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 .
 more frequently than adults , pediatric victims of severe traumatic brain injury experience diffuse severe cerebral edema without mass lesions . 
 these patients require methods to reduce intracranial pressure quickly and reliably . 
 surgical decompression provides rapid relief of increased intracranial pressure and is an alternative to maximal medical therapy for these individuals . 
 based on previous trials , most of which are anecdotal but now include attempts at case controlled and cohort matched investigations , ruf and colleagues describe a series of six pediatric patients treated with a prospectively implemented protocol of decompressive craniectomy for severe traumatic brain injury . 
 the heterogeneous approaches presented ( which include hemicraniectomy , bifrontal craniectomy , and suboccipital craniectomy ) undermine the applicability of the results . 
 however , this report , coupled with similar papers , does highlight the need for a true controlled trial of this modality to examine whether craniectomy can emerge as more than a second line option for the management of increased intracranial pressure . 
Introduction
Trials of decompressive craniectomy in pediatric patients
Discussion
Competing interests
Abbreviations