Malignant large artery stroke is associated with high mortality of 70% to 80% with best medical management. Decompressive craniectomy (DC) is a highly effective tool in reducing mortality. Convincing evidence has accumulated from several randomized trials, in addition to multiple retrospective studies, that demonstrate not only survival benefit but also improved functional outcome with DC in appropriately selected patients. This article explores in detail the evidence for DC, nuances regarding patient selection, and applicability of DC for supratentorial intracerebral hemorrhage and posterior fossa ischemic and hemorrhagic stroke.
Key points
- •
Acute occlusion of a proximal large intracranial artery has high risk of progression to malignant infarct.
- •
The results of best medical management including aggressive ICU measures are dismal, with mortality of up to 80%.
- •
Decompressive craniectomy (DC) is demonstrated to conclusively improve mortality to around 30%.
- •
DC also improves the chances of good functional outcome when performed within 48 hours in patients younger than 60 years of age but should be considered beyond these circumstances on a case-by-case basis.
- •
Better indicators of edema progression, patient eligibility, and clinical outcome measures are urgently required for use in larger randomized controlled trials.
- •
DC also serves an important role in managing select patients with supratentorial spontaneous hemorrhage, and posterior fossa hemorrhage and ischemic stroke.
Introduction
Progressive global or local intracranial mass effect is frequently encountered with large hemispheric infarcts (“malignant infarcts” ). The resulting increased intracranial pressure (ICP) results in the potential for worsened outcomes and dramatically increased mortality. Decompressive craniectomy (with capacious duraplasty; DC) is a highly effective procedure that is often warranted in such situations. DC for ischemic stroke has been conclusively proven to reduce mortality in large hemispheric infarcts and is a powerful tool in a comprehensive neurovascular team’s armamentarium. Despite the utility of DC, there are schools of thought that discourage surgery because of the biased perception that patients survive but are left with severe burdensome disability. This article discusses the available literature and demonstrates the effectiveness of DC in malignant infarction and functional outcome. Also discussed is the role of DC in posterior fossa (cerebellar) stroke and spontaneous intracerebral hematomas (ICH).
Introduction
Progressive global or local intracranial mass effect is frequently encountered with large hemispheric infarcts (“malignant infarcts” ). The resulting increased intracranial pressure (ICP) results in the potential for worsened outcomes and dramatically increased mortality. Decompressive craniectomy (with capacious duraplasty; DC) is a highly effective procedure that is often warranted in such situations. DC for ischemic stroke has been conclusively proven to reduce mortality in large hemispheric infarcts and is a powerful tool in a comprehensive neurovascular team’s armamentarium. Despite the utility of DC, there are schools of thought that discourage surgery because of the biased perception that patients survive but are left with severe burdensome disability. This article discusses the available literature and demonstrates the effectiveness of DC in malignant infarction and functional outcome. Also discussed is the role of DC in posterior fossa (cerebellar) stroke and spontaneous intracerebral hematomas (ICH).
Ischemic hemispheric stroke (supratentorial)
Epidemiology
The prevalence of malignant ischemic stroke is reported to be between 2% and 8% of all patients with ischemic stroke. The mortality rate of patients with malignant stroke who undergo aggressive nonoperative management is in the range of 40% to 80%. Performing a DC can reduce this mortality rate to 30% ( Table 1 ).
| Trial | Year | Age (y) | No. of Patients (n) | Time to Surgery from Onset of Stroke (h) | Medical Arm | Surgical Arm | ||
|---|---|---|---|---|---|---|---|---|
| Mortality (%) | mRS >4 (%) | Mortality (%) | mRS >4 (%) | |||||
| Destiny-I | 2007 | 18–60 | 32 | 12–36 | 53 | 73 | 17.6 | 53 |
| Decimal | 2007 | 18–55 | 38 | <24 | 77.8 | 23 | 25 | 50 |
| Hamlet | 2009 | 18–60 | 64 | <96 | 59 | 15 | 22 | 53 |
| Pooled Analysis | 2007 | 18–60 | 32 | <48 | 71 | 7 | 22 | 35 |
| Destiny-II | 2011 | >61 | 49 | <48 | 70 | 28 | 33 | 60 |
| HeADDFIRST | 2014 | 18–75 | 26 | <96 | 40 | 60 | 21 | 72 |
Pathophysiology of Malignant Stroke
Microscopic and cellular changes
Neuronal death in ischemia occurs through apoptosis, necrosis, and autophagy. Briefly, cellular events begin with deprivation of glucose and oxygen, energy failure, ATP depletion and loss of ion exchange function of membrane pumps, terminal depolarization and glutamate-mediated calcium excitotoxicity, calcium-dependent enzyme activation, generation of free radicals, and ultimately degradation of cellular molecules. Both cytotoxic edema (from above) and vasogenic edema (later on from blood-brain barrier disruption) occur in malignant stroke. Identifying individual genetically determined factors of cell death and inflammation could serve as molecular markers of malignant stroke risk in a given patient.
Macroscopic pathology
Within the macroscopic region of infarct, there are well-described zones of decreasing cerebral blood flow and increasing impairment of function ( Fig. 1 ). This concept of ischemic penumbra and potentially salvageable brain tissue is central to strategic implementation of therapies including DC. Animal studies have convincingly demonstrated improvement in cortical perfusion, reduction in infarct size, and clinical function following experimental middle cerebral artery (MCA) occlusion. Progressive swelling of infarct tissue leads to transtentorial herniation in a craniocaudal direction and midline shift with subfalcine herniation. Continued swelling can recruit additional arterial territories (posterior and anterior cerebral arteries, respectively) resulting in multiterritory infarction and worsened outcome.
Predictors of Progression
Time since stroke
Cerebral edema progresses during the first 24 to 48 hours after the onset of ischemic stroke and can result in herniation after Day 2 (although herniation can occur earlier than this in some cases).
National Institutes of Health stroke scale
A high initial stroke score, especially involving a score more than 1 on item 1a of the National Institutes of Health stroke scale, has been shown to correlate with an increased risk of progression to malignant edema. Patients with National Institutes of Health stroke scale score of 18 or more on admission are at increased risk of developing malignant cerebral edema.
Computed tomography
A large hypodensity occupying more than two-thirds of the MCA territory is an important predictor of malignant progression. Additional features portending progression include appearance of edema within 6 hours, basal ganglia involvement, dense MCA sign, and midline shift more than 5 mm in the first 2 days. The risk of malignant course is estimated by ASPECTS (Alberta Stroke Program Early CT score), where 7 was the cutoff score to determine progression to malignant infarction with 50% sensitivity and 86% specificity. On computed tomography (CT) perfusion maps the early involvement of more than two-thirds of the MCA territory predicted malignant course with 92% sensitivity and 94% specificity.
MRI
An MRI-measured infarct volume of greater than 145 mL on diffusion-weighted imaging done within 14 hours of stroke onset was predictive of clinical deterioration in a study reported by Oppenheim and colleagues.
The risk for malignant stroke progression is likely linked to the quality of the collateral circulation. Mathematical prediction models incorporating quality of collateral circulation, infarct size, and cellular ischemia response have the potential to guide timely institution of early DC.
Best Medical Management
Medical management of patients with malignant MCA infarction specifically is not well defined and follows general management of raised ICP. Most authors have recommended osmotherapy with mannitol or hypertonic saline, head end elevation to 30°, short-term hyperventilation, blood pressure control, maintenance of normal blood glucose, body temperature, and intravascular volume to reduce ICP. Despite best medical management, patients continue to deteriorate and hence it should be considered as a bridge to more definitive therapy, which is surgical decompression consisting of hemicraniectomy. ICP monitoring may help guide management of intracranial hypertension in patients who are not surgical candidates.
Data on Decompressive Craniectomy Before Randomized Controlled Trials
Gupta and colleagues performed a systematic review of 15 studies consisting of a total of 138 patients. The overall mortality in this cohort was 24%, which compared favorably with published reports suggesting mortality of 78% in this patient population. Additionally, 42% of the patients had a good outcome, defined as patients who were independent (7%) or who had mild to moderate disability (35%).
Data from Randomized Controlled Trials on Hemicraniectomy for Malignant Ischemic Stroke
Table 1 is a compilation of the landmark randomized controlled trials (RCTs) comparing DC plus medical management with medical management alone in malignant stroke involving the MCA territory.
Study design
The study design of all six multicenter prospective RCTs was similar with some notable differences. Patients were randomized to surgical treatment versus medical management. The trials included patients of less than or equal to 60 years of age except HeADDFIRST (18–75 years). The DESTINY II trial was focused on patients older than 60 years. The primary outcome was defined by the MRS (modified rankin scale) score, which was dichotomized between favorable outcome (0–3) and unfavorable outcome (4–6) in the DECIMAL, DESTINY, and HAMLET trials. In the pooled analysis of 2007 (included patients from the three European RCTs [DECIMAL, DESTINY I, and HAMLET] to reliably predict the effects of surgery with respect to timing [<48 hours] and functional outcome in patients with ischemic stroke ) and DESTINY II trial, MRS was dichotomized between 0 and 4 (good outcome) and 5 and 6 (poor outcome). The HeADDFIRST trial reported primary outcome as case fatality at 21 days after treatment.
Surgical technique (craniectomy-duraplasty) was largely similar in all trials. However, the time interval allowed between symptom onset and surgery differed. DC was performed within 24 hours of stroke onset in DECIMAL, 96 hours in HAMLET and HeADDFIRST, 48 hours in DESTINY II, and between 12 and 36 hours in DESTINY I. Another important difference was in imaging selection criteria. DESTINY I and II required infarct size greater than two-thirds of MCA territory (including basal ganglia) on CT, infarct volume greater than 145 cm 3 on diffusion-weighted MRI in DECIMAL, MCA infarct size of at least two-thirds in HAMLET, and greater than 50% of the MCA territory in HeADDFIRST.
Results of the randomized controlled trials
Effects on mortality (MRS 6)
All the trials (except HeADDFIRST) showed statistically significant reduction in mortality in surgical patients ( Fig. 2 ). DECIMAL and HAMLET showed a statistically significant absolute risk reduction (ARR) of 53% at 6 months ( P <.001) and 37% at 1 year ( P <.002), respectively. DESTINY I reported 12% mortality in the surgical arm versus 53% in medical arm at 30 days ( P = .002). In the pooled analysis, ARR in the surgical arm was found to be 51% (95% confidence interval, 34–69) at 12 months. DESTINY II showed 43% and 76% mortality in the surgical and medical arm, respectively, at 12 months ( P <.01).
Effects on moderately severe disability (MRS 4)
The pooled analysis and the DESTINY II trial included MRS 4 in the good outcome category with the aim of demonstrating reduced mortality without an increase in severely disabled survivors (MRS 5). A major difference between MRS 4 and 5 is that the latter are completely dependent (including permanent vegetative state). Ultimately the pooled analysis results showed greater number of patients in MRS 0 to 4 in the surgical group (76%) versus medical (24%) at 1 year. This means that patients treated with DC have a statistically higher chance of having a good outcome with survival than medically treated survivors. The DESTINY II trial showed similar results (surgical decompression 38% vs medical 18%; P = .04). The effect, however, was not as large as in the trials involving younger (<60 years) patients.
Effects on severe disability (MRS 5)
DECIMAL, DESTINY, and HAMLET I showed a statistically significant reduction in patients with MRS 5 (severely disabled, bedridden, incontinent, and requiring constant nursing care and attention). In fact, the results of the DECIMAL trial reported no patients with MRS score of 5 at 1 year postsurgery ( P <.0001). The pooled analysis showed 41.9% (95% confidence interval, 25%–58.6%) ARR for bad outcome with surgery. The DESTINY II trial, however, had 28% patients in MRS 5 after surgery versus 13% after medical management. Although the result was caused by high mortality with medical treatment, it does indicate that DC can result in a significant number of severely disabled survivors in an elderly population (age >60). Further study is needed to determine the utility of DC in this age group. It is possible that further advances in medical therapy, rehabilitation, robotics, and brain computer interfaces will result in better outcomes. At our institution we consider craniectomy in select patients after careful discussion with the patients’ surrogates.
Effect on MRS 0 to 3 (good outcome)
The pooled analysis showed a statistically significant increase in number of patients in MRS 0 to 3 after surgical decompression versus best medical therapy for patients younger than age 60. These data are compelling and should be communicated in a meaningful way to surrogates of patients who have malignant MCA infraction.
Effect of timing of surgery on outcome
HAMLET afforded an opportunity to study the effect of timing on outcomes. Subgroup analyses indicated a far greater benefit of DC in patients operated within 48 hours in reducing the risk of severe disability or death (MRS 5/6; ARR 48%) versus those treated after 48 hours (ARR 27%). The pooled analysis confirmed this, with an ARR for MRS 5/6 of nearly 50% for patients operated within 24 hours. Recent guidelines recommend (class I, level B) performing hemicraniectomy within 48 hours in patients younger than 60 years of age. At our institution we generally favor early craniectomy for patients who show evidence for malignant MCA infarction based on these data.
Dominant hemisphere involvement
In a subgroup analysis of patients with dominant versus nondominant hemispheric stroke (in the DECIMAL trial), there was no statistically significant difference reported with respect to the primary functional outcomes. Several retrospective studies have reported significant improvement of aphasic symptoms after infarction of speech-dominant hemisphere treated by DC. There are no convincing long-term data in the literature that justify a hemisphere laterality bias in decision-making.
Additional evidence
A critically appraised topic was commissioned in 2011 by Starling and colleagues through development of a clinical scenario, structured clinical questions, search strategy and selection of an article, critical appraisal, evidence summary, clinical bottom lines, and expert commentary from vascular neurologists and a vascular neurosurgeon. They included data on malignant stroke from multicenter randomized trials and an updated meta-analysis. The study concluded that early surgical decompression (within 48 hours of stroke onset) reduces the risks of death and poor clinical outcome at 1 year in patients with large territory cerebral infarction.
Limitations of the randomized controlled trials
There are several limitations associated with these studies. The overall number of patients with good functional outcomes (MRS 0–3) was not statistically significant in the surgical arm (DECIMAL, DESTINY I, and HAMLET). The profile of surgical patients was probably not “real world.” For example, the DECIMAL trial excluded patients who were unable to undergo MRI or those who had received tissue plasminogen activator. HAMLET excluded patients who received tissue plasminogen activator within 12 hours of randomization. Patients had to have good baseline functional status as calculated by MRS. Best medical management varied between and within trials. Importantly average time from stroke onset to randomization varied from 24 to 96 hours. None of the investigators grading MRS outcome in DESTINY I and HAMLET were blinded. An overarching limitation is the reliance on MRS to grade outcomes. It is imperative to understand that MRS lends disproportionate importance to gait while neglecting other parameters, such as personal satisfaction, sense of fulfillment, caregiver satisfaction, cognitive function, symptoms of depression, and so forth. For instance, someone in a wheelchair could be highly productive on a personal and professional level. The significance of cultural differences in addition to the previously mentioned points, in individual cases, should also be recognized.
Surgical Technique
We prefer to place the head in rigid three-pin fixation. A large reverse question mark flap is turned to allow access to a large part of the hemicranium. A large craniectomy is performed involving the frontotemporoparietal region without injury to the venous sinuses. Avoiding the frontal air sinus is also preferred to avoid risks of infection and cerebrospinal fluid leak. It is critical to take the inferior bone cut as low as possible to the floor of the middle fossa and ronguer/drill additional bone to accomplish this. A typical craniectomy flap measures at least 15 cm anteroposteriorly and 10 to 12 cm craniocaudal. The dura is opened in a C-shaped or stellate manner. When the anterior temporal lobe is infarcted and tentorial herniation is present or impending, it is our preference to perform an anterior temporal lobectomy with resection of the uncus and visualization of the tentorial edge, third nerve, and midbrain. This reduces brainstem compression in cases of refractory postoperative swelling and likely results in less need to return to the operating room. A lax duraplasty is performed with autologous pericranial graft. The closure must be capacious; one must be able to pick up and freely slide the lax dural sac. Meticulous intradural and epidural hemostasis is achieved. Muscle is reapproximated loosely or not at all. Scalp is closed in layers (drains are optional but often preferred). A parenchymal or subdural ICP monitor is optional. The bone flap is typically discarded because we prefer delayed cranioplasty with a custom implant. Alternately one could store the bone flap in the abdominal wall or cryopreserve it. Postoperatively, we transfer patients to the neurosurgical intensive care unit without extubation.
Postoperative Management
Standard intensive care unit management of increased ICP is carried out. Early extubation without gagging is attempted. Early enteral nutrition is initiated by postoperative Day 1. Subcutaneous heparin is initiated as chemical deep venous thrombosis prophylaxis after 24 hours unless contraindications exist. We have a low threshold for performing early tracheostomy and/or endoscopic percutaneous gastrostomy. With stable postoperative CT, aspirin is initiated after 24 hours. Aggressive physical therapy, speech therapy, and rehabilitation are an integral part of postoperative management.
Complications of Decompressive Craniectomy
Hygroma or subdural fluid collection is the most frequently encountered complication, occurring in 50% to 58% of patients in a study reported by Aarabi and colleagues (most are clinically insignificant). Hydrocephalus is seen as a delayed complication in 7% to 12% of the patients and may require shunt placement (our own experience suggests a lower risk than what has been published). Infection is reported between 2% and 7% (our experience suggests this may be closer to 1% and is minimized by avoidance of frontal sinus violation and using pericranium instead of artificial dural substitutes). Sinking flap syndrome (syndrome of the trephined) occurs in some patients but is ameliorated by cranioplasty. Overall it is our impression that the complication rate from this procedure is acceptably low and should not be the reason to withhold this life saving procedure for patients who could benefit.
Decompressive Craniectomy for Malignant Middle Cerebral Artery Stroke: A Case Illustration
A 61-year-old man presented with acute right hemiplegia caused by embolic occlusion of right M1 following recent aortic root surgery. CT revealed large right MCA territory infarct (>2/3) ( Fig. 3 ). Because of large infarct size and high mortality with medical management, a decision to proceed with DC was made after discussion with family ( Fig. 4 ). He demonstrated excellent recovery following DC. Cranioplasty with custom implant was performed ( Fig. 5 ). His 5-month MRS was 3. He and his family were happy that every effort was made to save his life in the acute setting including performance of DC.
Related posts:
Controversies in Spinal and Cranial Surgery
Lumbar Radiculopathy in the Setting of Degenerative Scoliosis
Bone Morphogenic Protein Use in Spinal Surgery
The Case for Deformity Correction in the Management of Radiculopathy with Concurrent Spinal Deformity
Surgical Treatment of Trigeminal Neuralgia
Comparison of Prenatal and Postnatal Management of Patients with Myelomeningocele
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
