Biomechanical and ergonomic risks associated with cervical musculoskeletal dysfunction amongst surgeons: A systematic review.

INTRODUCTION: Surgeons are at high risk of developing musculoskeletal symptoms due to a range of factors including, maladaptive positioning and surgical ergonomics. Cervical muscle strain and biomechanical load is most prevalent due to repetitive motions and prolonged static neck positioning. This issue is apparent through reports of prevalence between 10 and 74.4% among surgeons. The aim of this systematic review is to provide an objective assessment of the clinical evidence available and a descriptive analysis of the effects of kinematics and surgical ergonomics on the prevalence of surgeons' cervical musculoskeletal pain. METHODS: This is PRISMA-compliant systematic review of clinical studies assessing the prevalence of cervical musculoskeletal dysfunction in surgeons by searching PUBMED and Ovid EMBASE databases from inception to 19th October 2023. Study quality was graded according to the National Institutes of Health study quality assessment tools. RESULTS: A total of 9 studies were included in the final qualitative analysis. The use of loupes, open surgery and excessive neck flexion (>30°) were associated with cervical dysfunction. Comparison of study outcomes was challenging due to heterogeneity within study methods and the paucity of methodological quality. CONCLUSION: The current literature assessing ergonomic and biomechanical factors predisposing surgeons to cervical musculoskeletal dysfunction is insufficient to provide reliable guidance for clinicians. Although the literature identifies factors contributing to work-related cervical dysfunction, few attempt to evaluate interventions for improved surgical ergonomics. An objective assessment of interventions that prompt postural correction with the aim to improve neck pain in surgeon cohorts is warranted.

The correlation between altmetric score and traditional measures of article impact for studies pertaining to spine trauma.

PURPOSE: It is becoming increasingly common for researchers to share scientific literature via social media. Traditional bibliometrics have long been utilized to measure a study's academic impact, but they fail to capture the impact generated through social media sharing. Altmetric Attention Score (AAS) is a weighted count of all the online attention garnered by a study, and it is currently unclear whether a relationship with traditional bibliometrics exists. METHODS: We identified the five highest-rated spine-specific and five highest-rated general orthopedic journals by Scopus CiteScore 2020. We then identified all the spine trauma studies across a 5-year span (2016-2020) within these journals and compared AAS with traditional bibliometrics using Independent t-tests and Pearson's correlational analyses. RESULTS: No statistically significant relationships were identified between AAS and traditional bibliometrics for articles pertaining to spine trauma: Level of Evidence (R = - 0.02, p = 0.34), H-Index Primary Author (R = < - 0.01, p = 0.50), H-Index Senior Author (R = - 0.04, p = 0.24), and Number of Citations (R = 0.01, p = 0.40). The top five articles by AAS include those pertaining to motorcycle injuries (AAS = 687), orthosis in thoracolumbar fractures (AAS = 199), golfing injuries (AAS = 166), smartphone-based teleradiology (AAS = 41), and auto racing injuries (AAS = 39). CONCLUSION: The lack of overlap between these types of metrics suggests that AAS or similar alternative metrics should be used to measure an article's social impact. The social impact of an article should likewise be a factor in determining an article's overall impact along with its academic impact as measured by bibliometrics.

IgE, IgE Receptors and Anti-IgE Biologics: Protein Structures and Mechanisms of Action.

The evolution of IgE in mammals added an extra layer of immune protection at body surfaces to provide a rapid and local response against antigens from the environment. The IgE immune response employs potent expulsive and inflammatory forces against local antigen provocation, at the risk of damaging host tissues and causing allergic disease. Two well-known IgE receptors, the high-affinity FcεRI and low-affinity CD23, mediate the activities of IgE. Unlike other known antibody receptors, CD23 also regulates IgE expression, maintaining IgE homeostasis. This mechanism evolved by adapting the function of the complement receptor CD21. Recent insights into the dynamic character of IgE structure, its resultant capacity for allosteric modulation, and the potential for ligand-induced dissociation have revealed previously unappreciated mechanisms for regulation of IgE and IgE complexes. We describe recent research, highlighting structural studies of the IgE network of proteins to analyze the uniquely versatile activities of IgE and anti-IgE biologics.

The efficacy of remote virtual care in comparison to traditional clinical visits for elective orthopaedic patients: A meta-analysis of prospective randomised controlled trials.

INTRODUCTION: The Orthopaedic Trauma Association has recommended limitation of in-person encounters to absolute necessity. One method of ensuring standard patient care within these guidelines is through the implementation of telemedicine. AIMS: To evaluate the efficacy of telemedicine for elective orthopaedic patients in the recovery and/or rehabilitation period. METHODS: A systematic review and meta-analysis of articles in Medline/PubMed and The Cochrane Library databases was performed according to the PRISMA guidelines for prospective randomised controlled trials to compare clinical and symptomatic measures for elective patients managed routinely with remote care compared to those managed with standard in-clinic management. To be included for meta-analysis, parameters must be evaluated in ≥3 studies. RESULTS: Eleven studies were included in the meta-analyses. Both telemedicine and control cohorts were comparable for patient satisfaction (RR, 0.98; 95% CI, 0.90-1.07; I2 = 0%; p = 0.52) and patient retention analysis (RR, 1.25; 95% CI, 0.51-3.06; p = 0.54; I2 = 0%). Similarly, there was no statistical difference appreciated between cohorts for overall Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (p = 0.30), Timed Up and Go Test (p = 0.40), and Stair Test (p = 0.18). Significant difference did exist for visual analogue scale (VAS) scores (p = 0.02) in favour of in-clinic management. CONCLUSION: Telemedicine will serve an integral aspect of healthcare delivery throughout the current COVID-19 pandemic and beyond in an effort to deliver safe, efficient and time-sensitive care to the orthopaedic patient population. The results of our meta-analyses indicate that virtual consultations are as effective as traditional in-person consultations for the care of elective orthopaedic patients in the recovery and rehabilitation period. However, further studies are needed to evaluate for initial consultations and certain sub-specialties of orthopaedics.

Auto-Decompression - Preserved Neurological Function in Bilateral Cervical Facet Dislocations

Introduction Bilateral cervical facet dislocation (BCFD) is an uncommon injury with a high incidence of severe neurological impairment. We describe 4 cases of BCFD with preserved neurological function. Cases Case 1: A 78-year-old female who suffered two ground level falls (GLFs). Pre-operative American Spinal Injury Association (ASIA) Score was C5D. Imaging revealed a BCFD at C6/C7 and a C6 laminar fracture. Case 2: A 63-year-old male suffered a fall down 14 steps. Pre-operative ASIA score was E. Imaging demonstrated a BCFD at C7/T1, and a C6 laminar fracture. Case 3: A 46-year-old male collided with a tree while descending a hill on a bicycle. Pre-operative ASIA score was C6D. Imaging revealed a BCFD at C7/T1 and a C7 laminar fracture. Case 4: A 67-year-old male suffered a GLF while exiting a stationary car. Pre-operative ASIA score on admission was E. Imaging revealed a BCFD at C6/C7 with bilateral laminar fractures at C5 and C6. Outcome All cases underwent 2-stage surgical fixation. All cases maintained or had an improved ASIA score post-operatively. Conclusion In all cases, the presence of concurrent laminar fractures resulted in an auto-decompression of the spinal canal, preserving neurological function.

A global assessment of freshwater mollusk shell oxygen isotope signatures and their relation to precipitation and stream water.

Records of δ18O in stream flow are critical for understanding and modeling hydrological, ecological, biogeochemical and atmospheric processes. However, the number of such records are extremely limited globally and the length of such time series are usually less than a decade. This situation severely handicaps their use in model testing and evaluation. Here we present a global assessment of freshwater mollusk (bivalves & gastropods) isotope data from 25 river basins that have stream water isotope values, water temperature data and shell material isotope signatures. Our data span a latitude range of 37.50°S to 52.06°N. We show that δ18O signatures in freshwater mollusks are able to explain 95% of the variance of stream water δ18O. We use shell δ18O values and water temperature data to reconstruct stream water δ18O signatures. With freshwater mussel life expectancy ranging from a few years up to 200 years, this translation of mollusk metabolic properties into long term stream water isotope records is a promising approach for substantially extending global stream water isotope records in time and space.

Interpersonal sensitivity in those at clinical high risk for psychosis mediates the association between childhood bullying victimisation and paranoid ideation: A virtual reality study.

BACKGROUND: Experience of bullying victimisation in childhood and heightened interpersonal sensitivity have been independently linked to the clinical high risk for psychosis. AIM: To examine the potential mediating effect of interpersonal sensitivity in explaining the link between childhood bullying victimisation and real-time paranoid ideation in adult participants at clinical high risk for psychosis. METHOD: In a cross-sectional study data were collected for 64 individuals at clinical high risk for psychosis. Measures included history of bullying victimisation, interpersonal sensitivity and state paranoid ideation following exposure to a social virtual reality environment. The virtual reality scenario was a London Underground journey. RESULTS: Path analysis indicated that interpersonal sensitivity fully explained the significant association between severe bullying victimisation in childhood and paranoid ideation in the clinical-high risk group. Based on AIC criteria the best model selected was the full mediation model: severe bullying→interpersonal sensitivity→state paranoid ideation. The results suggest that severity of bullying is more important than frequency of bullying in explaining state paranoid ideation. CONCLUSIONS: The significant role played by interpersonal sensitivity in the association between being bullied in childhood and paranoid ideation in the clinical high risk group suggests that this could become a target for intervention.

Ultrasound-guided approach to nerves (direct vs. tangential) and the incidence of intraneural injection: a cadaveric study.

This study evaluated the incidence of nerve puncture and intraneural injection based on the needle approach to the nerve (direct vs. tangential). Two expert operators in regional anaesthesia performed in-plane ultrasound-guided nerve blocks (n = 158) at different levels of the brachial plexus in cadavers, aiming either directly for the nerve (n = 77) or tangentially inferior to the nerve (n = 81). After reaching the outer limit of the nerve, the needle was intentionally advanced approximately 1 mm in both approaches, and 0.2-0.5 ml of saline was injected. Each operator classified (in real time) the needle tip and injectate as intraneural or not. Video clips showing the final position of the needle and the injection were evaluated in the same manner by seven independent expert observers who were blinded to the aims of this study. In addition, 20 injections were performed with ink for histological evaluation. Intraneural injections of saline were observed by the operator in 58% (45/77) of cases using the direct approach and 12% (10/81) of cases using the tangential approach (p < 0.001). The independent observers agreed with the operator in a substantial number of cases (Cohen's kappa index 0.65). Histological studies showed intraneural spread in 83% (5/6) of cases using the direct approach and in 14% (2/14) of cases using the tangential approach (p = 0.007). No intrafascicular injections were observed. There was good agreement between the operators' assessment and subsequent histological evaluation (Cohen's kappa = 0.89). Simulation of an unintentional/accidental advancement of the needle 'beyond the edge' of the nerve suggests significantly increased risk of epineural perforation and intraneural injection when a direct approach to the nerve is used, compared with a tangential approach.

Ontogeny of human IgE-expressing B cells and plasma cells.

BACKGROUND: IgE-expressing (IgE+ ) plasma cells (PCs) provide a continuous source of allergen-specific IgE that is central to allergic responses. The extreme sparsity of IgE+ cells in vivo has confined their study almost entirely to mouse models. OBJECTIVE: To characterize the development pathway of human IgE+ PCs and to determine the ontogeny of human IgE+ PCs. METHODS: To generate human IgE+ cells, we cultured tonsil B cells with IL-4 and anti-CD40. Using FACS and RT-PCR, we examined the phenotype of generated IgE+ cells, the capacity of tonsil B-cell subsets to generate IgE+ PCs and the class switching pathways involved. RESULTS: We have identified three phenotypic stages of IgE+ PC development pathway, namely (i) IgE+ germinal centre (GC)-like B cells, (ii) IgE+ PC-like 'plasmablasts' and (iii) IgE+ PCs. The same phenotypic stages were also observed for IgG1+ cells. Total tonsil B cells give rise to IgE+ PCs by direct and sequential switching, whereas the isolated GC B-cell fraction, the main source of IgE+ PCs, generates IgE+ PCs by sequential switching. PC differentiation of IgE+ cells is accompanied by the down-regulation of surface expression of the short form of membrane IgE (mIgES ), which is homologous to mouse mIgE, and the up-regulation of the long form of mIgE (mIgEL ), which is associated with an enhanced B-cell survival and expressed in humans, but not in mice. CONCLUSION: Generation of IgE+ PCs from tonsil GC B cells occurs mainly via sequential switching from IgG. The mIgEL /mIgES ratio may be implicated in survival of IgE+ B cells during PC differentiation and allergic disease.

Validating the GTP-cyclohydrolase 1-feedback regulatory complex as a therapeutic target using biophysical and in vivo approaches.

BACKGROUND AND PURPOSE: 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4 ) is an essential cofactor for nitric oxide biosynthesis. Substantial clinical evidence indicates that intravenous BH4 restores vascular function in patients. Unfortunately, oral BH4 has limited efficacy. Therefore, orally bioavailable pharmacological activators of endogenous BH4 biosynthesis hold significant therapeutic potential. GTP-cyclohydrolase 1 (GCH1), the rate limiting enzyme in BH4 synthesis, forms a protein complex with GCH1 feedback regulatory protein (GFRP). This complex is subject to allosteric feed-forward activation by L-phenylalanine (L-phe). We investigated the effects of L-phe on the biophysical interactions of GCH1 and GFRP and its potential to alter BH4 levels in vivo. EXPERIMENTAL APPROACH: Detailed characterization of GCH1-GFRP protein-protein interactions were performed using surface plasmon resonance (SPR) with or without L-phe. Effects on systemic and vascular BH4 biosynthesis in vivo were investigated following L-phe treatment (100 mg·kg(-1) , p.o.). KEY RESULTS: GCH1 and GFRP proteins interacted in the absence of known ligands or substrate but the presence of L-phe doubled maximal binding and enhanced binding affinity eightfold. Furthermore, the complex displayed very slow association and dissociation rates. In vivo, L-phe challenge induced a sustained elevation of aortic BH4 , an effect absent in GCH1(fl/fl)-Tie2Cre mice. CONCLUSIONS AND IMPLICATIONS: Biophysical data indicate that GCH1 and GFRP are constitutively bound. In vivo, data demonstrated that L-phe elevated vascular BH4 in an endothelial GCH1 dependent manner. Pharmacological agents which mimic the allosteric effects of L-phe on the GCH1-GFRP complex have the potential to elevate endothelial BH4 biosynthesis for numerous cardiovascular disorders.

Uncertainty quantification for nuclear density functional theory and information content of new measurements.

Statistical tools of uncertainty quantification can be used to assess the information content of measured observables with respect to present-day theoretical models, to estimate model errors and thereby improve predictive capability, to extrapolate beyond the regions reached by experiment, and to provide meaningful input to applications and planned measurements. To showcase new opportunities offered by such tools, we make a rigorous analysis of theoretical statistical uncertainties in nuclear density functional theory using Bayesian inference methods. By considering the recent mass measurements from the Canadian Penning Trap at Argonne National Laboratory, we demonstrate how the Bayesian analysis and a direct least-squares optimization, combined with high-performance computing, can be used to assess the information content of the new data with respect to a model based on the Skyrme energy density functional approach. Employing the posterior probability distribution computed with a Gaussian process emulator, we apply the Bayesian framework to propagate theoretical statistical uncertainties in predictions of nuclear masses, two-neutron dripline, and fission barriers. Overall, we find that the new mass measurements do not impose a constraint that is strong enough to lead to significant changes in the model parameters. The example discussed in this study sets the stage for quantifying and maximizing the impact of new measurements with respect to current modeling and guiding future experimental efforts, thus enhancing the experiment-theory cycle in the scientific method.

Inhibition of allergen-dependent IgE activity by antibodies of the same specificity but different class.

IgG4 purified from patients undergoing specific allergen immunotherapy inhibits the activities of the serum IgE in in vitro assays and is thought to reduce the symptoms of the disease. However, it is not known whether this is related to an intrinsic property of this subclass or only the allergen specificity. We tested the hypothesis that allergen specificity is the critical determinant for this activity using a panel of antibodies with identical specificity but different subclasses. The different antibodies were all able to inhibit the activity of IgE to the same extent. We demonstrate that specificity is the dominant factor determining the ability of an antibody to block allergen-dependent IgE activity.

Serratus plane block: a novel ultrasound-guided thoracic wall nerve block.

We present a novel ultrasound-guided regional anaesthetic technique that may achieve complete paraesthesia of the hemithorax. This technique may be a viable alternative to current regional anaesthetic techniques such as thoracic paravertebral and central neuraxial blockade, which can be technically more challenging and have a higher potential side-effect profile. We performed the serratus block at two different levels in the midaxillary line on four female volunteers. We recorded the degree of paraesthesia obtained and performed fat-suppression magnetic resonance imaging and three-dimensional reconstructions of the spread of local anaesthetic in the serratus plane. All volunteers reported an effective block that provided long-lasting paraesthesia (750-840 min). There were no side-effects noted in this initial descriptive study. While these are preliminary findings, and must be confirmed in a clinical trial, they highlight the potential for the serratus plane block to provide analgesia following surgery on the thoracic wall. We suggest that this novel approach appears to be safe, effective, and easy to perform, and is associated with a low risk of side-effects.

Comparison of the Baska(®) mask with the single-use laryngeal mask airway in low-risk female patients undergoing ambulatory surgery.

We compared the Baska(®) mask with the single-use classic laryngeal mask airway (cLMA) in 150 females at low risk for difficult tracheal intubation in a randomised, controlled clinical trial. We found that median (IQR [range]) seal pressure was significantly higher with the Baska mask compared with the cLMA (40 (34-40 [16-40]) vs 22 (18-25 [14-40]) cmH2O, respectively, p < 0.001), indicating a better seal. In contrast, the first time success rate for insertion of the Baska mask was lower than that seen with the cLMA (52/71 (73%) vs 77/99 (98%), respectively, p < 0.001). There were no differences in overall device insertion success rates (78/79 (99%) vs 68/71 (96%), respectively, p = 0.54). The Baska mask proved more difficult to insert, requiring more insertion attempts, taking longer to insert and had higher median (IQR [range]) insertion difficulty scores (1.6 (0.8-2.2 [0.1-5.6]) vs 0.5 (0.3-1.4 [0.1-4.0]), respectively, p < 0.001). There was also an increased rate of minor blood staining of the Baska mask after removal, but there were no differences in other complication rates, such as laryngospasm, or in the severity of throat discomfort. In conclusion, in clinical situations where the seal with the glottic aperture takes priority over ease of insertion, the Baska mask may provide a useful alternative to the cLMA.