Decompressive craniectomy for the management of patients with refractory hypertension: should it be reconsidered?

Decompression craniectomy after traumatic brain injury: recent experimental results

Among the secondary events occurring after traumatic brain injury (TBI) pathologically increased intracranial pressure (ICP) correlates most closely with poor outcome. In addition to infusion of hypertonic solutions, e.g. mannitol, and other medical measures, decompression of the brain by surgical removal of a portion of the cranium (craniectomy) has been used for many decades as an intuitive strategy for the treatment of post-traumatic ICP increase. The lack of evidence-based clinical and controversial experimental data, however, resulted in decompressive craniectomy to be recommended by most national and international guidelines only as a third tier therapy for the treatment of pathologically elevated ICP. Ongoing clinical trials on the use of decompressive craniectomy after TBI may clarify many aspects of the clinical application of this technique, however, some important pathophysiological issues, e.g. the timing of decompression craniectomy, its effect on brain edema formation, and its role for secondary brain damage, are still widely discussed and can only be addressed in experimental settings. The aim of the current review was therefore to summarize and discuss recent experimental data dealing with the use of decompression craniectomy following TBI. The present results suggest that surgical decompression effectively prevents secondary brain damage when performed early enough. Although caution should be taken when transferring conclusions drawn from experimental settings to the clinical situation, the current literature suggests that the timing of decompression may be of utmost importance in order to exploit the full neuroprotective potential of craniectomy following TBI.

Aspects on decompressive craniectomy in patients with traumatic head injuries

In patients with traumatic brain injury (TBI), intracranial hypertension secondary to cerebral edema is a major problem. A last-tier treatment in these cases is decompressive craniectomy. The aim of the present retrospective investigation was to (1) study the long-time outcome in patients with traumatic head injuries with intracranial hypertension treated with decompressive craniectomy; (2) examine the effects on intracranial pressure (ICP) by the craniectomy; and (3) investigate the possible relationship between the size of the removed bone-flap and the effects on ICP. Among the about 150 patients with severe TBI treated at our neurointensive care unit during 1997-2002, 19 patients were treated with decompressive craniectomy. All patients were young (mean 22 +/- 11 years, range 7-46 years), and 68% were male. The mean ICP was reduced from 29.2 +/- 3.5 before to 11.1 +/- 6.0 mm Hg immediately after the craniectomy; at 24 h after the craniectomy, the mean ICP was 13.9 +/- 9.7 mm Hg. Paired-samples t-test revealed a statistically significant decrease, both when comparing the preoperative values to the values immediately postoperative as well as to the values after 24 h (p < 0.01). A significant correlation between the size of the craniectomy and the decrease in ICP was found using Pearson regression analysis. The outcome of all patients could be assessed. The survival rate was 89%. Two patients died (both day 4 after the trauma); 68% of the patients had a favorable outcome (Glasgow Outcome Scale [GOS] score of 4 or 5); 16% were severely disabled (GOS score of 3); and one patient (5%) was left in a vegetative state.

Outcome after surgical decompression of severe traumatic brain injury

One of the factors that affects outcome following severe traumatic brain injury is development and progression of cerebral oedema with associated increase in intracranial pressure (ICP). Uncontrolled elevations of ICP may compromise energy metabolism of the injured brain and lead to secondary injury, affecting neurological outcome of the patient. Decompressive craniectomy has been used for over a century as a treatment of refractory brain swelling in a variety of neurological conditions. However, conclusive evidence of whether it has a beneficial or adverse affect on outcome is lacking. This article reviews the existing evidence on the role of decompressive craniectomy in management of patients with traumatic brain injury and stresses the need for randomised controlled trials.

CURRENT CONTROVERSIES IN THE MANAGEMENT OF PATIENTS WITH SEVERE TRAUMATIC BRAIN INJURY

BACKGROUND

Traumatic brain injury is a major cause of mortality and morbidity, particularly among young men. The efficacy and safety of most of the interventions used in the management of patients with traumatic brain injury remain unproven. Examples include the 'cerebral perfusion pressure-targeted' and 'volume-targeted' management strategies for optimizing cerebrovascular haemodynamics and specific interventions, such as hyperventilation, osmotherapy, cerebrospinal fluid drainage, barbiturates, decompressive craniectomy, therapeutic hypothermia, normobaric hyperoxia and hyperbaric oxygen therapy.

METHODS

A review of the literature was performed to examine the evidence base behind each intervention.

RESULTS

There is no class I evidence to support the routine use of any of the therapies examined.

CONCLUSION

Well-designed, large, randomized controlled trials are needed to determine therapies that are safe and effective from those that are ineffective or harmful.

Decompressive craniectomy for the treatment of refractory high intracranial pressure in traumatic brain injury

BACKGROUND

High intracranial pressure (ICP) is the most frequent cause of death and disability after severe traumatic brain injury (TBI). High ICP is treated by general maneuvers (normothermia, sedation etc) and a set of first line therapeutic measures (moderate hypocapnia, mannitol etc). When these measures fail to control high ICP, second line therapies are started. Among these, second line therapies such as barbiturates, hyperventilation, moderate hypothermia or removal of a variable amount of skull bone (known as decompressive craniectomy) are used.

OBJECTIVES

To assess the effects of secondary decompressive craniectomy (DC) on outcome and quality of life in patients with severe TBI in whom conventional medical therapeutic measures have failed to control raised ICP.

SEARCH STRATEGY

We searched the Cochrane Injuries Group's Trial Register, CENTRAL, MEDLINE, EMBASE, Best Evidence, Clinical Practice Guidelines, PubMed, CINAHL, the National Research Register and Google Scholar. We also handsearched relevant conference proceedings and contacted experts in the field and the authors of included studies.

SELECTION CRITERIA

Randomized or quasi-randomized studies assessing patients over the age of 12 months with a severe TBI who underwent DC to control ICP refractory to conventional medical treatments.

DATA COLLECTION AND ANALYSIS

Two authors independently examined the electronic search results for reports of possibly relevant trials and for retrieval in full. One author applied the selection criteria, performed the data extraction and assessed methodological quality. Study authors were contacted for additional information.

MAIN RESULTS

We found one trial with 27 participants conducted in the pediatric population (>18 years). DC was associated with a risk ratio (RR) for death of 0.54 (95% CI 0.17 to 1.72), and RR of 0.54 for death, vegetative status or severe disability 6 to 12 months after injury (95% CI 0.29 to 1.07).

AUTHORS' CONCLUSIONS

There is no evidence to support the routine use of secondary DC to reduce unfavourable outcome in adults with severe TBI and refractory high ICP. In the pediatric population DC reduces the risk of death and unfavourable outcome. Despite the wide confidence intervals for death and the small sample size of the only study identified, this treatment maybe justified in patients below the age of 18 when maximal medical treatment has failed to control ICP. To date, there are no results from randomised trials to confirm or refute the effectiveness of DC in adults. However, the results of non-randomized trials and controlled trials with historical controls involving adults, suggest that DC may be a useful option when maximal medical treatment has failed to control ICP. There are two ongoing randomized controlled trials of DC (Rescue ICP and DECRAN) that may allow further conclusions on the efficacy of this procedure in adults.

Decompressive craniectomy in traumatic brain injury: outcome following protocol-driven therapy

Although decompressive craniectomy following traumatic brain injury is an option in patients with raised intracranial pressure (ICP) refractory to medical measures, its effect on clinical outcome remains unclear. The aim of this study was to evaluate the outcome of patients undergoing this procedure as part of protocol-driven therapy between 2000-2003. This was an observational study combining case note analysis and follow-up. Outcome was assessed at an interval of at least 6 months following injury using the Glasgow Outcome Scale (GOS) score and the SF-36 quality of life questionnaire. Forty-nine patients underwent decompressive craniectomy for raised and refractory ICP (41 [83.7%] bilateral craniectomy and 8 [16.3%] unilateral). Using the Glasgow Coma Scale (GCS), the presenting head injury grade was severe (GCS 3-8) in 40 (81.6%) patients, moderate (GCS 9-12) in 8 (16.3%) patients, and initially mild (GCS 13-15) in 1 (2.0%) patient. At follow-up, 30 (61.2%) patients had a favorable outcome (good recovery or moderate disability), 10 (20.48) remained severely disabled, and 9 (18.4%) died. No patients were left in a vegetative state. Overall the results demonstrated that decompressive craniectomy, when applied as part of protocol-driven therapy, yields a satisfactory rate of favorable outcome. Formal prospective randomized studies of decompressive craniectomy are now indicated.

The role of decompressive craniectomy in the management of traumatic brain injury: a critical review

Brain swelling and intracranial hypertension following severe head injury are known to contribute to secondary brain damage, and have been shown to adversely affect patient outcome. The use of unilateral craniectomy following the evacuation of a mass lesion, such as acute subdural haematoma or traumatic intracerebral haematoma, is accepted practice. The following review focuses on a bi-fronto-temporal decompressive craniectomy, used as an isolated operation for the control of intracranial hypertension, secondary to diffuse brain swelling refractory to medical management. Though the operation is being increasingly used, current opinion is still divided regarding its overall effects on outcome. This review examines the experimental and clinical evidence for and against the use of decompressive craniectomy, highlights the lack of class I evidence relevant to this topic and emphasises the necessity for well-designed prospective randomised controlled trials.

Traumatic brain injury in children--clinical implications

Traumatic brain injury (TBI) is the leading cause of death in childhood; however only very few studies focusing on the specific pathophysiology and treatment have been published to date. Head trauma is more likely in young children than in adults given the same deceleration of the body due to their large and heavy heads and weak cervical ligaments and muscles. Resulting brain injury is more severe due to their thin, pliable skulls and the yet unfused sutures. Accordingly, children below the age of 4 years have lower chances of a full recovery after severe TBI, although in general, neurologic recovery after severe brain injury in children is better than in adults. The time course of brain injury can be divided into two steps: primary and secondary injury. Primary brain injury exclusively results from the initial impact. In contrast, adverse physiologic conditions during recovery after head trauma may account for additional brain damage, which is then referred to as secondary brain injury. As primary brain injury can only be influenced by preventive measures, all therapeutic efforts during the post-injury period focus on the reduction of secondary injury to the traumatized brain. Several mechanisms have been identified to be involved in the development of post-traumatic secondary brain injury, which render the rationale for the key treatment strategies. Three evidence based measures are of critical importance to prevent or minimize secondary brain injury: (1) avoid hypoxemia, (2) avoid post-traumatic arterial hypotension, and (3) refer the traumatized child to an experienced trauma team at a center that provides the availability of special equipment, e.g. for surgical procedures and airway management, for this age group. For several other therapeutical means, e.g. hypothermia or specific surgical interventions, clinical evidence to date is insufficient to allow recommendation as rescue treatment for children at risk of severe neurological sequelae following TBI. This review discusses the clinical implication of pathophysiologic mechanisms of TBI in the developing brain according to the recent literature and current guidelines. It follows the clinical approach to a head injured child, that can be divided into three phases, i.e. initial assessment and stabilization, followed by first tier, and if necessary second tier therapeutic interventions to assure adequate oxygenation and perfusion of the brain.

Decompressive craniectomy in head injury

PURPOSE OF REVIEW

To examine the evidence for the role of decompressive craniectomy in the management of traumatic brain injury.

RECENT FINDINGS

This review highlights the importance of brain swelling and raised intra-cranial pressure (ICP) as of the one fundamental pathophysiological processes following traumatic brain injury. The role of protocol driven therapy in controlling raised intra-cranial pressure is discussed, with the staged application of medical interventions (including hypothermia and barbiturates). If these measures fail to control ICP, a surgical option - removal of the skull (decompressive craniectomy) can be considered. The evidence for this operation is reviewed in terms of data published in peer-reviewed journals since 1997. This evidence consists pre-dominantly of case series with no definitive Class I evidence and demonstrates a wide range of outcomes with no clear consensus regarding the indications for the operation.

SUMMARY

Decompressive craniectomy is currently being applied in the management of traumatic brain injury with a wide range of outcomes reported in the literature. Current opinion on the role of this operation is therefore divided and it is now appropriate to proceed to prospective randomised studies.

What is the optimal cerebral perfusion pressure in children suffering from traumatic coma?

Head injury is a major cause of death and disability in children. Despite advances in resuscitation, emergency care, intensive care monitoring, and clinical practices, there are few data demonstrating the predictive value of certain physiological variables regarding outcome in this patient population. Mean arterial blood pressure (MABP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP = MABP − ICP) are routinely monitored in patients in many neurological intensive care units throughout the world, but there is little evidence indicating that advances in care have been matched with corresponding improvements in outcome.

Nonetheless, there is evidence that hypotension immediately following head injury is predictive of early death, and many patients with these features die with clinical signs of brain herniation caused by intracranial hypertension. Furthermore, available data indicate that a minimal and a mean CPP measured during intensive care are good predictors of outcome in survivors, but a target threshold to improve outcome has yet to be defined.

Some medical management strategies can have detrimental effects, and there is now a good case for undertaking a controlled trial of immediate or delayed craniectomy. Independent outcome in children following severe head injury is associated with higher levels of CPP. The ability to tolerate different levels of CPP may be related to age, and therefore any such surgical trial would need a carefully defined protocol so that the potential benefit of such a treatment is maximized.

Traumatic brain injury

PURPOSE OF REVIEW

Management of the patient with traumatic brain injury is a rapidly advancing field, characterized in recent years by an improved understanding of intracranial pathophysiology and ways in which outcomes can be improved. Many traditional therapies, such as fluid restriction and hyperventilation, have been called into question and are no longer recommended. Other proposed therapies, such as deliberate hypothermia, remain controversial. This detailed review of the recent literature helps the reader come to an understanding of current scientific and evidence-based practices in this area, with emphasis on those therapies most likely to be of use to the practicing intensivist.

RECENT FINDINGS

High-quality care of the traumatic brain injury patient demands the integrated activities of a number of different medical and nursing specialties. The best outcomes today are achieved by those systems that are able to focus as a team on the collective goal of minimizing secondary brain injury, and the respiratory therapist adjusting the patient's mechanical ventilation may be just as important to this effort as the attending neurosurgeon. Although the search for new diagnostic, prognostic, and therapeutic modalities continues (many of the more promising of which are reviewed in this article), it is clear that there exists no "silver bullet" therapy that will help all patients. Instead, it is the systematic integration and application of many small advances that will ultimately lead to better outcomes.

SUMMARY

Some issues in traumatic brain injury have now been resolved, and specific recommendations can be made. Fluid therapy directed toward a euvolemic state is now universally recommended, for example, as is the role of intracranial pressure monitoring. Other areas, such as the use of hypertonic saline, remain controversial. In both cases the authors have made an effort to cite the most recent literature, so that readers can draw their own conclusions from the original source material.