User:Samerhoz/sandbox

Cisternostomy: Cisternostomy is defined as opening the supratentorial basal cistern on the infratentorial subarachnoid space through fenestration of the proximal Sylvian, optic-carotid, chiasmatic and suprasellar cisterns with fenestration of the liliequist’s membrane, a novel technique that incorporates the knowledge of skull base and microvascular surgery, has been recently proposed and was found to decrease brain swelling, mortality, and morbidity. CSF-shift-edema: Recently, it has been suggested that glymphatic removal of excess interstitial fluid is likely decreased following injury or infarction. Accordingly, an additional source of brain swelling may be implicated in the pathophysiology of post-traumatic swelling. Briefly, following TBI, CSF could be shifted from the cerebral cisterns to the brain, leading to a severe brain swelling. This phenomenon of “CSF-shift edema,” resulting from a movement of the cisternal CSF into the brain, would occur through the para-vascular spaces. In this regard, it is assumed that, following TBI, there is an increased pressure in the subarachnoid compartment, as a consequence of post-traumatic subarachnoid hemorrhage. Such increased pressure would promote the CSF- shift edema that, in turn, would exacerbate the brain swelling and allow the intra-cerebral pressure to steeply risk. The possible role of para-vascular spaces in TBI has already been suggested. It has been reported that TBI can cause a long-lasting impairment of glymphatic clearance of waste products such as b-amyloid, and may be responsible for chronically enlarged Virchow-Robin space, often seen in these patient groups.

Cisternostomy, defined as the opening of the basal cisterns to atmospheric pressure, results in a backward shift of fluid from the edematous brain parenchyma to the cisterns through the para-vascular spaces. Cisternostomy would create a pressure gradient, allowing the ISF to be shifted from the edematous brain toward the lower atmospheric pressure of the opened basal cisterns through the paravascular pathway. This surgical procedure, therefore, would reverse the direction of the “CSF-Shift edema,” thus alleviating the brain swelling. In addition, the movement of fluid from the injured brain towards the cisterns, achieved by cisternostomy, washes out lactate and other harmful sub- stances like excitotoxic neurotransmitters, free oxygen radicals, and others from the interstitium. Those substances would otherwise accumulate in the brain interstitium, enhancing vaso- genic and/or cytotoxic brain edema, cellular damage, inflammation cascade, and apoptosis