Reduction of intracranial pressure Though the procedure is considered a last resort, some evidence suggests that it does improve outcomes by lowering
intracranial pressure (ICP), the pressure within the skull. Raised intracranial pressure is very often debilitating or fatal because it causes compression of the brain and restricts
cerebral blood flow. The aim of decompressive craniectomy is to reduce this pressure. The part of the skull that is removed is called a bone flap. A study has shown that the larger the removed bone flap is, the more ICP is reduced.
DECRA trial In March 2011, investigators from Australia and several other countries published the results of the DECRA trial in
The New England Journal of Medicine. This was a randomized trial comparing decompressive craniectomy to best medical therapy run between 2002 and 2010 to assess the optimal management of patients with medically refractory ICP following diffuse non-penetrating head injury. The study investigators found that decompressive craniectomy was associated with worse functional outcomes, as measured by a standard metric, than best medical care. There were no differences in deaths between groups. However, the results of the DECRA trial have been rejected or at least questioned by many practicing neurosurgeons, and a concurrently published editorial raises several study weaknesses. First, the threshold for defining increased ICP, and the time allowed before declaring ICP medically refractory, are not what many practicing physicians would consider increased or refractory. Second, out of almost 3500 potentially eligible patients, only 155 patients were enrolled, showing that the study cannot be generalized to all patients with severe non-penetrating brain injury. Lastly, more subjects in the craniectomy group had unreactive pupils than patients in the medical therapy group after randomisation and before surgical intervention; thus making this a possible confounding factor.
Other effects In addition to reducing ICP, studies have found decompressive craniectomy to improve
cerebral perfusion pressure The procedure is recommended especially for young patients in whom ICP is not controllable by other methods.
Children In severely head injured children, a study has shown that decompressive craniectomy resulted in good recovery in all children in the study, suggesting the procedure has an advantage over non-surgical treatment in children. In one of the largest studies on pediatric patients, Jagannathan et al. found a net 65% favorable outcomes rate in pediatric patients for accidental trauma after craniectomy when followed for more than five years. Only three patients were dependent on caregivers. This is the only prospective randomly controlled study to date to support the potential benefit of decompressive craniectomy following traumatic brain injury. ==Follow-up treatment==