Ankle fusion percutaneous home run screw fixation: Technical aspects and soft tissue structures at risk

INTRODUCTION

The objective of this cadaveric study was to identify the number of attempts necessary for a perfect positioning of the ankle fusion home run screw and the neurovascular and tendinous structures at risk.

METHODS

Eleven cadaveric limbs were used. Guidewires were percutaneously placed into the distal posterolateral aspect of the leg, under fluoroscopic guidance, with the ankle held in neutral position. Malpositioned guidewires were not removed and served as guidance for the following wires. The number of guidewires needed to achieve an acceptable positioning of the implant was noted. Neurovascular and tendinous injuries were assessed, and the shortest distance between the closest guidewire and the soft tissue structures was measured using a precision digital caliper.

RESULTS

Mean number of guidewires needed to achieve acceptable positioning of the implant was 2.34 (SD 0.81, range 2-4). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon 5.35 mm (SD 2.74 mm); peroneal tendons 9.65 mm (SD 5.19 mm); posteromedial neurovascular bundle 12.78 mm (SD 7.14 mm). The sural bundle was in contact with the guide pin in 5/11 specimens (45.5%) and impaled in 3/11 specimens (27.3%). The average distance from the sural nerve bundle was 3.58 mm (SD 2.16 mm).

CONCLUSIONS

The placement of percutaneous ankle fusion home run screws is technically demanding requiring multiple attempts for acceptable placement. Important tendinous and neurovascular structures are in close proximity to the guidewires. The sural bundle was either injured or in direct contact with the guide wire in approximately 73% of the cases. When using a home run screw, a mini-open approach is recommended.

LEVEL OF EVIDENCE

Level V, cadaveric study.

Impact of government health coverage for ART: The results of a 5-year experience in Quebec

An analysis of national registry data for 5 years of in-vitro fertilization (IVF) funding in Quebec, Canada was compared with the previous complete year of non-funded IVF cycles, as well as the first complete year following the end of funding. The number of cycles, livebirth rates, age group of patients treated, use of donor gametes, multiple pregnancy rates and cycle cancellation rates were assessed. The total number of IVF cycles performed increased dramatically during the funded period, averaging over 10,000 cycles per year. There was no change in the age group distribution of patients treated, but less egg donation was performed. Interestingly, funding was also associated with an increase in the IVF cycle cancellation rate (17.0% versus 34.4%, P < 0.001), a dramatic decline in the multiple pregnancy rate (25.6% versus 4.9%, P < 0.001), and a decline in the livebirth rate per fresh embryo transfer in stimulated IVF cycles (32.3% versus 25.5%, P < 0.001). Although the livebirth rate for stimulated IVF declined, over 9000 babies were born as a result of the coverage. Lessons learned from this experience could help develop a more fiscally responsible programme that still facilitates access to IVF care.

Therapeutic doses of neostigmine, depolarising neuromuscular blockade and muscle weakness in awake volunteers: a double-blind, placebo-controlled, randomised volunteer study

Neostigmine reverses non-depolarising neuromuscular blockade, but may cause muscle weakness when administered after full recovery of neuromuscular function. We hypothesised that neostigmine in therapeutic doses impairs muscle strength and respiratory function in awake healthy volunteers. Twenty-one volunteers were randomised to receive two doses of either intravenous (i.v.) neostigmine 2.5 mg with glycopyrrolate 450 μg (neostigmine group, n = 14) or normal saline 0.9% (placebo group, n = 7). The first dose was administered immediately after obtaining baseline measurements, and the second dose was administered 15 min later. All 14 volunteers in the neostigmine group received the first dose, mean (SD) 35 (5.8) μg.kg^-1 , but only nine of these volunteers agreed to receive the second dose, 34 (3.5) ?g.kg^-1 . The primary outcome was hand grip strength. Secondary outcomes were train-of-four ratio, single twitch height, forced expiratory volume in 1 s, forced vital capacity, forced expiratory volume in 1 s/forced vital capacity ratio, oxygen saturation, heart rate and mean arterial pressure. The first dose of intravenous neostigmine with glycopyrrolate resulted in reduced grip strength compared with placebo, -20 (20) % vs. +4.3 (9.9) %, p = 0.0016; depolarising neuromuscular blockade with decreased single twitch height, -14 (11) % vs. -3.8 (5.6) %, p = 0.0077; a restrictive spirometry pattern with decreased predicted forced expiratory volume in 1 s, -15 (12) % vs. -0.47 (3.4) %, p = 0.0011; and predicted forced vital capacity, -20 (12) % vs. -0.59 (3.2) %, p < 0.0001 at 5 min after administration. The second dose of neostigmine with glycopyrrolate further decreased grip strength mean (SD) -41 (23) % vs. +1.0 (15) %, p = 0.0004; single twitch height -25 (15) % vs. -2.5 (6.6) %, p = 0.0030; predicted forced expiratory volume in 1 s -23 (24) % vs. -0.7 (4.4) %, p = 0.0063; and predicted forced vital capacity, -27.1 (22.0) % vs. -0.66 (3.9) %, p = 0.0010. Train-of-four ratio remained unchanged (p = 0.22). In healthy volunteers, therapeutic doses of neostigmine induced significant and dose-dependent muscle weakness, demonstrated by a decrease in maximum voluntary hand grip strength and a restrictive spirometry pattern secondary to depolarising neuromuscular blockade.

Palliative Care Referrals for Advanced Non-small-cell Lung Cancer (NSCLC): Patient and Provider Attitudes and Practices

BACKGROUND

Early palliative care (PC) improves quality of life and prolongs survival for patients with metastatic non-small cell lung cancer (NSCLC). Despite these benefits, patient- and provider-specific barriers lead to underutilization of PC. To investigate these barriers, this 2 part study surveyed United States oncologists and patients with NSCLC.

PATIENTS AND METHODS

Oncologists in the International Association for the Study of Lung Cancer membership directory were surveyed on referral practice and attitudes regarding the role of PC for patients with NSCLC. Patients with advanced NSCLC at the Vanderbilt Ingram Cancer Center were surveyed separately regarding their understanding of PC and factors influencing them to seek referral.

RESULTS

Of 279 oncologists, 93 responded. Eighty-three percent believe definitive evidence exists supporting early PC; however, in practice, oncologists only refer an average of 19% of patients at diagnosis. Reasons for not referring included lack of symptoms (56%), belief that oncologists can manage PC independently (46%), not wanting to burden patients with appointments (41%), concern that referral may not be well received (38%), and long wait times (20%). Of 100 patients with NSCLC, 64% were unfamiliar with PC. Six percent had seen a PC provider. Ninety-eight percent of patients would accept referral if recommended by their oncologist. Patients desired referral for uncontrolled pain (95%), weak support system (86%), other cancer-related symptoms (85%), goals of care discussion (76%), and depression/anxiety (76%).

CONCLUSION

Although most oncologists acknowledge benefits of early PC for patients with metastatic NSCLC, a minority of patients are referred. Few patients with NSCLC are familiar with PC, but most are interested in referral.

Assessing PM2.5 Model Performance for the Conterminous U.S. with Comparison to Model Performance Statistics from 2007-2015

Previous studies have proposed that model performance statistics from earlier photochemical grid model (PGM) applications can be used to benchmark performance in new PGM applications. A challenge in implementing this approach is that limited information is available on consistently calculated model performance statistics that vary spatially and temporally over the U.S. Here, a consistent set of model performance statistics are calculated by year, season, region, and monitoring network for PM2.5 and its major components using simulations from versions 4.7.1-5.2.1 of the Community Multiscale Air Quality (CMAQ) model for years 2007-2015. The multi-year set of statistics is then used to provide quantitative context for model performance results from the 2015 simulation. Model performance for PM2.5 organic carbon in the 2015 simulation ranked high (i.e., favorable performance) in the multi-year dataset, due to factors including recent improvements in biogenic secondary organic aerosol and atmospheric mixing parameterizations in CMAQ. Model performance statistics for the Northwest region in 2015 ranked low (i.e., unfavorable performance) for many species in comparison to the 2007-2015 dataset. This finding motivated additional investigation that suggests a need for improved speciation of wildfire PM2.5emissions and modeling of boundary layer dynamics near water bodies. Several limitations were identified in the approach of benchmarking new model performance results with previous results. Since performance statistics vary widely by region and season, a simple set of national performance benchmarks (e.g., one or two targets per species and statistic) as proposed previously are inadequate to assess model performance throughout the U.S. Also, trends in model performance statistics for sulfate over the 2007 to 2015 period suggest that model performance for earlier years may not be a useful reference for assessing model performance for recent years in some cases. Comparisons of results from the 2015 base case with results from five sensitivity simulations demonstrated the importance of parameterizations of NH3 surface exchange, organic aerosol volatility and production, and emissions of crustal cations for predicting PM2.5 species concentrations.

The prevalence of sarcopenia in community-dwelling older adults, an exploration of differences between studies and within definitions: a systematic review and meta-analyses

Background

sarcopenia in ageing is a progressive decrease in muscle mass, strength and/or physical function. This review aims to summarise the definitions of sarcopenia in community-dwelling older adults and explore similarities and differences in prevalence estimates by definition.

Methods

a systematic review was conducted to identify articles which estimated sarcopenia prevalence in older populations using search terms for sarcopenia and muscle mass. Overall prevalence for each sarcopenia definition was estimated stratified by sex and ethnicity. Secondary analyses explored differences between studies and within definitions, including participant age, muscle mass measurement techniques and thresholds for muscle mass and gait speed.

Results

in 109 included articles, eight definitions of sarcopenia were identified. The lowest pooled prevalence estimates came from the European Working Group on Sarcopenia/Asian Working Group on Sarcopenia (12.9%, 95% confidence interval: 9.9-15.9%), International Working Group on Sarcopenia (9.9%, 3.2-16.6%) and Foundation for the National Institutes of Health (18.6%, 11.8-25.5%) definitions. The highest prevalence estimates were for the appendicular lean mass (ALM)/weight (40.4%, 19.5-61.2%), ALM/height (30.4%, 20.4-40.3%), ALM regressed on height and weight (30.4%, 20.4-40.3%) and ALM / body mass index (24.2%, 18.3-30.1%) definitions. Within definitions, the age of study participants and the muscle mass cut points used were substantive sources of between-study differences.

Conclusion

estimates of sarcopenia prevalence vary from 9.9 to 40.4%, depending on the definition used. Significant differences in prevalence exist within definitions across populations. This lack of agreement between definitions needs to be better understood before sarcopenia can be appropriately used in a clinical context.

The effect of preload on electromyographic train-of-four ratio at the first dorsal interosseous muscle during spontaneous recovery from neuromuscular blockade

Accurate and reliable quantitative neuromuscular function monitoring is desirable for the optimal management of neuromuscular blockade, selection of the most appropriate reversal agent and dosage, and assessing the completeness of reversal to exclude residual neuromuscular blockade. Applying preload to the thumb may affect the precision of electromyography. This study compared the precision and agreement of electromyography with and without preload during recovery from non-depolarising neuromuscular blockade. After induction of anaesthesia and before neuromuscular blockade, the supramaximal current required at the first dorsal interosseous muscle with and without preload was determined. During recovery, train-of-four ratios were recorded using electromyography every 20 seconds. Alternating pairs of measurements (with and without preload) were obtained until spontaneous recovery was achieved. The preload device applied a resting tension of 75-150 g to the thumb. Bland-Altman analysis for repeated measurements was used to assess precision and agreement of electromyography responses with and without muscle preload. Two hundred and seventy-five sets of repeated measurements were collected from 35 participants. The repeatability coefficient for train-of-four ratios recorded by electromyography with a preload was 0.030 (95% confidence intervals, CI, 0.028 to 0.031) versus 0.068 (95% CI 0.064 to 0.072) without. Train-of-four ratios with preload demonstrated a bias of +0.038 (95% CI 0.037 to 0.042) compared to electromyography without, with 95% limits of agreement of 0.035-0.111. Preload significantly improved the precision of electromyographic train-of-four ratios, with 95% of consecutive measurements differing by less than 3%. Furthermore, electromyography with preload demonstrated a positive bias of 0.04 compared with electromyography alone, the clinical significance of which requires further research.

Mobile Source Contributions to Ambient Ozone and Particulate Matter in 2025

The contribution of precursor emissions from 17 mobile source sectors to ambient ozone and fine particulate matter levels across the U.S. were evaluated, using the CAMx photochemical model, to identify which mobile source sectors are projected to have the largest impacts on air pollution in 2025. Both onroad and nonroad sectors contribute considerably to projected air pollution across much of the country. Summer ozone season ozone contributions between 2 and 5 ppb, which are among the highest levels presented on the maps of mobile source sectors, are largely found in the southeast United States from the onroad sectors, most notably light-duty and heavy-duty vehicles, and along the coastline from the Category 3 (C3) marine sector. Annual average PM2.5 contributions between 0.5 to 0.9 μg/m3, which are among the highest levels presented on the maps of mobile source sectors, are found throughout the Midwest and along portions of the east and west coast from onroad sectors as well as nonroad diesel and rail sectors. Additionally, contributions of precursor emissions to ambient ozone and PM2.5 levels were evaluated to understand the range of impacts from precursors in the various mobile source sectors. For most mobile source sectors, in most locations, NOX emissions contributed more to ozone than VOC emissions, and secondary PM2.5 contributed more to ambient PM2.5 than primary PM2.5. The largest ozone levels on the maps showing contributions from mobile source NOX emissions tended to be between 2 and 5 ppb, while the largest ozone levels on the maps showing contributions from mobile source VOC emissions tended to be between 0.9 and 2 ppb, except for southern California where ozone contributions from VOC emissions from onroad light duty vehicles were between 2 and 5 ppb. The largest contributions to ambient PM2.5 on the maps showing primary and secondary contributions from mobile source sectors tended to be between 0.1 and 0.5 μg/m3. The contribution from primary PM2.5 extended over localized areas (urban-scale) and the contribution from secondary PM2.5 extended over more regional (multi-state) areas.

Evaluation of self-collected vaginal specimens for the detection of high-risk human papillomavirus infection and the prediction of high-grade cervical intraepithelial lesions in a high-burden, low-resource setting

OBJECTIVES

To compare the performance of self-collected vaginal (V) specimens with clinician-collected cervical (C) specimens for detection of high-risk human papillomavirus (hrHPV) and cervical disease using the Cepheid Xpert HPV, Roche Cobas 4800 HPV and Hologic Aptima HPV assays.

METHODS

Women aged 30-59 years (n = 1005) were recruited at two clinics in Papua New Guinea, and they provided specimens for testing at point-of-care using the Xpert HPV Test, and for subsequent testing using the Cobas HPV (n = 981) and Aptima HPV (n = 983) assays. Liquid-based cytology was performed on C specimens to predict underlying high-grade squamous intraepithelial lesions (HSIL). V specimen results of each assay were evaluated against a constructed reference standard and for detection of HSIL or worse.

RESULTS

There was substantial (κ >0.6) agreement in hrHPV detection between V and C specimens across all three assays. The sensitivity, specificity, and positive and negative predictive values of Xpert HPV using self-collected V specimens for the detection of HPV type 16 according to the constructed reference standard were 92.1%, 93.1%, 63.6% and 98.9%, respectively; compared with 90.4%, 94.3%, 67.8% and 98.7% for Cobas 4800 HPV; and 63.2%, 97.2%, 75.0% and 95.3% for Aptima HPV. Similar results were observed for all hrHPV types (combined) and for HPV types 18/45, on all three assays. The detection of any hrHPV using self-collected specimens had high sensitivity (86%-92%), specificity (87%-94%) and negative predictive value (>98%) on all assays for HSIL positivity.

CONCLUSIONS

Xpert HPV, using self-collected vaginal specimens, has sufficient accuracy for use in point-of-care 'test-and-treat' cervical screening strategies in high-burden, low-resource settings.

MAGI2 is an independent predictor of biochemical recurrence in prostate cancer

BACKGROUND

Membrane-associated guanylate kinase, WW and PDZ domain-containing protein 2 (MAGI2) promotes the activity of phosphatase and tensin homolog (PTEN). Recent studies suggest that dysregulation of this signaling pathway has a role in prostate carcinogenesis. Our study aims to determine the prognostic significance of MAGI2 expression in prostate cancer.

METHODS

Tissue microarrays from 51 radical prostatectomy cases including benign prostatic tissue, high grade prostatic intraepithelial neoplasia (HGPIN), and adenocarcinoma were constructed. Immunohistochemistry with double staining for MAGI2 and p63 was performed and analyzed by image analysis as percent of analyzed area (%AREA). Multivariable logistic regression was used to correlate MAGI2 expression with clinical outcomes. Generalized Estimating Equations (GEE) with linear and logistic regression was used to correlate MAGI2 with intrapatient histology.

RESULTS

MAGI2 %AREA was inversely associated with progression from HGPIN to adenocarcinoma of low to high Gleason score (OR, 0.980; slope, -0.02; P = 0.005) and HGPIN to cancer of any Gleason score (OR, 0.969; P = 0.007). After adjusting for grade, stage, and margin status, MAGI2 %AREA was a significant independent predictor of biochemical recurrence (BCR) (OR, 0.936; 95%CI, 0.880-0.996; P = 0.037; bootstrap P = 0.017). The addition of MAGI2 %AREA to these standard clinical parameters improved accuracy of predicting BCR by 2.9% (91.0% vs 88.1%).

CONCLUSIONS

These results reveal that MAGI2 expression is reduced during prostate cancer progression and that retention of MAGI2 signal reduces odds of BCR. The study results further suggest a possible role of MAGI2 in prostate neoplasia. Decreased MAGI2 expression may help predict prostate cancer aggressiveness and provide new insight for treatment decisions and post-operative surveillance intervals.

Sensitivity of Ambient Atmospheric Formaldehyde and Ozone to Precursor Species and Source Types Across the United States

Formaldehyde (HCHO) is an important air pollutant from both an atmospheric chemistry and human health standpoint. This study uses an instrumented photochemical Air Quality Model, CMAQ-DDM, to identify the sensitivity of HCHO concentrations across the United States (U.S.) to major source types and hydrocarbon speciation. In July, biogenic sources of hydrocarbons contribute the most (92% of total hydrocarbon sensitivity), split between isoprene and other alkenes. Among anthropogenic sources, mobile sources of hydrocarbons and nitrogen oxides (NO _x) dominate. In January, HCHO is more sensitive to anthropogenic hydrocarbons than biogenic sources, especially mobile sources and residential wood combustion (36% of national hydrocarbon sensitivity). While ozone (O₃) is three times more sensitive to NO _x than hydrocarbons across most areas of the U.S., HCHO is six times more sensitive to hydrocarbons than NO _x, largely due to sensitivity to biogenic precursors and the importance of low-NO _x chemistry. In winter, both HCHO and O₃ show negative sensitivity to NO _x (increases with the removal of NO _x), although O₃ increases are larger. Relative sensitivities do not change substantially across different regions of the country.