Alexander G. Weil

The combination of subdural and depth electrodes for intracranial EEG investigation of suspected insular (perisylvian) epilepsy

Purpose:  We present two methods of implantation for the investigation of suspected insular and perisylvian epilepsy that combine depth and subdural electrodes to capitalize on the advantages of each technique.

Decompressive craniectomy is not an independent risk factor for communicating hydrocephalus in patients with increased intracranial pressure.

BACKGROUNDIt was recently suggested that communicating hydrocephalus is an almost universal finding after hemicraniectomy and that early cranioplasty may prevent the need for permanent cerebrospinal fluid diversion in these patients. OBJECTIVETo conduct a study in an attempt to verify these findings. METHODSThe medical records of all patients who underwent decompressive craniectomy for medically refractory elevated intracranial pressure between 2001 and 2009 were retrospectively reviewed. Patients with subarachnoid hemorrhage, intraventricular hemorrhage, or head trauma were excluded. Hydrocephalus was classified as internal or external and as clinically significant or asymptomatic. RESULTSThe patient population consisted of 17 patients, 8 men and 9 women, with a median age of 44 years (range, 27–53 years). Etiologies included malignant middle cerebral artery territory infarction in 12 patients, hemorrhagic transformation of ischemic cerebrovascular accident in 2 patients, dural sinus thrombosis in 2 patients, and hemorrhagic cerebrovascular accident in 1 patient. The extent of craniectomy ranged from a large bone flap in 4 patients to a standard hemicraniectomy in 13 patients. Two patients died and 1 was lost to follow-up during the acute stage. The remaining 14 patients underwent cranioplasty after a median interval of 21 days (range, 3–42 days). In none of these patients did clinically significant hydrocephalus develop requiring cerebrospinal fluid diversion. Asymptomatic extra-axial cerebrospinal fluid collections developed in 2 patients that resolved spontaneously after cranioplasty. CONCLUSIONOur results suggest that, contrary to some beliefs, hydrocephalus does not frequently occur after decompressive craniectomy.

Quality of Life Following Hemicraniectomy for Malignant MCA Territory Infarction

OBJECTIVE Decompressive hemicraniectomy (DH) has been shown to reduce mortality in patients with malignant middle cerebral artery (MCA) territory infarction. However, many patients survive with moderate-to-severe disability and controversy exists as to whether this should be considered good outcome. To answer this question, we assessed the quality of life (QoL) of patients after DH for malignant MCA territory infarction in our milieu. METHODS The outcome of all patients undergoing DH for malignant MCAterritory infarction between 2001 and 2009 was assessed using retrospective chart analysis and telephone follow-up in survivors. Functional outcome was determined using Glasgow outcome scale, modifed Rankin scale (mRS), and Barthel index (BI). The stroke impact scale was used to assess QoL. RESULTS There were 14 patients, 6 men and 8 women, with a mean age of 44 years (range 27-57). All patients had reduced level of consciousness preoperatively. Five had dominant-hemisphere stroke. Median time to surgery was 45 hours (range 1- 96). Two patients died and one was lost to follow-up. Of 11 survivors, 7 (63.6%) had a favorable functional outcome (mRS<4). No patient was in persistent vegetative state. Despite impaired QoL, particularly in physical domains, the majority of interviewed patients and caregivers (7 of 8), including those with dominant-hemisphere stroke, were satisfied after a median follow-up of 18 months (range 6-43). CONCLUSION Most patients report satisfactory QoL despite significant disability even in the face of moderate-to-severe disability and dominant-hemsiphere stroke. Dominant-hemisphere malignant MCA territory infarction should not be considered a contraindication to DH.

Angiographic pitfall: duplicated tapered A1 segment of the anterior cerebral artery mimicking an anterior communicating artery aneurysm.

We describe a misleading case of a partially occluded A1 segment duplication that mimicked an ACoA aneurysm on computed tomography angiography and conventional angiography and led to surgical intervention. The location of such an anomaly at the ACoA on the side of least hemodynamic stress may provide a clue to recognizing this variant.

Presurgical thalamocortical connectivity is associated with response to vagus nerve stimulation in children with intractable epilepsy

Although chronic vagus nerve stimulation (VNS) is an established treatment for medically-intractable childhood epilepsy, there is considerable heterogeneity in seizure response and little data are available to pre-operatively identify patients who may benefit from treatment. Since the therapeutic effect of VNS may be mediated by afferent projections to the thalamus, we tested the hypothesis that intrinsic thalamocortical connectivity is associated with seizure response following chronic VNS in children with epilepsy. Twenty-one children (ages 5–21 years) with medically-intractable epilepsy underwent resting-state fMRI prior to implantation of VNS. Ten received sedation, while 11 did not. Whole brain connectivity to thalamic regions of interest was performed. Multivariate generalized linear models were used to correlate resting-state data with seizure outcomes, while adjusting for age and sedation status. A supervised support vector machine (SVM) algorithm was used to classify response to chronic VNS on the basis of intrinsic connectivity. Of the 21 subjects, 11 (52%) had 50% or greater improvement in seizure control after VNS. Enhanced connectivity of the thalami to the anterior cingulate cortex (ACC) and left insula was associated with greater VNS efficacy. Within our test cohort, SVM correctly classified response to chronic VNS with 86% accuracy. In an external cohort of 8 children, the predictive model correctly classified the seizure response with 88% accuracy. We find that enhanced intrinsic connectivity within thalamocortical circuitry is associated with seizure response following VNS. These results encourage the study of intrinsic connectivity to inform neural network-based, personalized treatment decisions for children with intractable epilepsy.

Surgery for aggressive behavior disorder.

very concerned with the message this report sends to the neuro-surgical community regarding (1) the surgical treatment of ag-gressiveness disorder and (2) the standards in scientific and ethi-cal rigor in the study of neuromodulation of mood disorders.W e believe it is premature to be performing bilateral, ablative, irreversible lesions in these patients with aggressive behavior dis-order. There are no studies, and no rationale in the literature, nei-ther in humans nor in animals, that have shown the efficacy of capsulotomy and cingulotomy in the treatment of aggressive be-havior except for a highly questionable publication [2]Re . gandg ricingulotomy alone, the same can be said, except for a publication from a congress proceeding in 1970 in which the authors mention 5 ‘poor results’ in 10 patients [3] . The combination of these two types of surgeries, as is the case in this study, has never been de-scribed in the treatment of aggression. We also read with interest the previous report by the same group published 1 year ago of very similar structure [4] an d con-tent to the present article [1] . That previous paper reported on a series of patients operated on for the same condition, with the same procedure, by the same surgeons, at the same institution, during the same time interval. We were surprised that there is no mention of this previous work in the present paper. We invite the authors to clarify several significant discrepancies observed be-tween their previous report [4] and the current article published in

Treatment of Ruptured Aneurysms: Earlier is Better

I f o R ebleeding is the primary cause of early morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH) (2, 5, 20). The efficacy of aneurysm obliteration at reventing rebleeding and improving outcome after SAH has een well established since the 1970s. However, the debate ver optimal timing of aneurysm treatment after SAH has carried n for over 4 decades (1, 2, 4, 7-15, 17-21). Initially, the debate entered on the risks of rebleeding encountered while awaiting ate surgery ( 10 days) versus the morbidity incurred by operatng early ( 3 days) on an acutely injured and swollen brain or uring the intermediate period of cerebral vasospasm (3 to 10 ays). In the early 1980s, the International Cooperative Study, a arge, multicenter, prospective, observational trial, addressed the ssue of optimal timing for surgery. This study found that early urgery ( 3 days) was at least equivalent to delayed surgery 10 days) in terms of mortality and morbidity for good grade atients (7, 8). Over the next decade (1980s), improvements in he overall medical management of SAH, and in particular, the revention and treatment of vasospasm and delayed cerebral schemia, provided a further rationale for neurosurgeons to erform early aneurysm surgery (16, 18, 19). The vast majority of tudies that ensued, including one randomized control trial and ultiple observational studies, suggested that early and even ntermediate surgery were associated with a better outcome and horter hospitalization than later surgery in aneurysmal SAH atients, especially in good clinical grade patients, but also in oor-grade patients (4, 12, 13). Early aneurysm obliteration ( 72 ours), either by neurosurgical clipping or endovascular coiling, as been widely adopted by neurovascular centers worldwide for ver a decade.

Endoscopic third ventriculostomy for obstructive hydrocephalus due to intraventricular hemorrhage.

BACKGROUND Although endoscopic third ventriculostomy (ETV) is the first-line treatment for obstructive hydrocephalus due to various pathologies, its role in hemorrhage-related obstructive hydrocephalus is poorly defined. We report our experience with ETV for hemorrhage-related obstructive hydrocephalus, demonstrate it feasibility, and discuss potential advantages over more conventional treatment modalities. METHODS We performed a retrospective analysis of 78 consecutive patients who underwent ETV in our institution between January 2003 and January 2011. We identified 17 consecutive patients who underwent ETV for obstructive hydrocephalus related to intraventricular hemorrhage (IVH). RESULTS ETV was performed in 9 men and 8 women (mean age: 58 years; range: 42-79). All patients had IVH (n = 17), either alone (n = 3) or with intracranial hemorrhage (n = 4) or subarachnoid hemorrhage (SAH) (n = 10). Endoscopic clot evacuation was performed in seven cases (41%). External ventricular drain (EVD) was avoided in two patients. 15 patients had external EVD, and EVD wean was performed on average 5 days post-ETV. Two patients died in the early postoperative period (< 1 month) from the initial cerebral insult. For the 15 surviving patients, the average modified Rankin Scale (mRS) at last follow-up (15 months; range: 1-48) was 2.4. Thus most surviving patients were independent (mRS < 3). Of those 15 patients, one died (malignancy) at last follow-up. Twelve patients (80%) were ventriculoperitoneal shunt-free. The three shunt-dependent patients had significant SAH (100%). CONCLUSION ETV with or without endoscopic clot evacuation is feasible for patients with hemorrhage-related obstructive hydrocephalus. Potential advantages include avoiding or reducing duration of EVD placement and preventing ventriculoperitoneal shunt placement. Further large prospective randomized trials are needed to evaluate the safety and efficacy of ETV with or without clot evacuation for IVH-related obstructive hydrocephalus.

Arteriovenous malformation of the pineal gland

Dear Editor, We would like to bring to your readers’ attention a case of an arteriovenous malformation (AVM) of the pineal gland that was confirmed on histopathological examination following successful surgical removal. To our knowledge, a compact nidus located purely within the pineal gland has been reported only twice, without histopathological demonstration [6, 10]. We wish to emphasize the impact that precise identification of a deep central AVM’s location has on its therapeutic management. To our knowledge, this is the first report of a histopathologically proven intraparenchymal pineal AVM. A 50-year-old woman presented with intraventricular hemorrhage and hydrocephalus. Magnetic resonance imaging (MRI) revealed an AVM of the posterior third ventricle fed by both posterolateral choroidal arteries (PLChA) and draining into an ectatic vein of Galen (VG) (Fig. 1a, b). A flow-related aneurysm of the right PLChA was identified as the probable site of rupture and it was embolized. The AVM was then resected through a supracerebellar-infratentorial approach. The postoperative course was uneventful and there was no residual AVM on postoperative angiography. Histopathological examination confirmed that the AVM’s compact nidus was entirely located within the pineal parenchyma (Fig. 1c). Although there is no consensus on the optimal treatment of ruptured deep central AVMs, the precise location of the AVM may guide towards an optimal treatment plan including: observation, surgical removal, stereotactic radiosurgery (SRS), endovascular therapy (EVT), or a combination of these modalities. The key issue in the therapeutic decision process is the risk associated with AVM accessibility. Lower-risk accessible lesions may be treated with surgery, whereas higher-risk lesions are more prone to be treated with SRS or ETV, with or without additional surgery or complementary SRS [1–3, 5–10]. In his classification of deep central AVMs, Yasargil [10] included a pineal AVM case in the group of mesencephalic AVMs. Another case of pineal AVM has since been reported, and it too was considered to belong to the dorsal midbrain group of AVMs [6]. It is important, however, to recognize that AVMs of the pineal gland are distinct from AVMs of the midbrain or other deep central structures (e.g., thalamus). Although surgical resection of pineal gland AVMs can be performed safely, intraparenchymal AVMs located deep in the thalamus or midbrain are expected to harbor greater surgical risk [1–3, 5–10]. Knowledge of the exact location of deep central AVMs is also a major determinant of its surgical approach. Whereas pineal gland AVMs and superior colliculi AVMs are readily accessible through a supracerebellar-infratentorial approach, this route offers less optimal exposure below the level of the superior colliculus [4]. Recognizing the existence of a pineal gland AVM is important; it influences the choice of treatment modality and surgical approach. Intraparenchymal pineal AVMs should be distinguished from AVMs of other deepseated locations (e.g., midbrain) and from the grouping of heterogeneous AVMs that make up so-called pineal region AVMs. A. G. Weil : S. Obaid :N. McLaughlin :M. W. Bojanowski (*) Department of Surgery, Division of Neurosurgery, Centre Hospitalier de l’Universite de Montreal (CHUM), Hôpital Notre-Dame, 1560 rue Sherbrooke Est, Montreal, QC, Canada H2L 4M1 e-mail: michel.bojanowski.chum@ssss.gouv.qc.ca

L’épilepsie insulaire : l’expérience montréalaise

In this article, we review recently published data on the role of the insula in refractory partial epilepsy and summarize our own experience in the investigation and treatment of this entity. Case studies and evoked responses obtained from insular cortical stimulation reveal a wide array of clinical manifestations which may mimic temporal, frontal or parietal lobe seizures. Clinicians should hence lower their threshold to sample the insula with intracerebral electrodes. Lack of recognition of insular seizures may explain part of epilepsy surgery failures. Advances in microneurosurgery open the way to safer insular resection.