| Part Ⅰ The construction of an improved model of acute subdural hematoma in ratsObjective To establish a new improved model of acute subdural hematoma in rats,and to provide a suitable model for the study of brain trauma.Methods Thirty adult male SD rats were randomly divided into two groups.The traditional group was based on Miller’s model construction method,and the improved group was based on the improved needle,injection site,and procedure.The improved model was evaluated by comparing the physiological indexes,behavioral scores,magnetic resonance performance and HE staining results of the two groups of rats.Result The physical signs of the two groups of rats were basically the same.The survival rate in the improved group was higher than that in the traditional group.MRI showed that the hematoma in the improved model was thicker and concentrated at the injection side.He staining indicated that the improved method had less intrusion on the cortex around the injection site and fewer interference factors than the traditional model.Compared with the traditional model,the improved model can better simulate human hematoma,and the model has high success rate,simple operation and good reproducibility.Conclusion The improved model is built on the basis of the traditional model.Although there are differences between human mortality rate and human mortality rate,the improved model is easy to operate and has a better effect in simulating human hematoma.Moreover,the improved model can be applied to more researches such as blood flow study.Part Ⅱ Effect of acute subdural hematoma on cerebral surface blood flow in ratsObjective To investigate the changes of cerebral surface blood flow in rats with acute subdural hematoma.Methods Thirty adult male SD rats were randomly divided into two groups.Grind the7mm×5mm transparent bone window on the top.No hematoma was injected in Sham group.0.2m L group was injected with hematoma volume 0.2m L.The amount of hematoma in 0.4m L group was 0.4m L.Laser speckle imaging system was used to observe the changes of blood flow in superior sagittal sinus,vein and artery on the cerebral surface of the opposite hemisphere of the hematoma through transparent bone window.The blood perfusion rate was calculated preoperatively,postoperatively and at30 min,60min,90 min and 120 min respectively,and the intracranial pressure was monitored.Blood flow changes before and after subdural hematoma and under different hematoma volumes were compared.Result The blood perfusion rates of superior sagittal sinus,vein and artery in the two experimental groups were significantly decreased after operation and 30 min and 60 min after operation compared with those before operation and Sham group.The blood perfusion rates of the superior sagittal sinus at 90 min and 120 min after surgery in the two experimental groups were significantly different from those in the preoperative group and the Sham group,while the differences between veins and arteries were not statistically significant.There was no statistical significance in the preoperative intracranial pressure between the two experimental groups and the Sham group,and the intracranial pressure at each time point after the operation was significantly higher than that before the operation and the Sham group.The two experimental groups were compared with each other,and there was no statistical significance in superior sagittal sinus,vein and artery at each time point.The two experimental groups were compared with each other,and the preoperative difference was not statistically significant.The intracranial pressure at each time point after the operation was significantly different from that of the preoperative group and the Sham group.Summing up the above,after the occurrence of acute subdural hematoma,intracranial pressure increased in rats,and blood flow in the superior sagittal sinus and the cerebral surface veins and arteries on the opposite side of the hematoma decreased significantly for a certain period of time.The veins and arteries could be compensated for recovery 90 minutes after the formation of the hematoma,while the superior sagittal sinus could not be recovered.In rats,when the hematoma volume was below 0.4m L,the degree of blood flow decline was not related to the amount of hematoma.Conclusion In conclusion,acute subdural hematomas can cause both high intracranial pressure and impaired blood circulation to the brain,which may contribute to secondary damage.Therefore,in the clinical treatment of subdural hematoma,preoperative attention should be paid to the patient’s cerebral circulation through imaging and other means,in order to avoid postoperative complications such as cerebral circulation ischemia and cerebral infarction.Part Ⅲ Changes and mechanism of cerebral surface blood flow during acute intraoperative brain bulge in ratsObjective To explore the mechanism and influence of cerebral surface blood flow changes in rats with intraoperative acute intraoperative brain bulge,and to provide a new idea for the treatment strategy of intraoperative intraoperative brain bulge.Methods Eighteen adult male SD rats were randomly divided into two groups.After the subdural hematoma model was made in rats of the three groups,a 2mm bone hole was drilled 2mm behind the coronal suture and 4mm to the left of the sagittal suture,and a water-injectable balloon was inserted into the epidural space.Then,a bone window with a size of 10mm×5mm was opened in the injected hemisphere of the hematoma.The skull was removed,and the dura was slowly and gradually cut open and the hematoma was removed.In Sham group,no operation was performed after hematoma clearance.In 0.05 m L group,after the hematoma was cleared,the balloon was slowly filled with 0.05 m L of water,and the brain tissue bulge was induced for 10 minutes before the balloon was removed.In the 0.1m L group,after the hematoma was cleared,the balloon was slowly filled with 0.1m L of water to induce the cerebral histocele,and the balloon was removed 10 minutes later.Laser speckle imaging system was used to observe the changes of blood flow in cerebral surface veins and arteries on the side of hematoma clearance through bone window.The blood perfusion rate was calculated after hematoma clearance,after balloon filling,10 min after balloon filling,10 min after balloon removing,and 10 min after balloon removing,respectively.The changes of cerebral surface blood flow before and after intraoperative brain bulge,before and after removing intraoperative brain bulge factors and under different degrees of intraoperative brain bulge were compared.Result After balloon filling and 10 min after balloon filling,venous and arterial blood flow decreased significantly in two experimental groups.After balloon removal and10 min after balloon removal,the blood flow of veins and arteries decreased significantly compared with that before operation,while the blood flow of veins and arteries increased significantly compared with that after balloon filling and 10 min after balloon filling.The intracranial pressure increased significantly after balloon filling,which was higher than normal intracranial pressure.The intracranial pressure decreased significantly after balloon removal and was lower than normal.Compared with the two experimental groups,there was no statistically significant difference in venous and arterial blood flow after hematoma clearance.There were significant differences in venous blood flow at each time point after balloon filling and balloon removal,while there was no statistical significance in arterial blood flow difference.After hematoma clearance,there was no significant difference in intracranial pressure between the two experimental groups.There were significant differences in intracranial pressure at each time point after balloon filling,but no significant differences in intracranial pressure at each time point after balloon removal.Summing up the above,venous and arterial blood flow decreased significantly with cerebral tissue bulge.If the brain tissue continues to bulge,this circulatory disorder will persist.When the inducement of intraoperative brain bulge is removed in time and the intracranial pressure is reduced,this circulatory disorder can be relieved,but it cannot be restored to the state without intraoperative brain bulge in a short time.There was no significant difference between different degrees of intraoperative brain bulge in the decrease of arterial blood flow,but there was a significant difference in the decrease of venous blood flow.Conclusion The more severe the intraoperative brain bulge is,the more severe the cerebral blood circulation disorder is,and the venous circulation disorder is more significant than the arterial circulation disorder.Therefore,investigators need to pay attention to the relationship between cerebral blood circulation and intraoperative acute intraoperative brain bulge,especially venous circulation.Cerebral circulation disorders may be intercausality with intraoperative acute intraoperative brain bulge,which also suggests that clinicians should pay attention to cerebral circulation problems in patients with craniocerebral injury before surgery,and should prevent or deal with cerebral circulation disorders in time during surgery and follow-up treatment.If intraoperative acute intraoperative brain bulge still occurs,the cause should be clarified as soon as possible.Removing the inducement can alleviate the circulatory disorder as far as possible and avoid a more serious vicious circle. |
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