The surgical options available for intractable hemispheric epilepsy have evolved since their initial description in the early 20th century. Surgical techniques have advanced, as has the ability to predict good surgical outcomes with noninvasive diagnostics. The authors review the history of hemispherectomy and detail the novel imaging and surgical strategies used to confer seizure freedom.
Alexandra D. Beier and James T. Rutka
George M. Ibrahim, Benjamin W. Barry, Aria Fallah, O. Carter Snead III, James M. Drake, James T. Rutka and Mark Bernstein
Epilepsy is a common childhood condition associated with a considerable medical and psychosocial burden. Children in whom medical treatment fails to reduce seizure burden represent an especially vulnerable patient population because prolonged, uncontrolled seizures are associated with poor developmental and neurocognitive outcomes. Surgical treatment in the form of cortical resection, functional disconnection, or neuromodulation may alleviate or significantly reduce the disease burden for a subset of these patients. However, there remains a dichotomy between the perceived benefits of surgery and the implementation of surgical strategies in the management of medically intractable epilepsy. The current paper presents an analysis of the bioethical implications of existing inequities in access to pediatric epilepsy surgery that result from inconsistent referral practices and discrepant evaluation techniques. The authors provide a basic bioethical framework composed of 5 primary expectations to inform public, institutional, and personal policies toward the provision of epilepsy surgery to afflicted children.
Arnold B. Etame, Roberto J. Diaz, Christian A. Smith, Todd G. Mainprize, Kullervo Hynynen and James T. Rutka
Recent advances in molecular neurooncology provide unique opportunities for targeted molecular-based therapies. However, the blood-brain barrier (BBB) remains a major limitation to the delivery of tumor-specific therapies directed against aberrant signaling pathways in brain tumors. Given the dismal prognosis of patients with malignant brain tumors, novel strategies that overcome the intrinsic limitations of the BBB are therefore highly desirable. Focused ultrasound BBB disruption is emerging as a novel strategy for enhanced delivery of therapeutic agents into the brain via focal, reversible, and safe BBB disruption. This review examines the potential role and implications of focused ultrasound in molecular neurooncology.
Corey Raffel and James T. Rutka
Paul A. Northcott, James T. Rutka and Michael D. Taylor
Advances in the field of genomics have recently enabled the unprecedented characterization of the cancer genome, providing novel insight into the molecular mechanisms underlying malignancies in humans. The application of high-resolution microarray platforms to the study of medulloblastoma has revealed new oncogenes and tumor suppressors and has implicated changes in DNA copy number, gene expression, and methylation state in its etiology. Additionally, the integration of medulloblastoma genomics with patient clinical data has confirmed molecular markers of prognostic significance and highlighted the potential utility of molecular disease stratification. The advent of next-generation sequencing technologies promises to greatly transform our understanding of medulloblastoma pathogenesis in the next few years, permitting comprehensive analyses of all aspects of the genome and increasing the likelihood that genomic medicine will become part of the routine diagnosis and treatment of medulloblastoma.
Mitchel S. Berger, William T. Couldwell, James T. Rutka and Nathan R. Selden
Andrew Jea, Shobhan Vachhrajani, Keyne K. Johnson and James T. Rutka
Although corpus callosotomy has been used effectively since the late 1930s to treat severe, medically intractable seizure disorders, particularly atonic or drop-attack seizures, controversy remains as to when, how, and how much surgery should be performed. Intraoperative determination of the extent of callosotomy, the need to stage the procedure, and the side of the interhemispheric approach represent technical issues that remain debatable. The authors report the 12-year experience of the senior author as well as surgical outcomes with corpus callosotomy using a frameless stereotactic neuronavigation system (ISG View Wand and BrainLab).
Thirteen consecutive children at The Hospital for Sick Children underwent single-stage corpus callosotomy for medically intractable seizures. The mean age was 10.3 years. Five children underwent partial callosotomy, and 8 underwent complete callosotomy. The side of operative approach to avoid large parasagittal bridging veins was determined by preoperative study of 3D MR imaging/MR venography reconstructed by the neuronavigation system. The extent of callosotomy was determined using intraoperative feedback from the neuronavigation system and postoperative MR imaging.
The extent of callosotomy determined by intraoperative neuronavigation and postoperative MR imaging correlated closely in all cases. There were no operative deaths. There was no significant postoperative morbidity related to venous infarction. Four of 5 patients in the partial callosotomy cohort and 7 of 8 patients in the complete callosotomy cohort showed significant improvement in seizure control.
The use of frameless stereotactic neuronavigation is a safe, effective, and important surgical adjunct in the planning and execution of successful corpus callosotomy in children with intractable epilepsy.
Zulma S. Tovar-Spinoza, Ayako Ochi, James T. Rutka, Cristina Go and Hiroshi Otsubo
Epilepsy surgery requires the precise localization of the epileptogenic zone and the anatomical localization of eloquent cortex so that these areas can be preserved during cortical resection. Magnetoencephalography (MEG) is a technique that maps interictal magnetic dipole sources onto MR imaging to produce a magnetic source image. Magneto-encephalographic spike sources can be used to localize the epileptogenic zone and be part of the workup of the patient for epilepsy surgery in conjunction with data derived from an analysis of seizure semiology, scalp video electroencephalography, PET, functional MR imaging, and neuropsychological testing. In addition, magnetoencephalographic spike sources can be linked to neuronavigation platforms for use in the neurosurgical field. Finally, paradigms have been developed so that MEG can be used to identify functional areas of the cerebral cortex including the somatosensory, motor, language, and visual evoked fields.
The authors review the basic principles of MEG and the utility of MEG for presurgical planning as well as intra-operative mapping and discuss future applications of MEG technology.
Scellig S. D. Stone and James T. Rutka
The management of medically refractory epilepsy poses both a valuable therapeutic opportunity and a formidable technical challenge to epilepsy surgeons. Recent decades have produced significant advancements in the capabilities and availability of adjunctive tools in epilepsy surgery. In particular, image-based neuronavigation and electrophysiological neuromonitoring represent versatile and informative modalities that can assist a surgeon in performing safe and effective resections. In the present article the authors discuss these 2 subjects with reference to how they can be applied and what evidence supports their use. As technologies evolve with demonstrated and potential utility, it is important for all clinicians who deal with epilepsy to understand where neuronavigation and neuromonitoring stand in the present and what avenues for improvement exist for the future.
Merdas Al-Otibi and James T. Rutka
Neurofibromatosis Type 1 (NF1) is one of the most common inherited diseases in humans. It is caused by a mutation in the NF1 gene on chromosome 17, and is associated with numerous central and peripheral nervous system manifestations. Children with NF1 are at high risk of harboring numerous lesions that may require the attention of a neurosurgeon. Some of these include optic nerve gliomas, hydrocephalus, intraspinal tumors, and peripheral nerve tumors. Although most of the neoplasms that affect the brain, spine, and peripheral nerves of children are low-grade lesions, there is a small but real risk that some of these lesions may become high grade over time, requiring other forms of therapy than surgery alone. Other associated disorders that may result from NF1 in childhood include Chiari malformation Type I, scoliosis, and pulsating exophthalmos from the absence of the sphenoid wing. In this review, the major lesions that are found in children with NF1 are reviewed as well as the types of treatment that are offered by neurosurgeons and other members of the treating team. Today, optimum care of the child with NF1 is provided by a multidisciplinary team comprising neurosurgeons, neurologists, ophthalmologists, radiologists, orthopedic surgeons, and plastic surgeons.