Bertrand Mathon

Surgical treatment for mesial temporal lobe epilepsy associated with hippocampal sclerosis.

INTRODUCTIONnHippocampal sclerosis is the most common cause of pharmacoresistant epilepsy amenable for surgical treatment and seizure control. The aim of this article is to review and evaluate the published literature related to the outcome of the surgical treatment of mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) and to describe the future prospects in this field.nnnSTATE OF ARTnSurgery of MTLE associated with HS achieves long-term seizure freedom in about 70% (62-83%) of cases. Seizure outcome is similar in the pediatric population. Mortality following temporal resection is very rare (<1%) and the rate of definitive neurological complication is low (1%). Gamma knife stereotactic radiosurgery used as a treatment for MTLE would have a slightly worse outcome to that of surgical resection, but would provide neuropsychological advantage. However, the average latency before reducing or stopping seizures is at least 9xa0months with radiosurgery. Regarding palliative surgery, amygdalohippocampal stimulation has been demonstrated to improve the control of epilepsy in carefully selected patients with intractable MTLE who are not candidates for resective surgery.nnnPERSPECTIVESnRecent progress in the field of imaging and image-guidance should allow to elaborate tailored surgical strategies for each patient in order to achieve seizure freedom. Concerning therapeutics, closed-loop stimulation strategies allow early seizure detection and responsive stimulation. It may be less toxic and more effective than intermittent and continuous neurostimulation. Moreover, stereotactic radiofrequency amygdalohippocampectomy is a recent approach leading to hopeful results. Closed-loop stimulation and stereotactic radiofrequency amygdalohippocampectomy may provide a new treatment option for patients with pharmacoresistant MTLE.nnnCONCLUSIONSnMesial temporal lobe surgery has been widely evaluated and has become the standard treatment for MTLE associated with HS. Alternative surgical procedures like gamma knife stereotactic radiosurgery and amygdalohippocampal stimulation are currently under assessment, with promising results.

Safety profile of intracranial electrode implantation for video-EEG recordings in drug-resistant focal epilepsy

Invasive electroencephalography recordings with depth or subdural electrodes are necessary to identify the ictogenic area in some drug-resistant focal epilepsies. We aimed to analyze the safety profile of intracranial electrode implantation in a tertiary center and the factors associated with its complications. We retrospectively examined complications in 163 intracranial procedures performed in adult patients. Implantation methods included oblique depth stereotactic approach (nxa0=xa0128) and medial–temporal depth stereotactic approach in combination with subdural strip placement (nxa0=xa035). 1201 depth macroelectrodes, 59 bundles of microelectrodes (in 30 patients) and 148 subdural electrodes were implanted. Complications were classified as major (requiring treatment or leading to neurological impairment) or minor. The rate of overall complications was 4.9xa0% (nxa0=xa08), with 3.1xa0% (nxa0=xa05) of major complications, though no permanent morbidity or mortality was recorded. Infection occurred in 1.2xa0% and hemorrhage in 3.7xa0% of patients. One hemorrhage occurred for every 225 electrodes implanted (4.4xa0‰). Microelectrodes were not responsible for any complications. Overall and hemorrhagic complications were significantly associated with MRI-negative cases (7.3 and 6.3xa0% versus 0xa0%, pxa0=xa00.04). We believe that intracranial electrode implantation has a favorable safety profile, without permanent deficit. These risks should be balanced with the benefits of invasive exploration prior to surgery. Furthermore, this study provides preliminary evidence regarding the safety of micro-macroelectrodes.

De novo arteriovenous malformation after brain radiotherapy for medulloblastoma in a child

A 5-year-old boy was operated on for a non-metastatic medulloblastoma of the fourth ventricle (figure 1). Chemotherapy and bifractionated craniospinal radiotherapy were administered. Four years later, T1-weighted MRI with contrast revealed abnormal vessels in the right sylvian fissure that gradually increased during follow-up; angiography confirmed an arteriovenous malformation (AVM) (figure 2). Even though it was asymptomatic, its location and growth prompted us to treat (embolization then excision of the residual nidus). This very rare case of supposed radiation-induced AVM suggests that when abnormal vasculature imaging occurs in follow-up1,2 further investigation with angiography is warranted, with consideration of further treatment.

Predictive factors of long-term outcomes of surgery for mesial temporal lobe epilepsy associated with hippocampal sclerosis

The reasons for failure of surgical treatment for mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) remain unclear. This retrospective study analyzed seizure, cognitive, and psychiatric outcomes, searching for factors associated with seizure relapse or cognitive and psychiatric deterioration after MTLE‐HS surgery.

Selective amygdalohippocampectomy via trans-superior temporal gyrus keyhole approach

BackgroundHippocampal sclerosis is the most common cause of drug-resistant epilepsy amenable for surgical treatment and seizure control. The rationale of the selective amygdalohippocampectomy is to spare cerebral tissue not included in the seizure generator.MethodDescribe the selective amygdalohippocampectomy through the trans-superior temporal gyrus keyhole approach.ConclusionSelective amygdalohippocampectomy for temporal lobe epilepsy is performed when the data (semiology, neuroimaging, electroencephalography) point to the mesial temporal structures. The trans-superior temporal gyrus keyhole approach is a minimally invasive and safe technique that allows disconnection of the temporal stem and resection of temporomesial structures.

Complications after surgery for mesial temporal lobe epilepsy associated with hippocampal sclerosis

BACKGROUNDnHippocampal sclerosis is the most common cause of drug-resistant epilepsy amenable for surgical treatment and seizure control. This study aimed to analyze morbidities related to surgery of mesial temporal lobe epilepsy associated with hippocampal sclerosis and to identify possible risk factors for complications.nnnMETHODSnA retrospective analysis of postoperative complications was made for 389 operations performed between 1990 and 2015 on patients aged 15-67 years (mean 36.8). Three surgical approaches were used: anterior temporal lobectomy (ATL) (nxa0= 209), transcortical selective amygdalohippocampectomy (SAH) (nxa0= 144), and transsylvian SAH (nxa0= 36). Complications were classified as minor or major if there was a neurologic impairment or if further surgical or medical treatment was necessary.nnnRESULTSnComplications followed 15.4% of operations. They were classed as major for 4.1% of patients, but there were no mortalities. Persistent neurologic deficits occurred in 0.5% of patients. In 3 cases (0.8%) additional surgery was necessary to treat an intracranial hematoma, a delayed hydrocephalus, and a subdural empyema. Symptomatic visual field defects (VFDs) were frequent and included contralateral superior quadrantanopia (8.2%) or hemianopia (1.3%). Overall complications (Pxa0= 0.04) and symptomatic VFDs (Pxa0= 0.04) were most frequent in operations on men. Major complications occurred most often with the ATL surgical approach than with transcortical SAH (Pxa0= 0.03).nnnCONCLUSIONSnMajor complications occur rarely after mesial temporal surgery on epileptic patients. They occur more often following the ATL rather than transcortical SAH approach. Complications tend to be temporary with symptoms of limited duration for surgery performed by experienced teams on carefully selected and evaluated patients.

Long-term Outcome After Multiple Burr Hole Surgery in Children With Moyamoya Angiopathy: A Single-Center Experience in 108 Hemispheres

BACKGROUNDnMultiple burr hole (MBH) surgery is a simple, safe, and effective indirect technique of revascularization in moyamoya angiopathy (MM). However, it is not yet recognized as a first-line treatment.nnnOBJECTIVEnTo assess the long-term outcome and perioperative complications in a large single-center cohort of children with MM who underwent burr hole surgery.nnnMETHODSnThis study is a retrospective analysis of children who underwent surgery for MM in a national reference center for pediatric stroke between 1999 and 2015. Sixty-four children (108 hemispheres, median age 7 years) were consecutively treated. The indication for revascularization was previous stroke or transient ischemic attack (TIA) or rapidly progressive disease on brain magnetic resonance imaging (MRI) and digital subtraction angiography. Children were followed with clinical examinations, telephone interviews, and MRI with any clinical recurrence of stroke or TIA used as the primary endpoint. Surgical mortality and morbidity were documented.nnnRESULTSnSixty-four patients were operated (bilateral MBH n = 39, unilateral procedure n = 25). At a mean follow-up of 4.2 years and 270.6 patient years, 89.1% of patients had not suffered any recurrent stroke or TIA. A second surgery was required in 5 cases after unilateral revascularization, and in 3 cases after bilateral MBH. Mortality associated with the procedure was 0. Postoperative Matsushima angiographic grading was the only predictive factor of ischemic recurrence ( P = .036).nnnCONCLUSIONnIn pediatric MM, MBH compares favorably to other indirect or direct revascularization techniques in children in the prevention of stroke or TIA.

Increasing the effectiveness of intracerebral injections in adult and neonatal mice: a neurosurgical point of view

Intracerebral injections of tracers or viral constructs in rodents are now commonly used in the neurosciences and must be executed perfectly. The purpose of this article is to update existing protocols for intracerebral injections in adult and neonatal mice. Our procedure for stereotaxic injections in adult mice allows the investigator to improve the effectiveness and safety, and save time. Furthermore, for the first time, we describe a two-handed procedure for intracerebral injections in neonatal mice that can be performed by a single operator in a very short time. Our technique using the stereotaxic arm allows a higher precision than freehand techniques previously described. Stereotaxic injections in adult mice can be performed in 20 min and have >90% efficacy in targeting the injection site. Injections in neonatal mice can be performed in 5 min. Efficacy depends on the difficulty of precisely localizing the injection sites, due to the small size of the animal. We describe an innovative, effortless, and reproducible surgical protocol for intracerebral injections in adult and neonatal mice.

[Evolution of ideas and techniques, and future prospects in epilepsy surgery].

INTRODUCTIONnThe aim of this article was to review and evaluate the published literature related to the outcome of epilepsy surgery, while placing it in an historical perspective, and to describe the future prospects in this field.nnnSTATE OF ARTnTemporal lobe surgery achieves seizure freedom in about 70% of cases. Seizure outcome is similar in the pediatric population. Extratemporal resections impart good results to 40% to 60% of patients, with a better prognosis in the case of frontal lobe surgery. Pediatric hemispherotomy leads to seizure control in about 80% of children. Radiosurgery used as a treatment for temporal mesial epilepsy has an outcome quite similar to that obtained with surgical resection, but provides a neuropsychological advantage. Radiosurgery is also effective in 60% of children treated for seizures related to hypothalamic hamartoma. Regarding palliative surgery, callosotomy and multiple subpial transections show satisfactory outcomes in over 60% of cases. Neuromodulation techniques (vagus nerve stimulation and bilateral stimulation of the anterior nucleus of the thalamus) allow a 50% reduction of seizures in half of patients.nnnPERSPECTIVESnTranscranial magnetic stimulation combined with electroencephalography seems a promising technique because of its diagnostic, prognostic and therapeutic applications. Transcranial ultrasound stimulation, which can reversibly control neuronal activity, is also under consideration. Concerning neuromodulation, trigeminal nerve stimulation may become an alternative to vagus nerve stimulation; while other targets of deep brain stimulation are being evaluated. Also, the possibility of coupling SEEG seizure focus detection with concomitant laser or radiofrequency focus destruction is under development.nnnCONCLUSIONSnConstant evolution of epilepsy surgery has improved patient outcomes over time. Current research and development axes suggest the continuation of this trend and a reduction of the invasiveness of surgical procedures.

Teaching neuroimages: Burkitt dural lymphoma mimicking a subacute subdural hematoma.

A 59-year-old woman with no history of trauma presented with severe headaches and right-sided weakness. A CT scan showed a left hemispheric isodense subdural collection thought to be consistent with a subacute subdural hematoma (figure 1A). The patient underwent a single parietal burr hole for evacuation, but the neurosurgeon found subdural fleshy tissue and performed a biopsy. Immediate postoperative MRI showed a homogeneous hypercellular subdural mass (figure 1, B–F).1 Pathology was consistent with Burkitt lymphoma (figure 2). Retrospectively, the homogeneous density of the collection argued against hematoma. In nonemergent situations, an atypical radiologic appearance of a subdural hematoma may suggest the need for further radiologic investigations before surgical evacuation.2