Corey Raffel

Nationwide Children's Hospital, Columbus, Ohio, United States

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Publications (80)312.29 Total impact

  • Corey Raffel, James T Rutka
    Neurosurgical FOCUS 01/2011; 30(1):Introduction. DOI:10.3171/2011.1.FOCUS.Intro · 2.14 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the yield of electroencephalography and structural and functional neuroimaging in children having resective epilepsy surgery before 5 years of age. Charts of all 28 children (54% male) having resective surgery before 60 months of age at the Mayo Clinic between January 2002 and June 2009 were reviewed. Mean age at seizure onset was 9.6 months (S.D. 12.7); mean age at surgery was 28.8 months (S.D. 17.7). Sixteen children (57%) had partial-onset seizures, 8 (29%) had partial-onset seizures and spasms, and 4 (14%) had spasms alone. Initial surgery type was hemispherectomy in 6 cases, multilobar resection in 8, temporal in 7, and extratemporal in 7. Only 10 of the 25 children (40%) with recorded seizures preoperatively had a well-localized, single ictal focus. Ictal discharge was generalized in 8/25 cases (32%), both generalized and focal in 1 case (4%), hemispheric in 4 cases (16%), and absent in 1 case (4%). Findings from magnetic resonance imaging were abnormal in 27 cases, and revealed focal pathology in 20. Surgical outcome was favorable, with 18 of the 27 survivors (67%) being free, or nearly free, of disabling seizures. In summary, electroencephalography frequently failed to indicate a single ictal focus in young children having epilepsy surgery. In contrast, magnetic resonance imaging was more helpful, revealing focal abnormalities in 74% of patients.
    Pediatric Neurology 11/2010; 43(5):335-40. DOI:10.1016/j.pediatrneurol.2010.06.002 · 1.50 Impact Factor
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    ABSTRACT: Arteriovenous malformation (AVM) is the most common cause of spontaneous intraparenchymal hemorrhage in children, excluding hemorrhages of prematurity and early infancy. Because most children diagnosed with an AVM undergo initial treatment emergently, the natural history of AVMs in the pediatric population is not well understood. Most pediatric AVMs do not come to clinical attention unless they hemorrhage. Therefore, their optimal management remains controversial. Children with intracranial AVMs represent a special challenge in that they harbor unacceptable lifelong risks of hemorrhage and potential neurologic deficits. Patients should be evaluated on a case-by-case basis to determine the best multidisciplinary treatment regimen that can be used to preserve neurologic function and eradicate the AVM with the lowest risk of mortality. Successful treatment depends on the location and size of the AVM, its hemodynamic properties, the clinical condition of the patient, and the treatment modality selected. The armamentarium for AVM management has grown with technological advances and now includes microsurgical resection, endovascular embolization, radiosurgery, or any combination of these modalities. Microsurgical resection remains the gold standard for treatment of accessible pediatric AVMs, especially in cases that present with intracranial hemorrhage. Newer modalities, such as embolization and radiosurgery, have provided additional tools to help children with large or deep-seated lesions that would be deemed unresectable with microsurgical techniques alone. Long-term follow-up with repeated diagnostic imaging is important despite complete obliteration of the lesion to rule out the small possibility of AVM recurrence.
    Neurosurgery clinics of North America 07/2010; 21(3):443-56. DOI:10.1016/ · 1.54 Impact Factor
  • Chapter: Ependymomas
    Nicholas Wetjen, Corey Raffel
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    ABSTRACT: Ependymomas are rare tumors of neuroectodermal origin and the third most common pediatric brain tumor following astrocytoma and medulloblastoma. They arise from radial glial-like stem cells in the cerebral subven-tricular zone (SVZ), lining the fourth ventricle, and within the spinal cord. The typical location of these tumors is different in adults and children. Most childhood ependymomas are intracranial, while in adults they more commonly occur in the spinal cord. They locate infratentorially in 65% of pediatric cases, most often arising from the floor of the fourth ventricle. The remaining 35% of ependymo-mas in children occur equally divided between the spinal cord and supratentorial intracranial space.
    12/2009: pages 503-512;
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    ABSTRACT: Large dural arteriovenous malformations (DAVMs) accompanied by cardiac failure usually carry a poor prognosis with a high risk of morbidity and death. The authors report on the case of a male neonate with a massive DAVM who presented at birth with macrocephaly and high-output cardiac failure. The child initially underwent treatment with surgical clipping of the large main feeding artery. Hydrocephalus, thought to be due to venous hypertension, developed when the boy was 8 months old. The condition resolved after interventional embolization treatment. The patient did not require placement of a ventriculoperitoneal shunt. At 21 months of age, the child had near normal development without any focal neurological deficits.
    Journal of Neurosurgery Pediatrics 03/2009; 3(2):105-9. DOI:10.3171/2008.11.PEDS0876 · 1.37 Impact Factor
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    ABSTRACT: Intracranial subdural grid monitoring is a useful diagnostic technique for surgical localization in patients with intractable partial epilepsy. The rationale for the present study was to assess the morbidity of intracranial recordings and the surgical outcomes. We retrospectively reviewed the clinical data for 189 unique patients undergoing 198 intracranial subdural grid monitoring sessions between 1996 and 2004 at a tertiary epilepsy center. The mean age of patients undergoing monitoring was 28 +/- 14 years. An average of 63 +/- 23 electrodes were inserted. The mean duration of monitoring was 8 +/- 4 days. Localization of an epileptogenic zone occurred in 156 sessions (79%) resulting in 136 resections (69%). There were 13 major complications (6.6%), including five infections and six hematomas. Three patients (1.5%) developed permanent deficits related to implantation. Sixty-two (47%) of 136 patients undergoing resection were seizure-free after resection. An additional 38 patients (28%) had a significant reduction in seizures. The mean follow-up was 51 +/- 30 months. The duration of monitoring, bone flap replacement, number of electrodes, and perioperative corticosteroids were not associated with infection or complication. Subdural grid monitoring for identification an epileptogenic focus is high yield, revealing a focus in 79% of monitoring sessions. Complications rarely result in permanent morbidity (1.5%). Surgical outcome indicated that 74% of patients experienced a favorable reduction in seizure tendency.
    Neurosurgery 10/2008; 63(3):498-505; discussion 505-6. DOI:10.1227/01.NEU.0000324996.37228.F8 · 3.03 Impact Factor
  • Peter Kalina, Jonathan Morris, Corey Raffel
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    ABSTRACT: We describe the clinical manifestations, radiographic features, and management options of an extensive spontaneous spinal epidural hematoma in a 7-month boy who had severe hemophilia that had not been previously diagnosed, despite a baseline factor VIII level less than 1% of normal. We believe this to be the youngest reported case of a symptomatic spontaneous spinal epidural hemorrhage in an infant subsequently initially establishing a diagnosis of hemophilia.
    Emergency Radiology 08/2008; 15(4):281-4. DOI:10.1007/s10140-007-0667-0
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    ABSTRACT: Bovine tissues are now routinely used for dural closure in cranial and spinal surgery. The authors report the case of an 18-year-old woman with a history of myelomeningocele who had symptoms of tethered cord syndrome and presented to a regional hospital. At that hospital she underwent a cord untethering procedure. The spinal dura was closed with Durepair, a dural substitute derived from fetal bovine skin. Her postoperative course was complicated by a cerebrospinal fluid leak that was surgically repaired. Following this, she developed erythroderma, intermittent fevers, eosinophilia, and marked elevation in serum immunoglobulin E. She was then transferred to the authors' institution. A skin antigen test to beef was administered, which revealed a positive reaction. A radioallergosorbent test to beef also yielded positive results. She was taken to the operating room for removal of the bovine graft due to concern for an allergic reaction to the graft. The graft material showed evidence of eosinophilic infiltration. Her clinical symptoms and laboratory values all improved after surgery. To the authors' knowledge this is the first reported case of an allergic reaction to bovine-based dural substitutes.
    Journal of Neurosurgery Pediatrics 03/2008; 1(2):167-9. DOI:10.3171/PED/2008/1/2/167 · 1.37 Impact Factor
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    ABSTRACT: Dysembryoplastic neuroepithelial tumor (DNT) is an increasingly recognized surgically curable tumor that characteristically presents with seizures in children. We report a case of a patient who underwent resection of a histologically proven DNT at 6 years of age. The resection was thought to be total at the time of surgery, and this impression was confirmed on postoperative imaging. Following the initial resection, the patient underwent surveillance imaging at regular intervals. Six years following the initial surgery, surveillance imaging demonstrated an enlarging area of signal abnormality at the site of the prior resection. The patient underwent a second resection with pathological confirmation of DNT recurrence. Although recurrence of DNT following resection is rare, this case suggests that surveillance imaging may have a role in patients with DNT, even following resections that are thought to be complete.
    Pediatric Neurosurgery 02/2008; 44(4):333-6. DOI:10.1159/000138372 · 0.50 Impact Factor
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    ABSTRACT: A pseudotumoral presentation of acute cerebellitis is rare. The authors report two cases of children with hemicerebellar involvement, neither case being postinfectious nor vaccination related. One patient underwent biopsy sampling revealing marked parenchymal and leptomeningeal inflammation, and in the other, near-complete resolution of neuroimaging abnormalities was demonstrated. The literature is reviewed and therapy considerations are emphasized.
    Journal of Neurosurgery 08/2007; 107(1 Suppl):57-61. DOI:10.3171/PED-07/07/057 · 3.23 Impact Factor
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    ABSTRACT: Complications arising from the placement of ventriculoperitoneal (VP) shunts are well documented. A case of infertility is presented that was thought to result from factors related to the distal end of a VP shunt residing within a patient's abdomen. A 30-year-old female with a 3-year history of infertility was referred for fallopian tube blockage. An exploratory laparoscopy revealed multiple adhesions adjoining the distal end of her fallopian tubes. The distal portion of a VP shunt placed at childhood (with subsequent revisions) was found entangled among grossly inflamed and densely adhesive pelvic viscera. Laparoscopic adhesiolysis was performed and the patient's fallopian tubes were reconstituted. The distal portion of the VP shunt was freed from the surrounding viscera and was not revised. VP shunts may produce adhesive disease and complicate fertility via mechanical, chemical, and/or infectious processes.
    Pediatric Neurosurgery 02/2007; 43(2):146-8. DOI:10.1159/000098391 · 0.50 Impact Factor
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    ABSTRACT: Randomized controlled trials of neurosurgical procedures involving children have been organized infrequently; as a consequence, the majority of pediatric neurosurgical practice is not supported by class I data. Furthermore, many trials that have been reported suffer from serious methodological shortcomings such as insufficient power and poor statistical analysis. Finally, several trials of neurosurgical techniques that are frequently performed on children have either excluded children from participation or include an insufficient number of children to draw strong conclusions. Despite these shortcomings, pediatric neurosurgery, like all fields in medicine, is gradually moving towards a more stringent evidence-based medicine standard. This chapter will attempt to summarize the recent progress that has been made in this area.
    Progress in neurological surgery 02/2006; 19:97-106. DOI:10.1159/000095185
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    ABSTRACT: Subependymal giant cell astrocytomas (SEGAs) are a common manifestation of tuberous sclerosis (TS). These evolving tumors have a propensity to cause obstructive hydrocephalus, usually due to obstruction at the level of the foramen of Monro. Differentiating SEGAs from subependymal nodules (SENs) before obstruction occurs may improve the morbidity associated with these tumors. In this study the authors' aim was to determine imaging characteristics of proven tumors in a single-center pediatric population. The authors retrospectively reviewed all records and images obtained in patients with TS in whom results of biopsy sampling had proven that their tumors were SEGAs. Time to presentation, signs and symptoms at presentation, and imaging characteristics of the evolving tumors were noted. Twelve patients with 14 SEGAs proven by the results of biopsy sampling were reviewed. Resection was recommended for symptomatic and neuroimaging evidence of hydrocephalus (41%), tumor growth without evidence of hydrocephalus (33%), and for poorly controlled seizures (25%). The mean diameter of the tumors at the time of resection was 1.9 cm (range 0.3-4 cm), and no tumor recurred. Because of the pathological and radiographic continuum of SENs and SEGAs, it remains difficult to predict whether and when a given lesion will progress. Tumor growth and contrast enhancement are the most common signs of progression on neuroimages, and may be seen prior to the development of obstructive hydrocephalus. Patients with SENs and SEGAs should undergo follow-up neuroimaging at yearly intervals, and if lesions show signs of progression (contrast enhancement or growth), these intervals should be shortened and consideration given to early resection.
    Neurosurgical FOCUS 02/2006; 20(1):E5. DOI:10.3171/foc.2006.20.1.6 · 2.14 Impact Factor
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    Corey Raffel
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    ABSTRACT: Medulloblastoma is a primary brain tumor found in the cerebellum of children. The tumor occurs in association with two inherited cancer syndromes: Turcot syndrome and Gorlin syndrome. Insights into the molecular biology of the tumor have come from looking at alterations in the genes altered in these syndromes, PTC and APC, respectively. Murine models of medulloblastoma have been constructed based on these alterations. Additional murine models that, while mimicking the appearance of the human tumor, seem unrelated to the human tumor's molecular alterations have been made. In this review, the clinical picture, origin, molecular biology, and murine models of medulloblastoma are discussed. Although a great deal has been discovered about this tumor, the genetic alterations responsible for tumor development in a majority of patients have yet to be described.
    Neoplasia 07/2004; 6(4):310-22. DOI:10.1593/neo.03454 · 5.40 Impact Factor
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    Cormac O Maher, Corey Raffel
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    ABSTRACT: Primary brain tumors are the most common solid neoplasms of childhood. The diagnosis of brain tumors in the general pediatric population remains challenging. Nevertheless, it is clear that refinements in imaging, surgical technique, and adjunctive therapies have led to longer survival and an improving quality of life in children with brain tumors.
    Pediatric Clinics of North America 05/2004; 51(2):327-57. DOI:10.1016/S0031-3955(03)00206-2 · 2.20 Impact Factor
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    ABSTRACT: RAPID ADVANCES IN the technology used to study nucleic acids have revealed a great deal regarding the underlying biology of cancer. Most cancers arise as a result of chromosomal rearrangements and deoxyribonucleic acid mutations that lead to the activation of proto-oncogenes and loss of function of tumor suppressor genes. There are a number of different molecular routes that lead to these common goals, necessitating several different techniques of mutational analysis. Although many of these techniques can be difficult in practice, most are conceptually simple. We discuss several of the current techniques in cytogenetics and molecular genetics that are widely used in cancer biology laboratories. Understanding the molecular events that lead to cancer should allow the future development of targeted, nontoxic therapeutics similar to modern-day antibiotics. These technologies are being progressively applied in clinical neurosurgery, where they will be used to detect, diagnose, stratify, and treat cancers of the nervous system. High demand from an increasingly educated patient population means that neurosurgeons will need to be familiar with many of these techniques.
    Neurosurgery 12/2003; 53(5):1168-78; discussion 1178. DOI:10.1227/01.NEU.0000088807.95566.9B · 3.03 Impact Factor
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    ABSTRACT: Previous studies have reported that as many as 30% of resident and fellow applicants misrepresent their publication record on their residency and fellowship applications. To determine if neurologic surgery residency applicants were guilty of similar rates of misrepresentation, we reviewed the applications submitted to our institution in the year 2001-2002. There were 102 applications submitted to our neurologic surgery residency program for the 2001-2002 academic year. All publications listed by applicants on the Central Application Service for Neurologic Surgery were verified using various online bibliographic databases including MEDLINE and an interlibrary search. Manuscripts listed as being "in press" were authenticated by contacting the journals' editorial office while those listed as either "in preparation" or "submitted for publication" were excluded. Seventy-three (71.6%) candidates reported 212 published citations, including 129 (61%) journal articles, 13 (6%) book chapters, and 70 (33%) printed abstracts. Twelve of these applicants also listed 13 papers as being "in press." Overall, among the entire applicant pool, there were nine examples of possible misrepresentation in six applicants (6%). One applicant provided inadequate information to verify a book chapter. Another candidate cited four journal articles with the authors' names, even though his name was not listed among them. Two applicants included one citation each without listing any of the authors' names. Verification of these citations revealed that neither of them was a coauthor, although one was acknowledged. Among the articles listed as "in press," one was still under consideration for publication, and one could not be verified because of the journal's discontinuation. We confirmed that applicants who reported their names along with their published citations did so honestly and accurately. In our study, misrepresentation of published manuscripts among neurologic surgery residency applicants was rare when compared to candidates in other specialties.
    Surgical Neurology 11/2003; 60(4):280-3; discussion 283-4. DOI:10.1016/S0090-3019(03)00429-4 · 1.67 Impact Factor
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    ABSTRACT: We present six cases of a plexiform nerve sheath tumor of childhood that previously had been designated a form of malignant peripheral nerve sheath tumor (MPNST), and we provide evidence that such tumors are in fact benign plexiform cellular schwannomas. At presentation, the four girls and two boys ranged in age from 2 to 15 months with tumors of the leg (four), deep groin and upper thigh (one), and pelvis (one). Of the six lesions, five were congenital and none was associated with type 1 neurofibromatosis. Tumor sizes ranged from 2.0 to 9 cm, with three larger than 5 cm. Three tumors were well circumscribed, two were purely infiltrative, and one had a mixed circumscribed and infiltrative growth pattern. Peripheral nerve involvement was evident in two cases. Grossly, the tumors were multinodular or plexiform in configuration and, on sectioning, lobulated and homogeneously tan without necrosis. Characteristic histologic features included hypercellularity, composition of cells spindle in shape with elongate hyperchromatic nuclei, and indistinct cellular outlines. Their nuclei varied minimally in size and shape but were at least three times the size of typical neurofibroma nuclei. Mitoses were seen in every tumor and in the areas of greatest proliferative activity ranged from 4 to 31/10 high power fields. MIB-1 staining of at least 30% of the cells was noted in three cases. In five cases in which p53 immunoreactions were performed, no nuclear staining was evident. That the tumors are schwannomas was evident from their uniform strong staining for S-100 protein and an ultrastructure in all five cases showing only differentiated neoplastic Schwann cells. Architecturally, the tumors differed from conventional schwannoma and nonplexiform cellular schwannomas by their lack of both well-formed capsules and degenerative changes. Follow-up was available in all cases and ranged from 2 to 13.6 years. All tumors recurred locally and were treated by local resections. With the exception of one child lost to follow-up at 25 months, all the children are alive and free of disease. Our data combined with cases previously reported by Meis-Kindblom and Enzinger show a childhood peripheral nerve tumor unassociated with type 1 neurofibromatosis, occurring most commonly in infants, often presenting as a congenital tumor and, though prone to local recurrence, having no metastatic potential. The behavior is that of a benign tumor, although its often rapid growth, hypercellularity and increased mitotic activity, sometimes locally aggressive behavior, and difficulties encountered in obtaining tumor-free margins are unsettling to pathologist and clinician alike. These features may lead to a misdiagnosis of malignancy, which could result in harmful overtreatment.
    American Journal of Surgical Pathology 11/2003; 27(10):1321-9. DOI:10.1097/00000478-200310000-00004 · 4.59 Impact Factor
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    ABSTRACT: Linear sebaceous nevus syndrome (LSNS) is a rare neurocutaneous syndrome that is associated with seizures and mental retardation. The cortical abnormalities that are associated with this syndrome include focal cortical dysplasia, partial hemimegalencephaly and holohemispheric hemimegalencephaly. Few reports have addressed the utility of cortical resections for epilepsy treatment in the setting of LSNS. We report 3 children with this syndrome who underwent extensive cortical resections and experienced significant improvement in seizure frequency. Our results support the utility of extensive cortical resections for children with this condition.
    Pediatric Neurosurgery 10/2003; 39(3):129-35. DOI:10.1159/000071649 · 0.50 Impact Factor
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    ABSTRACT: Neurostimulation is a recent development in the treatment of epilepsy. Vagus nerve stimulation (VNS), the only approved neurostimulation therapy for epilepsy to date, has proved to be a viable adjunctive treatment option. The exact mechanism of action of VNS is not fully understood. In 2 randomized double-blind trials, seizure frequency declined approximately 30% after 3 months of treatment. Long-term follow-up studies suggest that response improves over time, with approximately 35% of patients experiencing a 50% reduction and 20% experiencing a 75% reduction in seizure frequency after 18 months of treatment. Unfortunately, the number of patients rendered medication-free and seizure-free with VNS is low. Vagus nerve stimulation is best viewed as an option for patients who are not surgical candidates or who hesitate to take the risk of surgery yet continue to have seizures despite maximal medical therapy. Stimulation of other regions of the central nervous system for treating epilepsy, including the anterior and centromedian nuclei of the thalamus, the hippocampus, the subthalamic nucleus, and the cerebral neocortex, is currently under investigation. We review the history, proposed mechanisms of action, clinical trials, adverse effects, and future direction of VNS and other modalities of neurostimulation therapy for epilepsy.
    Mayo Clinic Proceedings 03/2003; 78(2):238-48. DOI:10.4065/78.2.238 · 5.81 Impact Factor

Publication Stats

3k Citations
312.29 Total Impact Points


  • 2009–2011
    • Nationwide Children's Hospital
      Columbus, Ohio, United States
  • 2008
    • University of Michigan
      • Department of Neurosurgery
      Ann Arbor, MI, United States
  • 1996–2007
    • Mayo Clinic - Rochester
      • Department of Neurosurgery
      Rochester, Minnesota, United States
  • 2006
    • Boston Children's Hospital
      • Department of Neurosurgery
      Boston, MA, United States
  • 2002
    • Mayo Foundation for Medical Education and Research
      Rochester, Michigan, United States
  • 1997–1999
    • University of Maryland, Baltimore
      • Department of Neurosurgery
      Baltimore, Maryland, United States
  • 1988–1997
    • Children's Hospital Los Angeles
      • • Division of Hematology-Oncology
      • • Division of Neurosurgery
      Los Ángeles, California, United States
  • 1995
    • Dartmouth–Hitchcock Medical Center
      Lebanon, New Hampshire, United States
  • 1990–1993
    • Wolfson Childrens Hospital
      Jacksonville, Florida, United States
  • 1991
    • University of Utah
      • Department of Pediatrics
      Salt Lake City, UT, United States