Repositioning a slumped person in a wheelchair. A biomechanical analysis of three transfer techniques

The purpose of this study was to determine the effect of three lifting techniques (unassisted lift, vertically assisted lift, and horizontally assisted lift) and two patient masses (65 kg and 75 kg) on loads acting on the lifter's spine when repositioning a wheelchair bound patient to a more upright sitting position. A static biomechanical model was used in conjunction with ground reaction force and videographic data to estimate compression and shear forces at the lumbosacral (L5/S1) joint. Results indicated that: L5/S1 compression forces associated with both unassisted and assisted transfers were of sufficient magnitude to warrant mechanical assistance; the two person technique with the assistant pushing the legs toward the back of the chair was associated with the lowest spinal loads; and L5/S1 compression forces were significantly greater for the vertically assisted lift compared to the unassisted lift. If a manual transfer is to be performed, the horizontally assisted lift is recommended to minimize loads on the lumbar spine of the lifter.