Biomechanical Comparison of Anterior Cervical Plate Fixation Versus Integrated Fixation Cage for Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Cadaveric, biomechanic study. OBJECTIVE: To compare the range of motion profiles of the cervical spine following one-level anterior cervical discectomy and fusion (ACDF) constructs instrumented with either an interbody cage and anterior plate or integrated fixation cage in a cadaveric model. SUMMARY OF BACKGROUND DATA: While anterior plates with interbody cages are the most common construct of fixation in ACDF, newer integrated cage-plate devices seek to provide similar stability with a decreased implant profile. However, differences in postoperative cervical range of motion between the 2 constructs remain unclear. METHODS: Six cadaveric spines were segmented into 2 functional spine units (FSUs): C2-C5 and C6-T2. Each FSU was nondestructively bent in flexion-extension (FE), right-left lateral bending (LB), and right-left axial rotation (AR) at a rate of 0.5°/s under a constant axial load until a limit of 2-Nm was reached to evaluate baseline range of motion (ROM). Matched pairs were then randomly assigned to undergo instrumentation with either the standard anterior cage and plate (CP) or the integrated fixation cage (IF). Following instrumentation, ROM was then remeasured as previously described. RESULTS: For CP fixation, ROM increased by 61.2±31.7% for FE, 36.3±20.4% for LB, and 31.7±19.1% for AR. For IF fixation, ROM increased by 64.2±15.5% for FE, 56.7±39.8% for LB, and 94.5±65.1% for AR. There was no significant difference in motion between each group across FE, LB, and AR. CONCLUSION: This biomechanical study demonstrated increased motion in both the CP and IF groups relative to the intact, un-instrumented state. However, our model showed no differences in ROM between CP and IF constructs in any direction of motion. These results suggest that either method of instrumentation is a suitable option for ACDF with respect to constructing stiffness at time zero.

Evaluation of inactivation of bovine coronavirus by low-level radiofrequency irradiation.

Inactivation of influenza A virus by radiofrequency (RF) energy exposure at levels near Institute of Electrical and Electronics Engineers (IEEE) safety thresholds has been reported. The authors hypothesized that this inactivation was through a structure-resonant energy transfer mechanism. If this hypothesis is confirmed, such a technology could be used to prevent transmission of virus in occupied public spaces where RF irradiation of surfaces could be performed at scale. The present study aims to both replicate and expand the previous work by investigating the neutralization of bovine coronavirus (BCoV), a surrogate of SARS-CoV-2, by RF radiation in 6-12 GHz range. Results showed an appreciable reduction in BCoV infectivity (up to 77%) due to RF exposure to certain frequencies, but failed to generate enough reduction to be considered clinically significant.

Hooks Versus Pedicle Screws at the Upper Instrumented Level: An In Vitro Biomechanical Comparison.

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: The aim was to compare motions at the upper instrumented vertebra (UIV) and supra-adjacent level (UIV+1) between two fixation techniques in thoracic posterior spinal fusion constructs. We hypothesized there would be greater motion at UIV+1 after cyclic loading across all constructs and bilateral pedicle screws (BPSs) with posterior ligamentous compromise would demonstrate the greatest UIV+1 range of motion. SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis is a well-recognized complication following long thoracolumbar posterior spinal fusion, however, its mechanism is poorly understood. MATERIALS AND METHODS: Twenty-seven thoracic functional spine units were randomly divided into three UIV fixation groups (n=9): (1) BPS, (2) bilateral transverse process hooks (TPHs), and (3) BPS with compromise of the posterior elements between UIV and UIV+1 (BPS-C). Specimens were tested on a servohydraulic materials testing system in native state, following instrumentation, and after cyclic loading. functional spine units were loaded in flexion-extension (FE), lateral bending, and axial rotation. RESULTS: After cyclic testing, the TPH group had a mean 29.4% increase in FE range of motion at UIV+1 versus 76.6% in the BPS group ( P <0.05). The BPS-C group showed an increased FE of 49.9% and 62.19% with sectioning of the facet joints and interspinous ligament respectively prior to cyclic testing. CONCLUSION: BPSs at the UIV led to greater motion at UIV+1 compared to bilateral TPH after cyclic loading. This is likely due to the increased rigidity of BPS compared to TPH leading to a "softer" transition between the TPH construct and native anatomy at the supra-adjacent level. Facet capsule compromise led to a 49.9% increase in UIV+1 motion, underscoring the importance of preserving the posterior ligamentous complex. Clinical studies that account for fusion rates are warranted to determine if constructs with a "soft transition" result in less proximal junctional kyphosis in vivo .

Evaluation of Viral Inactivation on Dry Surface by High Peak Power Microwave (HPPM) Exposure.

Previous research has shown that virus infectivity can be dramatically reduced by radio frequency exposure in the gigahertz (GHz) frequency range. Given the worldwide SARS-CoV-2 pandemic, which has caused over 1 million deaths and has had a profound global economic impact, there is a need for a noninvasive technology that can reduce the transmission of virus among humans. RF is a potential wide area-of-effect viral decontamination technology that could be used in hospital rooms where patients are expelling virus, in grocery and convenience stores where local populations mix, and in first responder settings where rapid medical response spans many potentially infected locations within hours. In this study, we used bovine coronavirus (BCoV) as a surrogate of SARS-CoV-2 and exposed it to high peak power microwave (HPPM) pulses at four narrowband frequencies: 2.8, 5.6, 8.5, and 9.3 GHz. Exposures consisted of 2 µs pulses delivered at 500 Hz, with pulse counts varied by decades between 1 and 10,000. The peak field intensities (i.e. the instantaneous power density of each pulse) ranged between 0.6 and 6.5 MW/m2 , depending on the microwave frequency. The HPPM exposures were delivered to plastic coverslips containing BCoV dried on the surface. Hemagglutination (HA) and cytopathic effect analyses were performed 6 days after inoculation of host cells to assess viral infectivity. No change in viral infectivity was seen with increasing dose (pulse number) across the tested frequencies. Under all conditions tested, exposure did not reduce infectivity more than 1.0 log10. For the conditions studied, high peak power pulsed RF exposures in the 2-10 GHz range appear ineffective as a virucidal approach for hard surface decontamination. © 2023 Bioelectromagnetics Society.

Observed Reductions in the Infectivity of Bioaerosols Containing Bovine Coronavirus Under Repetitively Pulsed RF Exposure.

OBJECTIVE: The purpose of the present study is to investigate the inactivation of bioaerosols containing Bovine Coronavirus, BCoV, under repetitively pulsed radio frequency (RF) electromagnetic exposure. METHODS: These experiments were performed in a waveguide containing a flowing aerosol stream and were limited to a single RF waveform: ∼2 µs square envelope, 5.6 GHz, 4.8 kHz repetition rate. Aerosol streams were exposed to RF electric field amplitudes in the range of 41.9 +/-6.2 kV/m. Under laminar flow conditions, 75% of the total collected aerosol stream spends 0.85 seconds or less in the RF exposure region. RESULTS: Application of the RF waveform changed mean survival rate of the aerosolized BCoV by -0.58 decades (roughly a 74% reduction) and impacted the variance and standard deviation of the experimental results, with the RF exposure data showing an 800% increase in variance and 196% increase in standard deviation over the control results. Experimental results were compared to those from an analytic electromagnetic-heating inactivation model. CONCLUSION: The comparison indicated the feasibility that the observed reduction in BCoV survival rate might be due to a combination of thermal effects and non-thermal electric field effects. SIGNIFICANCE: Developing better insight into the mechanisms of inactivation is important for understanding the potential limits of efficacy for this method. Additionally, these results contribute an important baseline for the impact of electromagnetic fields on aerosolized pathogens.

Arthroscopic Anatomic Knotless Coracoclavicular Ligament Repair Without Coracoid Drilling.

Acromioclavicular joint injuries are common in young active patients. A wide variety of surgical techniques exist to address specific complications associated with surgery. Complications after surgery include loss of reduction, fracture of the clavicle or coracoid, failure of fixation, and prominent and symptomatic hardware. This technique aims to reduce these complications with an arthroscopic anatomic coracoclavicular ligament repair using knotless adjustable loop buttons with fifth-generation suture tape and no drilling of the coracoid.

Assessing the Impact of the American Heart Association's Research Portfolio: A Scientific Statement From the American Heart Association.

A task force composed of American Heart Association (AHA) Research Committee members established processes to measure the performance of the AHA's research portfolio and evaluated key outcomes that are fundamental to the overall success of the program. This report reviews progress that the AHA research program has had in achieving its goals relevant to the research programs in the AHA's research portfolio from 2008 to 2017. Comprehensive performance metrics were identified to assess the impact of AHA funding on researchers' career progress and research outcomes. Metrics included bibliometric analysis (ie, tracking of publications and their impact) and career development measures (ie, subsequent grant funding, intellectual property, faculty appointment/promotion, or industry position). Publication rates ranged from ≈0.5 to 4 publications per year, with a strong correlation between number of publications per year and later career stage. The Field-Weighted Citation Index, a metric of bibliometric impact, was between 1.5 and 3.0 for all programs, indicating that AHA awardee publications had a higher citation impact compared with similar publications. To gain insight into the career progression of AHA awardees, a 2-year postaward survey was distributed. Of the Postdoctoral Fellowship recipient respondents, 72% obtained academic research positions, with the remaining working in industry or government research settings; 72% of those in academic positions obtained additional funding. Among respondents who were Beginning Grant-in-Aid and Scientist Development Grant awardees, 45% received academic promotions and 83% obtained additional funding. Measuring performance of the AHA's research portfolio is critical to ensure that its strategic goals are met and to show the AHA's commitment to high-quality, impactful research.

Molecular dynamics simulations explore effects of electric field orientations on spike proteins of SARS-CoV-2 virions.

Emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its current worldwide spread have caused a pandemic of acute respiratory disease COVID-19. The virus can result in mild to severe, and even to fatal respiratory illness in humans, threatening human health and public safety. The spike (S) protein on the surface of viral membrane is responsible for viral entry into host cells. The discovery of methods to inactivate the entry of SARS-CoV-2 through disruption of the S protein binding to its cognate receptor on the host cell is an active research area. To explore other prevention strategies against the quick spread of the virus and its mutants, non-equilibrium molecular dynamics simulations have been employed to explore the possibility of manipulating the structure-activity of the SARS-CoV-2 spike glycoprotein by applying electric fields (EFs) in both the protein axial directions and in the direction perpendicular to the protein axis. We have found out the application of EFs perpendicular to the protein axis is most effective in denaturing the HR2 domain which plays critical role in viral-host membrane fusion. This finding suggests that varying irradiation angles may be an important consideration in developing EF based non-invasive technologies to inactivate the virus.

Biomechanical Comparison of Anatomic Restoration of the Ulnar Footprint vs Traditional Ulnar Tunnels in Ulnar Collateral Ligament Reconstruction.

BACKGROUND: Current techniques for ulnar collateral ligament (UCL) reconstruction do not reproduce the anatomic ulnar footprint of the UCL. The purpose of this study was to describe a novel UCL reconstruction technique that utilizes proximal-to-distal ulnar bone tunnels to better re-create the anatomy of the UCL and to compare the biomechanical profile at time zero among this technique, the native UCL, and the traditional docking technique. HYPOTHESIS: The biomechanical profile of the anatomic technique is similar to the native UCL and traditional docking technique. STUDY DESIGN: Controlled laboratory study. METHODS: Ten matched cadaveric elbows were potted with the forearm in neutral rotation. The palmaris longus tendon graft was harvested, and bones were sectioned 14 cm proximal and distal to the elbow joint. Specimen testing included (1) native UCL testing performed at 90° of flexion with 0.5 N·m of valgus moment preload, (2) cyclic loading from 0.5 to 5 N·m of valgus moment for 1000 cycles at 1 Hz, and (3) load to failure at 0.2 mm/s. Elbows then underwent UCL reconstruction with 1 elbow of each pair receiving the classic docking technique using either anatomic (proximal to distal) or traditional (anterior to posterior) tunnel locations. Specimen testing was then repeated as described. RESULTS: There were no differences in maximum load at failure between the anatomic and traditional tunnel location techniques (mean ± SD, 34.90 ± 10.65 vs 37.28 ± 14.26 N·m; P = .644) or when including the native UCL (45.83 ± 17.03 N·m; P = .099). Additionally, there were no differences in valgus angle after 1000 cycles across the anatomic technique (4.58°± 1.47°), traditional technique (4.08°± 1.28°), and native UCL (4.07°± 1.99°). The anatomic group and the native UCL had similar valgus angles at failure (24.13°± 5.86° vs 20.13°± 5.70°; P = .083), while the traditional group had a higher valgus angle at failure when compared with the native UCL (24.88°± 6.18° vs 19.44°± 5.86°; P = .015). CONCLUSION: In this cadaveric model, UCL reconstruction with the docking technique utilizing proximal-to-distal ulnar tunnels better restored the ulnar footprint while providing valgus stability comparable with reconstruction with the docking technique using traditional anterior-to-posterior ulnar tunnel locations. These results suggest that utilization of the anatomic tunnel location in UCL reconstruction has similar biomechanical properties to the traditional method at the time of initial fixation (ie, not accounting for healing after reconstruction in vivo) while keeping the ulnar tunnels farther from the ulnar nerve. Further studies are warranted to determine if an anatomically based UCL reconstruction results in differing outcomes than traditional reconstruction techniques. CLINICAL RELEVANCE: Current UCL reconstruction techniques do not accurately re-create the ulnar UCL footprint. The UCL is a dynamic constraint to valgus loads at the elbow, and a more anatomic reconstruction may afford more natural joint kinematics. This more anatomic technique performs similarly to the traditional docking technique at time zero, and the results of this study may offer a starting point for future in vivo studies.

Severe Acute Respiratory Syndrome Coronavirus 2 and Respiratory Virus Sentinel Surveillance, California, USA, May 10, 2020-June 12, 2021.

State and local health departments established the California Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Respiratory Virus Sentinel Surveillance System to conduct enhanced surveillance for SARS-CoV-2 and other respiratory pathogens at sentinel outpatient testing sites in 10 counties throughout California, USA. We describe results obtained during May 10, 2020‒June 12, 2021, and compare persons with positive and negative SARS-CoV-2 PCR results by using Poisson regression. We detected SARS-CoV-2 in 1,696 (19.6%) of 8,662 specimens. Among 7,851 specimens tested by respiratory panel, rhinovirus/enterovirus was detected in 906 (11.5%) specimens and other respiratory pathogens in 136 (1.7%) specimens. We also detected 23 co-infections with SARS-CoV-2 and another pathogen. SARS-CoV-2 positivity was associated with male participants, an age of 35-49 years, Latino race/ethnicity, obesity, and work in transportation occupations. Sentinel surveillance can provide useful virologic and epidemiologic data to supplement other disease monitoring activities and might become increasingly useful as routine testing decreases.

Lay Stakeholders in Science and Research Initiative: A Science Advisory From the American Heart Association.

The American Heart Association (AHA) is the largest not-for-profit funder of cardiovascular and cerebrovascular disease research in the United States. It has supported research of independent scientists for 7 decades with the goal of finding novel discoveries that will reduce death and disability from these diseases and ultimately improve overall health. In 2014, the AHA approved a pilot initiative to include lay stakeholders (patients, caregivers, and passionate advocates) in its research and science operations. The initiative was based on the premise that lay stakeholders would add a unique and necessary perspective that would improve decisions concerning research funding, research direction, and scientific guidelines. The AHA developed a framework for the initiative that defined lay stakeholder, created a volunteer recruitment and training program, established policies for incorporating lay stakeholders into science operations, and set metrics for evaluating the initiative over time. It has instituted creative ways to engage lay volunteers and to foster lay and scientist cooperation. Program assessments have been consistently positive and have identified needed future improvements. The benefits of lay/scientist collaboration have far exceeded the AHA's expectations. The AHA will continue to strengthen lay volunteer engagement throughout its science and research operations; to focus on developing a larger, diverse group of qualified lay stakeholders; to educate scientists on how to communicate research effectively to the public and donors; and to retain the respect of donors for the rigors of its research funding, scientific statements, and clinical guidelines.

A Biomechanical Comparison of High-Tensile Strength Tape Versus High-Tensile Strength Suture for Tendon Fixation Under Cyclic Loading.

PURPOSE: To compare the biomechanical properties of high-tensile strength tape and high-tensile strength suture across 2 selected stitch techniques, the Krackow and whip stitch, in securing tendinous tissue during 5,000 cycles of nondestructive loading followed by a load to failure. METHODS: Fourteen matched pairs each of cadaveric Achilles, quadriceps, and patellar tendons (n = 84) were randomly assigned to either Krackow or whip stitch and sutured with either 2-mm high-tensile strength tape or No. 2 high-tensile strength suture. Specimens were preloaded to 20 N, cyclically loaded from 20 to 200 N for 5,000 cycles at 2 Hz, and then loaded to failure at 200 mm/min. Linear mixed models evaluated the effects of suture material and stitch technique on cyclic normalized tendon-suture elongation, total normalized tendon-suture elongation at 5,000 cycles, and maximum load at failure. RESULTS: Across all suture constructs, normalized elongation was greater during the initial 10 cycles, compared with all subsequent cycling intervals (all P < .001). There was less total normalized elongation (ß = -0.239; P = .007) and greater maximum load at failure in tape (ß = 163.71; P = .014) when used in the Krackow stitch compared with the whip stitch. CONCLUSIONS: Our findings indicate that tape used in the Krackow stitch maintains the most favorable fixation strength after enduring cyclic loading, with greater maximum load at failure. In addition, overall normalized elongation during long-term cyclic loading was predominately affected by the stitch technique used, regardless of the suture material; however, tape allowed less normalized elongation during the initial loading cycles, especially when placed in the whip stitch. CLINICAL RELEVANCE: Understanding the potential short- and long-term outcomes of suture material and stitch technique on securing tendinous tissue under repetitive stresses can help inform clinicians on optimal tendon fixation techniques for early postoperative activities.

Risk Factors for Failure of Nonoperative Treatment of Posterior Shoulder Labral Tears on Magnetic Resonance Imaging.

INTRODUCTION: There are no reports in the literature describing risk factors for failure of nonoperative treatment of patients with posterior labral tears on magnetic resonance imaging (MRI). The purpose of this study is to identify risk factors for failure of nonoperative treatment in patients with an isolated posterior glenoid labral tear identified on MRI only. Patients with posterior labral tears on MRI who fail to improve with nonoperative treatment likely share a constellation of clinical history, physical exam, and radiographic findings. METHODS: One hundred and fifty-nine active duty military service members under the age of 40 with a posterior labral tear seen on MRI and who were clinically evaluated by a musculoskeletal trained physician were identified. We retrospectively evaluated their records ensuring a minimum of 2 years follow-up after MRI to identify surgical intervention for the posterior labral tear during this time period. Patients were stratified into two groups, those treated with any combination of nonoperative modalities and those treated with posterior labral repair surgery during the 2 years after the MRI. The electronic medical records were reviewed for clinical presentation and physical exam results. We measured multiple radiographic parameters, including glenoid version, size of the tear, and bone loss on MRI. Qualitative and quantitative data were compared between groups using Fisher's exact test and Student's t-test, respectively. This study was conducted under institutional review board approval. RESULTS: Of the 157 patients' shoulders in our study, 52% (n = 82) of patients with posterior labral tears underwent nonoperative treatment while 48% (n = 75) underwent surgery. The significant risk factors associated with surgery were a history of a specific injury, primary presenting complaint of instability, patient reported history of subluxation, inability to trust their shoulder with overhead activity, decreased strength with weight lifting, positive posterior load/shift exam, positive anterior apprehension, increased osseous glenoid retroversion, increased humeral head subluxation ratio, and anterior labral height (P < 0.05). Patients with a chief complaint of pain were much more likely to succeed with nonoperative treatment while those with instability underwent surgery more often. Ten (12.5%) of the surgical procedures included an anterior and posterior labral repair/stabilization procedure. CONCLUSION: Patients with an MRI confirmed posterior labral tear, which present with subjective complaints and physical exam maneuvers consistent with instability, appear less likely to be treated nonoperatively. Increased glenoid retroversion and posterior humeral head subluxation may also predispose patients toward surgical treatment. Additionally, posterior labral tears may extend into the anterior labrum more frequently than is recognized on MRI.

Reliability of the Walter Reed Classification for Heterotopic Ossification Severity in Amputees.

OBJECTIVE: At this time, there is no validated tool for describing heterotopic ossification (HO) severity or measuring efficacy of therapies after amputation. This study aims to validate the Walter Reed classification system for reliable characterization of HO burden in residual limbs. DESIGN: Descriptive, Level IV. SETTING: US Military Trauma Referral Center. STUDY POPULATION: Five orthopaedic surgeon raters with varying experience levels assessed orthogonal radiographs of 100 randomly selected residual upper and lower limbs after combat-related amputation. INTERVENTION: A standardized education session on the Walter Reed HO classification system followed by 2 grading sessions, separated by a 2-week waiting period. MAIN OUTCOME MEASURES: Scores were analyzed for interobserver and intraobserver reliability using weighted Cohen's kappa, intraclass correlation coefficient, and Krippendorff's alpha for ordinal variables. RESULTS: After the waiting period, 89% of HO was rated the same by observers with an intraobserver kappa = 0.83 (95% confidence interval [CI] 0.75-0.92). Interobserver reliability was evaluated using group-wise comparison among observers, resulting in an overall Krippendorff's alpha = 0.78 (95% CI 0.76-0.80). Using intraclass correlation coefficient, interrater consistency was 0.94 (95% CI 0.91-0.96). CONCLUSIONS: The Walter Reed HO classification system is substantially reliable for use by raters with any level of orthopaedic training. In addition, it is reliable for evaluation of both through bone and disarticulation type amputations in the upper and lower extremities. However, in 11% of cases, a secondary read may vary, suggesting that this system is useful for understanding HO and developing interventions but may benefit from further refinement, including advanced imaging and clinical correlation.

Palliative Care and Cardiovascular Disease and Stroke: A Policy Statement From the American Heart Association/American Stroke Association.

The mission of the American Heart Association/American Stroke Association includes increasing access to high-quality, evidence-based care that improves patient outcomes such as health-related quality of life and is consistent with the patients' values, preferences, and goals. Awareness of and access to palliative care interventions align with the American Heart Association/American Stroke Association mission. The purposes of this policy statement are to provide background on the importance of palliative care as it pertains to patients with advanced cardiovascular disease and stroke and their families and to make recommendations for policy decisions. Palliative care, defined as patient- and family-centered care that optimizes health-related quality of life by anticipating, preventing, and treating suffering, should be integrated into the care of all patients with advanced cardiovascular disease and stroke early in the disease trajectory. Palliative care focuses on communication, shared decision making about treatment options, advance care planning, and attention to physical, emotional, spiritual, and psychological distress with inclusion of the patient's family and care system. Our policy recommendations address the following: reimbursement for comprehensive delivery of palliative care services for patients with advanced cardiovascular disease and stroke; strong payer-provider relationships that involve data sharing to identify patients in need of palliative care, identification of better care and payment models, and establishment of quality standards and outcome measurements; healthcare system policies for the provision of comprehensive palliative care services during hospitalization, including goals of care, treatment decisions, needs of family caregivers, and transition to other care settings; and health professional education in palliative care as part of licensure requirements.