事故傷害是兒童死亡原因的第一位，而墜落(fall)是僅次於交通意外之事故。墜落事故導致之傷害中頻率最高、嚴重性最大者為頭部傷害，嚴重之頭部傷害不僅造成死亡，存活者可能發生心智或肢體上諸多後遺症。愈小之兒童因生理系統尚未發展成熟、缺乏安全認知，愈容易在遊戲或日常生活之中發生墜落事故，地點以居家環境及遊戲場為主。人體自多少高度墜落、且頭部碰撞地面會產生致命之頭部傷害？臨床醫學界仍處於爭論之中。這問題之關鍵在於頭部碰撞過程中承受之最大角速度、角加速度、線性加速度及HIC 值未能得知；而影響頭部受力之主要因子包括：墜落高度、地面性質、頸部作用與軀幹質量等因素。然而，生物力學界尚待針對兒童墜落事故之頭部傷害詳加探討、釐清傷害機轉與準據，進而謀求防護之道。應用方面，兒童遊戲場地面使用軟性材料作為防護頭部傷害之鋪面，現有之檢測標準僅針對鋪面材料之衝擊力學性質作評估，而不是以實際人體墜落時頭部受力及頭部傷害發生率為考量，因此檢測標準之規範是否能達到預期之防護目的仍有待釐清。本計畫延續此刻進行之墜落事故電腦模擬研究，並以墜落案例資料為基礎，以兩年時間設計、製作兒童人偶模型，進行人偶模型之墜落實驗，探討兒童墜落事故中頭部傷害問題。第一年：收集、訪視兒童墜落事故之臨床案例，建立案例之資料庫；建立一台具人體頭頸部動態特性之6 歲兒童墜落測試人偶，並設計一只量測人偶頭部角加速度之換能器(transducer)，將此人偶模型作為下一年度實驗研究之基礎。第二年：持續建立案例資料庫；以兒童人偶墜落實驗、配合資料庫案例，探討兒童墜落事故頭部傷害之機轉與準據；並運用人偶實驗模型探討遊戲場鋪面之防護效能。研究成果除了頭部傷害之學術探討外，可作為設置兒童遊戲場鋪面及制訂標準之參考。 Injuries have been recognized as leading cause of death in children. Falls are the second leading event among childhood accidents and frequently result in head injury. Severe head injury is not only a cause of death, but also a high incidence of complaints in the survivals. In children, the cognitive ability in terms of hazard awareness and the neuromuscular system are not yet sufficiently developed. Thus, falls occur frequent in childhood and take mainly at home and playground. In the literature surveys, one finds that there is a debate about the fall height needed to sustain severe head injury. The main reason is that the tolerance of head on peak angular acceleration, linear acceleration and HIC indexes during head impact is unclear. As a matter of fact, the fall height, properties of ground surface, neck and torso effects would markedly affect the loading of head. However, few studies based on biomechanics methods have evaluated the child head injuries in fall accident, the mechanism and criteria of head injury were unclear. In playground safety, protective surfacing established around the equipment against head injuries. However, standard specification of the surfacing merely demanded the impact-absorbing properties of the material rather than evaluating the realistic loading of head and incidence of head injury. The objectives of this two-year proposal are to study the above-mentioned problems by combining children fall accident reconstruction with drop experiment of child dummy. In first year, a data bank of head-first fall accident reconstruction would be established to study the head injuries; a fall dummy based on head/neck complex of Hybrid III 6-year-old child dummy and a transducer for evaluating angular acceleration of head will be established. In second year, mechanic response of head-neck complex during impact and head injury criteria in children falls will be investigated by using the child dummy, in which the initial conditions and contact surface based on the data bank. Moreover, the child dummy will be applied to evaluate the protective performance of playground surfacing against head injury in fall accident. The outcomes of this project will not only be an academic research but also the improvement of the standards for head protection.
