Manual patient handling commonly induces high mechanical load on the lower back of healthcare workers. A long-term research project, the 'Third Dortmund Lumbar Load Study' (DOLLY 3), was conducted to investigate the lumbar load of caregivers during handling activities that are considered 'definitely endangering' in the context of worker's compensation procedures. Nine types of handling activities in or at a bed or chair were analysed. Measurement of action forces via specifically developed devices and posture recording by means of optoelectronic marker capturing and video recordings in order to quantify several lumbar-load indicators was previously described in detail. This paper provides the results of laboratory examinations and subsequent biomechanical model calculations focused on lumbar load and the potentials of load reduction by applying biomechanically 'optimized' transfer modes instead of a 'conventional' technique and, for a subgroup of tasks, the supplementary usage of small aids such as a sliding mat or a glide board. Lumbosacral-disc compressive force may vary considerably with respect to the performed task, the mode of execution, and individual performance. For any activity type, highest values were found for conventional performance, lower ones for the improved transfer mode, and the lowest compressive-force values were gathered when small aids were applied. Statistical significance was verified for 13 of these 17 comparisons. Analysing indicators for asymmetric loading shows that lateral-bending and torsional moments of force at the lumbosacral disc may reach high values, which can be reduced considerably by implementing an improved handling mode. When evaluating biomechanical loads with respect to age- and gender-specific work-design limits, none of the analysed tasks, despite execution mode, resulted in an acceptable load range. Therefore, applying a biomechanically adequate handling mode combined with small aids to lower the friction between patient and surfaces is highly recommended, especially to prevent overload in older caregivers.

BackgroundThe human spine is often exposed to mechanical load in vocational activities especially in combination with lifting, carrying and positioning of heavy objects. This also applies in particular to nursing activities with manual patient handling. In the present study a detailed investigation on the load of the lumbar spine during manual patient handling was performed.MethodsFor a total of 13 presumably endangering activities with transferring a patient, the body movements performed by healthcare workers were recorded and the exerted action forces were determined with regard to magnitude, direction and lateral distribution in the time course with a "measuring bed", a "measuring chair" and a "measuring floor". By the application of biomechanical model calculations the load on the lowest intervertebral disc of the lumbar spine (L5-S1) was determined considering the posture and action force data for every manual patient handling.ResultsThe results of the investigations reveal the occurrence of high lumbar load during manual patient handling activities, especially in those cases, where awkward postures of the healthcare worker are combined with high action forces caused by the patient's mass. These findings were compared to suitable issues of corresponding investigations provided in the literature. Furthermore measurement-based characteristic values of lumbar load were derived for the use in statement procedures concerning the disease no. 2108 of the German list of occupational diseases.ConclusionsTo protect healthcare workers from mechanical overload and the risk of developing a disc-related disease, prevention measures should be compiled. Such measures could include the application of "back-fairer" nursing techniques and the use of "technical" and" small aids" to reduce the lumbar load during manual patient handling. Further studies, concerning these aspects, are necessary.

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Moving patients or other care activities with manual patient handling is characterized by high mechanical load on the lumbar spine of healthcare workers (HCWs). During the patient transfer activity, the caregivers exert lifting, pulling, and pushing forces varying over time with respect to amplitude and direction. Furthermore, the caregivers distinctly change their posture and frequently obtain postures asymmetrical to the median sagittal plane, including lateral bending and turning the trunk. This paper describes a procedure to determine lumbar load during patient transfer supported by measurement techniques and an exemplary application; this methodology represents the basis of a complex research project, the third 'Dortmund Lumbar Load Study (DOLLY 3)'. Lumbar load was determined by simulation calculations using a comprehensive biomechanical model ('The Dortmunder'). As the main influencing factors, the hand forces of the caregiver exerted during typical patient transfers and the posture and movements of the HCW were recorded in laboratory studies. The action forces were determined three-dimensionally with the help of a newly developed 'measuring bed', two different 'measuring chairs', a 'measuring bathtub', and a 'measuring floor'. To capture the forces during transfers in or at the bed, a common hospital bed was equipped with an additional framework, which is attached to the bedstead and connected to the bedspring frame via three-axial force sensors at the four corners. The other measuring systems were constructed similarly. Body movements were recorded using three-dimensional optoelectronic recording tools and video recordings. The posture and force data served as input data for the quantification of various lumbar-load indicators.

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