Understanding Vibration Injury

描述（申请人提供）：拟议研究的目标与国家职业研究议程的国家建设议程中的肌肉骨骼疾病战略目标7.0一致，以减少美国建筑工人中与工作相关的肌肉骨骼疾病的发生率和严重程度。估计有150万工人在建筑业、制造业、农林渔业和采矿业使用动力工具，并且目前暴露于一定水平的手臂振动，使他们处于发展手臂振动综合征（HAVS）的风险中，在工作10年后患病率为10-50%。HAVS的主要神经和动脉病变是手指的衰弱性麻木和血流减少。方法：在研究中将人类暴露在有害的振动中是不道德的，因此具有与人类手指相似的神经和动脉的动物模型替代物是必不可少的。采用两种鼠尾振动模型：一种模拟手臂振动的正弦分量，另一种模拟手臂振动的冲击波分量。振动频率（Hz）、加速度（m/s2 r.m.s.）、评估导致HAVS的振幅（mm）和持续时间（振动/天和振动天数）。我们新开发的脉冲冲击波模型可从铆接锤中产生0.5 Hz至21 kHz以上的振动分量，产生许多冲击工具特有的冲击波振动。冲击波振动损伤在90多年前就被认识到，但一直被忽视。这种知识差距必须得到解决，因为严重的HAVS可能在2.5个月内发生，而非冲击动力工具需要数年时间才能发展。正弦振动一直是振动研究的主要焦点，因为大多数工具具有在30-250 Hz范围内的主频率，大多数HAVS归因于该主频率。被忽视的事实是，非冲击工具产生冲击波，尽管不太经常。冲击工具，如铆钉锤、削片机、石材切割机、冲击钻和道路破碎机，在每个工作循环中都产生冲击波脉冲。拟议的研究振动的大鼠尾巴定量调查的频率，加速度，振幅和持续时间的关系，皮肤，动脉和骨骼肌的神经支配的结构损伤和功能缺陷有关的感觉和肌肉无力的损失（神经传导速度，冯弗雷触觉，热敏感性，冷浸激发复温和恢复血流）。拟议的研究调查了4个目标：目的1研究持续时间、频率、加速度和振幅对大鼠尾部正弦振动模型血管持续收缩的剂量效应。目的2研究冲击波振动暴露持续时间与神经和动脉组织损伤程度的剂量效应关系。目的3通过反复测量，评价每天12分钟冲击波振动后1天、1周和10周大鼠尾部神经支配和血液供应功能障碍的发生和可恢复性。目的4观察连续1天、1周和10周每天12 min冲击波振动对大鼠尾部神经支配和血供结构性损伤的发生和可恢复性。对现有模式的挑战：对冲击振动数据的需求至关重要，因为现有的国际标准ISO 5349在风险计算中没有考虑脉冲振动和高频成分，因此，该标准严重低估了对工人的伤害。ISO 5349衰减了高频贡献，因为研究报告称人类不会“感觉”超过1000 Hz的振动。预期成果：拟议的研究将证明“你感觉不到的东西会伤害你”。剂量反应数据将有助于制定基于证据的指导方针，以保护工人，并挑战制造商消除有害振动。我们的合作者，Dong博士，在NIOSH HELD研究实验室Morgantown，WV将测试防振手套保护的功效，并开发新的工程方法来测量工作场所的冲击振动，以便监测暴露。改变工作场所保护的障碍：拟议研究的结果将促进对正弦和冲击波振动对组织损伤的剂量反应关系的理解。这些数据将指导制定干预措施，降低工作场所手臂振动损伤的风险。

DESCRIPTION (provided by applicant): The goal of the proposed research aligns with the Musculoskeletal Disorders Strategic Goal 7.0 in the National Construction Agenda of the National Occupational Research Agenda to reduce the incidence and severity of work-related musculoskeletal disorders among construction workers in the U.S. Based on U.S. Bureau of Labor statistics and published epidemiological data, an estimated 1.5 million workers use powered tools in the construction, manufacturing, agriculture-forestry and fishing, and mining Sectors and are currently exposed to levels of hand-arm vibration putting them at risk for developing hand-arm vibration syndrome (HAVS) with a prevalence of 10-50% after working 10 years. The major nerve and artery pathologies of HAVS are debilitating numbness and reduced blood flow in the fingers. The Approach: Exposing humans to damaging vibration in a research study is unethical so animal model surrogates with nerves and arteries similar in structure and function to those in human fingers are essential. Two rat-tail vibration models are utilized: one simulating the sinusoidal and the other simulating impulse shock wave components of hand-arm vibration. The risk factors of vibration frequency (Hz), acceleration (m/s2 r.m.s.), amplitude (mm) and duration (vibration/day and days of vibration) that lead to HAVS are assessed. Our newly developed, impulse shock wave model delivers vibration with 0.5 Hz to over 21 kHz components from a riveting hammer that generates shock wave vibration characteristic of many impact tools. Shock wave vibration injury, recognized over 90 years ago, has been neglected. This knowledge gap must be addressed because severe HAVS can onset in 2.5 months compared to taking years to develop from non-impact powered tools. Sinusoidal vibration has been the major focus of vibration research because most tools have a dominant frequency in the 30-250 Hz range to which most HAVS has been attributed. Overlooked is the fact that non-impact tools generate shock waves albeit less regularly. Impact tools, such as riveting hammers, chippers, stone cutters, impact drills and road breakers, generate shock wave pulses with each duty cycle. The proposed studies of the vibrated rat-tail investigate quantitatively the relationships of frequency, acceleration, amplitude and duration to structural damage of the innervation of skin, artery and skeletal muscle and the functional deficits related to loss of feeling and muscle weakness (nerve conduction velocity, von Frey touch perception, thermal sensitivity, and cold immersion provocation rewarming and return of blood flow). The proposed research investigates 4 aims: Aim 1 To investigate the dose response of duration, frequency, acceleration and amplitude on the induction of persistent vasoconstriction in the rat-tail sinusoidal vibration model, Aim 2 To define the dose response relationship of shock wave vibration exposure duration with the levels of nerve and artery tissue injury, Aim 3 To evaluate by repeated measures the occurrence and recoverability of vibration-induced functional deficits in the innervation and blood supply of the rat-tail following 12 minute shock wave vibration per day for 1 day, 1 week and 10 weeks, and Aim 4 To evaluate the occurrence and recoverability of vibration-induced structural deficits in the innervation and blood supply of the rat-tail following 12 minute shock wave vibration per day for 1 day, 1 week and 10 weeks. Challenge to existing paradigm: The need for data on shock vibration is critical because the existing International Standard ISO 5349 does not take into account impulse vibration and high frequency components in risk calculation, and therefore, the Standard seriously underestimates the harm to workers. ISO 5349 attenuates high frequency contribution because of studies reporting that humans do not "feel" vibrations >1000 Hz. Expected outcomes: The proposed research will demonstrate that "what you can't feel can hurt you". The dose response data will aid development of evidenced-base guidelines for protecting workers and challenge manufacturers to eliminate offensive vibration. Our collaborator, Dr. Dong, at the NIOSH HELD research laboratory Morgantown, WV will test the efficacy of antivibration glove protection and develop new engineering methods to measure shock vibration in the workplace so that exposure can be monitored. Changing barriers to workplace protection: The results of the proposed research will advance the understanding of the dose response relationships of sinusoidal and shock wave vibration to tissue injury. These data will guide development of interventions that lower risk of hand arm vibration injury in the workplace.