Experimental And Clinical Research On Variations Of Intracranial Pressure Pre And Post Decompressive Cranioectomy

Part1Experimental study on intracranial pressure after decompressive craniectomyObjective:To observe variations of intracranial pressure (ICP) pre and post decompressive craniectomy(DC), and to investigate the impact of DC on ICP alteration and the cranial compliance.Methods:The surgical procedure of DC was operated on the adult skull mold, ICP was monitored, and the pressure-volume curve was plot.Results:The initial ICP of the mold filled with diluted contrast was3mmHg, and the baseline volume was1120ml. The ICP began to rise slowly below60ml of additional cranial contents, but the ICP rose sharply above90ml of additional cranial contents. Temporal-parietal bone flaps of different sizes (26332,37,42,47,56,76,95,113,131cm2) generated different abrupt-point related volume:100ml,105ml,110ml,115ml,120ml,127ml,140ml,155ml,156ml,158ml. Frontal bone flaps of different sizes (26,32,37,42,47,56,76,95cm2) generated lower abrupt-point related volume:85ml,89ml,94ml,99ml,105ml,112ml,120ml and133ml respectively. But parietal-occipital bone flaps of different sizes (26,32,37,42,47,56,76,95cm2) generated nearly the same abrupt-point related volume as98ml,103ml,108ml,113ml,120ml,128ml,140ml, and156ml respectively. After different sizes of decompressive craniectomy at different levels of intracranial pressure, ICP decreased rapidly. While below25mmHg nearly every bone flap could reduce ICP to baseline which is3mmHg. When the ICP was above30mmHg, larger bone flaps led to greater ICP decrease. When the intracranial pressure was higher than40mmHg,5ml of cranial volume could make ICP drop sharply to3-5mmHg.Conclusion:The pressure-volume curve of model was in accordance with the physiological pressure-volume curve basically. DC could quickly and effectively reduce ICP; Under high ICP, larger bone flap produced larger compensatory volume and greater decline of intracranial pressure; The pressure-volume curve altered after decompressive craniectomy. The larger the bone flap was, the pressure-volume curve shifted more obviously to the right along the horizontal axis, and more compensatory cranial volume was gained, accordingly the cranial compliance was better. However, the decompressive effect decreased when the temporal-parietal bone flap was beyond the parietal tuber. The decompressive effect of the simple frontal bone flaps was poorer than temporal-parietal flaps or the parietal-occipital flaps. When the ICP was high, mini-loss of intracranial volume could gain great decrease of ICP.Part2Clinical study on variations of intracranial pressure after decompressive craniectomy in severe traumatic brain injury Objective:To study the pathophysiology variation of ICP after decompressive craniectomy (DC) in severe traumatic brain injury (TBI), and to explore the relationship between ICP alteration and DC. To identify the roles of decompressive craniectomy and intracranial pressure monitoring in the procedure of treating patients with severe traumatic brain injury.Methods:Fourteen patients with severe traumatic brain injury gained fronto-tempo-parietal DC or tempo-parietal DC. The pre-operation states included diffuse brain swelling or diffuse axonal injury with severe disability or deteriorating neurological disorders. The ICP was monitored before and after DC, right after the dura opening, and24h after DC. The survivors were followed up by structured telephone interview and the outcomes were ranked by GOSE (Extended Glasgow outcome scales, GOSE). We defined unfavorable outcomes as patients with scales5-8and unfavorable outcomes with scales1-4.Results:All the14patients got the operations of ICP transducer-probe implantation and decompressive craniectomy. The ICP before craniectomy, after craniectomy, right after dural opening, and24h after DC were38.9±6.2mmHg,22.5±3.3mmHg,6.8±2mmHg,12.2±3.7mmHg respectively. Six months later, Patients were followed up and ranked by GOSE (Scales1for three, Scales2for two, Scales2-4for two and Scales5-8for seven). That was,3died,2at vegetable state,2disabled and7with common life.Conclusions:Decompressive craniectomy could effectively reduce the malignantly increased intracranial pressure. The larger the bone flap was, the greater the compensatory space was got, and the decompressive effect was more obvious. Because ICP decreased significantly after the Dura opening, the Dura should be expanded completely to reduce ICP and gain more compensatory space. Monitoring of ICP was beneficial for the treatment of patients with severe traumatic brain injury, and may predict favorable outcome. As to what is the role of Decompressive Craniectomy in the treatment of sTBI, it is controversial, so more randomized controlled tests (RCT) are need to carry out. And also more efforts should be put into the study of the mechanism of cerebral edema and the exploration of new medicine.