340 research outputs found

    A new mini-navigation tool allows accurate component placement during anterior total hip arthroplasty.

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    Introduction: Computer-assisted navigation systems have been explored in total hip arthroplasty (THA) to improve component positioning. While these systems traditionally rely on anterior pelvic plane registration, variances in soft tissue thickness overlying anatomical landmarks can lead to registration error, and the supine coronal plane has instead been proposed. The purpose of this study was to evaluate the accuracy of a novel navigation tool, using registration of the anterior pelvic plane or supine coronal plane during simulated anterior THA. Methods: Measurements regarding the acetabular component position, and changes in leg length and offset were recorded. Benchtop phantoms and target measurement values commonly seen in surgery were used for analysis. Measurements for anteversion and inclination, and changes in leg length and offset were recorded by the navigation tool and compared with the known target value of the simulation. Pearson\u27s Results: The device accurately measured cup position and leg length measurements to within 1° and 1 mm of the known target values, respectively. Across all simulations, there was a strong, positive relationship between values obtained by the device and the known target values ( Conclusion: The preliminary findings of this study suggest that the novel navigation tool tested is a potentially viable tool to improve the accuracy of component placement during THA using the anterior approach

    Hybrid Biosynthetic Autograft Extender for Use in Posterior Lumbar Interbody Fusion: Safety and Clinical Effectiveness

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    Autologous iliac crest bone graft is the preferred option for spinal fusion, but the morbidity associated with bone harvest and the need for graft augmentation in more demanding cases necessitates combining local bone with bone substitutes. The purpose of this study was to document the clinical effectiveness and safety of a novel hybrid biosynthetic scaffold material consisting of poly(D,L-lactide-co-glycolide) (PLGA, 75:25) combined by lyophilization with unmodified high molecular weight hyaluronic acid (10-12% wt:wt) as an extender for a broad range of spinal fusion procedures. We retrospectively evaluated all patients undergoing single- and multi-level posterior lumbar interbody fusion at an academic medical center over a 3-year period. A total of 108 patients underwent 109 procedures (245 individual vertebral levels). Patient-related outcomes included pain measured on a Visual Analog Scale. Radiographic outcomes were assessed at 6 weeks, 3-6 months, and 1 year postoperatively. Radiographic fusion or progression of fusion was documented in 221 of 236 index levels (93.6%) at a mean (±SD) time to fusion of 10.2+4.1 months. Single and multi-level fusions were not associated with significantly different success rates. Mean pain scores (+SD) for all patients improved from 6.8+2.5 at baseline to 3.6+2.9 at approximately 12 months. Improvements in VAS were greatest in patients undergoing one- or two-level fusion, with patients undergoing multi-level fusion demonstrating lesser but still statistically significant improvements. Overall, stable fusion was observed in 64.8% of vertebral levels; partial fusion was demonstrated in 28.8% of vertebral levels. Only 15 of 236 levels (6.4%) were non-fused at final follow-up

    What is a fish? The life and legend of David L.G. Noakes

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    David Lloyd George Noakes (1942–2020) is best known for his insatiable curiosity, his quick wit and dry sense of humor, his scientific contributions to the field of animal behaviour, and his ability to form and maintain long-lasting connections. His research interests were vast but remained grounded in early life history, behaviour, social behaviour, the evolution of behaviour, behavioural genetics, and evolutionary ecology. David had a remarkable ability to establish and maintain strong connections within the international academic community. David was also internationally recognized for his numerous contributions as a scientific editor, promoting accessibility to the international community that he served. We memorialize David’s legacy in this tribute article, ensuring that his accomplishments and the momentous impact he had on the scientific community are not soon forgotten

    Global biogeography of SAR11 marine bacteria

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    The ubiquitous SAR11 bacterial clade is the most abundant type of organism in the worldĝ€™s oceans, but the reasons for its success are not fully elucidated. We analysed 128 surface marine metagenomes, including 37 new Antarctic metagenomes. The large size of the data set enabled internal transcribed spacer (ITS) regions to be obtained from the Southern polar region, enabling the first global characterization of the distribution of SAR11, from waters spanning temperatures ĝ̂'2 to 30°C. Our data show a stable co-occurrence of phylotypes within both ĝ€̃ tropicalĝ€™ (>20°C) and ĝ€̃ polarĝ€™ (<10°C) biomes, highlighting ecological niche differentiation between major SAR11 subgroups. All phylotypes display transitions in abundance that are strongly correlated with temperature and latitude. By assembling SAR11 genomes from Antarctic metagenome data, we identified specific genes, biases in gene functions and signatures of positive selection in the genomes of the polar SAR11ĝ€"genomic signatures of adaptive radiation. Our data demonstrate the importance of adaptive radiation in the organismĝ€™s ability to proliferate throughout the worldĝ€™s oceans, and describe genomic traits characteristic of different phylotypes in specific marine biomes. © 2012 EMBO and Macmillan Publishers Limited All rights reserved

    Rapid alteplase administration improves functional outcomes in patients with stroke due to large vessel occlusions

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    Background and Purpose: We report the relation of onset-to-treatment time and door-to-needle time with functional outcomes and mortality among patients with ischemic stroke with imaging-proven large vessel occlusion treated with intravenous alteplase. Methods: Individual patient-level data from the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) collaboration were pooled from 7 trials that randomized patients to mechanical thrombectomy added to best medical therapy versus best medical therapy alone. Analysis was restricted to patients who received alteplase directly at the endovascular hospital. The primary outcome was disability defined on the modified Rankin Scale at 3 months. Results: Among 601 patients, mean age was 66.0 years (SD, 13.9), 50% were women, and median National Institutes of Health Stroke Scale score was 17. Onset-to-treatment time was median 125 minutes (interquartile range, 90–170). Door-to-treatment time was median 38 minutes (interquartile range, 26–55). Each 60-minute onset-to-treatment time delay was associated with greater disability at 90 days; the odds of functional independence (modified Rankin Scale, 0–2) at 90 days was 0.82 (95% CI, 0.66–1.03). With each 60-minute delay in door-to-needle time; the odds of functional independence was 0.55 (95% CI, 0.37–0.81) at 90 days. The absolute decline in the rate of excellent outcome (modified Rankin Scale, 0–1 at 90 days) was 20.3 per 1000 patients treated per 15-minute delay in door-to-needle time. The adjusted absolute risk difference for a door-to-needle time &lt;30 minutes versus 30 to 60 minutes was 19.3% for independent outcome (number-needed-to-treat ≈5 to gain 1 additional good outcome). Symptomatic intracranial hemorrhage occurred in 3.4% of patients, without a significant time dependency: odds ratio, 0.74 (95% CI, 0.43–1.28). Conclusions: Faster intravenous thrombolysis delivery is associated with less disability at 3 months among patients with large vessel occlusion

    Efficacy of endovascular thrombectomy in patients with M2 segment middle cerebral artery occlusions: meta-analysis of data from the HERMES Collaboration

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    Background: The Society of Neurointerventional Surgery revised its operational definition of emergent large vessel occlusion (ELVO) recently to include proximal M2 segment middle cerebral artery (MCA) occlusions. We sought to assess the benefit of endovascular thrombectomy (EVT) over best medical care for M2 segment MCA occlusion. Methods: Patient level data from trials in the HERMES Collaboration were included. The HERMES core laboratory identified patients with M2 segment MCA occlusions and further classified them as proximal versus distal, anterior versus posterior division, and dominant versus co-dominant versus non-dominant. Primary outcome was modified Rankin Scale (mRS) score 0–2 at 90 days. Secondary outcomes were modified Thrombolysis in Cerebral Infarction (mTICI) rates at end of procedure, 90-day mRS shift, 90-day mRS 0–1, 24 hours National Institute of Health Stroke Scale (NIHSS) score 0–2, symptomatic intracerebral hemorrhage (ICH), and death. Results: 130 patients with M2 MCA (proximal location n=116 vs distal n=14, anterior division n=72 vs posterior n=58, dominant n=73 vs co-dominant n=50 vs non-dominant n=7) were included. Successful reperfusion (mTICI 2b or 3) among those undergoing EVT was seen in 59.2% of patients. Treatment effect favored EVT (adjusted OR 2.39, 95% CI 1.08 to 5.28, p=0.03) for 90-day mRS 0–2 (58.2% EVT vs 39.7% control). Direction of benefit favored EVT for other outcomes. Treatment effect favoring EVT was maximal in patients with proximal M2 segment MCA occlusions (n=116, adjusted OR 2.68, 95% CI 1.13 to 6.37) and in dominant M2 segment MCA occlusions (n=73, adjusted OR 4.08, 95% CI 1.08 to 15.48). No sICH (0%) was observed in patients treated with EVT compared with five (7.9%) in the control arm. Conclusion: Patients with proximal M2 segment MCA occlusions eligible for EVT trial protocols benefited from EVT

    Confirmatory study of time-dependent computed tomographic perfusion thresholds for use in acute ischemic stroke

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    Background and Purpose: Computed tomographic perfusion (CTP) thresholds associated with follow-up brain infarction may differ by time from symptom onset to imaging and reperfusion. We confirm CTP thresholds over time to imaging and reperfusion in patients with acute ischemic stroke from the HERMES collaboration (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) data. Methods: Patients with occlusion on CT angiography were acutely imaged with CTP. Noncontrast CT and magnetic resonance-diffusion weighted imaging at 24 to 48 hours defined follow-up infarction. Reperfusion was assessed on conventional angiogram. Tmax, cerebral blood flow (CBF), and cerebral blood volume maps were derived from delay-insensitive CTP postprocessing. These parameters were analyzed using receiver operator characteristics to derive optimal thresholds based on time from stroke onset-to-CTP or to reperfusion. ANOVA and linear regression were used to test whether the derived CTP thresholds were different by time. Results: One hundred thirty-seven patients were included. Tmax thresholds of &gt;15.7 s and &gt;15.8 s and absolute CBF thresholds of &lt;8.9 and &lt;7.5 mL·min−1·100 g−1 for gray matter and white matter respectively were associated with infarct if reperfusion was achieved &lt;90 minutes from CTP with stroke onset-to-CTP &lt;180 minutes. The discriminative ability of cerebral blood volume was modest. There were no statistically significant relationships between stroke onset-to-CTP time and Tmax, CBF, and cerebral blood volume thresholds (all P&gt;0.05). A statistically significant relationship was observed between CTP-to-reperfusion time and the optimal thresholds for Tmax (P&lt;0.001) and CBF (P&lt;0.001). Similar but more modest relationship was noted for onset-to-reperfusion time and optimal thresholds for CBF (P≤0.01). Conclusions: CTP thresholds based on stroke onset and imaging time and taking into account time needed for reperfusion may improve infarct prediction in patients with acute ischemic stroke

    Does sex modify the effect of endovascular treatment for ischemic stroke? A subgroup analysis of seven randomized trials

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    Background and Purpose: Previous studies have reported less favorable outcome and less effect of endovascular treatment (EVT) after ischemic stroke in women than in men. Our aim was to study the influence of sex on outcome and on the effect of EVT for ischemic stroke in recent randomized trials on EVT. Methods: We used data from 7 randomized controlled trials on EVT within the HERMES collaboration. The primary outcome was 90-day functional outcome (modified Rankin Scale). We compared baseline characteristics and outcomes between men and women. With ordinal logistic regression, we evaluated the association between EVT and 90-day functional outcome for men and women separately, adjusted for potential confounders. We tested for interaction between sex and EVT. Results: We included 1762 patients in the analyses, of whom 833 (47%) were women. Women were older (median, 70 versus 66 years; P&lt;0.001), were smoking less often (30% versus 44%; P&lt;0.001), and had higher collateral grades (grade 3: 46% versus 35%; P&lt;0.001) than men. Functional independence (modified Rankin Scale score, 0–2) at 90 days was reached by 318 women (39%) and 364 men (39%). The effect of EVT on the ordinal modified Rankin Scale was similar in women (adjusted common odds ratio [acOR], 2.13; 95% CI, 1.47–3.07) and men (acOR, 2.16; 95% CI, 1.59–2.96), with a P for interaction of 0.926. Conclusions: Sex does not influence clinical outcome after EVT and does not modify treatment effect of EVT. Therefore, sex should not be a consideration in the selection of patients for EVT

    Polymorphisms of an Innate Immune Gene, Toll-Like Receptor 4, and Aggressive Prostate Cancer Risk: A Systematic Review and Meta-Analysis

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    Background: Toll-like receptor 4 (TLR4) is one of the best known TLR members expressed on the surface of several leukocytes and tissue cells and has a key function in detecting pathogen and danger-associated molecular patterns. The role of TLR4 in the pathophysiology of several age-related diseases is also well recognized, such as prostate cancer (PCa). TLR4 polymorphisms have been related to PCa risk, but the relationship between TLR4 genotypes and aggressive PCa risk has not been evaluated by any systematic reviews. Methods: We performed a systematic review and meta-analysis of candidate-gene and genome-wide association studies analyzing this relationship and included only white population. Considering appropriate criteria, only nine studies were analyzed in the meta-analysis, including 3,937 aggressive PCa and 7,382 controls. Results: Using random effects model, no significant association was found in the ten TLR4 SNPs reported by at least four included studies under any inheritance model (rs2737191, rs1927914, rs10759932, rs1927911, rs11536879, rs2149356, rs4986790, rs11536889, rs7873784, and rs1554973). Pooled estimates from another ten TLR4 SNPs reported by three studies also showed no significant association (rs10759930, rs10116253, rs11536869, rs5030717, rs4986791, rs11536897, rs1927906, rs913930, rs1927905, and rs7045953). Meta-regression revealed that study type was not a significant source of between-study heterogeneity. Conclusions: TLR4 polymorphisms were not significantly associated with the risk of aggressive PCa

    Volumetric and spatial accuracy of CTP estimated ischemic core volume in patients with acute ischemic stroke

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    Background and Purpose— The volume of estimated ischemic core using computed tomography perfusion (CTP) imaging can identify ischemic stroke patients who are likely to benefit from reperfusion, particularly beyond standard time windows. We assessed the accuracy of pretreatment CTP estimated ischemic core in patients with successful endovascular reperfusion. Methods— Patients from the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) and EXTEND-IA TNK (Tenecteplase Versus Alteplase Before Endovascular Therapy for Ischemic Stroke) databases who had pretreatment CTP, &gt;50% angiographic reperfusion, and follow-up magnetic resonance imaging at 24 hours were included. Ischemic core volume on baseline CTP data was estimated using relative cerebral blood flow &lt;30% (RAPID, iSchemaView). Follow-up diffusion magnetic resonance imaging was registered to CTP, and the diffusion lesion was outlined using a semiautomated algorithm. Volumetric and spatial agreement (using Dice similarity coefficient, average Hausdorff distance, and precision) was assessed, and expert visual assessment of quality was performed. Results— In 120 patients, median CTP estimated ischemic core volume was 7.8 mL (IQR, 1.8–19.9 mL), and median diffusion lesion volume at 24 hours was 30.8 mL (IQR, 14.9–67.6 mL). Median volumetric difference was 4.4 mL (IQR, 1.2–12.0 mL). Dice similarity coefficient was low (median, 0.24; IQR, 0.15–0.37). The median precision (positive predictive value) of 0.68 (IQR, 0.40–0.88) and average Hausdorff distance (median, 3.1; IQR, 1.8–5.7 mm) indicated reasonable spatial agreement for regions estimated as ischemic core at baseline. Overestimation of total ischemic core volume by CTP was uncommon. Expert visual review revealed overestimation predominantly in white matter regions. Conclusions— CTP estimated ischemic core volumes were substantially smaller than follow-up diffusion-weighted imaging lesions at 24 hours despite endovascular reperfusion within 2 hours of imaging. This may be partly because of infarct growth. Volumetric CTP core overestimation was uncommon and not related to imaging-to-reperfusion time. Core overestimation in white matter should be a focus of future efforts to improve CTP accuracy
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