实验性脑积水分流后脑顺应性的改变

目的：用梗阻性脑积水犬模型，观察脑积水分流前、后及阻断分流后脑顺应性的变化。方法：随机将成年健康杂种犬18只分为2组。实验组(12只)，向四脑室注入氰基丙烯酸凝胶诱导脑积水，诱导术后第8周，测量实验犬颅内压及其低压（5～15?mmHg）、高压（15～25?mmHg）时的脑顺应性，随后对脑积水犬进行脑室-腹腔分流手术；第10周再次测量分流后的颅内压和脑顺应性，并阻断分流管；第11周做颅内压和脑顺应性的最后测量。实验前和每次测量前，犬进行磁共振成像（MRI）检查。对照组(6只)，仅注入等量的生理盐水。结果：实验组MRI证实有10只犬形成脑积水。分流前的颅内压实验组（9.98±1.84）mmHg明显高于对照组（3.82±1.19）mmHg，P<0.01；分流后颅内压恢复正常（4.28±1.25）mmHg，P>0.05，阻断分流管后很快恢复到分流前状态。高压时的脑顺应性在脑积水分流前、后和阻断分流后3个阶段是逐渐降低的［（0.065±0.008） ml/mmHg，（0.053±0.013） ml/mmHg，（0.032±0.005） ml/mmHg，P<0.05］。结论：犬梗阻性脑积水模型很适合脑积水的病理生理和治疗研究，脑顺应性下降可能是脑积水分流失败后呈急性恶化发病的机制之一。

Changes of brain compliance after ventriculoperitoneal shunt in hydrocephalus

To observe the changes of pre and post ventriculoperitoneal shunt and shunt occlusion on brain compliance in hydrocephalus by using a canine model of obstructive hydrocephalus. Methods： Eighteen adult healthy mongrel dogs, twelve in which was as hydrocephalus models and six as controls, were used in the experiment. Eight weeks after inducement of hydrocephalus, intracranial pressure (ICP) and brain compliance at low (5 15?mmHg) and high (15 25?mmHg) pressure were measured. Following this procedure, ventriculoperitoneal shunts were implanted in all dogs. Two weeks later, the same measurements were repeated, and the shunt systems were occluded. The last measurements were obtained after one week. All dogs underwent magnetic resonance imaging four times before inducement of hydrocephalus and before each measurement. Results: In the experimental group, hydrocephalus confirmed by MRI was successfully induced in ten dogs. ICP of hydrocephalus dogs（9.98±1.84?mmHg）was significantly higher than that in control group（3.82±1.19?mmHg，　P<0.01）. After shunt placement, significant improvement was observed in their hydrocephalus symptoms and in ICP （4.28±1.25?mmHg，P>0.05）. However, shunt occlusion reversed these improvements quickly to the pre shunt status and carried a risk of critical symptoms poor outcomes. Brain compliance measured at high pressure demonstrated a significant gradual decrease at each measurement. Conclusions： The canine model of obstructive hydrocephalus should facilitate the study of the pathophysiology and the treatment of hydrocephalus. The decrease in brain compliance may be one of the factors responsible for the acute pathological changes after thefailure of shunt in hydrocephalus.