Microscopic changes in the spinal extensor musculature in people with chronic spinal pain: a systematic review.

BACKGROUND CONTEXT: Chronic spinal pain is one the most common musculoskeletal disorders. Previous studies have observed microscopic structural changes in the spinal extensor muscles in people with chronic spinal pain. This systematic review synthesizes and analyzes all the existing evidence of muscle microscopic changes in people with chronic spinal pain. PURPOSE: To assess the microscopy of spinal extensor muscles including the fiber type composition, the area occupied by fiber types, fiber size/cross sectional area (CSA), and narrow diameter (ND) in people with and without chronic spinal pain. Further, to compare these outcome measures across different regions of the spine in people with chronic neck, thoracic and low back pain. STUDY DESIGN: Systematic review with meta-analysis. METHODS: MEDLINE (Ovid Interface), Embase, PubMed, CINAHL Plus, and Web of Science were searched from inception to October 2020. Key journals, conference proceedings, grey literature and hand searching of reference lists from eligible studies were also searched. Two independent reviewers were involved in the selection process. Only studies examining the muscle microscopy of the spinal extensor muscles (erector spinae [ES] and/or multifidus [MF]) between people with and without chronic spinal pain were selected. The risk of bias from the studies was assessed using modified Newcastle Ottawa Scale and the level of evidence was established using the GRADE approach. Data were synthesized based on homogeneity on the methodology and outcome measures of the studies for ES and MF muscles and only four studies were eligible for analysis. RESULTS: All the five studies included were related to chronic low back pain (CLBP). Meta-analysis (inverse variance method for random effect to calculate mean difference and 95% CI) was performed for the ES fiber type composition by numbers for both type I and type II fibers (I2=43% and 0% respectively indicating homogeneity of studies) and showed no difference between the people with and without CLBP with an overall effect estimate Z= 1.49 (p=.14) and Z=1.06 (p=.29) respectively. Meta-analysis was performed for ES fiber CSA for both type I and type II fibers (I2=0 for both) and showed no difference between people with and without CLBP with an overall effect estimate Z=0.08 (p=.43) and Z=0.75 (p=.45) respectively. Analysis was not performed for ES area occupied by fiber types and ND due to heterogeneity of studies and lack of evidence respectively. Similarly, meta-analysis was not performed for MF fiber type composition by numbers due to heterogeneity of studies. MF analysis for area occupied by fiber type, fiber CSA and ND did not yield sufficient evidence. CONCLUSIONS: For the ES muscle, there was no difference in fiber type composition and fiber CSA between people with and without CLBP and no conclusions could be drawn for ND for the ES. For the MF, no conclusions could be drawn for any of the muscle microscopy outcome measures. Overall, the quality of evidence is very low and there is very low evidence that there are no differences in microscopic muscle features between people with and without CLBP.

Disasters and development: Part 2: Understanding and exploiting disaster-development linkages.

This lesson is a continuation of Disasters and Development: Part 2: Understanding and Exploiting Disaster-Development Linkages published in Prehospital and Disaster Medicine in Volume 17, Number 3. It identifies the goals of a specific damage mitigation project that can be incorporated into a regular development project and the mechanisms for obtaining the mitigation component of such a project. Mechanisms for assessing the success of such a project are discussed. It stresses the importance of the application of building codes, associated training programs, and more extensive use of zoning regulations in urban development that decrease the population at risk and the likelihood of damage to industrial facilities. Disasters can elevate the development potential of a society at risk for damage from a hazard. The political impact of damage and disruption can be a catalyst for change. Development opportunities often are compromised because of an excessive focus on relief assistance. Interventions designed to mitigate the damage from a given hazard are particularly effective when they focus on areas at particularly high risk for actualization of the hazard. Support from the private sector, including the non-formal sector, is a key element of successful reconstruction management. The period of recovery is an opportunity for general assistance to government with administrative procedures, including enhanced management training programs.

Disasters and development: Part 3: Assessing trade-offs in investing in vulnerability reduction.

This lesson describes how a government decides whether and how much it should spend on vulnerability reduction. There are techniques and methods by which decision-makers compare development alternatives. The differences between the risk that a potentially catastrophic event will occur and uncertainty are described, with uncertainty providing greater difficulty in economic analyses. There is a range of methods for identifying the complex mix of competing costs and benefits associated with any restructuring of investment priorities to accomplish disaster mitigation. The possibilities are described in terms of the opportunity costs and present value. Impact and consequent losses include: (1) direct monetary effects; (2) indirect monetary effects; (3) direct, non-monetary effects; (4) indirect, non-monetary effects; and (5) loss of non-renewable natural resources. The difficulties in assigning values to these effects are described, as well as the means of judging the cost-effectiveness of such interventions. An advantage of screening projects using a framework of analytical methods is that it can assist in focusing on a variety of possible outcomes and make the factors influencing these outcomes quite explicit.

Disasters and development: Part I. Relationships between disasters and development.

This module introduces a paradigm for understanding the disaster/development interface. Specifically, the module asserts that disasters and development are linked closely in that disasters can both destroy development initiatives and create development opportunities, and that development schemes can both increase and decrease vulnerability. The module consists of four parts: Part One introduces these concepts and discusses how disasters can vary from one type of hazard to another, as well as from one type of economic condition to another. Part Two develops the paradigm in depth, and provides case examples to amplify the points made in the text. Part Three describes and discusses different methods and tools for analyzing decisions for potential investment of resources, and should enhance the reader's capacity to analyze the mitigational benefits of development alternatives in both the pre- and post-disaster context. Part Four conceptualizes the role of UN agencies, NGOs, and the affected communities in promoting development based on the concepts discussed in the module. This training module, Disasters and Development, initially was designed to introduce this aspect of disaster management to an audience of UN organization professionals who form disaster management teams, as well as to government counterpart agencies, non-governmental organizations (NGOs), and donors. The educational process has been designed to increase the audience's awareness of the nature and management of disasters, in order to lead to better performance in disaster preparedness and response. The content has been written by experts in the field of disaster management and in general follows the UNDP/UNDRO Disaster Management Manual and its principles, procedures, and terminology.

Disasters and development: Part 2: understanding and exploiting disaster-development linkages.

Disasters can impede the effectiveness of development resource allocation. The damage sustained from an event can be classified into four categories: (1) Loss of resources; (2) Interruption of programs and switching of crucial resources to other, shorter-term needs; (3) Negative impacts upon investment climates; and/or (4) Disruption of the non-formal sector (local businesses). Disasters have a particularly destructive economic impact in areas in which there are few alternatives for assets that are destroyed or in areas in which the resources already are at critical levels. Development processes can both increase and/or decrease the vulnerability of a society to hazards. There are dearly established linkages between poverty, marginalization, over-population, and vulnerability. To a large extent, vulnerability derives from poverty. The poor are more likely to live in vulnerable areas (slopes prone to landslides, flood plains, marginal agricultural land), have difficulty accessing education and information, have fewer assets to invest in resources to reduce vulnerability, and are more prone to become malnourished and have chronic illnesses that predispose them to injury and death. Development may be associated with the production of new hazards accepted by a society because the perceived benefits of the development project far exceed the relative risk associated with the project. Therefore, risk assessments must be part of any program planning and evaluation. Training and education are of critical importance in preventing increased vulnerability as a result of development strategies. Development also can progress in a manner that will result in mitigation of the impacts of an event on a given society (increase absorbing capacity and/or buffering capacity, elimination of hazards or the risk of them producing a disaster). Such mitigation measures can be either structural or nonstructural. There exists a wide range of options for incorporating mitigation measures in development projects. Two case studies provide exercises that incorporate the concepts provided in this discussion: (1) The 1985 earthquake in Mexico City; and (2) Agricultural development in northern Sudan.