REVIEW ARTICLE Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Infarction An Update Suresh Subramaniam, MD, MSc, and Michael D. Hill, MD, MSc, FRCPC Background: Malignant middle cerebral artery (MCA) infarction is a devastating disease affecting a minority of stroke victims. The mortality rate from malignant MCA infarction managed with conservative medical treatment is estimated at 80%. Standard medical management includes physiologic support, osmotherapy, intubation and mechanical ventilation, and intracranial pressure monitoring. Decompressive hemicraniectomy has been viewed with skepticism because of lack of evidence from randomized controlled trials. Methods: Narrative review of recent surgical evidence in favor of hemicraniectomy. Results: Current evidence from randomized controlled trials and a recent pooled analysis, show clear benefit from hemicraniectomy with improved survival and better functional outcomes. Discussion: Hemicraniectomy for malignant MCA infarction is a life saving procedure. Further data on quality of life outcomes and patient and caregiver burden are required. Until that time, selection of patients for hemicraniectomy still requires an individual approach. Key Words: hemicraniectomy, malignant infarction (The Neurologist 2009;15: 178 –184) M alignant middle cerebral artery (MCA) infarction is a term used to describe complete MCA territory infarction with significant space occupying effect and herniation of brain tissue.1 The incidence of malignant MCA infarction is estimated to be less than 1% of all strokes. The mortality with conservative forms of medical treatment is approximately 80% and coma terminates in brain death within 2 to 5 days of onset.1 Death usually occurs from progressive swelling of the ischemic brain tissue, brain tissue shifts, focal increase in intracranial pressure (ICP), and the extension of ischemia to adjacent vascular territories. Survivors of this kind of stroke are disabled with poor quality of life.2,3 Until recently, several case studies and nonrandomized studies had suggested that decompressive hemicraniectomy with durotomy or duraplasty could improve survival in malignant MCA infarction but not functional outcomes.2–5 Numerous developments have occurred in the understanding of the pathophysiology of malignant MCA infarction resulting in improvements in medical and surgical management of such patients. Recent completion of the 3 European hemicraniectomy randomized controlled trials have shed light on the functional quality of life of these patients for the first time.6,7 A recent pooled analysis provides evidence for a favorable functional outcome for patients with malignant From the Calgary Stroke Program, Department of Clinical Neurosciences, Medicine, Community Health Sciences, University of Calgary, Calgary, Alberta, Canada. Reprints: Michael D. Hill, MD, MSc, FRCPC, Calgary Stroke Program, Hotchkiss Brain Institute, Department of Clinical Neurosciences, University of Calgary, Foothills Hospitals, Rm 1242A, 1403 29th St. NW, Calgary, Alberta, T2N 2T9 Canada. E-mail: [email protected]. Copyright © 2009 by Lippincott Williams & Wilkins ISSN: 1074-7931/09/1504-0178 DOI: 10.1097/NRL.0b013e3181963d19 178 | www.theneurologist.org MCA infarction undergoing hemicraniectomy. This article provides a review of the latest updates that have taken place in the surgical management of malignant MCA infarction, highlighting the current evidence for survival benefit and favorable outcome, from recent randomized controlled trials. CLINICAL COURSE OF MASSIVE CEREBRAL INFARCTION The most common underlying vascular lesion in malignant MCA infarction is carotid-T or carotid-L occlusion that involves the terminal internal carotid artery (ICA), A1-ACA, and M1-MCA or just the ICA terminus and the M1-MCA (carotid-L occlusion). This produces ischemia of the MCA and variously the ACA, anterior choroidal artery, and if a fetal-type posterior cerebral artery (PCA) circulation is present, in the PCA territories.1 Most often, patients with malignant MCA infarction have head turning and gaze deviation secondary to involvement of frontal eye fields, gross higher cortical dysfunction with global aphasia in dominant hemisphere involvement or severe hemispatial neglect in nondominant hemisphere involvement, flaccid hemiplegia, and hemianesthesia.8 The most common underlying vascular lesion in malignant MCA infarction is carotid-T or carotid-L occlusion. In addition to the neurologic symptoms from hemispheric infarction, the additional manifestations evolving from malignant MCA infarction are largely because of focal edema and displacement of the brain, rather than a global increase in ICP. This is a critical pathophysiologic point, in that, an external ventricular drain is not a solution to a worsening focal ICP problem. Cerebral autoregulation is impaired in areas around the infarction because of focal increase in ICP greater than 20 mmHg.9 Patients at risk for focal increase in ICP are mainly those with greater than 50% infarction of the MCA territory.10 Patients who deteriorate following malignant MCA infarction have symptoms of nausea, vomiting, headache, increasing somnolence, and respiratory compromise as early as 3 hours after the stroke onset and this usually heralds mass effect from brain edema. Mass effect is an expected complication, particularly in young patients with malignant MCA infarction because they have not suffered the atrophy that becomes permissive in allowing older patients to tolerate focal infarct-related edema. Young patients with massive infarction may suffer sudden herniation as early as 1 to 5 days after admission.11 Mass effect can progress rapidly over minutes to hours to cause herniation of brain tissue through dural spaces and may produce subfalcine, uncal, transtentorial and tonsillar herniation, often terminating in rapid death.12 Patients with maligThe Neurologist • Volume 15, Number 4, July 2009 The Neurologist • Volume 15, Number 4, July 2009 Decompressive Hemicraniectomy nant MCA infarction require careful physiological support in an intensive care unit with high-observation nursing because of the potential for rapid deterioration and the need for airway management. The additional manifestations evolving from malignant MCA infarction are largely because of focal edema and displacement of the brain, rather than a global increase in ICP. IDENTIFICATION OF PATIENTS FOR HEMICRANIECTOMY Early and prompt identification of patients at risk for developing malignant MCA infarction syndrome is crucial for patient selection for decompressive hemicraniectomy. Neuroimaging provides an invaluable tool for identifying these patients at risk for developing brain edema. Neurologic deterioration often correlates with horizontal displacement of the anterior septum and pineal gland as seen on CT scan. The presence of low-density infarction that occupies more than 50% of the MCA territory on CT scan is a reliable predictor of impending brain edema formation following a large hemispheric infarction. Early (less than 6 hours) CT scan changes of greater than 50% MCA infarction or local brain edema producing effacement of sulci or compression of the lateral ventricle have been associated with fatal outcomes. These CT scan changes have 94% specificity and 61% sensitivity.13 Early radiologic signs visualized on CT scan that are predictive of malignant MCA transformation include anteroseptal shift of greater than 5 mm, pineal shift greater than 2 mm, hydrocephalus, temporal lobe infarction, and the presence of other vascular territory infarction (ACA and/or PCA territories).14 Pineal gland shift measurements are sometimes predictive of neurologic deterioration. A pineal shift of 2.5 to 4 mm is associated with drowsiness, 6 to 9 mm with stupor, and greater than 9 mm with coma. Patients with a baseline National Institutes of Health Stroke Scale (NIHSS) score greater than or equal to 20 in patients with dominant hemisphere infarctions, or greater than or equal to 15 points with nondominant hemispheric infarction within 6 hours of symptom onset accompanied by more than 50% hypodensity on CT scan are at high risk for developing fatal brain edema.15 Terminal internal carotid artery (carotid-T or carotid-L) occlusion demonstrated on angiography, is a better predictor than CT scan cortical hypodensity in patients with malignant MCA infarction. The absence of collateral supply, recanalization, and ICA occlusion are the predictors of death in patients with malignant MCA infarction.1 Early (less than 6 hours) CT scan changes of greater than 50% MCA infarction or local brain edema producing effacement of sulci or compression of the lateral ventricle have been associated with fatal outcomes. © 2009 Lippincott Williams & Wilkins FIGURE 1. Three-dimensional rendered image of a patient depicting the boundaries on different regions of the cranium for optimal resection of the bone flap in decompressive hemicraniectomy and durotomy (Courtesy of Ross Mitchell’s Laboratory, University of Calgary, Calgary, Alberta, Canada). DESCRIPTION OF SURGICAL TECHNIQUE FOR HEMICRANIECTOMY AND DURAPLASTY Hemicraniectomy surgery was first performed as a treatment for acute subdural hematoma.16 Hemicraniectomy involves removal of bone from 1 side of the skull measuring roughly 13 cm in the antero-posterior dimension, and from the floor of the middle cranial fossa to at least 9 cm superiorly, and simultaneously performing a generous dural opening. The minimal adequate decompression is defined by the following bony boundaries (Fig. 1): 1. 2. 3. 4. Anterior, frontal to midpupillary line. Posterior, approximately 4 cm to the external auditory canal. Superior, to the superior sagital sinus. Inferior, to the floor of the middle cranial fossa. Bone removed during a hemicraniectomy can be saved in the peritoneum or in a bone bank in antibiotic solution at 80°C. Bone is replaced after the swelling has subsided in 2 to 8 weeks, but typically closer to 4 weeks. Cruciate or circumferential durotomy must be performed over the entire region of bony decompression to insure that nothing resists the expanding brain from being able to herniate outward. Dural grafting is performed with loose closure of the dura with allograft or pericranium. In general, no brain resection or ventriculostomy is required (see following comments on temporal lobe infarction). This complete procedure opens a new pathway of least resistance for the swelling brain ipsilateral to the lesion. Removal of a large part of the skull theoretically reduces the ICP, ongoing ischemia, and prevents swollen brain tissue from displacing adjacent healthy tissue. The size of the bone flap determines the magnitude of decompression achieved and significantly increases when the diameter exceeds 12 cm. Sometimes, a repeat hemicraniectomy may be required for clinical and/or radiographic evidence of persisting herniation. www.theneurologist.org | 179 Subramaniam and Hill CURRENT EVIDENCE FOR DECOMPRESSIVE HEMICRANIECTOMY Until recently, there were no randomized controlled clinical trials performed in malignant MCA infarction patients undergoing decompressive hemicraniectomy. A majority of the evidence was obtained from uncontrolled case series and retrospective studies purporting that hemicraniectomy was a life-saving procedure.2,4,5 Previous studies did not consider quality of life and social disability measures as outcomes, and as a result, it was unclear whether decompressive hemicraniectomy was improving survival of the malignant MCA patients at the cost of dependent functional outcomes with poor quality of life.3,17 It was only recently that 1 North American randomized controlled trial (HeADDFIRST) and 3 European randomized controlled trials 关decompressive craniectomy in malignant MCA infarction (DECIMAL), decompressive surgery for the treatment of malignant infarction of the middle cerebral artery (DESTINY), hemicraniectomy after middle cerebral artery infarction with life-threatening Edema trial (HAMLET)兴 provided an invaluable data on the functional outcomes of patients with malignant MCA infarction undergoing hemicraniectomy.6,7,18,19 A recent pooled analysis of the 3 European randomized controlled trials by Vahedi et al proved that hemicraniectomy is a life-saving procedure and can result in a favorable functional outcome when offered early to younger patients (less than 60 years of age).20 It is important to remember that, in all these trials, clinical management was likely unblinded to treatment modality (despite attempts to preserve blinding), raising the issue of bias toward hemicraniectomy. It is entirely possible that bias among investigators could have influenced decisions not to pursue aggressive care and withhold treatment in the medically managed group, thus leading to differences in outcomes favoring hemicraniectomy. Unfortunately, this issue is not resolvable. A pooled analysis of the 3 European randomized controlled trials proved that hemicraniectomy is a lifesaving procedure and can result in a favorable functional outcome when offered early to younger patients. DECIMAL is a French trial that assessed the efficacy of early decompressive hemicraniectomy on functional outcomes.7 Enrollment in DECIMAL was terminated prematurely because of improved survival with hemicraniectomy. Patients between 18 and 55 years of age were included within 24 hours of a malignant MCA infarction with NIHSS score of greater than or equal to 16, CT scan of the head involving more than 50% of the MCA territory, and a diffusion-weighted imaging (DWI) infarct volume of greater than or equal to 145 cm3. Thirty-eight patients were randomized to receive standard medical therapy alone or standard medical therapy with decompressive hemicraniectomy and durotomy. For the surgical group of patients, hemicraniectomy had to be done no later than 6 hours after randomization and up to 30 hours after the onset of symptoms. The primary outcome was a favorable functional outcome defined by patient survival with a modified Rankin score (mRS) less than or equal to 3 at 6 months. The mRS is a 7-point functional disability scale, where 0 means no neurologic symptoms at all, 6 means death. A score of 3 implies that a patient is able to 180 | www.theneurologist.org The Neurologist • Volume 15, Number 4, July 2009 walk independently but requires help with some activities of daily living. Secondary end points were survival, mRS, Barthel Index greater than 85, NIHSS, and Stroke Impact Scale (SIS) at 12 months. The proportion of patients with a mRS less than or equal to 3 at the 6-month follow-up was 25% in the surgical group and 5.6% in the medical treatment group. Fifty percent in the surgical group had a mRS less than or equal to 3 compared with 22.2% in the medical group at 1-year follow-up. The primary outcome was not significant between the medical and surgical groups. The secondary outcomes were significantly different between the medical and surgical groups at 6 and 12 months when analyzed on the basis of nondichotomized mRS. The dramatic life-saving effect of hemicraniectomy was evident with an absolute-risk reduction of 52.8% in mortality in the surgical group compared with the medical group. At the end of the follow-up, 67% of the survivors in the surgical group and 50% in the medical group were at home. In the predefined subgroup analysis, DWI infarct volume at the beginning of enrolment in the medical group correlated with the mRS at 6 months. In the surgical group, there was a trend toward worse outcomes in patients with higher infarct volumes at the time of enrollment and younger age correlated with better functional outcomes at 6 months. There was no significant difference between dominant and nondominant hemisphere infarction outcomes at the end of 1-year follow-up. Interviews at the end of 1-year showed that hemicraniectomy patients were satisfied with their quality of life. The DECIMAL trial thus showed that, among patients with malignant MCA infarction, early decompressive hemicraniectomy when offered to younger patients led to better functional outcome and survival compared with medical management alone. DESTINY is a German trial that randomized 32 patients with malignant MCA infarction to decompressive hemicraniectomy plus medical management or medical management alone.6 Patients aged 18 to 60 years with NIHSS score greater than 18 for nondominant hemisphere and greater than 20 for dominant hemisphere, CT scan showing infarction of at least two-thirds of the MCA territory, and onset of symptoms ⬎12 and ⬍36 hours before hemicraniectomy were enrolled. The NIHSS score in the medical treatment group was higher than the surgical group at baseline. The primary outcome was the 30-day mortality and secondary outcomes looked at functional recovery at 6 and 12 months. In the hemicraniectomy group, 88% of the patients survived compared with 47% in the medical group after 30 days. Survival after 6 and 12 months was 82% in the surgical group and 47% in the medical group. Analysis of functional outcomes at 6 and 12 months showed positive results in favor of hemicraniectomy. Forty-seven percent in the surgical group versus 27% in the medical group reached an mRS of 0 to 3; 77% in the surgical group reached mRS of 0 to 4 versus 33% in medical group. Eighty-two percent in the surgical group and 47% in the medical group were alive. In an interview with patients and their caregivers, there was 100% satisfaction with the hemicraniectomy procedure in the surgical group. The trial was not blinded and there were 2 major protocol violations but the overall result suggested that hemicraniectomy led to improved survival and better functional outcomes. The HAMLET trial is an ongoing study with 112 patients aged between 18 and 60 years with a malignant MCA infarction randomized to hemicraniectomy with medical treatment versus best medical treatment.19 The enrolment included patients with CT scan showing greater than two-thirds involvement of the MCA territory, NIHSS score ⬎16 for nondominant hemisphere, and NIHSS score ⬎21 for dominant hemispheric infarcts in a treatment window of 96 hours. The primary outcome was functional outcome as determined by the mRS at 1-year dichotomized as good (mRS 0 –3) and poor (mRS 4 to dead). Secondary outcomes were mRS of 0 to 2 at 12 months, NIHSS score, Barthel’s index, depression scores, visual analog scales, and quality of life assessment tools at 1 and 3 years. © 2009 Lippincott Williams & Wilkins The Neurologist • Volume 15, Number 4, July 2009 The hemicraniectomy and durotomy on deterioration from infarction related swelling trial (HeADDFIRST) was the first North American trial to randomize 26 patients between the ages 18 to 75 with a NIHSS score ⬎18, premorbid mRS ⬍2, and CT evidence of a massive (⬎180 mL) MCA infarction plus or minus ACA or PCA infarction.18 All patients initially received standard medical therapy and were subsequently randomized to hemicraniectomy plus standard medical therapy or standard medical therapy alone. This randomization was based on midline shift within 96 hours defined as ⬎7-mm anteroseptal or ⬎4-mm pineal shift. Primary outcomes measures were mortality, functional outcome, quality of life, caregiver burden, patient perceptions of survivorship, and acute health care utilization measured 21, 90, and 180 days after stroke onset. Mortality was 40% in the medical group versus 23% in surgical group at 21 days. The trial showed an early benefit in favor of surgery at 21 days but failed to show any sustained benefit at 3 and 6 months or improved functional outcomes at 6 months. HeADDFIRST remains published only in the abstract form. The robust amount of information favoring hemicraniectomy for improved survival and functional outcomes from the DECIMAL and DESTINY trials led to the investigators of these trials combining their data with HAMLET to perform a pooled analysis. In the pooled analysis, the inclusion criteria were the following: patients aged 18 to 60 years with malignant MCA infarction, NIHSS score ⬎15, decrease in the level of consciousness to a score of 1 or greater on item 1a of NIHSS, greater than 50% involvement of the MCA on CT scan, DWI infarct volume ⬎145 cm3, inclusion within 45 hours after onset of symptoms, and an informed consent by the patient or a legal representative.20 The authors looked at the dichotomized mRS (0 – 4 as favorable and 5 to death as unfavorable) as the primary outcome measure. Secondary analyses included an alternative dichotomized mRS (0 –3 as favorable and 4 to death as unfavorable) and case fatality at 1 year. Ninety-three patients were included, of whom 51 were randomized to hemicraniectomy and 42 to conservative medical management. The results showed a dramatic increase in the primary outcome for the hemicraniectomy group. Seventy-five percent in the hemicraniectomy groups had a mRS ⱕ 4 compared with 24% in the medical group (ARR ⫽ 51%). This resulted in a number needed to treat (NNT) of 2 for prevention of mRS 5 or death and 4 for prevention of mRS 4 to death. The mortality at 1 year was 71% for medical group versus 21% for surgical group resulting in an absolute benefit of 50% which translates to a NNT of 2 to prevent 1 death. There was no significant heterogeneity between the 3 trials in the pooled analyses. A subgroup analysis was done according to age (less than or greater than 50), timing of randomization (less than or greater than 24 hours), and presence of aphasia. Hemicraniectomy was beneficial in all the subgroups. Quality of life measures could not be looked at because the individual trials (DECIMAL, DESTINY, HAMLET) were incomplete at the time of the pooled analyses. These data have not yet been published but will provide a critical counterbalance to the question of whether a life-saving procedure is considered worthwhile by the patient and family. On comparison of functional outcomes among survivors, 75% of patients who received medical therapy had a favorable outcome (mRS ⱕ3) at 1 year compared with 55% who underwent hemicraniectomy.21 It can be argued that medical therapy leads to death or survival with a good favorable outcome whereas hemicraniectomy produces more survivors who are moderate to severely disabled. However, in a malignant MCA infarction trial, where the mortality of the medically treated group is 80%, it may be inadequate to compare outcomes only in survivors. Hemicraniectomy increases the likelihood of achieving a mRS ⱕ3 by 23% at the expense of a 29%-increased chance of sustaining a moderate to severe disability. Hence, the decision to proceed with hemicraniectomy has to be made on an individual basis. © 2009 Lippincott Williams & Wilkins Decompressive Hemicraniectomy A number needed to treat (NNT) of 2 for prevention of mRS 5 or death and 4 for prevention of mRS 4 to death. Hemicraniectomy increases the likelihood of achieving a mRS ⱕ3 by 23% at the expense of a 29%-increased chance of sustaining a moderate to severe disability. OUR RECOMMENDATION ON OFFERING HEMICRANIECTOMY TO MALIGNANT MCA PATIENTS Given the data from DECIMAL, DESTINY, and the pooled analyses in favor of hemicraniectomy for malignant MCA infarction, the next challenge would be whether we can apply the evidence. A number of questions arise when one considers hemicraniectomy for malignant MCA infarction. The key questions to consider when dealing with a decision to proceed with hemicraniectomy are age, patient selection, timing of surgery, and presence of a dominant hemispheric infarction. Impact of Age on Outcomes in Patients Undergoing Hemicraniectomy Age is a powerful predictor of functional outcome in patients undergoing hemicraniectomy.4,22 Based on the results from the pooled analyses, it is clear that hemicraniectomy is beneficial when offered to younger patients (in this case results dichotomized at 50 years).20 When drawing a conclusion regarding age from the trials, 1 important distinction between the European and the North American trials is that the upper limit for age was 60 years for DECIMAL, DESTINY, and HAMLET and 75 years for HeADDFIRST. Thus the dilemma of offering hemicraniectomy remains when encountering an older patient (⬎60 years). Previously, it was thought that older patients performed worse than younger patients because of the fact that older patient more often had associated comorbidities contributing to a poor outcome.4 Only 27 patients in the pooled analysis were 50 years of age or older. Given the survival benefit of hemicraniectomy for younger patients, more data are needed to determine whether hemicraniectomy is an appropriate treatment option for patients aged 60 to 80 years. Patient Selection for Hemicraniectomy Hemicraniectomy is usually considered when there are unequivocal clinical and neuroimaging signs of impending brain edema, clinical deterioration is occurring (eg, reduced level of consciousness), and in some centers when medical measures such as hypertonic saline or osmotic agents have failed. It is imperative to recognize the patients at risk for forming brain edema and herniation, so that timely hemicraniectomy can be offered. However, the major difficulty lies in identifying the patients at risk for brain edema formation. Clinically, younger age, NIHSS score ⬎15, nausea, vomiting within the first 24 hours and signs of herniation are www.theneurologist.org | 181 Subramaniam and Hill The Neurologist • Volume 15, Number 4, July 2009 FIGURE 2. Proposed management algorithm of high-risk group of patients with malignant MCA infarction. known clinical predictors for brain edema after MCA infarction.23 The presence of these signs justifies the need for repeating (every 12 hours) neuroimaging to offer early hemicraniectomy. There were substantial differences between DECIMAL, DESTINY, and HAMLET with respect to imaging modalities and timing. DECIMAL was the only trial to incorporate DWI infarct volume an inclusion criterion. Patients were enrolled in DECIMAL only if they had a DWI infarct volume of ⬎145 cm3. DWI infarct volume correlated well with outcomes in the medical group and patients with ⬎200 cm3 DWI volume did not survive without hemicraniectomy. Performing an MRI in acute strokes may not be practical in some centers. DESTINY and HAMLET enrolled patients with more than 50% involvement of the MCA territory. Unfortunately, no specific CT scan markers for malignant MCA transformation were identified in DESTINY. There is definitely a need for future randomized controlled studies to evaluate radiologic markers as predictors of brain edema formation following MCA infarction. To identify the high-risk group of malignant MCA infarction patients potentially eligible for decompressive hemicraniectomy, we propose a management algorithm as outlined in Figure 2. Hemicraniectomy is usually considered when there are unequivocal clinical and neuroimaging signs of impending brain edema, clinical deterioration is occurring and in some centers when medical measures such as hypertonic saline or osmotic agents have failed. 182 | www.theneurologist.org Timing of Hemicraniectomy The optimal timing of hemicraniectomy for malignant MCA infarction remains unknown. Previous case series have reported that early hemicraniectomy for malignant MCA infarction improves survival and outcomes.4 It has been argued that early hemicraniectomy prevents irreversible damage to adjacent brain tissue. Controversy exists over whether hemicraniectomy should be offered to malignant MCA patients at the time of diagnosis as opposed to patients who are symptomatic from brain edema and practices vary widely among centers. Some patients may respond well to medical management for raised ICP and brain edema, and it may be unnecessary to subject these patients to hemicraniectomy. On the other hand, waiting for early deterioration signs to occur might delay management. The timing of hemicraniectomy was limited to less than 48 hours after the stroke onset in DECIMAL and DESTINY, and was less than 96 hours for HAMLET. In the pooled analyses, there was no difference in outcome if hemicraniectomy was performed in the first 24 hours compared with later time window up to 48 hours.20 It remains to be seen whether hemicraniectomy has any benefit on survival and outcome after 48 hours of stroke onset. HAMLET is the only study that addresses the time window for randomization up to 96 hours and the full results of this trial are eagerly awaited.19 Hemicraniectomy can, however, be a planned procedure. In our view, it is relevant to identify the patients early, serially image them and plan for the procedure. Clinically, the useful observation is an early change in the level of consciousness. Note that coma in large hemispheric infarction is most commonly related to subfalcine herniation rather than rostral-caudal degeneration. Anatomy is relevant here; if there is a large degree of temporal lobe infarction, very early hemicraniectomy is preferred to prevent uncal herniation. Early hemicraniectomy may both theoretically protect brain by preserving local capillary level perfusion pressures and prevent the need for intubation, for airway compromise and the evolution of complications such as aspiration pneumonia. For patients requiring © 2009 Lippincott Williams & Wilkins The Neurologist • Volume 15, Number 4, July 2009 hemicraniectomy beyond 48 hours, surgical decisions must be made on an individual basis. In general, the careful clinician should not be surprised by the need for hemicraniectomy and should proceed in an anticipatory fashion. One possibly common approach to hemicraniectomy is to use medical therapy first. This would include intensive care support, intubation with careful physiological control, use of osmotic agents, hypertonic saline, and in some centers hypothermia as a general measure to reduce intracranial pressure. However, earlier hemicraniectomy has the potential to avoid the complications of such care which include pneumonia, deep venous thrombosis, malnutrition, and others. It is our view, that if a hemicraniectomy is desirable, that it should be done early, before aggressive medical measures are needed and thereby avoid the complications of prolonged intubation. Decompressive Hemicraniectomy Other Considerations—Social Support and Anatomy Other considerations at the time of hemicraniectomy include, we believe, some assessment of social support. This procedure does not occur in a sphere isolated to the patient. A hemicraniectomy commits the patient and his/her family to 4 to 6 months of inpatient rehabilitation and 6 months or more of outpatient rehabilitation, physical changes to the home which will include costs for renovations, and increased costs for devices (eg, wheelchairs, transportation, etc.). It is very challenging to make a comprehensive assessment of these social factors when decisions about surgery need to be made in the relative urgency of an acute stroke situation. A hemicraniectomy commits the patient and his/her It is our view, that if a hemicraniectomy is desirable, family to 4 to 6 months of inpatient rehabilitation that it should be done early, before aggressive and 6 months or more of outpatient rehabilitation. medical measures are needed and thereby avoid the complications of prolonged intubation. Hemicraniectomy for Dominant Hemispheric Infarction Performing hemicraniectomy in patients who have suffered large dominant hemisphere infarction has been viewed with skepticism.2,4 However, in the long term, aphasia may be less disabling than severe hemispatial neglect.24 Moreover, functional MRI studies have demonstrated that most functional recovery from aphasia is because of cortical reorganization in the nondominant (usually right) hemisphere.25 Significant improvement in aphasia can occur after hemicraniectomy because of cortical reorganization of adjacent areas of normal brain tissue that surrounds the language areas.26 In the DECIMAL trial, there was no significant difference in outcome after 1 year between dominant and nondominant hemispheric strokes. All 10 survivors of hemicraniectomy in DECIMAL acknowledged that ‘life is worth living’ following the procedure and 6 of 10 survivors were aphasic. In the pooled analyses performed by Vahedi et al, hemicraniectomy was beneficial in improving survival and functional outcomes regardless of the presence or absence of aphasia at baseline. There are subtleties here, however, that we must consider. The major outcome of the pooled analysis was mRS 0 to 4 versus 5 to 6. At such a dichotomy of the mRS, higher cortical function (aphasia or hemispatial neglect) does not influence the outcome. Finer grades of outcome assessment, including quality of life assessments, are needed to help us determine if the differences in outcome depend upon the hemisphere involved. In general, the current evidence supports considering hemicraniectomy of both dominant and nondominant hemispheric infarction. The anatomy of infarction is important. Involvement of the MCA territory only likely provides the best prognosis. If the ACA territory is additionally involved, outcomes may be markedly different because of an involvement of the medial frontal lobes. Personality change, abullia and dysexecutive syndromes are symptoms which interact substantially with the capacity of family supports to function well, and can result in very poor long term outcomes. If the PCA territory is additionally involved, vision and reading add additional disability; in western society, which is so visually dependent (eg, driving, computers, reading, television), vision impairment may also lead to poorer long term outcomes. Additionally, PCA involvement may lead to substantial temporal lobe infarction with subsequent uncal herniation, something which anatomically is not well relieved by the more superior hemicraniectomy with duroplasty procedure. If life preservation is the goal, temporal lobectomy or infarct-ectomy may be required in cases where large temporal lobe infarction is present. In the pooled analyses, the anatomy of infarction was not assessed as a predictor of outcome, but certainly may have played a role in the selection of patients for trial entry. Our view is that a judgment must be made by the attending physician on the amount and localization of tissue involved before offering this procedure. Involvement of the MCA territory only likely provides the best prognosis. CONCLUSIONS The current evidence supports considering hemicraniectomy of both dominant and nondominant hemispheric infarction. © 2009 Lippincott Williams & Wilkins It is now clear that hemicraniectomy is both a life-saving and disability-reducing procedure in malignant MCA infarction. However, more data are still required to address unresolved issues. Hemicraniectomy and duroplasty should be considered in all patients with large hemispheric infarction but should not be offered to all. A careful assessment of the interplay of factors including age, comorbid illness, radiologic size, and anatomy of the infarct with www.theneurologist.org | 183 The Neurologist • Volume 15, Number 4, July 2009 Subramaniam and Hill predicted brain modalities affected, and social situation is required. Dominant hemisphere infarction is not an automatic contraindication to this procedure. In those patients for whom hemicraniectomy is indicated, we favor early and planned surgery. REFERENCES 1. Hacke W, Schwab S, Horn M, et al. Malignant middle cerebral artery territory infarction: clinical course and prognostic signs. Arch Neurol. 1996;53:309 – 315. 2. Robertson SC, Lennarson P, Hasan DM, et al. Clinical course and surgical management of massive cerebral infarction. Neurosurgery. 2004;55:55– 61; discussion 61–2. 3. Walz B, Zimmermann C, Böttger S, et al. Prognosis of patients after hemicraniectomy in malignant middle cerebral artery infarction. J Neurol. 2002;249:1183–90. 4. Schwab S, Steiner T, Aschoff A, et al. Early hemicraniectomy in patients with complete middle cerebral artery infarction. Stroke. 1998;29:1888 –1893. 5. Wijdicks EF, Diringer MN. Middle cerebral artery territory infarction and early brain swelling: progression and effect of age on outcome. Mayo Clin Proc. 1998;73:829 – 836. 6. Juttler E, Schwab S, Schmiedek P, et al. Decompressive surgery for the treatment of malignant infarction of the middle cerebral artery (DESTINY): a randomized, controlled trial. Stroke. 2007;38:2518 –2525. 7. Vahedi K, Vicaut E, Mateo J, et al. Sequential-design, multicenter, randomized, controlled trial of early decompressive craniectomy in malignant middle cerebral artery infarction (DECIMAL Trial). Stroke. 2007;38:2506 –2517. 8. Demchuk AM, Krieger DW. Mass effect with cerebral infarction. Curr Treat Options Neurol. 1999;1:189 –199. 9. Frank JI. Large hemispheric infarction, deterioration, and intracranial pressure. Neurology. 1995;45:1286 –1290. 10. Ropper AH. Lateral displacement of the brain and level of consciousness in patients with an acute hemispheral mass. N Engl J Med. 1986;314:953–958. 11. Subramaniam S, Hill MD. Massive cerebral infarction. Neurologist. 2005;11: 150 –160. 12. Krieger DW, Demchuk AM, Kasner SE, et al. Early clinical and radiological predictors of fatal brain swelling in ischemic stroke. Stroke. 1999;30:287– 292. 184 | www.theneurologist.org 13. von Kummer R, Meyding-Lamade U, Forsting M, et al. Sensitivity and prognostic value of early CT in occlusion of the middle cerebral artery trunk. Am J Neuroradiol. 1994;15:9 –15; discussion 16 – 8. 14. Barber PA, Demchuk AM, Zhang J, et al. Computed tomographic parameters predicting fatal outcome in large middle cerebral artery infarction. Cerebrovasc Dis. 2003;16:230 –235. 15. Demchuk A, Krieger D. Large middle cerebral artery infarction. Neurology. 1998;51:1514 –1515. 16. Ransohoff J, Benjamin V. Hemicraniectomy in the treatment of acute subdural haematoma. J Neurol Neurosurg Psychiatry. 1971;34:106. 17. Carter BS, Ogilvy CS, Candia GJ, et al. One-year outcome after decompressive surgery for massive nondominant hemispheric infarction. Neurosurgery. 1997;40:1168 –1175; discussion 1175– 6. 18. Frank J. Hemicraniectomy and Durotomy upon deterioration from inafrction related swelling trial (HeADDFIRST): first public presentation of primary study findings. Neurology. 2003;60(suppl 1):A426. 19. Hofmeijer J, Amelink GJ, Algra A, et al. Hemicraniectomy after middle cerebral artery infarction with life-threatening Edema trial (HAMLET). Protocol for a randomised controlled trial of decompressive surgery in spaceoccupying hemispheric infarction. Trials. 2006;7:29. 20. Vahedi K, Hofmeijer J, Juettler E, et al. Early decompressive surgery in malignant infarction of the middle cerebral artery: a pooled analysis of three randomized controlled trials. Lancet Neurol. 2007;6:215–222. 21. Puetz V, Campos CR, Eliasziw M, et al. Assessing the benefits of hemicraniectomy: what is a favorable outcome? Lancet Neurol. 2007;6:580; author reply 580 –1. 22. Koh MS, Goh KY, Tung MY, et al. Is decompressive craniectomy for acute cerebral infarction of any benefit? Surg Neurol. 2000;53:225–230. 23. Kasner SE, Demchuk AM, Berrouschot J, et al. Predictors of fatal brain edema in massive hemispheric ischemic stroke. Stroke. 2001;32:2117–2123. 24. Paolucci S, Antonucci G, Pratesi L, et al. Functional outcome in stroke inpatient rehabilitation: predicting no, low, and high response patients. Cerebrovasc Dis. 1998;8:228 –234. 25. Cao Y, Vikingstad EM, George KP, et al. Cortical language activation in stroke patients recovering from aphasia with functional MRI. Stroke. 1999; 30:2331–2340. 26. Heiss WD, Karbe H, Weber-Luxenburger G, et al. Speech-induced cerebral metabolic activation reflects recovery from aphasia. J Neurol Sci. 1997;145: 213–217. © 2009 Lippincott Williams & Wilkins
© Copyright 2024