Hand-Transmitted Vibration and Biodynamic Response of the Human Hand-Arm: A Critical Review

Abstract

Hand-arm vibration syndrome (HAVS) has been associated with prolonged exposure to vibration transmitted to the human hand-arm system from hand-held power tools, vibrating machines, or hand-held vibrating workpieces. The biodynamic response of the human hand and arm to hand transmitted vibration (HTV) forms an essential basis for effective evaluations of exposures, vibration-attenuation mechanisms, and potential injury mechanisms. The biodynamic response to HTV and its relationship to HAVS are critically reviewed and discussed to highlight the advances and the need for further research. In view of its strong dependence on the nature of HTV and the lack of general agreement on the characteristics of HTV, the reported studies are first reviewed to enhance an understanding of HTV and related issues. The characteristics of HTV and relevant unresolved issues are discussed on the basis of measured data, proposed standards, and measurement methods, while the need for further developments in measurement systems is emphasized. The studies on biodynamic response and their findings are grouped into four categories based on the methodology used and the objective. These include studies on (1) through-the-hand-arm response, expressed in terms of vibration transmissibility; (2) to-the-hand response, expressed in terms of the force-motion relationship of the hand-arm system; (3) to-the-hand biodynamic response function, expressed in terms of vibration energy absorption; and (4) computer modeling of the biodynamic response characteristics.

Mechanical exposure concepts using force as the agent

“…In the case of bone and articular cartilage, the process of mechanotransduction, or how cells detect strain and transduce it to a cellular response is central. Not all musculoskeletal disorders can be understood through the use of this approach; reduced blood flow with resulting localized muscle hypoxia (20) or increased tissue shear stress in hand-arm vibration resulting in damage (21,22) may need modified approaches.…”

Variation between manufacturers’ declared vibration emission values and those measured under simulated workplace conditions for a range of hand-held power tools typically found in the construction industry

“…Continued usage of high-magnitude vibrating tools can result in Secondary Raynaud's Disease where the fingers become blanched (Mansfield 2005), also known as Vibration White Finger, a part of Hand-Arm Vibration Syndrome, HAVS (Dong, Rakheja et al 2001, Wasserman 1985. In 2005, the European Union Physical Agents (Vibration) Directive (2002) came into force setting limits on the vibration exposure to which a worker may be subjected in a working day.…”

Los guantes antivibratorios: ¿une avenida de prevención eficaz y aplicable?

“…Las principales críticas enunciadas y que siguen siendo de actualidad son las siguientes: -Los espectros M y H actuales de la norma ISO 10819:1996 no representan la vibración producida por las numerosas herramientas vibrantes (Griffin, 1997;Dong, Rakheja, Schopper, Han & Smutz, 2001). -La idea de recurrir a los factores de ponderación de las frecuencias de la norma ISO 5349-1:2001 utilizados para estudiar la transmisibilidad de la vibración en la mano están siendo revisados.…”

“…-La variabilidad de las medidas intra e interindividuales hace más difícil la distinción entre un guante antivibratorio y otro que no lo es. Además, la cantidad de sujetos es insuficiente para juzgar sobre la eficacia de diferentes tipos de guantes (Paddan & Griffin, 1997;Griffin, 1998;Hewitt, 1998;Dong et al, 2001;Boileau, Rakheja & Boutin, 2002;O'Boyle & Griffin, 2001;Laszlo & Griffin, 2011). Por otra parte, si la variabilidad entre los sujetos alcanza un 20 %, un guante podría ser reconocido como antivibratorio en un laboratorio y no en otro (Pinto, Stacchini, Bovenzi, Paddan & Griffin, 2001;Dong et al, /2004).…”

“…En cuanto a los estudios de laboratorio, es difícil transponer los resultados para los trabajadores expuestos a una gama variada de herramientas cuyas frecuencias vibratorias varían, con dimensiones de mangos diferentes de las del mango instrumentado, una gran variedad de amplitud vibratoria y en contextos de trabajo variables. La eficacia de los guantes antivibratorios depende de varios factores: las características biodinámicas del sistema manobrazo (Dong et al, 2005), la variabilidad interindividual Hewitt, 1998), la variabilidad intraindividual (O'Boyle & Griffin, 2001;Hewitt, 1998), la mala alineación del adaptador Smutz, 2001), entre otros. En consecuencia, aunque los guantes estén identificados como antivibratorios en el laboratorio, según las recomendaciones de la norma, resulta poco probable que aseguren la atenuación de las vibraciones en las manos.…”