Surgical brain injury (SBI) is a form of brain trauma caused by various forms of neurosurgical interventions including brain tumor excision, evacuation of intracerebral hemorrhage and brain lobectomy (e.g., in epilepsy surgery). Cerebral edema and brain swelling typically occurs soon after SBI and commonly peaks on post-operative day 3 to 7. SBI may cause secondary damages due to disruption of the blood–brain barrier (BBB), release of inflammatory cytokines (e.g., tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, toll-like receptor (TLR-2) and TLR-4,) as well as increased expressions of Fas and Fas-L, free radical overload, dysfunctions of membrane ionic pumps and many other pathophysiological changes. Severe cerebral edema may eventually lead to elevated intracranial pressure (ICP), neurological deterioration or even death. Other long-term effects in survivors include sensori-motor and cognitive dysfunctions due to secondary, delayed degenerative changes. Given the large number of routine neurosurgical operations performed world-wide on a day-to-day basis, the prevention of SBI is just as important as the treatment of accident-related traumatic brain injury (TBI). The latter differs from SBI in that it is not amendable to pre-emptive therapy whereas SBI can theoretically be prevented, at least during routine elective surgery. The issue of how best to prevent cerebral edema and secondary damages in these situations are critical and deserve our research effort.
Traditionally, dexamethasone (DEXA) and other glucocorticoids (GCs) have been used as adjunctive agents during neurosurgical operations to reduce brain edema, maintain BBB integrity and minimize inflammatory responses. It has also been used in TBI patients since 1960s. However, several major studies conducted between 1979 and 2004 demonstrated that the use of GCs in severe TBI had no beneficial effect and may in fact be deleterious. Given that SBI is essentially a form of brain traumaalso, there is no logical reason why GCs should be beneficial in SBI. In this respect, our group has been investigating alternative strategies for the treatment of SBI.