Musculoskeletal disorders and the workplace : low back and upper extremities

EXECUTIVE SUMMARY 1 PART I: INTRODUCTION 1 INTRODUCTION 17 Charge to the Panel, 18 Background, 20 Approach to the Problem, 21 The Whole Person: Injury, Illness, and Disease, 23 Levels of Analysis: Individuals and Populations, 27 Contextual Factors, 28 Mechanical, Physiological, and Psychological Factors, 31 Guide to the Report, 35 2 DIMENSIONS OF THE PROBLEM 38 Musculoskeletal Disorders in the General Population, 38 Work-Related Musculoskeletal Disorders, 44 Data on Economic Costs, 57 Limitations of the Data, 59 Summary, 64 x CONTENTS 3 METHODOLOGICAL ISSUES AND APPROACHES 65 Research Perspectives, 66 Determining Causality Within Studies, 71 Criteria for Causality Across Studies, 77 Study Designs, 79 Pattern of Evidence Comparisons, 81 PART II: REVIEW OF THE EVIDENCE 4 EPIDEMIOLOGIC EVIDENCE 85 Methods, 85 Results, 98 Conclusion, 113 Appendix, 117 5 TISSUE MECHANOBIOLOGY 184 Pain Pathways from Peripheral Tissues, 185 Literature Review, 187 Vertebral Bone and Spinal Disc, 187 Tendons and Ligaments, 194 Skeletal Muscle, 199 Peripheral Nerve, 210 Spinal Nerve Roots, 213 Summary, 216 6 BIOMECHANICS 219 Concepts of Load Tolerance, 219 Low Back Mechanics, 235 Upper Body Biomechanics, 253 7 OCCUPATIONAL STRESS 287 General Models of Occupational Stress, 288 Biological Response, 289 Occupational Stress and Work-Related Musculoskeletal Disorders: Some Working Hypotheses, 291 Summary, 300 CONTENTS xi 8 INTERVENTIONS IN THE WORKPLACE 301 Context, 302 Principles of Ergonomics, 303 Specific Interventions: Back, 308 Specific Interventions: Upper Extremities, 314 Challenges During the Process of Ergonomic Intervention, 320 Summary, 327 9 WORK NOW AND IN THE FUTURE 330 Trends in Employment by Industry Sector and Occupation, 331 External Factors Influencing the Nature of Work, 335 Summary, 346 PART III: IMPLICATIONS 10 PATTERNS OF EVIDENCE 351 Back Disorders and the Workplace, 354 Upper Extremity Disorders and the Workplace, 358 Summary, 361 11 CONCLUSIONS AND RECOMMENDATIONS 364 Conclusions, 364 Recommendations, 365 Additional Considerations, 367 12 RESEARCH AGENDA 370 Methodological Research, 370 Topic Area Research, 372 REFERENCES 375 xii CONTENTS APPENDIXES A Answers to Questions Posed by Congress, 431 B Dissent, Robert M. Szabo, 439 C Panel Response to the Dissent, 458 D Contributors to the Report, 461 E Biographical Sketches of Panel Members and Staff, 465