الفهرس 
Introduction and Aim of The workOnly 14 pages are availabe for public view
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Abstract
ICP was noted to be the most significant factor in predicting outcome following traumatic brain injury (TBI).
Although many medical modalities were used for the control of elevated ICP caused by S-TBI, all of these measures failed to control the elevation of ICP in many conditions.
The surgical intervention in the form of DC was tried in order to control the refractory elevation of ICP since the beginning of neurosurgery, as a palliative treatment to relieve high intracranial pressure in patients with inoperable brain tumors, hydrocephalus, or head injuries, and since 1901, when it was described for treatment of post-traumatic brain oedema which was refractory to conventional medical treatment, interest in the procedure has either increased or decreased at various times.
In the last two decades, the interest in this procedure increased more and more, and the number of the published articles in the medical literature regarding the role of DC in the management of patients with severe traumatic brain injury has been geometrically increased.
Most of published articles refere to decompressive craniectomy as an effective method for management of rises in intracranial pressure (ICP) that are refractory to medical therapy. Randomised controlled studies have demonstrated favourable outcomes in traumatic brain injury.
In addition, numerous experimental models have demonstrated that DC reduces secondary brain injury. These effects are thought to be the result of an increase in collateral cerebral circulation, reduction in tissue edema, and improvement in oxygenation and energy metabolism New clinical research has provided evidence that decompressive craniectomy may improve O2 delivery to brain cells when the incidence of cerebral ischemia is at its peak.
Furthermore, postoperative radiological evaluation in cases of DC shows amelioration of midline shift, and improvement of the preoperative compression of the basal cisterns.
Thus, DC interrupts the vicious cycle of intracranial hypertension via the impairment of the cerebral perfusion pressure (CPP), which inevitably results into further ICP increasing and may eventually lead to cellular injury and death.
Inspite of all of these vital effects, the final outcome after decompressive craniectomy in cases of refractory increase in intracranial pressure caused by traumatic brain injury still a matter of controversy, so we aim in this study to review the literature discussing the evaluation of outcome of decompressive craniectomy as a treatment of elevated ICP after sever head injury and factors affecting it.
The issue of unsatisfactory outcome after decompressive craniectomy inspite of its almost sure effect in lowering elevated ICP, it’s favourable effect in brain tissue oxygenation, and it’s effective role in prevention of brain herniation was a matter of much interest by most of studies planned for evaluation of outcome of this procedure in case of traumatic brain injury.
It was noted that the good selection for patients which would subjected to DC, good timing of surgical intervention, the surgical technique used for decompression, the threshold of ICP elevation at which surgical decompression should be done, and avoidance of post operative complications as much as possible, are the most important determinant factors for better outcome.
Regarding patient selection, the literature indicate that age of the patient is one of the most important factors determining the outcome of decompressive craniectomy, with better result in pediatric population below the age of 18. Some authors states that decompressive craniectomy in pediatric traumatic brain injuries is no longer an intervention used as a last resort but an effective first line treatment which have to be considered.
On the other hand, most of studies states that decompressive craniectomy above the age of 50 is associated with poor outcome, with high incidence of post operative complications, while its not indicated in patients above the age of 65 after sever head injury because of it’s associated serious complications and high mortality rate post operative.
In addition, the literature states that the conscious level of the patient preoperative is one of the most important outcome determinant factors of decompressive craniectomy. It was found that patients with GCS below 8 are susceptible to more complications and worse outcome than patients with GCS of 8 or higher preoperative.
The presence of signs and symptoms of brain herniation is one of the poor outcome indicators as stated by literature, which recommend surgical intervention in the form of DC before incidence of brain herniation.
Also, the chances of survival following DC in patients with primary brainstem injury are greatly reduced, so several authors consider this a contraindication to this form of intervention.
The degree of elevation of ICP after head injury plays a role in outcome of decompressive craniectomy as some authers states that ICP Should preferably be less than 40 mm Hg at the time of decompression. Clinical data show that patients with sustained ICP of more than 40 mm Hg did comparatively poorly after DC as compared to those whose ICP was lower at the time of surgery.
The degree of midline shift in the initial computed tomography has been found to correlate well with the quality of outcome following DC. Preoperative midline shift greater than 1 cm is believed to be a significant predictor of poor outcome.
Timing of the operation still a point of controversy, with some papers states that so early surgical intervention is associated with more unfavorable outcome and more complications which might be avoided if the medical treatment had the full chance to relieve the elevation of ICP, while some other studies recommend surgical intervention within 48 hours, and states that early DC is associated with better outcome.
There is no consensus about the threshold of ICP elevation at which DC should be done, Many investigators suggest that a single episode of ICP> 20 mmHg lasting at least for 5 minutes is an indication for performing DC, while others suggest a higher ICP threshold of 25 to 30 mmHg lasting for at least one hour.
The technique by which surgical decompression is achieved is one of the most important determinant factors for outcome of DC. Clinical data shows better outcome with large decompresssive craniectomies as large fronto-tempro-parietal craniectomy (hemicraniectomy) done when lesion or swelling is confined to one cerebral hemisphere, and bifrontal or bilateral hemicraniectomy done for relieve of diffuse brain swelling.
It was found that its so important to achieve good decompression for temporal lobe to avoid uncal herniation, and good decompression for the anterior cranial fossa till its base to avoid subfalcine herniation.
Most of studies state that opening of the dura is very important to achieve good decompression, with controversy about the ideal technique should be used for this purpose . Some authors prefer to perform a wide opening to the dura in a cruciate manner accompanied by augmentative duroplasty with the introduction of the vascular tunnel technique in order to avoid compression of the superficial cerebral blood vessels at the edges of the durtomy. This technique gives the brain a wide area to swell without being compressed. Another technique is introduced by some other authors to avoid herniation of brain tissue through the craniectomy edges by doing multiple stabs in the dura, which make the more elastic and more liable to expand without herniation of the brain and compression of it’s superficial blood vessels.
In conclusion, the outcome of decompressive crainectomy following traumatic brain injury is generally favourable as it was stated by most of studies done to evaluate its outcome and factors affecting it, however, the outcome and indicactions of this procedure still a matter of controversy, waiting for the results of the ongoing international, multicentre, prospective, randomised, controlled trial on the role of decompressive craniectomy in management of severe uncotrolabe elevation of ICP (RESQUEicp), in order to find an answer to the controversial questions related to the outcome of decompressive craiectomy as a treatment of uncontrollable elevation of ICP after traumatic brain injury.