Back problems and atherosclerosis. The Study of Osteoporotic Fractures

Chronic Low Back Pain: History, Symptoms, Pain Mechanisms, and Treatment

Chronic low back pain (cLBP) is the most frequently reported cause of years lived with disability. Identifying the anatomical structures or dysfunction contributing to patients' symptoms is critical to guiding treatment. The etiology of back pain and differential diagnosis is often broad, ranging from non-degenerative cLBP (trauma, tumor, inflammation, infection, etc.) to degenerative (also described as nonspecific) cLBP. After eliminating suspicion for more insidious causes of cLBP, a thorough investigation can be conducted in an attempt to identify a source of degenerative cLBP. Degenerative cLBP can originate from many sources, and a detailed understanding of the structures potentially involved is invaluable for an accurate diagnosis. This review article aims to provide a broad overview of the utility of clinical history, physical exam findings, imaging findings, and diagnostic procedures in identifying the cause of patients' cLBP. We provide a framework to help guide clinicians by dividing the structures into groups as follows: anterior vertebral column, posterior vertebral column, and extra-vertebral pain. For each condition listed, we touch on the treatment options that can be considered.

Pathophysiological Aspects of Muscle Atrophy and Osteopenia Induced by Chronic Constriction Injury (CCI) of the Sciatic Nerve in Rats

Skeletal muscle atrophy is a condition characterized by a loss of muscle mass and muscle strength caused by an imbalance between protein synthesis and protein degradation. Muscle atrophy is often associated with a loss of bone mass manifesting as osteoporosis. The aim of this study was to evaluate if chronic constriction injury (CCI) of the sciatic nerve in rats can be a valid model to study muscle atrophy and consequent osteoporosis. Body weight and body composition were assessed weekly. Magnetic resonance imaging (MRI) was performed on day zero before ligation and day 28 before sacrifice. Catabolic markers were assessed via Western blot and Quantitative Real-time PCR. After the sacrifice, a morphological analysis of the gastrocnemius muscle and Micro-Computed Tomography (Micro-CT) on the tibia bone were performed. Rats that underwent CCI had a lower body weight increase on day 28 compared to the naive group of rats (p < 0.001). Increases in lean body mass and fat mass were also significantly lower in the CCI group (p < 0.001). The weight of skeletal muscles was found to be significantly lower in the ipsilateral hindlimb compared to that of contralateral muscles; furthermore, the cross-sectional area of muscle fibers decreased significantly in the ipsilateral gastrocnemius. The CCI of the sciatic nerve induced a statistically significant increase in autophagic and UPS (Ubiquitin Proteasome System) markers and a statistically significant increase in Pax-7 (Paired Box-7) expression. Micro-CT showed a statistically significant decrease in the bone parameters of the ipsilateral tibial bone. Chronic nerve constriction appeared to be a valid model for inducing the condition of muscle atrophy, also causing changes in bone microstructure and leading to osteoporosis. Therefore, sciatic nerve constriction could be a valid approach to study muscle-bone crosstalk and to identify new strategies to prevent osteosarcopenia.

[Influence of chronic pain in osteoarthritis on the risk of cardiovascular diseases and modern methods of drug prevention]

The purpose of the review of scientific medical literature was to evaluate the data of the epidemiology of osteoarthritis (OA) and cardiovascular diseases (CVD) with the analysis of risk factors, pathophysiological and pathobiochemical mechanisms of the relationship between OA and the risk of developing CVD in the presence of chronic pain, modern strategies for screening and management of this cohort of patients, the mechanism of action and pharmacological effects of chondroitin sulfate (CS). Conclusions were drawn about the need for additional clinical and observational studies of the efficacy and safety of the parenteral form of CS (Chondroguard) in patients with chronic pain in OA and CVD, improvement of clinical recommendations for the treatment of chronic pain in patients with OA and cardiovascular risk, with special attention to interventions that eliminate mobility restrictions in patients and the inclusion of basic and adjuvant therapy with DMOADs to achieve the goals of multipurpose monotherapy in patients with contraindications to standard therapy drugs.

Health disparities in chronic back pain and associated mortality seen in ischemic cardiac disease: a commentary

Prescription opioid use for nonmalignant chronic pain has grown in the US over the last decade. Those with chronic back pain have a higher risk of mortality from ischemic heart disease than those without. Studies have demonstrated a higher prevalence of cardiac disease in adults who report chronic pain. In addition, there is research that supports some association with pain sites and cardiovascular morbidity. Studies have also shown a high-grade chronic neck pain to be more associated with cardiovascular conditions when compared to moderate or low-grade chronic pain. Given this information, it is important to assess pain medication burden present in those who have a diagnosis of coronary artery disease and chronic lower back pain.

The Association Between Atherosclerosis and Low Back Pain: A Systematic Review

OBJECTIVE

To assess the evidence of association between atherosclerosis and low back pain (LBP). TYPE: Focused systematic review.

LITERATURE SURVEY

PubMed, Web of Science, CINAHL, and EMBASE were searched for original research articles, not limited by language, from January 1, 1990, to October 31, 2016.

METHODOLOGY

Titles and then abstracts were identified using predefined search terms and excluded based on lack of relevancy. This was followed by full-text reviews. Two authors independently assessed methodological quality based on Cochrane Handbook for Systematic Reviews of Interventions.

SYNTHESIS

A total of 26 studies met the inclusion criteria. The quality of the studies was low to moderate. There was significant heterogeneity across articles with respect to methodology. There was insufficient evidence to support an association between ischemia and low back pain.

CONCLUSIONS

The cause of LBP remains poorly understood. Better insight into how intervertebral disk changes relate to LBP is needed to guide future research. High-quality prospective studies are needed to answer the question of whether atherosclerosis is a risk factor for LBP.

LEVEL OF EVIDENCE

II.

Is Chronic Low Back Pain Associated with the Prevalence of Coronary Heart Disease when Genetic Susceptibility Is Considered? A Co-Twin Control Study of Spanish Twins

Objective

To investigate the chronic low back pain and coronary heart disease relationship, after adjusting for relevant confounders, including genetics.

Methods

In a cross-sectional design, 2148 twins were recruited from the Murcia Twin Registry, Spain. The exposure was chronic LBP and the outcomes were myocardial infarction and other coronary heart diseases—lifetime and in the last 2 years–based on standardized health-related questionnaires. First, logistic regression analysis investigated associations of the total sample followed by a matched co-twin control analyses, with all complete twin pairs discordant for chronic LBP utilised, separated for zygosity—dizygotic (DZ) and monozygotic (MZ) pairs, which adjusted for shared familial factors, including genetics.

Results

Chronic LBP pain is associated with lifetime myocardial infarction [odds ratio (OR) = 2.69, 95% confidence interval (CI) = 1.35–5.36], other coronary heart diseases over a lifetime (OR = 2.58, 95% CI: 1.69–3.93) and in the last two years (OR = 2.19, 95% CI: 1.33–3.60), while there was a borderline association with myocardial infarction in the last 2 years (OR = 2.64, 95% CI: 0.98–7.12). Although the magnitude of the association remained or increased in the co-twin control analyses, none reached statistical significance.

Conclusion

Chronic LBP is associated with a higher prevalence of myocardial infarction and coronary heart disease. It is possible that this association remains even when controlling for genetics and early shared environment, although this should be investigated with larger samples of twins discordant for LBP.

Self-reported pain severity is associated with a history of coronary heart disease

BACKGROUND

Previous studies have found an association between chronic pain and cardiovascular (CV) mortality.

OBJECTIVE

To explore the relationship between the severity of pain and non-fatal CV disease.

METHODS

A total of 45,994 adults randomly selected from general practice registers in Manchester and Aberdeen were posted a survey, which included a Chronic Pain Grade questionnaire, pain manikin and questions about lifestyle and medical history. A single component measuring pain severity was extracted using factor analysis. Logistic regression was used to test for an association between quintiles of pain severity and a history of CV disease, adjusting for confounders.

RESULTS

Of the 15,288 responders, 61% (n = 9357) reported pain for ≥ 1 day in the past month. Compared with the first (lowest) pain severity quintile, the fully adjusted odds ratio for heart attack in the second severity quintile was 1.25 (95% confidence interval 0.68, 2.30); third quintile: 1.65 (0.93, 2.94); fourth quintile: 1.76 (1.00, 3.11) and fifth (highest) quintile 2.47 (1.43, 4.28). Corresponding figures for angina (excluding heart attack) were: 1.79 (0.93, 3.45), 1.91 (1.00, 3.62), 1.03 (0.50, 2.11) and 3.17 (1.71, 5.85).

CONCLUSION

A history of CV disease is reported more often in those with severe pain than would be expected by chance, even when adjusting for shared risk factors.

Changes of low back pain after vascular reconstruction for abdominal aortic aneurysm and high aortic occlusion: a retrospective study

BACKGROUND

The purpose of the present study is to clarify the influence of acute and chronic interruption of blood flow from lumbar arteries as well as the influence of vascular reconstruction on low back pain, back muscles, and lumbar discs.

METHODS

Subjects were 34 patients with AAA in whom vascular reconstruction was performed. A second group was comprised of 9 patients with HAO. The presence of low back pain before surgery and at follow-up examination was retrospectively examined in the AAA group and the HAO group to investigate postoperative changes. The CSA and degeneration of the multifidus muscle and the lumbar discs on magnetic resonance imaging were assessed in the AAA group and control group.

RESULTS

Low back pain, significant atrophy, or degeneration of the multifidus muscle or degeneration of the lumbar disc did not newly develop after surgery in the AAA group. These results indicated that acute interruption of lumbar arteries did not induce the development or deterioration of low back pain and organic changes in the back muscles or lumbar discs. The frequency of low back pain before surgery was significantly higher in the HAO group than that in the AAA group. However, the frequency of low back pain after surgery did not differ significantly between the 2 groups because low back pain in the HAO group was improved after surgery.

CONCLUSION

The finding that low back pain was improved by merely performing treatment for the vascular system might provide support for the presence of vascular backache.

Serum lipids and low back pain: an association? A follow-up study of a working population sample

STUDY DESIGN

Cohort study with 5-, 10-, and 28-year follow-up.

OBJECTIVES

To examine associations between baseline serum lipid concentrations and later low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Atherosclerosis of the lumbar vessels has been suggested as a mechanism leading to disc degeneration and LBP. Cholesterol is considered essential for atherosclerosis development.

METHODS

A sample (n = 902) of employees in an engineering company was examined for serum total cholesterol and triglycerides, body mass index (BMI), smoking, exercise, work history, and LBP in 1973. By November 2000, 232 subjects had died. In 1978, 748 (84% of the survivors), in 1983, 654 (76%), and in 2000, 546 (81%) responded to a follow-up questionnaire.

RESULTS

In men, baseline serum total cholesterol predicted new cases of radiating LBP in the 5-year follow-up (highest tertile vs. lowest: odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-5.9) and in the 10-year follow-up (OR, 2.8; 95% CI, 1.3-6.1), adjusted for age, occupational class, work history, BMI, smoking and exercise. Also, serum triglycerides predicted new cases in the latter examination (OR, 2.6; 95% CI, 1.2-5.8). In women, no associations were seen until the 10-year follow-up, when their results were similar to those in men. In the total material, serum total cholesterol predicted radiating LBP reported both at the 10- and the 28-year follow-up.

CONCLUSIONS

High serum lipids predicted incident radiating LBP, consistent with the atherosclerosis-LBP hypothesis.

Comorbidity with low back pain: a cross-sectional population-based survey of 12- to 22-year-olds

STUDY DESIGN

Cross-sectional, population-based survey.

OBJECTIVES

To investigate the pattern of comorbidity with low back pain in adolescents.

SUMMARY OF BACKGROUND DATA

Low back pain is usually dealt with as a specific and independent entity. However, the existing literature shows comorbidity to be common with low back pain, suggesting that low back pain may be part of a broader pattern of general health. The present knowledge is based on studies of adult populations; therefore, associations could be explained by work and lifestyle factors. Information in this area is lacking regarding subjects still unaffected by such factors.

METHODS

A questionnaire-survey about general health, including low back pain, was carried out among twins registered in the population-based Danish Twin Registry. Associations between disorders were calculated and patterns of comorbidity investigated, by means of logistic regression and a finite mixture model. Finally a twin-control study was conducted.

RESULTS

A total of 9,567 individuals, 12 to 22 years of age, responded to the questionnaire. Positive associations between low back pain and asthma and headache/migraine were demonstrated, mainly because of study participants with several disorders. No association between low back pain and atopic dermatitis/hay fever was found. The presence of two other disorders increased the probability of low back pain considerably more than the presence of only one other disorder. The finite mixture model indicated that the probability of belonging to a frail subgroup decreased from 60% at age 13 to 25% at age 21, and in the frail subgroups nearly all report low back pain and headache in the older ages. Furthermore, increasing duration of low back pain increased the likelihood of having other disorders. Results from the twin-control study were similar.

CONCLUSION

Young people are more likely to suffer from asthma and headache, but not from atopic dermatitis/hay fever, if they have low back pain. All of the investigated disorders cluster in some individuals. A model of common origin for these seemingly independent disorders should be considered.

Is low back pain part of a general health pattern or is it a separate and distinctive entity? A critical literature review of comorbidity with low back pain

INTRODUCTION

Research concerning the development of low back pain (LBP) has traditionally focused on risk factors in search of explanations. This review focuses on comorbidity as a first step in identifying a frail subpopulation with a higher risk of developing low back pain, in particular persistent low back pain. Research into comorbidity might yield a greater understanding of the underlying mechanism for low back pain. Data sources Medline was searched from the beginning of the data base to December 2000, followed by a search through the authors' personal collections of epidemiologic literature regarding low back pain. All articles written in English were included if they related LBP to at least one other physical disorder. Articles were excluded if the prevalence of such disorders could not be compared to that of a control group or to the expected prevalence in a normal population. Data extraction The retrieved articles were evaluated for quality based on predefined methodological criteria, whereupon information about associations between low back pain and other physical disorders was extracted.

RESULTS

Twenty-three articles were included. They showed positive associations to all disorders investigated (headache/migraine, respiratory disorders, cardiovascular disease, general health, and others) with the exception of diabetes. There was very little information regarding temporality, therefore there are no clues as to causal mechanisms.

CONCLUSION

The literature leaves no doubt that diseases cluster in some individuals and that low back pain is part of this pattern. However, the nature of the relationship between low back pain and other disorders is still unclear.

Influence of smoking on the health status of spinal patients: the National Spine Network database

STUDY DESIGN

Multicenter, cross-sectional analysis of data from the National Spine Network.

OBJECTIVES

Investigate the association between the smoking status of spinal patients, duration and severity of symptoms, and their self-reported health status.

BACKGROUND

Although cigarette smoking was identified as a potential risk factor for lower back pain many years ago, more recent research is challenging this finding.

METHODS

The National Spine Network database contains information on the initial visit of spinal patients visiting physicians at 23 health care institutions in the United States. All patients for whom data were available regarding smoking status are included in this study (n = 25,455).

RESULTS

Data from a total of 25,455 patients (11,494 men and 13,961 women) were included in the study; 16.7% (n = 4249) were smokers. Smokers were younger than nonsmokers (44.2 vs. 48.7 years) and were more likely to report severe back symptoms (37 vs. 50%) and to report symptoms of depression (54 vs. 37%). Smokers of each gender scored 10-15 points lower than nonsmokers on each of the SF-36 subscales. These differences persisted when the absolute scores were compared with age- and sex-specific population norms and after adjustment for comorbid conditions, educational level, and depression. Similar results were obtained when the cohort was stratified by primary diagnosis or by surgical status. When postsurgical patients were grouped by time since surgery, those who were nonsmokers reported improved health status by time period; those who smoked did not.

CONCLUSIONS

Smokers and nonsmokers had had spinal symptoms for similar duration, but the smokers reported more severe symptoms, which were present for a greater proportion of time each day. Also, the smokers had lower physical and mental health status scores (based on the SF-36) than did nonsmokers.

Low back pain and lifestyle. Part I: Smoking. Information from a population-based sample of 29,424 twins

STUDY DESIGN

A cross-sectional postal survey of 29,424 people aged 12-41 years obtained from a population-generated panel of twin individuals.

OBJECTIVES

To study whether smoking causes low back pain.

SUMMARY OF BACKGROUND DATA

Despite insufficient evidence in the epidemiologic literature, it has become increasingly accepted that smoking causes low back pain and that discontinuation of smoking is a suitable means of secondary prevention.

METHODS

Dose-response was examined for smoking (daily use, number of years smoked, and total cigarette use during the years of smoking) in correlation with low back pain (occurring 1-7 days, 8-30 days, and > 30 days in the past year). A possible modifying effect was studied for age, gender, and body mass index. A negative gradient was sought in relation to the time since smoking was discontinued. The prevalence of low back pain was studied in monozygotic twin pairs, only one of whom smoked.

RESULTS

There was a significant positive association between smoking and low back pain that increased with the duration of low back pain: occurring 1-7 days (odds ratio, 1.4), 8-30 days (odds ratio, 2.1), and more than 30 days (odds ratio, 3) in the past year. However, these differences in reports of low back pain disappeared in monozygotic twin pairs discordant on present smoke status. There was no biologic gradient for any of the low back pain definitions or measures of smoking-dose, and the prevalence of low back pain did not decrease with the number of years since smoking was stopped. Smaller people (youngsters, women, people with low body mass index) were not more vulnerable to development of low back pain with smoking.

CONCLUSIONS

There is a definite link between smoking and low back pain that increases with the duration and frequency of the low back pain problem, but this link is unlikely to be causal.