the modern concept of decompression for traumatic brain injury ( tbi ) was introduced by harvey cushing before world war i . the monro - kellie hypothesis dictates that the amount of space within the skull is constant ; therefore , when the pressure is raised death occurs by herniation when the capacity for adjustment by fluid shifts from the cerebrospinal fluid and vascular compartments are already maximized . increasing the skull size by removing bone and opening the dura delays or prevents these limits from being reached . however , in the 90 years since cushing made these observations , medical , radiographic , and surgical advances in the management of tbi have obviated the need for an aggressive surgical approach in all but a minority of cases . in spite of the ability to control intracranial pressure ( icp ) elevation in most cases with removal of mass lesions , osmotic diuretics , ventricular drainage , sedative / hypnotic agents , and prevention of hypercapnea , occasional cases occur in which icp elevation accelerates in spite of maximal conservative medical therapy , and then so - called heroic measures are employed . these are considered at the ' option ' level in the american association of neurological surgeons criteria for management of severe brain injury   because no large randomized trial has proven their efficacy . in the pediatric population , ruf and colleagues   as well as taylor and associates   have addressed the issue of using decompressive craniectomy as a more formal part of a head injury protocol before going to other ' option ' therapies once icp elevation is affirmed . bifrontal decompressive craniectomy is an aggressive approach described by kjellberg and prieto   before the era of modern neuroimaging with computed tomography . this approach is particularly useful in the pediatric population , in which diffuse injury without mass lesions and with icp elevation is relatively common . hemicraniectomy represents a large cranial and dural decompression , often associated with removal of mass lesions such as subdural hematoma or traumatic intracerebral hematoma . bitemporal decompressions are unilateral or bilateral bony decompressions designed to take the pressure off the temporal lobes to prevent uncal herniation , and have been used in other cranial conditions such as pseudotumor cerebri . gower and coworkers   reported 40% mortality and 50% favorable outcome in a study of subtemporal decompression for icp control in 10 patients with closed head injury who had failed medical therapy , including barbiturate coma . cerebellar decompression for mass lesion is a standard neurosurgical response to any process in the posterior fossa ( hemorrhage , tumor , infection , or stroke ) that threatens cerebellar tonsillar herniation . the paper by ruf and colleagues   purports to be a pilot study employing decompressive craniectomy in a standardized approach following development of medically refractory icp in the pediatric population . of the six cases presented , three involve bifrontal craniectomies : two unilateral and one cerebellar . the patients underwent surgery between hospital days 1 and 6 and had icp as low as 20 and as high as 70 mmhg . glasgow outcome scale findings are not provided ; however , at least four of the patients appeared to have no more than a mild disability . they randomly assigned 27 patients to craniectomy or medical management alone and found that the craniectomy patients obtained lower icp and better outcomes . in the control group only 14% of children had a favorable outcome , as indicated by 6-month glasgow outcome scale scores . that study suggested ( as statistical significance was not met because of the small numbers ) that aggressive early decompressive craniectomy may benefit this patient group . polin and colleagues   explored the use of decompressive bifrontal craniectomy in victims of tbi . this group used a cohort control matching protocol employing the traumatic coma databank to match subjects based on age , icp , radiographic findings , and admission glasgow coma scale score . in a conditional logistic regression analysis comparing all 92 control patients with the craniectomy population , those investigators detected a significant influence of the operation on favorable outcome ( wald = 6.097 ; p = 0.014 ) . medical management alone carried a 3.86-fold greater risk for unfavorable outcome than did decompressive craniectomy . a pediatric subgroup was identified that appeared to benefit from the procedure ( p = 0.025 ) . the authors further identified a subgroup of patients who received surgery within 48 hours and who never had sustained icp elevation over 40 mmhg . the pediatric patients in this subset had favorable outcomes in 8 out of 10 cases , with statistically improved outcomes compared with control individuals . we think it unlikely that decompressive craniectomy will become a commonplace management scheme for tbi . standard medical management allows control of icp while preserving the ability to conduct a neurologic examination . the role of decompression as compared to that of other ' option ' therapies , such as hypothermia and barbiturate coma , is still evolving . the advantage of decompressive craniectomy over these other therapies is the rapid and generally permanent decline in icp , maintenance of neurologic status , and even the ability to obtain a neurologic examination after the procedure is performed . the disadvantages are the need for at least two surgeries ( one to replace the bone flap ) and the theoretical development of bifrontal contusions after decompression . decompressive hemicraniectomy and duraplasty for evacuation of mass lesions and management of unilateral hemispheric swelling is more widely accepted in head injury management . most surgeons have first hand experience with delayed cerebral swelling after removal of a subdural hematoma , presumably caused by venous infarction and/or cerebral contusion . some will remove the bone flap prophylactically after such operations and others the paper by ruf and colleagues   provides more ammunition for the argument that decompressive craniectomy is a safe and effective method of icp reduction in severe tbi with associated icp elevation refractory to standard management . however , this approach remains a second tier strategy recommended only at the option level . for this scheme to become more prevalent , a large - scale multicenter trial such as that being planned by coplin and colleagues   would be necessary .