Did you know? Our brain is actually “floating” in a fluid environment that protects it from impacts through the cushioning effect of the fluid, while providing nutrients and maintaining metabolism, and this magical fluid is our brain crest fluid. Surgery causes the “barrier” to be opened. Normally, the brain crest fluid is completely isolated from the outside world by several layers of meninges, but since surgery must break through the meninges to reach brain tissue, this barrier can be opened, providing an opportunity for bacteria to enter the brain and cause serious infections. Increased intracranial pressure causes the “breach” to leak again At the end of the surgery, the surgeon will repair the breach in the meninges, but this must be done “drip-free”, which as you can imagine is very difficult. Most of the time, the meningeal rupture will heal on its own with the help of your surgeon; however, anything that raises your intracranial pressure, such as prolonged coughing, sneezing, heavy lifting, prolonged desk work, constipation, etc., or if you blow your nose hard, can cause a post-operative crestal fluid leak. It is important to note that some patients, due to the special location of the intracranial tumor, are likely to cause obstruction of the circulation of the cerebral crest fluid, resulting in hydrocephalus and secondary abnormal elevation of intracranial pressure; and some patients, due to postoperative radiation therapy, have local tissue damage – these cases are relatively more prone to cerebral crest fluid leakage and have to be repaired after surgery.