颅内压变化引起的颅骨表面应变分析

Strain analysis on the superficial surface of skull as intracranial pressure changing

  • 摘要: 成年人顶部的正常颅内压平均值约为3.62kPa,颅内压波动2.5kPa左右时,颅内压轻度异常;当波动值达到3.5kPa左右时,出现脑震荡的症状;当波动值达到5kPa或更高时,人头颈部达到危重度伤.本文在颅内压正常波动值范围内,通过有限元MSC-PATRAN/NASTRAN软件分析了颅骨三层复合结构以及颅骨与硬脑膜组成的四层复合结构的表面应力和应变;同时,随颅内压变化进行了猪颅骨片,以及模拟人体颅脑真实受力的人颅骨和猪颅骨球冠应变实验.分析结果表明:当颅内压轻度异常时颅骨外表面产生的应变约为1.5×10-6,脑部出现脑震荡的症状时颅骨外表面产生的应变约为2.5×10-6,头颈部达到危重度伤时颅骨外表面产生的应变约为4×10-6.因此,随颅内压的变化颅骨外表面的应变是可测的,且在仪器检测范围内;本文所提出的微创颅内压应变电测法是可行的,即在颅骨外表面粘贴应变片,随颅内压的变化测颅骨应变,通过计算机进行数据处理获得颅内压变化量的方法.与临床上测量颅内压时钻孔或穿刺等方法比较,应变电测颅内压法对患者造成的损伤很小,属于微创或无创范围,具有安全易操作、减少感染、对患者创伤小、可长期测量等特点.

     

    Abstract: The average intracranial pressure (ICP) of parietal position for adults is normally about 3.62 kPa. The brain appears to be mild injury as the ICP variation is about 2.5 kPa, moderate injury as the ICP variation is about 3.5 kPa, and severe injury as the ICP variation is about or more than 5 kPa. This paper analyzed the stress and strain on the exterior surface of human skull and the composite structure composed by skull and duramater with the finite-element software MSC-PATRAN/NASTRAN. The experiments were carried out on the strains of porcine skull slices, porcine and human coronal skulls to simulate the actual situation in the human craniocerebra. The results show that the strains of mild injury, moderate injury and severe injury are 1.5×10-6, 2.5×10-6 and 4.0×10-6 respectively. It indicates that the strains on the exterior surface of skull are measurable and all within the range of instrument test. The minitraumatic method to measure ICP is feasible by pasting strain foils on the exterior surface of skull, by which ICP variation can be obtained through the corresponding operation to the strain of skull. Compared with the clinical methods of punching in the skull or puncturing in the spine cord, the strain-electrometric method is safe, simple, minitraumatic, accurate and feasible.

     

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