Adverse events following chiropractic care for subjects with neck pain

Tulder, M.W. van [Promotor]Knol, D.L. [Copromotor

On the Propagation of Slip Fronts at Frictional Interfaces

The dynamic initiation of sliding at planar interfaces between deformable and rigid solids is studied with particular focus on the speed of the slip front. Recent experimental results showed a close relation between this speed and the local ratio of shear to normal stress measured before slip occurs (static stress ratio). Using a two-dimensional finite element model, we demonstrate, however, that fronts propagating in different directions do not have the same dynamics under similar stress conditions. A lack of correlation is also observed between accelerating and decelerating slip fronts. These effects cannot be entirely associated with static local stresses but call for a dynamic description. Considering a dynamic stress ratio (measured in front of the slip tip) instead of a static one reduces the above-mentioned inconsistencies. However, the effects of the direction and acceleration are still present. To overcome this we propose an energetic criterion that uniquely associates, independently on the direction of propagation and its acceleration, the slip front velocity with the relative rise of the energy density at the slip tip.Comment: 15 pages, 6 figure

1D model of precursors to frictional stick-slip motion allowing for robust comparison with experiments

We study the dynamic behaviour of 1D spring-block models of friction when the external loading is applied from a side, and not on all blocks like in the classical Burridge-Knopoff-like models. Such a change in the loading yields specific difficulties, both from numerical and physical viewpoints. To address some of these difficulties and clarify the precise role of a series of model parameters, we start with the minimalistic model by Maegawa et al. (Tribol. Lett. 38, 313, 2010) which was proposed to reproduce their experiments about precursors to frictional sliding in the stick-slip regime. By successively adding (i) an internal viscosity, (ii) an interfacial stiffness and (iii) an initial tangential force distribution at the interface, we manage to (i) avoid the model's unphysical stress fluctuations, (ii) avoid its unphysical dependence on the spatial resolution and (iii) improve its agreement with the experimental results, respectively. Based on the behaviour of this improved 1D model, we develop an analytical prediction for the length of precursors as a function of the applied tangential load. We also discuss the relationship between the microscopic and macroscopic friction coefficients in the model.Comment: 13 pages, 14 figures, accepted in Tribology Letter

Dissipation of vibration in rough contact

The relationship which links the normal vibration occurring during the sliding of rough surfaces and the nominal contact area is investigated. Two regimes are found. In the first one, the vibrational level does not depend on the contact area, while in the second one, it is propor- tional to the contact area. A theoretical model is proposed. It is based on the assumption that the vibrational level results from a competition between two processes of vibration damping, the internal damping of the material and the contact damping occurring at the interface

BAck complaints in the elders - Chiropractic (BACE-C): Protocol of an international cohort study of older adults with low back pain seeking chiropractic care

Background: Low back pain is a common condition among older adults that significantly influences physical function and participation. Compared to their younger counterparts, there is limited information available about the clinical course of low back pain in older people, in particularly those presenting for chiropractic care. Improving our understanding of this patient population and the course of their low back pain may provide input for studies researching safer and more effective care than is currently provided. Objectives: The primary objectives are to examine the clinical course over one year of pain intensity, healthcare costs and pain, functional status and recovery rates of low back pain in people 55 years and older who visit a chiropractor for a new episode of low back pain. Methods: An international prospective, multi-center cohort study with one-year follow-up. Chiropractic practices are to be recruited in the Netherlands, Sweden, United Kingdom and Australia. Treatment will be left to the discretion of the chiropractor. Inclusion/Exclusion criteria: Patients aged 55 and older who consult a chiropractor for a new episode of low back pain, meaning low back pain for the first time or those patients who have not been to a chiropractor in the previous six months. This is independent of whether they have seen another type of health care provider for the current episode. Patients who are unable to complete the web-based questionnaires because of language restrictions or those with computer literacy restrictions will be excluded as well as those with cognitive disorders. In addition, those with a suspected tumor, fracture, infection or any other potential red flag or condition considered to be a contraindication for chiropractic care will be excluded. Data will be collected using online questionnaires at baseline, and at 2 and 6 weeks and at 3, 6, 9 and 12 months. Discussion: This study, to our knowledge, is the first large-scale, prospective, multicenter, international cohort study to be conducted in a chiropractic setting to focus on older adults with low back pain consulting a chiropractor. By understanding the clinical course, satisfaction and safety of chiropractic treatment of this common debilitating condition in the aged population, this study will provide input for informing future clinical trials. Trial registration: Nederlandse Trial Registrar NL7507

Benefits and harms of spinal manipulative therapy for the treatment of chronic low back pain: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE To assess the benefits and harms of spinal manipulative therapy (SMT) for the treatment of chronic low back pain. DESIGN Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES Medline, PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Physiotherapy Evidence Database (PEDro), Index to Chiropractic Literature, and trial registries up to 4 May 2018, including reference lists of eligible trials and related reviews. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Randomised controlled trials examining the effect of spinal manipulation or mobilisation in adults (≥18 years) with chronic low back pain with or without referred pain. Studies that exclusively examined sciatica were excluded, as was grey literature. No restrictions were applied to language or setting. REVIEW METHODS Two reviewers independently selected studies, extracted data, and assessed risk of bias and quality of the evidence. The effect of SMT was compared with recommended therapies, non-recommended therapies, sham (placebo) SMT, and SMT as an adjuvant therapy. Main outcomes were pain and back specific functional status, examined as mean differences and standardised mean differences (SMD), respectively. Outcomes were examined at 1, 6, and 12 months. Quality of evidence was assessed using GRADE. A random effects model was used and statistical heterogeneity explored. RESULTS 47 randomised controlled trials including a total of 9211 participants were identified, who were on average middle aged (35-60 years). Most trials compared SMT with recommended therapies. Moderate quality evidence suggested that SMT has similar effects to other recommended therapies for short term pain relief (mean difference −3.17, 95% confidence interval −7.85 to 1.51) and a small, clinically better improvement in function (SMD −0.25, 95% confidence interval −0.41 to −0.09). High quality evidence suggested that compared with non-recommended therapies SMT results in small, not clinically better effects for short term pain relief (mean difference −7.48, −11.50 to −3.47) and small to moderate clinically better improvement in function (SMD −0.41, −0.67 to −0.15). In general, these results were similar for the intermediate and long term outcomes as were the effects of SMT as an adjuvant therapy. Evidence for sham SMT was low to very low quality; therefore these effects should be considered uncertain. Statistical heterogeneity coul

Reduction of routine use of radiography in patients with ankle fractures leads to lower costs and has no impact on clinical outcome: an economic evaluation

Background: To evaluate the cost-effectiveness of a reduction in the number of routine radiographs in the follow-up of patients with ankle fractures.Methods: We performed an economic evaluation alongside the multicentre, randomised WARRIOR trial. Participants were randomised to a reduced imaging follow-up protocol (i.e. radiographs at week 6 and 12 follow-up obtained on clinical indication) or usual care (i.e. routine radiography at weeks 6 and 12). The Olerud & Molander Ankle Score (OMAS) was used to assess ankle function and the EQ-5D-3L was used to estimate Quality-Adjusted Life Years (QALYs). Costs and resource use were assessed using self-reported questionnaires and medical records, and analysed from a societal perspective. Multiple imputation was used for missing data, and data were analysed using seemingly unrelated regression analysis and bootstrapping.Results: In total, 246 patients had data available for analysis (reduced imaging = 118; usual care = 128). Fewer radiographs were obtained in the reduced imaging group (median = 4) compared with the usual-care group (median = 5). Functional outcome was comparable in both groups. The difference in QALYs was - 0.008 (95% CI:-0.06 to 0.04) and the difference in OMAS was 0.73 (95% CI:-5.29 to 6.76). Imaging costs were lower in the reduced imaging group (-(sic)48; 95% CI:- (sic)72 to -(sic)25). All other cost categories did not statistically differ between the groups. The probability of the reduced imaging protocol being cost-effectiveness was 0.45 at a wiliness-to-pay of (sic)20,000 per QALY.Conclusions: Reducing the number of routine follow-up radiographs has a low probability of being cost-effective compared with usual care. Functional outcome, health-related quality of life and societal costs were comparable in both groups, whereas imaging costs were marginally lower in the reduced imaging group. Given this, adherence to a reduced imaging follow-up protocol for those with routine ankle fractures can be followed without sacrificing quality of care, and may result in reduced costs.Trauma Surger

Lumbale herniaoperatie: Endoscopisch of open?

_Achtergrond en het waarom van de studie_ In Nederland vinden jaarlijks veel operaties voor een lumbale discushernia plaats. Patiënten krijgen meestal een open microdiscectomie, waarbij de hernia wordt opgeheven via een klein sneetje in de rug en de zenuwwortel wordt vrijgelegd (figuur a). Een andere techniek is percutane transforaminale endoscopische discectomie (PTED) (figuur b). Hierbij wordt de hernia onder indirect zicht opgeheven door een kleinere snee van 8 mm via het wortelkanaal, dus meer vanaf de zijkant. PTED vindt plaats in dagbehandeling onder lichte sedatie, waardoor de patiënt gedurende de ingreep aanspreekbaar is. Mogelijke voordelen van deze techniek zijn minder risico op littekenvorming en een snellere revalidatie. Een mogelijk nadeel is een groter risico op recidieven omdat er minder discusmateriaal kan worden uitgeruimd. PTED behoort nog niet tot het basispakket, omdat Zorginstituut Nederland meent dat PTED niet voldoet aan de stand van de wetenschap en praktijk. Met de PTED-studie willen wij de hypothese toetsen dat PTED bij patiënten met een lumbale hernia niet minder effectief is dan open microdiscectomie. Daarnaast zullen wij ook de kosteneffectiviteit analyseren. _Vraagstelling:_ Is PTED niet minder effectief en niet minder kosteneffectief dan microdiscectomie bij patiënten met lumbosacraal radiculair syndroom door een discushernia

Human antigen R as a therapeutic target in pathological cardiac hypertrophy

RNA binding proteins represent an emerging class of proteins with a role in cardiac dysfunction. We show that activation of the RNA binding protein human antigen R (HuR) is increased in the failing human heart. To determine the functional role of HuR in pathological cardiac hypertrophy, we created an inducible cardiomyocyte-specific HuR-deletion mouse and showed that HuR deletion reduces left ventricular hypertrophy, dilation, and fibrosis while preserving cardiac function in a transverse aortic constriction (TAC) model of pressure overload-induced hypertrophy. Assessment of HuR-dependent changes in global gene expression suggests that the mechanistic basis for this protection occurs through a reduction in fibrotic signaling, specifically through a reduction in TGF-β (Tgfb) expression. Finally, pharmacological inhibition of HuR at a clinically relevant time point following the initial development of pathological hypertrophy after TAC also yielded a significant reduction in pathological progression, as marked by a reduction in hypertrophy, dilation, and fibrosis and preserved function. In summary, this study demonstrates a functional role for HuR in the progression of pressure overload-induced cardiac hypertrophy and establishes HuR inhibition as a viable therapeutic approach for pathological cardiac hypertrophy and heart failure