Middle meningeal artery embolization for chronic subdural hematoma: a systematic review and meta-analysis

Middle meningeal artery (MMA) embolization has been proposed as a minimally invasive treatment for chronic subdural hematoma (cSDH). The aim of this systematic review and meta-analysis is to compare outcomes after MMA embolization versus conventional management for cSDH. We performed a systematic review of PubMed, Embase, Oxford Journal, Cochrane, and Google Scholar databases from April 1987 to October 2020 in accordance with PRISMA guidelines. Studies reporting outcomes after MMA embolization for ≥3 patients with cSDH were included. A meta-analysis comparing MMA embolization with conventional management was performed. The analysis comprised 20 studies with 1416 patients, including 718 and 698 patients in the MMA embolization and conventional management cohorts, respectively. The pooled recurrence, surgical rescue, and in-hospital complication rates in the MMA embolization cohort were 4.8% (95% CI 3.2% to 6.5%), 4.4% (2.8% to 5.9%), and 1.7% (0.8% to 2.6%), respectively. The pooled recurrence, surgical rescue, and in-hospital complication rates in the conventional management cohort were 21.5% (0.6% to 42.4%), 16.4% (5.9% to 27.0%), and 4.9% (2.8% to 7.1%), respectively. Compared with conservative management, MMA embolization was associated with lower rates of cSDH recurrence (OR=0.15 (95% CI 0.03 to 0.75), p=0.02) and surgical rescue (OR=0.21 (0.07 to 0.58), p=0.003). In-hospital complication rates were comparable between the two cohorts (OR=0.78 (0.34 to 1.76), p=0.55). MMA embolization is a promising minimally invasive therapy that may reduce the need for surgical intervention in appropriately selected patients with cSDH. Additional prospective studies are warranted to determine the long-term durability of MMA embolization, refine eligibility criteria, and establish this endovascular approach as a viable definitive treatment for cSDH.

Cerebral Venous Thrombosis at High Altitude: A Retrospective Cohort of Twenty-one Consecutive Patients

Background  Cerebral venous thrombosis (CVT) is a rare cerebrovascular disorder, comprising <1% of all strokes. The incidence of CVT is higher in females but a small number of cases suggest that men have a higher risk for CVT in high elevation. The aim of this retrospective cohort study is to investigate this gender-related relationship and to describe the baseline characteristics and treatment outcomes of patients who suffered CVT at high altitude in eastern Nepal. Methods  We conducted a retrospective analysis of 21 consecutive patients with CVT at a tertiary care center in Nepal from July 2017 to January 2018. Clinical data, radiologic characteristics, therapeutic strategies, and outcomes were analyzed. The Glasgow Outcome Scale (GOS) at discharge was reported for each patient.  Result The study cohort comprised 21 patients (76% males) with a mean of 56 years. Medical comorbidities included hypertension (76%) and diabetes mellitus (57%). All patients received low-molecular-weight heparin therapy (LMWH). Eight patients (38%) underwent decompressive craniectomy while the remaining 13 (62%) were treated with medical therapy alone. The GOS at discharge was 5 in 57%, 2-4 in 33%, and 1 in 10%. Conclusion  In our series, men were found to have a higher risk for CVT at high altitude. The reversal in the gender ratio could be related to elevation, but could also be confounded by alcoholism. Increasingly sophisticated imaging techniques, such as computed tomography venography (CTV) and magnetic resonance venography (MRV), have facilitated the diagnosis of CVT. LMWH is a safe and easily accessible treatment option, especially in developing countries. Further studies are needed to assess the incidence and prevalence of CVT in the developing world, to establish the gender-related trends.

High-Grade Aneurysmal Subarachnoid Hemorrhage: Predictors of Functional Outcome

BACKGROUND

Because the prognosis of high-grade aneurysmal subarachnoid hemorrhage (aSAH), classified as World Federation of Neurosurgical Societies (WFNS) grade IV-V, is generally poor, the functional outcomes of survivors have not been thoroughly explored. The aim of this retrospective cohort study is to determine predictors of functional independence in patients who survive a high-grade aSAH.

METHODS

We retrospectively evaluated consecutive patients with aSAH admitted to a single institution from January 2000 to April 2015. Adult (age ≥18 years) patients with WFNS grade IV-V aSAH were included for analysis. Patients without sufficient baseline data, those who died before discharge, and those without follow-up data were excluded. Univariable and multivariable logistic regression analyses were used to identify factors associated with functional independence, defined as a modified Rankin Scale score of 0-2, at last follow-up.

RESULTS

Of the 260 patients with a WFNS grade IV-V aSAH during the study period, 139 met the inclusion criteria. After a mean follow-up of 6.3 months, functional independence was achieved in 73% of high-grade aSAH survivors (101/139 patients) and in 39% of all high-grade aSAH cases (101/260 patients). Only a lack of cerebrospinal fluid shunt placement was found to be an independent predictor of functional independence in the multivariable analysis (odds ratio 0.28 [0.109-0.722]; P = 0.008).

CONCLUSIONS

Because functional independence can be achieved in the majority of high-grade aSAH survivors, aggressive initial management of high-grade aSAH is warranted. Strategies that reduce the need for permanent cerebrospinal fluid diversion may improve functional outcomes in survivors of high-grade aSAH.

Sylvian Arteriovenous Malformation Resection and Associated Middle Cerebral Artery Aneurysm Clipping: Technical Nuances of Concurrent Surgical Treatment

Approximately 10-30% of brain arteriovenous malformations (AVM) have associated arterial aneurysms (AAA), and the management of these lesions can be challenging. In this video technical note, we demonstrate the microsurgical treatment of an unruptured, Spetzler-Martin grade I AVM in the distal Sylvian fissure with two AAAs arising proximally from the inferior M2 trunk immediately distal to the middle cerebral artery (MCA) bifurcation. First, we resected the superficially located AVM to normalize the blood flow through the Sylvian vein. Next, we performed a Sylvian fissure dissection to access and clip the two MCA AAAs. We also discuss the technical nuances of tandem surgical intervention for AVMs with AAAs as it pertains to this case, particularly with respect to the order of lesion treatment, Sylvian fissure dissection, nidal resection, and aneurysm clipping.

Eyebrow Incision for Surgical Evacuation of a Lobar Intracerebral Hematoma with a Novel Endoport System

Large lobar intracerebral hemorrhages (ICHs) can cause rapid neurological deterioration, and affected patients have low rates of survival and functional independence. Currently, the role of surgical intervention in the management patients with lobar ICHs is controversial. Minimally invasive technologies have been developed which may potentially decrease the operative morbidity of ICH surgery. The aim of this case report is to describe the technical aspects of the use of a novel minimally invasive endoport system, the BrainPath (NICO, Indianapolis, IN, USA), through an eyebrow incision for evacuation of a large lobar hematoma. An 84-year-old female presented with a left frontal ICH, measuring 7.5 cm in maximal diameter and 81 cm³ in volume, secondary to cerebral amyloid angiopathy. Through a left eyebrow incision, a miniature modified orbitozygomatic craniotomy was performed, which allowed endoport cannulation of the hematoma from a lateral subfrontal cortical entry point. Endoport-assisted hematoma evacuation resulted in nearly 90% volume reduction and improvement of the patient's functional status at clinical follow-up. We found that minimally invasive endoport technology can be employed in conjunction with conventional neurosurgical skull base principles to achieve safe and effective evacuation of large lobar hematomas in carefully selected patients.

Cortical plasticity in patients with cerebral arteriovenous malformations

The aim of this review is to ascertain the evidence for cortical plasticity in arteriovenous malformation (AVM) patients. Chronic hypoperfusion due to vascular steal from cerebral AVM can result in a translocation of eloquent neurological functions to other brain areas, a phenomenon known as cortical plasticity. We performed a systematic literature review of the studies that have evaluated cortical plasticity in AVM patients. A total of 22 studies from 1996 to 2014 were included for the analyses. The evaluation of cortical plasticity was performed prior to AVM intervention in 109 patients, and during or after AVM intervention in 18. The most commonly assessed neurological functions were motor in 85% and language in 11% of the former cohort, and motor in 78% and language, cognition, and memory each in 39% of the latter cohort. Functional MRI was the most frequently used method for evaluating cortical plasticity, and was performed in 63% of the former and 56% of the latter cohort. In conclusion, cortical plasticity appears to be influenced by both AVM pathogenesis and intervention. Given the limited evidence that is currently available for cortical plasticity in AVM patients, further studies are warranted to determine its incidence and impact on long term clinical outcomes.

Endovascular coil embolization of a spinal epidural arteriovenous fistula with associated cord compression from an enlarging venous varix

Spinal arteriovenous fistulas (AVFs) completely isolated to the epidural compartment are exceedingly rare. As such, the optimal management of these lesions is poorly defined. The aim of this technical note is to describe our endovascular technique for the occlusion of a purely epidural AVF of the thoracic spine associated with cord compression from an associated enlarging venous varix. A 40-year-old male presented with severe right-sided back pain and anterior thigh numbness after a sports-related back injury six months previously. Spinal magnetic resonance imaging (MRI) showed an enhancing, extradural mass lesion at T12. Spinal angiography revealed an epidural AVF supplied by a radicular branch of the right T12 subcostal artery and draining into the paravertebral lumbar veins, as well as an adjacent 20 × 13 mm(2) contrast-filling sac, compatible with a dilated venous varix. There was no evidence of intradural venous drainage. We elected to proceed with endovascular treatment of the lesion. At the time of embolization five days later, the venous varix had enlarged to 26 × 16 mm(2). The T12 epidural AVF was completely occluded with two coils, without residual or recurrent AVF on follow-up angiography one month later. The patient made a full recovery, and complete resolution of the venous varix and cord compression were noted on MRI at three months follow-up. Endovascular coil embolization can be successfully employed for the treatment of appropriately selected spinal epidural AVFs. Cord compression from an enlarging venous varix can be treated concurrently with endovascular occlusion of an associated spinal epidural AVF.

Interhemispheric approach for endoscopic ligation of an anterior cranial fossa dural arteriovenous fistula

We describe the endoscopic ligation of an anterior cranial fossa (ACF) dural arteriovenous fistula (DAVF) through an interhemispheric approach. Intracranial DAVF of the ACF are rare and associated with an aggressive natural history, due to their ubiquitous direct cortical venous drainage and frequent coincidence of venous ectasia. Although surgical ligation is the preferred treatment for ACF DAVF, the role of endoscopy in the surgical management of DAVF is undefined. A 53-year-old woman was incidentally diagnosed with an ACF DAVF. Cerebral angiography showed a Borden type III, Cognard type IV left sided ACF DAVF, supplied by ethmoidal branches of the bilateral ophthalmic arteries and draining directly into an enlarged and ectatic left inferior frontal cortical vein, with a venous varix distal to the point of fistulization. An initial attempt at endovascular treatment from a transvenous approach was unsuccessful, due to significant stenosis of the left cavernous sinus. Therefore, we elected to proceed with surgical ligation. From an interhemispheric approach and under the guidance of frameless stereotactic neuronavigation, a 0° endoscope was advanced into the interhemispheric fissure until the arterialized draining vein was visualized. After dissecting along the draining vein to the point of fistulization, the proximal portion of the draining vein was ligated. Intraoperative angiography confirmed complete obliteration of the DAVF, and the patient was asymptomatic at the 6 week postoperative follow-up. Endoscopy provides excellent visualization of ACF DAVF and can safely facilitate surgical treatment in appropriately selected patients with these lesions.

Endovascular Mechanical Thrombectomy for Acute Ischemic Stroke: A New Standard of Care

The treatment of acute ischemic stroke (AIS) in the setting of intracranial large artery occlusion (LAO) with intravenous tissue plasminogen activator (IV-tPA) is associated with low rates of recanalization and high rates of neurological morbidity and functional dependence. Endovascular intervention, particularly mechanical thrombectomy, is a promising therapeutic adjunct to IV-tPA for the treatment of acute LAO. However, until recently, its efficacy has been controversial. In this brief review, we analyze the criticisms of three negative randomized controlled trials (RCT) of endovascular stroke treatment and evaluate the results from seven positive endovascular stroke RCTs that have recently been presented or published. IMS III, MR RESCUE, and SYTHESIS Expansion were three RCTs that failed to show a benefit from endovascular stroke therapy. Major criticisms of these studies included a lack of routine screening for LAO, resulting in the selection of AIS patients without LAO for endovascular intervention, and a low utilization rate of modern endovascular thrombectomy devices, leading to substandard rates of successful recanalization. MR CLEAN was the first phase III RCT to show a significant clinical benefit from endovascular stroke therapy. The dissemination of its findings elicited a cascade of positive results from, to date, six additional endovascular stroke RCTs, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, THERAPY, and THRACE, which were halted prematurely for efficacy. The cumulative evidence from these studies shows an overwhelming benefit from the endovascular treatment of acute LAO, therefore effectively establishing a new standard of care for the management of AIS.