普通型車いすシートのたわみが臀部ずれ力推定値に与える影響

本研究は, 普通型車いすシートのたわみが安楽座位時の臀部ずれ力推定値に与える影響を検討する目的で行った. 対象は健常成人男性14名(20.6±0.6歳)であった. 実験は, シートのたわみを調節することによって3条件(たわみ小, 中, 大)で行った. ずれ力の推定には筆者らの実験モデルを用いた. 統計学的解析は一元配置分散分析を用い, 3条件間で比較した. その結果, 臀部ずれ力推定値は「たわみ小」では47.9±7.0N, 「たわみ中」は42.8±4.7N, 「たわみ大」は39.8±6.6Nであり, 「たわみ小」と「中」の間(p<0.05)と, 「たわみ小」と「大」の間(p<0.01)に有意差が認められ, たわみが大きいほど, 即ち脊柱後彎頂点より相対的背もたれ高が高くなるほど臀部ずれ力は低値を示していた. 本研究により, 長時間の車いす座位をとる患者の車いすを考えるにあたっては, 脊柱後彎頂点と相対的背もたれ高との関係を考慮したたわみ量の調整・再検討が褥瘡予防の観点から重要であることが明らかとなった.
The purpose of this study was to investigate how deflection of a standard-type wheelchair seat would influence the estimated shear force on the buttocks in comfortable wheelchair sitting. Fourteen healthy males aged 20.6±0.6 years without pathologies in the leg and/or trunk participated in this study. The study was conducted under three conditions, i.e. small, medium, and big deflection, by controlling the deflection of the seat. The shear force on the buttocks was estimated using an experimental model proposed by us. For statistical analysis, a ONEWAY ANOVA was used with the level of significance at p value below .05 level. The results showed that the estimated shear force on the buttocks was 47.9 ± 7.0 N with the small deflection, 42.8±4.7 N with the medium deflection, and 39.8 ± 6.6 N with the big deflection. There was a significant difference in the estimated shear force between the small and medium (p<.05), and small and big deflections (p<.01). The estimated shear force on the buttocks was low if the height of the relative backrest the higher than the top of the spinal kyposis. This study suggested that from the viewpoint of preventing decubitus ulcers in wheelchair users who need to sit in a wheelchair for long periods, it is important to coordinate and re-examine the deflection of the seat and the height of the relative backrest in relation to the top of the spinal kyposis.