Improvement of brain tissue oxygen and intracranial pressure during and after surgical decompression for diffuse brain oedema and space occupying infarction

Comparative Study of Cerebral Perfusion in Different Types of Decompressive Surgery for Traumatic Brain Injury

Introduction Computed tomography perfusion (CTP) brain usefulness in the treatment of traumatic brain injury (TBI) is still being investigated. Comparative research of CTP in the various forms of decompressive surgery has not yet been reported to our knowledge. Patients with TBI who underwent decompressive surgery were studied using pre- and postoperative CTP. CTP findings were compared with patient's outcome.

Materials and Methods This was a single-center, prospective cohort study. A prospective analysis of patients who were investigated with CTP from admission between 2019 and 2021 was undertaken. The patients in whom decompressive surgery was required for TBI, were included in our study after applying inclusion and exclusion criteria. CTP imaging was performed preoperatively and 5 days after decompressive surgery to measure cerebral perfusion. Numbers of cases included in the study were 75. Statistical analysis was done.

Results In our study, cerebral perfusion were improved postoperatively in the all types of decompressive surgery (p-value < 0.05). But association between type of surgery with improvement in cerebral perfusion, Glasgow Coma Scale at discharge, and Glasgow Outcome Scale-extended at 3 months were found to be statistically insignificant (p-value > 0.05).

Conclusion CTP brain may play a role as a prognostic tool in TBI patients undergoing decompressive surgery.

Predictive role of trigeminal ganglion ischemia on scalp survival affected by temporal artery diameters: The first experimental study

Scalp arteries are mainly innervated by trigeminal, facial, and vagal nerves. The ischemic neurodegeneration of the trigeminal ganglion can impede scalp circulation via vasospasm-creating effects. This study was designed to investigate whether there is any link between the vasospasm index of deep temporal arteries and ischemic neuron densities of the trigeminal ganglion after subarachnoid hemorrhage. The study subjects included five normal control rabbits, six sham rabbits, and nine rabbits chosen from a formerly established experimental subarachnoid hemorrhage group created by cisternal homologous blood injection (0.75 mL). These rabbits, all male, were followed up for 3 weeks. The trigeminal ganglion and deep temporal artery vasospasm indexes were examined by stereological methods. Ischemic neuron densities of the trigeminal ganglion and vasospasm index values of deep temporal arteries were compared statistically. Postmortem examinations showed important vasospasms of deep temporal arteries, foramen magnum herniations, and neurodegeneration of the trigeminal ganglion. The mean vasospasm index values and degenerated neuron densities of the trigeminal ganglion were determined as 1.03 ± 0.13 and 10 ± 3/mm³ (p > 0.5) in the control group, 1.21 ± 0.18 and 35 ± 9/mm³ in the sham group (p < 0.005 for sham vs. control), and 2.54 ± 0.84 and 698 ± 134/mm³ in the experimental group (p < 0.0005 for sham vs. control and p < 0.00001 for study vs. control). There was an inverse relationship between the vasospasm index values and the degenerated neuronal density of the trigeminal ganglion. The high degenerated neuron density in the trigeminal ganglion had a facilitative effect on temporal artery vasospasm. Trigeminal ganglion neurodegeneration may promote temporal artery vasospasms after subarachnoid hemorrhage, which has not been previously mentioned in the literature.

Epidural Oscillating Cardiac-Gated Intracranial Implant Modulates Cerebral Blood Flow

BACKGROUND

We have previously reported a method and device capable of manipulating ICP pulsatility while minimally effecting mean ICP.

OBJECTIVE

To test the hypothesis that different modulations of the intracranial pressure (ICP) pulse waveform will have a differential effect on cerebral blood flow (CBF).

METHODS

Using an epidural balloon catheter attached to a cardiac-gated oscillating pump, 13 canine subjects underwent ICP waveform manipulation comparing different sequences of oscillation in successive animals. The epidural balloon was implanted unilaterally superior to the Sylvian sulcus. Subjects underwent ICP pulse augmentation, reduction and inversion protocols, directly comparing time segments of system activation and deactivation. ICP and CBF were measured bilaterally along with systemic pressure and heart rate. CBF was measured using both thermal diffusion, and laser doppler probes.

RESULTS

The activation of the cardiac-gate balloon implant resulted in an ipsilateral/contralateral ICP pulse amplitude increase with augmentation (217%/202% respectively, P < .0005) and inversion (139%/120%, P < .0005). The observed changes associated with the ICP mean values were smaller, increasing with augmentation (23%/31%, P < .0001) while decreasing with inversion (7%/11%, P = .006/.0003) and reduction (4%/5%, P < .0005). CBF increase was observed for both inversion and reduction protocols (28%/7.4%, P < .0001/P = .006 and 2.4%/1.3%, P < .0001/P = .003), but not the augmentation protocol. The change in CBF was correlated with ICP pulse amplitude and systolic peak changes and not with change in mean ICP or systemic variables (heart rate, arterial blood pressure).

CONCLUSION

Cardiac-gated manipulation of ICP pulsatility allows the study of intracranial pulsatile dynamics and provides a potential means of altering CBF.

Renal Decapsulation Prevents Intrinsic Renal Compartment Syndrome in Ischemia-Reperfusion-Induced Acute Kidney Injury: A Physiologic Approach

OBJECTIVES

Acute kidney injury is a serious complication with unacceptably high mortality that lacks of specific curative treatment. Therapies focusing on the hydraulic behavior have shown promising results in preventing structural and functional renal impairment, but the underlying mechanisms remain understudied. Our goal is to assess the effects of renal decapsulation on regional hemodynamics, oxygenation, and perfusion in an ischemic acute kidney injury experimental model.

METHODS

In piglets, intra renal pressure, renal tissue oxygen pressure, and dysoxia markers were measured in an ischemia-reperfusion group with intact kidney, an ischemia-reperfusion group where the kidney capsule was removed, and in a sham group.

RESULTS

Decapsulated kidneys displayed an effective reduction of intra renal pressure, an increment of renal tissue oxygen pressure, and a better performance in the regional delivery, consumption, and extraction of oxygen after reperfusion, resulting in a marked attenuation of acute kidney injury progression due to reduced structural damage and improved renal function.

CONCLUSIONS

Our results strongly suggest that renal decapsulation prevents the onset of an intrinsic renal compartment syndrome after ischemic acute kidney injury.

Prognostic value of changes in brain tissue oxygen pressure before and after decompressive craniectomy following severe traumatic brain injury

OBJECTIVE In severe traumatic brain injury (TBI), the effects of decompressive craniectomy (DC) on brain tissue oxygen pressure (PbtO2) and outcome are unclear. The authors aimed to investigate whether changes in PbtO2 after DC could be used as an independent prognostic factor. METHODS The authors conducted a retrospective, observational study at 2 university hospital ICUs. The study included 42 patients who were admitted with isolated moderate or severe TBI and underwent intracranial pressure (ICP) and PbtO2 monitoring before and after DC. The indication for DC was an ICP higher than 25 mm Hg refractory to first-tier medical treatment. Patients who underwent primary DC for mass lesion evacuation were excluded. However, patients were included who had undergone previous surgery as long as it was not a craniectomy. ICP/PbtO2 monitoring probes were located in an apparently normal area of the most damaged hemisphere based on cranial CT scanning findings. PbtO2 values were routinely recorded hourly before and after DC, but for comparisons the authors used the first PbtO2 value on ICU admission and the number of hours with PbtO2 < 15 mm Hg before DC, as well as the mean PbtO2 every 6 hours during 24 hours pre- and post-DC. The end point of the study was the 6-month Glasgow Outcome Scale; a score of 4 or 5 was considered a favorable outcome, whereas a score of 1-3 was considered an unfavorable outcome. RESULTS Of the 42 patients included, 26 underwent unilateral DC and 16 bilateral DC. The median Glasgow Coma Scale score at the scene of the accident or at the initial hospital before the patient was transferred to one of the 2 ICUs was 7 (interquartile range [IQR] 4-14). The median time from admission to DC was 49 hours (IQR 7-301 hours). Before DC, the median ICP and PbtO2 at 6 hours were 35 mm Hg (IQR 28-51 mm Hg) and 11.4 mm Hg (IQR 3-26 mm Hg), respectively. In patients with favorable outcome, PbtO2 at ICU admission was higher and the percentage of time that pre-DC PbtO2 was < 15 mm Hg was lower (19 ± 4.5 mm Hg and 18.25% ± 21.9%, respectively; n = 28) than in those with unfavorable outcome (12.8 ± 5.2 mm Hg [p < 0.001] and 59.58% ± 38.8% [p < 0.001], respectively; n = 14). There were no significant differences in outcomes according to the mean PbtO2 values only during the last 12 hours before DC, the hours of refractory intracranial hypertension, the timing of DC from admission, or the presence/absence of previous surgery. In contrast, there were significant differences in PbtO2 values during the 12- to 24-hour period before DC. In most patients, PbtO2 increased during the 24 hours after DC but these changes were more pronounced in patients with favorable outcome than in those with unfavorable outcome (28.6 ± 8.5 mm Hg vs 17.2 ± 5.9 mm Hg, p < 0.0001; respectively). The areas under the curve for the mean PbtO2 values at 12 and 24 hours after DC were 0.878 (95% CI 0.75-1, p < 0.0001) and 0.865 (95% CI 0.73-1, p < 0.0001), respectively. CONCLUSIONS The authors' findings suggest that changes in PbtO2 before and after DC, measured with probes in healthy-appearing areas of the most damaged hemisphere, have independent prognostic value for the 6-month outcome in TBI patients.

Early decompressive craniectomy for malignant cerebral infarction: Meta-analysis and clinical decision algorithm

BACKGROUND

Decompressive craniectomy (DC) is an aggressive life-saving surgical intervention for patients with malignant cerebral infarction (MCI). However, DC remains inconsistently and infrequently utilized, primarily due to enduring concern that increased survival occurs only at the cost of poor functional outcome. Our aim was to clarify the role of DC performed within 48 hours (early DC) for patients with MCI, including patients aged >60 years.

METHODS

We performed a meta-analysis of all available randomized controlled trials comparing early DC to best medical care for MCI. Studies were identified through literature searches of electronic databases including PubMed, EMBASE, and Scopus. We employed a Mantel-Haenszel fixed effects model to assess treatment effect on dichotomized modified Rankin Scale (mRS) outcomes at 12 months.

RESULTS

A total of 289 patients from 6 randomized controlled trials comparing early DC to best medical care were included. Early DC resulted in an increased rate of excellent outcomes, defined as mRS ≤2 (relative risk [RR] 2.81, 95% confidence interval [CI] 1.01-7.82, p = 0.047), and favorable outcomes, defined as mRS ≤3 (RR 2.06, 95% CI 1.25-3.40, p = 0.005). Early DC also increased the rate of survival with unfavorable outcomes, defined as mRS 4-5 (RR 3.03, 95% CI 1.98-4.65, p < 0.001).

CONCLUSIONS

Early DC increases the rate of excellent outcomes, i.e., functional independence, in addition to favorable and unfavorable outcomes; however, these findings must be interpreted within the context of patients' goals of care. We have developed a clinical decision algorithm that incorporates goals of care, which may guide consideration of early DC for MCI in clinical practice.

[Decompressive craniotomy in patients with intracranial aneurysmal hemorrhage]

Decompressive craniotomy (DCT) has been used for treatment of patients with acute aneurysmal subarachnoid hemorrhage (SAH) for more than 20 years. But so far, the attitude to this surgery is controversial, and the indications and contraindications for it are not clearly defined. The article reviews the domestic and foreign literature devoted to the issues of validity and efficacy of DCT in treatment of cerebral edema and intracranial hypertension in patients with aneurysmal SAH.

Monitoring of brain and systemic oxygenation in neurocritical care patients

Maintenance of adequate oxygenation is a mainstay of intensive care, however, recommendations on the safety, accuracy, and the potential clinical utility of invasive and non-invasive tools to monitor brain and systemic oxygenation in neurocritical care are lacking. A literature search was conducted for English language articles describing bedside brain and systemic oxygen monitoring in neurocritical care patients from 1980 to August 2013. Imaging techniques e.g., PET are not considered. A total of 281 studies were included, the majority described patients with traumatic brain injury (TBI). All tools for oxygen monitoring are safe. Parenchymal brain oxygen (PbtO2) monitoring is accurate to detect brain hypoxia, and it is recommended to titrate individual targets of cerebral perfusion pressure (CPP), ventilator parameters (PaCO2, PaO2), and transfusion, and to manage intracranial hypertension, in combination with ICP monitoring. SjvO2 is less accurate than PbtO2. Given limited data, NIRS is not recommended at present for adult patients who require neurocritical care. Systemic monitoring of oxygen (PaO2, SaO2, SpO2) and CO2 (PaCO2, end-tidal CO2) is recommended in patients who require neurocritical care.

Improved Hemodynamic Parameters in Middle Cerebral Artery Infarction After Decompressive Craniectomy

Background and Purpose—

Decompressive craniectomy (DC) reduces mortality and improves functional outcome in patients with malignant middle cerebral artery infarction. However, little is known regarding the impact of DC on cerebral hemodynamics. Therefore, our goal was to study the hemodynamic changes that may occur in patients with malignant middle cerebral artery infarction after DC and to assess their relationship with outcomes.

Methods—

Twenty-seven patients with malignant middle cerebral artery infarction who were treated with DC were studied. The perfusion CT hemodynamic parameters, mean transit time, cerebral blood flow, and cerebral blood volume were evaluated preoperatively and within the first 24 hours after DC.

Results—

There was a global trend toward improved cerebral hemodynamics after DC. Preoperative and postoperative absolute mean transit times were associated with mortality at 6 months, and the ratio of post- and preoperative cerebral blood flow was significantly higher in patients with favorable outcomes than those with unfavorable outcomes. Patients who underwent surgery 48 hours after stroke, those with midline brain shift >10 mm, and those who were >55 years showed no significant improvement in any perfusion CT parameters.

Conclusions—

DC improves cerebral hemodynamics in patients with malignant middle cerebral artery infarction, and the level of improvement is related to outcome. However, some patients did not seem to experience any additional hemodynamic benefit, suggesting that perfusion CT may play a role as a prognostic tool in patients undergoing DC after ischemic stroke.

Contemporary view on neuromonitoring following severe traumatic brain injury

Evolving brain damage following traumatic brain injury (TBI) is strongly influenced by complex pathophysiologic cascades including local as well as systemic influences. To successfully prevent secondary progression of the primary damage we must actively search and identify secondary insults e.g. hypoxia, hypotension, uncontrolled hyperventilation, anemia, and hypoglycemia, which are known to aggravate existing brain damage. For this, we must rely on specific cerebral monitoring. Only then can we unmask changes which otherwise would remain hidden, and prevent adequate intensive care treatment. Apart from intracranial pressure (ICP) and calculated cerebral perfusion pressure (CPP), extended neuromonitoring (SjvO₂, ptiO₂, microdialysis, transcranial Doppler sonography, electrocorticography) also allows us to define individual pathologic ICP and CPP levels. This, in turn, will support our therapeutic decision-making and also allow a more individualized and flexible treatment concept for each patient. For this, however, we need to learn to integrate several dimensions with their own possible treatment options into a complete picture. The present review summarizes the current understanding of extended neuromonitoring to guide therapeutic interventions with the aim of improving intensive care treatment following severe TBI, which is the basis for ameliorated outcome.

Decompressive craniectomy – friend or foe?

Decompressive craniectomy (DC) is the surgical management removing part of the skull vault over a swollen brain used to treat elevated intracranial pressure that is unresponsive to maximal medical therapy. The commonest indication for DC is traumatic brain injury (TBI) or middle cerebral artery (MCA) infarction, though DC has been reported to have been used for treatment of aneurysmal subarachnoid haemorrhage and venous infarction. Despite an increasing number of reports supportive of DC, the controversy over the suitability of the procedure and criteria for patient selection remains unresolved. Although the majority of published studies are retrospective, the recent publication of several randomised prospective studies prompts a re-evaluation of the use of DC. We review the literature concerning the pathophysiology, indication, surgical techniques and timing, complications and long-term effects of DC (including reversal with cranioplasty), in order to rationalise its use. We conclude that at the time of this review, though we cannot support the routine use of DC in TBI or MCA stroke, there is evidence that early and aggressive use of DC in TBI patients with intracranial haematomas or younger malignant MCA stroke patients may improve outcome. Though the results of the DECRA trial suggest that primary DC may worsen outcome, the decision to perform DC after diffuse TBI is still individualised. We await the results of the RESCUEicp trial to ascertain whether an evidence-based protocol for its use can be agreed in the future.

Brain-systemic temperature gradient is temperature-dependent in children with severe traumatic brain injury

OBJECTIVES

To understand the gradient between rectal and brain temperature in children after severe traumatic brain injury. We hypothesized that the rectal temperature and brain temperature gradient will be influenced by the child's body surface area and that this relationship will persist over physiologic temperature ranges.

DESIGN

Retrospective review of a prospectively collected pediatric neurotrauma registry.

SETTING

Academic, university-based pediatric neurotrauma program.

PATIENTS

Consecutive children (n = 40) with severe traumatic brain injury (Glasgow coma scale of <8) who underwent brain temperature monitoring (July 2003 to December 2008) were studied after informed consent was obtained. A subset of children (n = 24) were concurrently enrolled in a randomized, controlled clinical trial of early-moderate hypothermia for neuroprotection.

INTERVENTIONS

Data extraction of multiple clinical variables, including demographic data, body surface area, and rectal and brain temperature at recorded at hourly intervals.

MEASUREMENTS AND MAIN RESULTS

Paired brain and rectal temperature measurements (in degrees Celsius, n = 4369) were collected hourly and compared by using Pearson correlations. Patients were stratified according to body surface area (<1.0 m, 1.0-1.99 m, 2.0-2.99 m, and >3.0 m) and based on brain temperature (≤34.0, 34.1-36.0; 36.1-38, ≥38.1). Body surface area and brain temperature were compared between groups by using Pearson correlations with correction for repeated measures. Mean brain temperature-rectal temperature difference was calculated for stratified brain temperature ranges. Overall, brain and rectal temperatures were highly correlated (r = .86, p < .001). During brain hyperthermia, brain temperature-rectal temperature was similar to that reported in previous studies with brain temperature higher than rectal temperature (1.75 ± 0.4; r = .54). Surprisingly, this relationship was reversed during brain hypothermia (brain temperature-rectal temperature = -1.87 ± 0.8; r = .37), indicating a reversal of the brain-systemic temperature gradient. When stratified for body surface area, the correlation between rectal temperature and brain temperature remained strong (r = .78, 0.91, 0.79 and 0.95, respectively, p < .001). However, the correlation between brain temperature and rectal temperature was substantially decreased when stratified for brain temperature (r = .37, 0.58, 0.48, 0.54, p < .001). In particular, during moderate brain hypothermia (brain temperature ≤34), the correlation between brain temperature and rectal temperature was weakest, indicating the greatest variability during this condition which is often targeted for therapeutic trials.

CONCLUSIONS

Brain temperature and rectal temperature are generally well-correlated in children with traumatic brain injury. This relationship is different at the extremes of the physiologic temperature range, with the temperature gradient reversed during brain hypothermia and hyperthermia. Given that studies showing neuroprotection from hypothermia in animal models of brain injury generally target brain temperature, our data suggest the possibility that, if brain temperature were the therapeutic target in clinical trials, this would result in somewhat higher systemic temperature and potentially fewer side effects. This relationship may be exploited in future clinical trials to maintain brain hypothermia (for neurologic protection) at slightly higher systemic temperatures (and potentially fewer systemic side effects).

Decompressive craniectomy for elevated intracranial pressure and its effect on the cumulative ischemic burden and therapeutic intensity levels after severe traumatic brain injury

BACKGROUND

Increased intracranial pressure (ICP) can cause brain ischemia and compromised brain oxygen (PbtO2 < or = 20 mm Hg) after severe traumatic brain injury (TBI).

OBJECTIVE

We examined whether decompressive craniectomy (DC) to treat elevated ICP reduces the cumulative ischemic burden (CIB) of the brain and therapeutic intensity level (TIL).

METHODS

Ten severe TBI patients (mean age, 31.4 +/- 14.2 years) who had continuous PbtO2 monitoring before and after delayed DC were retrospectively identified. Patients were managed according to the guidelines for the management of severe TBI. The CIB was measured as the total time spent between a PbtO2 of 15 to 20, 10 to 15, and 0 to 10 mm Hg. The TIL was calculated every 12 hours. Mixed-effects models were used to estimate changes associated with DC.

RESULTS

DC was performed on average 2.8 days after admission. DC was found to immediately reduce ICP (mean [SEM] decrease was 7.86 mm Hg [2.4 mm Hg]; P = .005). TIL, which was positively correlated with ICP (r = 0.46, P < or = .001), was reduced within 12 hours after surgery and continued to improve within the postsurgical monitoring period (P </= .001). The duration and severity of CIB were significantly reduced as an effect of DC in this group. The overall mortality rate in the group of 10 patients was lower than predicted at the time of admission (P = .015).

CONCLUSION

These results suggest that a DC for increased ICP can reduce the CIB of the brain after severe TBI. We suggest that DC be considered early in a patient's clinical course, particularly when the TIL and ICP are increased.

Intensive care management of acute stroke: surgical treatment

Controversy still exists on surgical management of acute stroke. Even if surgical therapy represents often a life-saving measure, the issue of acceptable outcome remains open. Persuasive evidence for outcome benefit is limited. For large ischaemic strokes, recent convincing data suggest that decompressive surgery significantly reduces mortality and improves outcome quality. On the other hand, despite the long tradition in surgical removal of intracranial haematomas, the recent evidence has not been sufficient to resolve the basic argument whether to operate or not. Most recently, hopeful preliminary data have emerged on new approaches in the treatment of intraventricular haemorrhage. In this article, we review the current neurosurgical options in acute ischaemic and haemorrhagic stroke.

Cerebral Blood Flow and Metabolism Following Decompressive Craniectomy for Control of Increased Intracranial Pressure

OBJECTIVE

Decompressive craniectomy (DC) is a common practice for control of intracranial pressure (ICP) following traumatic brain injury (TBI), although the impact of this procedure on the fate of operated patients is still controversial.

METHODS

Cerebral blood flow (CBF) and metabolic rates were monitored prospectively and daily as a surrogate of neuronal viability in 36 TBI patients treated by DC and compared with those of 86 nonoperated patients. DC was performed either on admission (n = 29) or within 48 hours of admission (n = 7).

RESULTS

DC successfully controlled ICP levels and maintained CBF within a normal range although the cerebral metabolic rate of oxygen (CMRO2) was significantly lower in this group. In 7 patients, pre- and postoperative recordings showed a significant ICP decrease that correlated with CBF augmentation but not with concurrent improvement of CMRO2 that remained particularly low. Logistic regression analysis of all investigated variables showed that DC was not associated with higher mortality despite more severe injuries in this group. However, operated patients were 7-fold more likely to have poor functional outcomes than nonoperated patients. Good functional outcome was strongly associated with higher CMRO2 but not with higher CBF values. CMRO2 levels were significantly lower in the DC group, even after adjustment for injury severity, and showed a progressive and sustained trend of deterioration significantly different from that of the non-DC group.

CONCLUSION

These results suggest that DC may enhance survival in the presence of severe brain swelling, although it is unlikely to represent an adequate answer to mitochondrial damage responsible for cellular energy crisis and edema.

Cerebral hemodynamic changes in severe head injury patients undergoing decompressive craniectomy

OBJECTIVE

To assess the intracranial hemodynamic modifications induced by a decompressive craniectomy (DC) after severe traumatic brain injury (TBI), using transcranial Doppler (TCD) ultrasonography and intracranial pressure (ICP) sensor. Mortality rate and neurological outcomes were also evaluated after this procedure.

DESIGN

A prospective study was carried out on 26 TBI patients, measuring transcranial Doppler and ICP before, immediately after, and 48 hours after the DC, allowing for statistical analysis of hemodynamic changes. The mortality rate and the neurological outcomes were assessed.

MEASUREMENTS AND RESULTS

After DC, ICP decreased from 37+/-17 to 20+/-13 mm Hg (P=0.0003). The global cerebral blood flow was modified with diastolic velocities rising from 23+/-15 to 31+/-13 cm/s (P=0.0038) and a pulsatility index decreasing from 1.70+/-0.66 to 1.18+/-0.37 (P=0.0012). This normalization of the global cerebral hemodynamics after the DC was immediate, symmetric, and constant during the first 48 hours. Outcome was evaluated at 6 months: good recovery or moderate disability was observed in 11 patients (42%), persistent vegetative state in 7 patients (27%), and 8 patients died (31%).

CONCLUSIONS

The DC results in a significant, immediate, and durable improvement of ICP associated with a normalization of cerebral blood flow velocities in most TBI patients with refractory intracranial hypertension.

Hemicraniectomy for malignant middle cerebral artery infarction

PURPOSE OF REVIEW

Space-occupying, malignant hemispheric infarction is one of the most devastating forms of ischemic stroke. Several case series had suggested decompressive hemicraniectomy as a life-saving therapy, but, until recently, there was no proof for this procedure from randomized controlled trials.

RECENT FINDINGS

In 2007, results from a pooled analysis of three European trials as well as data from two of these trials were published and yield compelling evidence for the benefit of hemicraniectomy.

SUMMARY

Data from the published trials leave no doubt about the benefit especially the life-saving character of hemicraniectomy for malignant hemispheric infarction. However, some open questions (i.e. timing of surgery, age limit for hemicraniectomy) remain to be answered in the future.

Decompressive craniectomy in aneurysmal subarachnoid hemorrhage: relation to cerebral perfusion pressure and metabolism

INTRODUCTION

Outcome is poor in aneurysmal subarachnoid hemorrhage (SAH) patients with intracranial hypertension. As one treatment option for increased intracranial pressure (ICP), decompressive craniectomy (DC) is discussed. Its impact on cerebral metabolism and outcome in SAH patients is evaluated in this pilot study.

METHODS

A prospectively collected database of cerebral metabolism in SAH patients was analyzed retrospectively for individuals developing high ICP (>20 mmHg > 6 h/day, n = 18). Patients with intracranial hypertension were classified into groups with (n = 7) and without DC (n = 11). An age-matched control group was established (n = 89). Cerebral perfusion pressure (CPP) and high ICP treatment were analyzed for 7 days after SAH (or 72 h after craniectomy, respectively). Cerebral microdialysates were analyzed hourly. Twelve-month outcome was evaluated.

RESULTS

Groups were comparable for age, WFNS grade, and outcome. ICP was significantly reduced by DC (P < 0.01), however, in 43% of patients the effect was transient. An increase in the lactate/pyruvate ratio (P < 0.001) and glycerol levels (>200 muM) was observed before DC. In the DC group, glucose (P = 0.005) and pyruvate (P = 0.04) were higher, while glycerol levels were lower (P = 0.007) compared to the non-DC group, reflecting better aerobic glucose utilization and reduced cellular stress.

CONCLUSION

Outcome was poor in all SAH patients with intracranial hypertension. Although glucose utilization was improved after DC, no improvement in outcome could be shown for this small patient population. Future studies will have to demonstrate whether markers of cerebral crisis may support the decision for DC in aneurysmal SAH patients.

[Role of decompressive craniectomy in brain injury patient]

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and decompressive craniectomy (DC). However, neither barbiturates nor hypothermia have been demonstrated to improve its outcome. DC could be a therapeutic option in the management of ICH without intracerebral masses. Therefore, our goal has been to review and analyze the clinical usefulness of DC in patients with brain injury in an attempt to deal with some concerns of the critical care physicians. Can DC improve patient outcome? Currently, there are no randomized and controlled clinical trials supporting or rejecting the practice of DC in adults. Most published reports provide level II of evidence. However, most of those studies have shown that the outcome is better in patients with DC. When should DC be performed? It should be performed early to prevent ICH from occurring more than 12 hours. What are the effects of DC on intracranial pressure and brain oxygenation? In most patients, ICP can be maintained below 25 mmHg after a DC. However, to improve brain oxygenation (PtiO(2)), the probe must be placed in the healthy area of the most severely damaged cerebral hemisphere. What is the suggested surgical procedure? Frontal-subtemporal-parietal-occipital craniectomies, including enlargement of the dura by duroplasty. And finally, what are the current contraindications of DC? Glasgow Coma Scale score 3 points post-resuscitation states with dilated and arreactive pupils, age > 65 years old, ICH > 12 hours, persistent (a-yv)DO(2) < 3.2% or PtiO(2) < 10 mmHg maintained from the moment of admission.

Decompressive surgery for severe brain edema

Decompressive surgery has since long been a promising therapeutic approach for patients with acute severe brain injury at risk to develop severe brain edema. The underlying rationale of removing part of the cranium is to create space for the expanding brain to prevent secondary damage to vital brain tissue. However, until recently, randomized controlled trials that demonstrate the efficacy of decompressive surgery or benefit for outcome were missing. This has changed since the results of 3 randomized trials on hemicraniectomy in malignant infarction of the middle cerebral artery have been published in 2007. In this article, the current evidence for decompressive surgery in the treatment of cerebral ischemia, intracranial hemorrhage, traumatic brain injury, inflammatory diseases, or severe metabolic derangements is reviewed. Although there is increasing evidence for the efficacy of decompressive surgery in reducing intracranial pressure and even mortality, a critical point remains the definition of good or acceptable outcome.

Hemicraniectomy for space-occupying supratentorial ischemic stroke

Space-occupying, malignant hemispheric infarction is one of the most devastating forms of ischemic stroke. Until recently, there was no proven treatment. In 2007, results from randomized, controlled trials provided evidence for the benefit of early hemicraniectomy. This paper provides an overview on the current treatment options for malignant ischemic brain infarction, with a focus on hemicraniectomy. We also discuss major unsolved problems and open questions regarding the disease. Finally, we give a perspective on future clinical studies in this field of stroke.

[Aneurysmal subarachnoid hemorrhage. Significance and complications]

Despite substantial improvement in the management of patients with aneurysmal subarachnoid hemorrhage (SAH), including early aneurysm occlusion by endovascular techniques and surgical procedures, a significant percentage of patients with SAH still experience serious sequelae of neurological or cognitive deficits as a result of primary hemorrhage and/or secondary brain damage. Available neuromonitoring methods for early recognition of ischemia include, among others, measurement of brain tissue O(2) partial pressure, brain metabolism with microdialysis and monitoring of regional blood flow. The triple-H therapy (arterial hypertension, hypervolemia and hemodilution) is the treatment of choice of a symptomatic vasospasm and leads to an enduring recession of ischemic symptoms, if initiated early after the onset of a vasospasm-linked ischemic neurological deficit. Further promising therapy approaches are the administration of highly selective ET(A) receptor antagonists and intracisternal administration of vasodilators in depot form. This review summarizes the major neurological and non-neurological complications following aneurysm occlusion. Possible neuromonitoring techniques to improve diagnosis and therapy for treatment of symptomatic vasospasm as well as extracranial complications are discussed.

Effect of decompressive craniectomy on intracranial pressure and cerebrospinal compensation following traumatic brain injury

Object

Decompressive craniectomy is an advanced treatment option for intracranial pressure (ICP) control in patients with traumatic brain injury. The purpose of this study was to evaluate the effect of decompressive craniectomy on ICP and cerebrospinal compensation both within and beyond the first 24 hours of craniectomy.

Methods

This study was a retrospective analysis of the physiological parameters from 27 moderately to severely head-injured patients who underwent decompressive craniectomy for progressive brain edema. Of these, 17 patients had undergone prospective digital recording of ICP with estimation of ICP waveform–derived indices. The pressure-volume compensatory reserve (RAP) index and the cerebrovascular pressure reactivity index (PRx) were used to assess those parameters. The values of parameters prior to and during the 72 hours after decompressive craniectomy were included in the analysis.

Results

Decompressive craniectomy led to a sustained reduction in median (interquartile range) ICP values (21.2 mm Hg [18.7; 24.2 mm Hg] preoperatively compared with 15.7 mm Hg [12.3; 19.2 mm Hg] postoperatively; p = 0.01). A similar improvement was observed in RAP. A significantly lower mean arterial pressure (MAP) was needed after decompressive craniectomy to maintain optimum cerebral perfusion pressure (CPP) levels, compared with the preoperative period (99.5 mm Hg [96.2; 102.9 mm Hg] compared with 94.2 mm Hg [87.9; 98.9 mm Hg], respectively; p = 0.017). Following decompressive craniectomy, the PRx had positive values in all patients, suggesting acquired derangement in pressure reactivity.

Conclusions

In this study, decompressive craniectomy led to a sustained reduction in ICP and improvement in cerebral compliance. Lower MAP levels after decompressive craniectomy are likely to indicate a reduced intensity of treatment. Derangement in cerebrovascular pressure reactivity requires further studies to evaluate its significance and influence on outcome.

Decompressive craniectomy for massive cerebral infarction with enlarged cruciate duraplasty

The use of decompressive craniectomy for massive cerebral infarction is attracting renewed interest because conventional medical treatment is associated with high mortality. The technique of duraplasty may be important. We have developed a 4 step volume-enlarged cruciate duraplasty and report its use in 12 patients with massive cerebral infarction. None of the patients needed an additional anterior temporal lobectomy to reduce intraoperative intracranial pressure and none suffered epilepsy after the operation. This initial experience suggests that the use of a stepwise cruciate duraplasty during a decompression may promote clinical outcomes and further evaluation is merited.

Surgery for brain edema

Brain edema is a common pathophysiological process seen in many neurosurgical conditions. It can be localized in relation to focal lesions or generalized in diffuse types of brain injury. In addition to local adverse effects occurring at a cellular level, brain edema is associated with raised intracranial pressure (ICP), and both phenomena contribute to poor outcome in patients. One of the goals in treating patients with acute neurosurgical conditions in intensive care is to control brain edema and maintain ICP below target levels. The mainstay of treatment is medical therapy to reduce edema, but in certain patients--for example, those with diffuse severe traumatic brain injury (TBI) and malignant middle cerebral artery infarction--such treatment is not effective. In these patients, opening the skull (decompressive craniectomy) to reduce ICP is a potential option. In this review the authors discuss the role of decompressive craniectomy as a surgical option in patients with brain edema in the context of a variety of pathological entities. They also address the current evidence for the technique (predominantly observational series) and the ongoing randomized studies of decompressive craniectomy in TBI and ischemic stroke.

The role of surgery in ischemic stroke: decompressive surgery

PURPOSE OF REVIEW

This review gives an integrated view on the current status of decompressive surgery in space-occupying hemispheric brain infarction with a focus on new developments based on the available data of recent clinical trials, also including preliminary data from randomized trials reported at international stroke conferences in 2006.

RECENT FINDINGS

The treatment of ischemic brain infarction with life-threatening space-occupying edema is, because of a lack of prospective studies, one of the major controversial issues within neurocritical care medicine today. Only a few years ago, massive cerebral infarctions were regarded an untreatable disease with fatal outcome. The introduction of decompressive surgery (hemicraniectomy) has completely changed this point of view. Most of the reports, however, are retrospective with low numbers of patients. There are only few prospective trials that suggest a substantial benefit of decompressive surgery to significantly reduce mortality as compared to maximal conservative treatment alone. The control groups in these studies, however, consist of patients with higher age and higher rates of co-morbidities. Also, in most studies information on long-term outcome is insufficient. In 2006 long expected preliminary data from randomized trials of hemicraniectomy have been reported at international stroke conferences. They yield very positive results.

SUMMARY

Decompressive surgery appears to be a promising treatment option for patients with space-occupying hemispheric brain infarction.

Clinical review: Therapy for refractory intracranial hypertension in ischaemic stroke

The treatment of patients with large hemispheric ischaemic stroke accompanied by massive space-occupying oedema represents one of the major unsolved problems in neurocritical care medicine. Despite maximum intensive care, the prognosis of these patients is poor, with case fatality rates as high as 80%. Therefore, the term 'malignant brain infarction' was coined. Because conservative treatment strategies to limit brain tissue shift almost consistently fail, these massive infarctions often are regarded as an untreatable disease. The introduction of decompressive surgery (hemicraniectomy) has completely changed this point of view, suggesting that mortality rates may be reduced to approximately 20%. However, critics have always argued that the reduction in mortality may be outweighed by an accompanying increase in severe disability. Due to the lack of conclusive evidence of efficacy from randomised trials, controversy over the benefit of these treatment strategies remained, leading to large regional differences in the application of this procedure. Meanwhile, data from randomised trials confirm the results of former observational studies, demonstrating that hemicraniectomy not only significantly reduces mortality but also significantly improves clinical outcome without increasing the number of completely dependent patients. Hypothermia is another promising treatment option but still needs evidence of efficacy from randomised controlled trials before it may be recommended for clinical routine use. This review gives the reader an integrated view of the current status of treatment options in massive hemispheric brain infarction, based on the available data of clinical trials, including the most recent data from randomised trials published in 2007.