Hazards and risks leading to work-related neck and upper limb disorders (WRULDs)

Transcription

1 16 Hazards and risks leading t wrk-related neck Summary Wrk-related neck are the cmmnest ccupatinal diseases in Eurpe. They affect the neck, shulders, arms, hands, wrists and fingers, causing pain, discmfrt, numbness and tingling sensatins. Other symptms, which can be exacerbated by cld r the use f vibrating tls, include swelling in the jints, decreased mbility r grip strength, and a change in skin clur f the hands r fingers. WRULDs usually develp gradually, the cumulative effect f many, apparently mderate applicatins f frce, repeated ver an extended perid. The result is muscle fatigue, which can injure the sft tissue f the neck, shulders and upper limbs. The main risk factrs include heavy lads, awkward and static psture, repetitive mvement and t few perids f rest. If sufficient time fr rest is allwed, the bdy will recver and may even grw strnger. A pr wrking envirnment can als increase the risk f wrkers develping WRULDs. Fr example, excessive cld can make the hands feel numb, making it hard t grip and requiring mre frce t be applied. Psychscial factrs als have a part t play: wrkers wh perfrm mntnus jbs r wh are given incentives t wrk faster have a higher risk f develping WRULDs. At the very latest, risk assessment and preventin prgrammes must start as sn as any symptms are reprted. But, fr thse wrkers wh are at greater risk f develping WRULDS, measures shuld be taken befre any warning signs are bserved. What are WRULDs? Wrk-related neck are impairments f the bdily structure including tendns, ligaments, nerves, muscles, jints, bnes and the lcalised bld circulatin system that are caused primarily by wrk and the effects f the wrking envirnment. They affect the neck, shulders, and upper limbs (arms, hands, wrists and fingers) and can cause pain, discmfrt, numbness and tingling sensatins. Sufferers may als experience swelling in the jints, decreased mbility r grip strength, and a change in skin clur f the hands r fingers. These symptms can be exacerbated by cld r by the use f hand-held vibrating tls. WRULDs are smetimes called `sprains r strains, Repetitin Strain Injuries (RSIs) r Cumulative Trauma Disrders (CTDs). Yu may als hear them described by the medical terms such as tensynvitis r carpal tunnel syndrme. -1-

2 Symptms may take weeks, mnths r in sme cases years t develp. S, nce wrkers reprt them, actin must be taken withut delay. A better ptin, hwever, wuld be t try t stp the symptms develping in the first place. A prgramme f risk assessment fllwed by apprpriate wrkplace actin wuld reduce the chance wrkers at higher risk develping WRULDs. What are the cnsequences f WRULDs fr wrkers and emplyers? WRULDs are the cmmnest frm f ccupatinal disease in Eurpe, accunting fr mre than 45% f all ccupatinal diseases i. As well as the symptms described abve, wrkers must deal with a reductin in their ability t wrk, a ptential lss f earnings and pssible limitatins in their hme life r leisure activities. Emplyers must bear the csts f sickness absence, lwer prductivity and the pssibility f paying cmpensatin t wrkers frced t retire thrugh ill health. Further, the state will have t supprt the persn wh is unable t wrk. Hw are WRULDs caused? Physical wrk requires the applicatin f frce either t mve bjects r t keep them steady in the crrect psitin. When wrk is dne with the hands, varius sets f muscles in the neck, shulder, arms and hands cntract t hld the jints f the upper limb in psitin t mve bjects manually. The greater the frce required, the mre the muscle frces are sustained in the bdy parts invlved in perfrming the activity. WRULDs are caused by the effects f many repeated, apparently mderate applicatins f frce, sustained ver an extended perid. These lads d nt appear t cause immediate injury, but can result in muscle fatigue and lead t micrscpic injuries in the sft tissue structures f the neck and upper limbs. If sufficient time fr rest is allwed, the bdy will recver and may grw strnger (this is the gal f training r rehabilitatin). If there is nt enugh recvery time, r if frce must be sustained fr t lng, WRULDs can develp. i Eurstat, Wrk and Health in the EU: A Statistical Prtrait, Office fr Official Publicatins f the Eurpean Cmmunities, Luxemburg,

3 What factrs increase the risk f a wrker develping WRULDs? Main risk factrs: frce applicatins that result in high mechanical lads n the neck, shulders and upper limbs (see Figure 1 belw); awkward pstures that deviate frm the resting (neutral) pstures f jints, such as arms cntinuusly held abve head height r gripping with bent wrists. The mre psture deviates frm the resting psitin, the mre the muscles have t cntract t prduce the frce that is needed t perfrm wrk, and the higher the mechanical lad that must be sustained by the bdy; repetitive mvements where a similar mtin pattern is perfrmed ver and ver again withut stpping, especially if this invlves the same jint and muscle grups; prlnged wrk withut the pprtunity fr recvery that leads t fatigue (see Figure 2 belw); sharp edges n tls, machines r furniture that press int the fleshy tissues and cause distrtin and injury. These activities increase the risk f develping WRULDs in the neck and shulders: pstures that require the weight f the bdy parts and bjects t be held, such as wrking with elevated arms and hlding heavy bjects wrking with the head either bent r rtated pstures (fr example, using a micrscpe; turning the head t the side); prlnged wrk in static pstures (fr example, ffice wrk at cmputer wrkstatins); repeated elevatins f the arms r turning the head t the side. These activities increase the risk f develping WRULDs in the elbw, wrist and hands: use f high muscular frce t handle bjects, such as high gripping frce grasping with a large grip r pinch grip; wrking with the wrists in deviated pstures, twards either the little finger r thumb, are hazardus; repeating the same wrist mvements; sharp edges pressing n the wrists r hands. -3-

4 Figure 1 shws the bnes as the lever arms, the jints as the hinge pints, and the muscles prducing the frce at ne end f the lever. F m d m d g1 d g2 F g2 F g1 The arrws shw the magnitude and directin f the frces. The shulder muscles hld the arm extended. Hlding an bject f 1kg in the hand (F g2 ) with a lng lever arm (d g2 ) will increase the muscle frce needed up t abut 50 kg. Fr a 2 kg weight in an extended hand, the shulder muscles have t cntract with a frce f abut 70 kg that is, as if they were hlding the whle weight f the bdy! The way t reduce these frces n muscles is t keep the lever arms shrt i.e. by keeping the lad clse t the bdy. Figure 2 shws that if the individual s capacity is limited and as the reserve becmes reduced, there is an increased risk that peak lads can injure the persn. Limit f Capacity Mean lad Hurs The wrker will tire during lng spells f wrk, and sufficient rest perids are required t allw recvery. Fatigue reduces the capacity f the bdy. If the rest perids are t shrt, there is a greater risk that peak lads will lead t injuries. If there is insufficient recvery time, it is pssible that lads that are acceptable at the beginning f shift may cause verlading after several hurs wrk. The rate f fatigue increases with prlnged shifts. -4-

5 Further risk factrs assciated with the develpment f WRULDs Wrk envirnment: pr wrkspace layut can result in the adptin f stressful wrking pstures and the need t apply frce when reaching t full stretch; physical climate (temperature, air speed, humidity). The temperature f the wrkplace affects the bdy s muscles: excessive heat increases verall fatigue and prduces sweat which makes it hard t hld tls, requiring mre frce t be applied; excessive cld can make the hands feel numb, making it hard t grip and requiring mre frce; pr lighting can create glare r shadws, and these may require wrkers t mve int awkward psitins t see what they are ding clearly; high levels f nise may cause the bdy t tense, resulting in static bdy pstures and the mre rapid nset f fatigue; hand-held vibrating equipment may cause bld circulatin changes resulting in numbness, tingling r lss f sensatin, and the need t use mre frce when gripping. Individual variatin: the physical capacities f wrkers can vary dependent upn their bdy build, age, and the level f physical develpment. Previus injuries may have reduced the capacity f the bdy and made it mre vulnerable t impairment even after recvery; wrkers lack f experience r familiarity with the jb can increase their expsure t verlad. (Althugh apprpriate, jb-related training may help wrkers t reduce their expsure by enabling wrkers t use a better technique, r by taking shrt breaks and changing their psture mre ften); ill-fitting clthing r persnal prtective equipment can restrict pstures and may increase the frce applicatins necessary t d the wrk. Psychscial factrs and wrk rganisatin: affect hw wrkers feel abut their jb, such as the way the wrk is rganised, wh des which jb, hw jbs are dne, hw fast and fr hw lng; wrkers wh perfrm mntnus jbs that invlve nly a few, similar tasks r that have incentives r qutas t encurage a faster wrk rate have a higher risk f develping WRULDs; excessive wrk demands, limited cntrl by the wrker ver what they d, limited pprtunities fr scial interactin, r little supprt frm their managers, supervisrs and ther wrkers can all increase the risk f develping WRULDs. -5-

6 These factrs are thught t result frm stress that induces bimechanical and physilgical changes. Interactins All f the abve factrs may act n their wn r in cmbinatin t increase the risk f wrkers develping WRULDs. Research shws that the risk is greater if several apply; fr example, the risk f WRULDs increases with repeated hand mvements if there is need fr a high gripping frce at the same time. Relevant Eurpean legislatin Eurpean legislatin has been intrduced that places respnsibilities n emplyers t ensure that the risks f wrkers suffering frm WRULDs are minimised. The mst imprtant Eurpean directives are: Directive 89/391/EEC the framewrk directive that sets ut the basic requirements fr wrkplaces; Directive 90/270/EEC, which prvides the minimum safety and health requirements fr wrk with cmputer wrkstatins and equipment. Emplyers are bliged t: analyse wrkstatins evaluate safety and health cnditins remedy any risks t eyesight, physical prblems and prblems f mental stress; Directive 90/269/EEC, which prvides the minimum health and safety requirements fr the manual handling f lads, and ffers prtectin fr wrkers against the risk f shulder injuries as well as the lwer back. Emplyers shuld use apprpriate means t: avid the need fr manual handling f lads by wrkers take the apprpriate rganisatinal measures t reduce the risk if manual handling cannt be avided ensure that wrkers receive adequate infrmatin n the weight f a lad, the centre f gravity r the heaviest side when a package is unevenly laded ensure prper training and precise infrmatin n hw t handle lads crrectly. The requirements f ther Eurpean Directives, standards and guidelines, tgether with the prvisins f individual Member States, may als be relevant t preventing WRULDs. See the Agency s website fr mre infrmatin n the Eurpean legislatin relating t prtectin f wrkers: -6-

7 What can be dne t prevent WRULDs? The apprach incrprated within the abve legislatin is based upn an assessment f the hazards and risks in the wrkplace. Emplyers are required t evaluate risks t safety and health within their wrkplaces and then t imprve the standards f safety and health fr wrkers and thers wh may be at risk f harm. This prcess is called a risk assessment and cvers the range f factrs identified abve that are knwn t increase the risk f develping WRULDs. Risk assessment There are several mdels fr carrying ut a risk assessment. This is ne step-by-step apprach. 1. Lk fr the hazards Think abut the wrk that is dne and identify all hazards and their cmbinatins that may cause r increase the risk f WRULDs. 2. Decide wh may be harmed and hw Think abut everyne wh may be at risk. Specific attentin pay t thse wrkers at higher risk. Talk t the wrkers and their supervisrs. Invlve them in the risk assessment prcess and tell them what yu are ding t reduce risk. 3. Evaluate the risks and decide n actin Cnsider hw expsure t the identified risk factrs may lead t the develpment f WRULDs: can the hazard be remved cmpletely? can the risk be cntrlled? can prtective measures be taken t prtect the whle wrkfrce? is persnal prtective equipment needed t prtect the wrker frm a risk that cannt be cntrlled adequately by cllective preventive measures? 4. Take actin After cmpleting the risk assessment, a list f the preventive measures shuld be made in rder f pririty, and then actin shuld be taken with the invlvement f the wrkers and their representatives. Actin shuld be fcused n preventive measures t stp the injury r ill health ccurring in the first place, but cnsideratin shuld als be given t measures that wuld minimise the seriusness f any injury sustained. Wrkers shuld receive apprpriate infrmatin, educatin and training. Any hazards and risks discvered shuld be dcumented, tgether with the grups that suffer mst and the kind f injury sustained. Infrmatin shuld -7-

8 be prvided abut the measures t imprve health and safety in the wrkplace and abut hw t avid specific hazards and risks. When cnsidering preventive actins, a wide range f pssible changes shuld be cnsidered: wrkplace fr example, can the layut be imprved t avid wrkers perfrming tasks requiring high frce applicatins in awkward, static wrking pstures? wrk equipment fr example, are tls ergnmically designed? Can pwered tls be used t reduce the frce required fr a task? But will the use f such tls increase expsure t hand r arm vibratin? wrker they must be trained t increase their awareness f ergnmic factrs and t recgnise and avid unsafe wrking cnditins. Furthermre, wrkers must be cnvinced why it is imprtant t pay attentin t preventin and what happens if this is neglected. They shuld als be made aware f the benefits f adpting gd practices and wrk methds in terms f reduced suffering and n lst wages; wrk task ne f the mst imprtant requirements is t reduce the physical demands f the jb by decreasing the levels f frce, repetitin, awkward pstures and/r vibratin. This ften necessitates the use f new tls r wrking methds; wrk management fr example, by planning the wrk better r implementing safe systems f wrk. It may be pssible t reallcate tasks between wrkers t reduce repeated mtins, frceful hand exertins, and prlnged bending and twisting; at the rganisatinal level, practical slutins include develping apprpriate wrk/rest ratis t reduce fatigue, rganising breaks and rtating jbs. At the crprate level, a safety culture shuld be prmted t gain higher tp-level cmmitment and invlvement in identifying and cntrlling WRULDs risk factrs, and t imprve safety and surveillance measures. 5. Review the findings When a significant change is made t the wrk methds, it is imprtant t check that n new hazards are created in the prcess. -8-

9 Cnclusins A cnsiderable amunt f infrmatin exists abut the causes and preventin f WRULDs. This has resulted in the prvisin f gd practice guidelines, which enable risk factrs t be identified, risk assessments t be made and wrkplace actin taken t reduce the prevalence f these disrders. In the light f the gradual nset f WRULDs, it is essential that risk assessment and preventin prgrammes start as sn as any initial symptms r warning signs are reprted. It is als essential, hwever, that practive measures are taken fr thse grups f wrkers wh can be identified as being at greater risk. A number f techniques fr the assessment f expsure t WRULDs can be used t evaluate existing wrkplaces r thse at the design and develpment stage ii. Taking quick actin can bring benefits in terms f reduced suffering fr wrkers, and cuts in the csts f treatment and wrk absence fr emplyers. It can als imprve wrkplace prductivity. Fr further infrmatin abut WRULDs, see: ii David GC, Ergnmic methds fr assessing expsure t risk factrs fr wrk-related musculskeletal disrders, Occup Med (Lnd) 55(3): ,