combined with increased immigration from the species pool. In contrast to the hypothesis that disturbance and dispersal mediate the strength of niche assembly, both processes altered β-diversity through neutral-sampling effects on numbers of individuals and species in communities. Our synthesis suggests that stochastic effects of disturbance and dispersal on community assembly play an important, but underappreciated, role in mediating biotic homogenisation and biodiversity responses to environmental change.

Outcomes and Use of Laparoscopic Versus Open Gastric Resection

BACKGROUND AND OBJECTIVES

The advantages of laparoscopy over open surgery are well established. Laparoscopic resection for gastric cancer is safe and results in equivalent oncologic outcomes when compared with open resection. The purpose of this study was to assess the use of laparoscopy to treat gastric cancer and the associated outcomes.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project (NSQIP) dataset was queried for patients with gastric cancer (ICD-9 Code 151.0-151.9) from January 2005 through December 2012. Logistic regression was used to evaluate the 30-day morbidity and mortality of open gastrectomy (CPT code 43620-2, 43631-4) versus that of the laparoscopic procedure on the stomach (CPT code 43650), while adjusting for preoperative risk factors.

RESULTS

A total of 4116 patients with gastric cancer were identified and divided by surgical approach into 2 groups: open gastrectomy (n = 3725; 90.5%) and laparoscopic procedure on the stomach (n = 391; 9.5%). After adjustment for preoperative risk factors, complications were significantly fewer in laparoscopic versus open gastric resection (odds ratio [OR] 0.61, 95% confidence interval [CI] = 0.45-0.82; P = .001). After adjusting for preoperative risk factors, there was no statistically significant difference in mortality with laparoscopic compared to open gastric resection (OR 0.74; 95% CI = 0.32-1.72; P = .481).

CONCLUSIONS

Laparoscopy is underused in the treatment of gastric cancer. Given that laparoscopic gastric resection has a lower morbidity in comparison to open resection, steps should be made toward advancing the use of laparoscopy for gastric cancer.

The effect of tobacco use on outcomes of laparoscopic and open ventral hernia repairs: a review of the NSQIP dataset

INTRODUCTION

Tobacco smoking is a known risk factor for complications after major surgical procedures. The full effect of tobacco use on these complications has not been studied over large populations for ventral hernia repairs. This effect is more important as the preoperative conditioning, and optimization of patients is adopted. We sought to use the prospectively collected ACS-NSQIP dataset to evaluate respiratory and infectious complications for patients undergoing both laparoscopic and open ventral hernia repairs.

METHODS

The ACS-NSQIP dataset was queried for patients who underwent open or laparoscopic ventral hernia repairs, by primary procedure CPT codes, between years 2009-2012. Smoking use was registered as defined by the ACS-NSQIP, as both a current smoker (within the prior 12 months) or as a history of smoking (having ever smoked). Univariate and multivariate analyses were used to investigate postoperative complications for 30-day morbidity and mortality by smoking status while adjusting for preoperative risk factors.

RESULTS

The majority of cases were open, 82 %, compared to laparoscopic 18 %. Sex was evenly distributed with 58 % female and 42 % male; however, there was a difference in the distribution of current smokers (p = 0.03). On analysis there were significantly more respiratory complications (p = 0.0003) and infectious complications (p < 0.0001). When controlling for sex, age, and type of surgery, using logistic regression, there were associations between smoking in the prior 12 months and respiratory complications, including pneumonia (p < 0.0001), and re-intubation (p < 0.0001). Similar associations were seen on logistic regression if a patient ever smoked; including pneumonia (p < 0.0001), re-intubation (p < 0.0001), and failure to wean (p < 0.0001).

CONCLUSION

Smoking tobacco, both current and historical use, leads to an increase in both respiratory and infectious complications. As more centers try to preoperatively condition patients for elective hernia repairs, it is important to note that patients may never return to the baseline outcomes of patients who never smoked.

Patient Safety Indicators for Judging Hospital Performance

Patient Safety Indicators (PSIs) were originally intended for use as a screen for quality of care but are now being used to rank hospitals and to modify hospital reimbursement. PSI data are dependent on accuracy of clinical documentation and coding. Information on whether a PSI event is inherent to the nature of the operation or posed a significant impact on the outcome is lacking. Cases for one year at a single academic center were queried. Cases with target PSIs were included (n = 136). Cases were evaluated for both the inherent nature and significance of injury. Both patient safety officers agreed that the PSI event was inherent to the disease process, and thus, the procedure and was not a marker of patient safety (false positive) in 11.8% to 33.3% of cases. Both reviewers agreed that the events were not clinically significant in 11.8% to 30.4% of cases. This study found high false-positive rates and only moderate interrater reliability for 3 PSIs. PSIs as currently reported are not reliable enough to be utilized for ranking.

Tree-mycorrhizal associations detected remotely from canopy spectral properties

A central challenge in global ecology is the identification of key functional processes in ecosystems that scale, but do not require, data for individual species across landscapes. Given that nearly all tree species form symbiotic relationships with one of two types of mycorrhizal fungi - arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi - and that AM- and ECM-dominated forests often have distinct nutrient economies, the detection and mapping of mycorrhizae over large areas could provide valuable insights about fundamental ecosystem processes such as nutrient cycling, species interactions, and overall forest productivity. We explored remotely sensed tree canopy spectral properties to detect underlying mycorrhizal association across a gradient of AM- and ECM-dominated forest plots. Statistical mining of reflectance and reflectance derivatives across moderate/high-resolution Landsat data revealed distinctly unique phenological signals that differentiated AM and ECM associations. This approach was trained and validated against measurements of tree species and mycorrhizal association across ~130 000 trees throughout the temperate United States. We were able to predict 77% of the variation in mycorrhizal association distribution within the forest plots (P < 0.001). The implications for this work move us toward mapping mycorrhizal association globally and advancing our understanding of biogeochemical cycling and other ecosystem processes.

Using codispersion analysis to quantify and understand spatial patterns in species-environment relationships

The analysis of spatial patterns in species-environment relationships can provide new insights into the niche requirements and potential co-occurrence of species, but species abundance and environmental data are routinely collected at different spatial scales. Here, we investigate the use of codispersion analysis to measure and assess the scale, directionality and significance of complex relationships between plants and their environment in large forest plots. We applied codispersion analysis to both simulated and field data on spatially located tree species basal area and environmental variables. The significance of the observed bivariate spatial associations between the basal area of key species and underlying environmental variables was tested using three null models. Codispersion analysis reliably detected directionality (anisotropy) in bivariate species-environment relationships and identified relevant scales of effects. Null model-based significance tests applied to codispersion analyses of forest plot data enabled us to infer the extent to which environmental conditions, tree sizes and/or tree spatial positions underpinned the observed basal area-environment relationships, or whether relationships were a result of other unmeasured factors. Codispersion analysis, combined with appropriate null models, can be used to infer hypothesized ecological processes from spatial patterns, allowing us to start disentangling the possible drivers of plant species-environment relationships.