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OBJECT There is currently no consensus on the safety of sports participation for patients with Chiari I malformation (CM-I). The authors' goal was to define the risk of sports participation for children with the imaging finding of CM-I. METHODS A prospective survey was administered to 503 CM-I patients at 2 sites over a 46-month period. Data were gathered on imaging characteristics, treatment, sports participation, and any sport-related injuries. Additionally, 81 patients completed at least 1 subsequent survey following their initial entry into the registry and were included in a prospective group, with a mean prospective follow-up period of 11 months. RESULTS Of the 503 CM-I patients, 328 participated in sports for a cumulative duration of 4641 seasons; 205 of these patients participated in contact sports. There were no serious or catastrophic neurological injuries. One patient had temporary extremity paresthesias that resolved within hours, and this was not definitely considered to be related to the CM-I. In the prospective cohort, there were no permanent neurological injuries. CONCLUSIONS No permanent or catastrophic neurological injuries were observed in CM-I patients participating in athletic activities. The authors believe that the risk of such injuries is low and that, in most cases, sports participation by children with CM-I is safe.

OBJECTIVEIn children, the repair of skull defects arising from decompressive craniectomy presents a unique set of challenges. Single-center studies have identified different risk factors for the common complications of cranioplasty resorption and infection. The goal of the present study was to determine the risk factors for bone resorption and infection after pediatric cranioplasty.METHODSThe authors conducted a multicenter retrospective case study that included all patients who underwent cranioplasty to correct a skull defect arising from a decompressive craniectomy at 13 centers between 2000 and 2011 and were less than 19 years old at the time of cranioplasty. Prior systematic review of the literature along with expert opinion guided the selection of variables to be collected. These included: indication for craniectomy; history of abusive head trauma; method of bone storage; method of bone fixation; use of drains; size of bone graft; presence of other implants, including ventriculoperitoneal (VP) shunt; presence of fluid collections; age at craniectomy; and time between craniectomy and cranioplasty.RESULTSA total of 359 patients met the inclusion criteria. The patients’ mean age was 8.4 years, and 51.5% were female. Thirty-eight cases (10.5%) were complicated by infection. In multivariate analysis, presence of a cranial implant (primarily VP shunt) (OR 2.41, 95% CI 1.17–4.98), presence of gastrostomy (OR 2.44, 95% CI 1.03–5.79), and ventilator dependence (OR 8.45, 95% CI 1.10–65.08) were significant risk factors for cranioplasty infection. No other variable was associated with infection.Of the 240 patients who underwent a cranioplasty with bone graft, 21.7% showed bone resorption significant enough to warrant repeat surgical intervention. The most important predictor of cranioplasty bone resorption was age at the time of cranioplasty. For every month of increased age the risk of bone flap resorption decreased by 1% (OR 0.99, 95% CI 0.98–0.99, p < 0.001). Other risk factors for resorption in multivariate models were the use of external ventricular drains and lumbar shunts.CONCLUSIONSThis is the largest study of pediatric cranioplasty outcomes performed to date. Analysis included variables found to be significant in previous retrospective reports. Presence of a cranial implant such as VP shunt is the most significant risk factor for cranioplasty infection, whereas younger age at cranioplasty is the dominant risk factor for bone resorption.

OBJECTIVEThe long-term effects of surgical fusion on the growing subaxial cervical spine are largely unknown. Recent cross-sectional studies have demonstrated that there is continued growth of the cervical spine through the teenage years. The purpose of this multicenter study was to determine the effects of rigid instrumentation and fusion on the growing subaxial cervical spine by investigating vertical growth, cervical alignment, cervical curvature, and adjacent-segment instability over time.METHODSA total of 15 centers participated in this multi-institutional retrospective study. Cases involving children less than 16 years of age who underwent rigid instrumentation and fusion of the subaxial cervical spine (C-2 and T-1 inclusive) with at least 1 year of clinical and radiographic follow-up were investigated. Charts were reviewed for clinical data. Postoperative and most recent radiographs, CT, and MR images were used to measure vertical growth and assess alignment and stability.RESULTSEighty-one patients were included in the study, with a mean follow-up of 33 months. Ninety-five percent of patients had complete clinical resolution or significant improvement in symptoms. Postoperative cervical kyphosis was seen in only 4 patients (5%), and none developed a swan-neck deformity, unintended adjacent-level fusion, or instability. Of patients with at least 2 years of follow-up, 62% demonstrated growth across the fusion construct. On average, vertical growth was 79% (4-level constructs), 83% (3-level constructs), or 100% (2-level constructs) of expected growth. When comparing the group with continued vertical growth to the one without growth, there were no statistically significant differences in terms of age, sex, underlying etiology, surgical approach, or number of levels fused.CONCLUSIONSContinued vertical growth of the subaxial spine occurs in nearly two-thirds of children after rigid instrumentation and fusion of the subaxial spine. Failure of continued vertical growth is not associated with the patient’s age, sex, underlying etiology, number of levels fused, or surgical approach. Further studies are needed to understand this dichotomy and determine the long-term biomechanical effects of surgery on the growing pediatric cervical spine.

OBJECT Motocross racing is a popular sport; however, its impact on the growing/developing pediatric spine is unknown. Using a retrospective cohort model, the authors compared the degree of advanced degenerative findings in young motocross racers with findings in age-matched controls. METHODS Patients who had been treated for motocross-related injury at the authors' institution between 2000 and 2007 and had been under 18 years of age at the time of injury and had undergone plain radiographic or CT examination of any spinal region were eligible for inclusion. Imaging was reviewed in a blinded fashion by 3 physicians for degenerative findings, including endplate abnormalities, loss of vertebral body height, wedging, and malalignment. Acute pathological segments were excluded. Spine radiographs from age-matched controls were similarly reviewed and the findings were compared. RESULTS The motocross cohort consisted of 29 riders (mean age 14.7 years; 82% male); the control cohort consisted of 45 adolescents (mean age 14.3 years; 71% male). In the cervical spine, the motocross cohort had 55 abnormalities in 203 segments (average 1.90 abnormalities/patient) compared with 20 abnormalities in 213 segments in the controls (average 0.65/patient) (p = 0.006, Student t-test). In the thoracic spine, the motocross riders had 51 abnormalities in 292 segments (average 2.04 abnormalities/patient) compared with 25 abnormalities in 299 segments in the controls (average 1.00/patient) (p = 0.045). In the lumbar spine, the motocross cohort had 11 abnormalities in 123 segments (average 0.44 abnormalities/patient) compared with 15 abnormalities in 150 segments in the controls (average 0.50/patient) (p = 0.197). CONCLUSIONS Increased degenerative changes in the cervical and thoracic spine were identified in adolescent motocross racers compared with age-matched controls. The long-term consequences of these changes are unknown; however, athletes and parents should be counseled accordingly about participation in motocross activities.

The purpose of this study was to assess the health-related quality of life (HRQOL) and the impact of treatment on HRQOL in long-term survivors of pediatric low-grade gliomas (LGGs) using an adult instrument. QOL of 121 patients with a diagnosis of LGG from the Mayo Clinic were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-QLQ-C30 for cancer in general) and (EORTC QLQ-BN20 specific for brain tumors). Median follow-up was 21.9 years for the participants. Median age at diagnosis was 11.8 years and at assessment was 33 years. Mean (standard deviation) global QOL score for the study was 78 (18) and 76.4 (22.8) in a reference population of healthy adults. Using QLQ-C30, radiation treated patients compared to non-radiation patients reported lower physical functioning (p = 0.002), role functioning (p = 0.004), and more constipation problems (p < 0.001). Patients with tumor recurrence reported lower role functioning (p = 0.016), social functioning (p = 0.040), and more financial problems (p = 0.029) compared to their counterparts. Using QLQ-BN20, patients with deep tumors compared to cortical tumors reported more bladder control problems (p = 0.016). Radiation treated patients also reported more bladder control problems (p < 0.001) compared to their counterparts. In the multivariable analysis, radiation therapy remained an independent predictor of physical and role functioning as well as symptoms related to brain tumors like visual disorders and motor dysfunction. Global QOL of long-term survivors of pediatric LGGs is similar to that of a reference population of healthy adults. The following tumor and treatment related factors were most consistently associated with poorer QOL: CNS tumor location, post-operative radiation, and tumor recurrence. Future studies are necessary to identify strategies to improve QOL in this subgroup of patients.

Central nervous system primitive neuroectodermal tumors (CNS PNETs) predominantly occur in children and rarely in adults. Because of the rarity of this tumor, its outcomes and prognostic variables are not well characterized. The purpose of this study was to evaluate clinical outcomes and prognostic factors for children and adults with CNS PNET. The records of 26 patients (11 children and 15 adults) with CNS PNET from 1991 to 2011 were reviewed retrospectively. Disease-free survival (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method, and relevant prognostic factors were analyzed. For the cohort, both the 5-year DFS and the OS were 46 %. For pediatric patients, the 5-year DFS was 78 %; for adult patients, it was 22 % (P = 0.004). Five-year OS for the pediatric and adult patients was 67 and 33 %, respectively (P = 0.07). With bivariate analysis including chemotherapy regimen (high dose vs. standard vs. nonstandard) or risk stratification (standard vs. high) and age, the increased risk of disease recurrence in adults persisted. A nonsignificant tendency toward poorer OS in adult patients relative to pediatric patients also persisted. High-dose chemotherapy with stem cell rescue was associated with a statistically significant improvement in OS and a tendency toward improved DFS, although the findings were mitigated when the effect of age was considered. Local recurrence was the primary pattern of treatment failure in both adults and children. Our results suggest that adult patients with CNS PNETs have inferior outcomes relative to the pediatric cohort. Further research is needed to improve outcomes for CNS PNET in populations of all ages.

Summary Medically refractory epilepsy remains a major medical problem worldwide. Although some patients are eligible for surgical resection of seizure foci, a proportion of patients are ineligible for a variety of reasons. One such reason is that the foci reside in eloquent cortex of the brain and therefore resection would result in significant morbidity. This retrospective study reports our experience with a novel neurostimulation technique for the treatment of these patients. We identified three patients who were ineligible for surgical resection of the intracranially identified seizure focus because it resided in eloquent cortex, who underwent therapeutic trial of focal cortical stimulation delivered through the subdural monitoring grid. All three patients had a significant reduction in seizures, and two went on to permanent implantation, which resulted in long-term reduction in seizure frequency. In conclusion, this small case report provides some evidence of proof of concept of the role of targeted continuous neocortical neurostimulation in the treatment of medically refractory focal epilepsy, and provides support for ongoing investigations into this treatment modality. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

BACKGROUND: The majority of moyamoya surgical series have been confined to Asian and pediatric populations. Few have studied demographics, risk factors, and outcomes in adult North American populations. OBJECTIVE: To examine outcomes after revascularization for moyamoya in white and African American adults and to assess for predictors of recurrent stroke. METHODS: A retrospective review of 75 non-Asian patients undergoing 110 procedures at the Mayo Clinic was performed. Demographics, known moyamoya associations, cerebrovascular risk factors, and autoimmune diseases were recorded. Primary outcomes for vascular events were assessed with Kaplan-Meier analysis. Fisher exact methods were used to evaluate for associations with recurrent events. RESULTS: Mean age was 42 years, and mean follow-up was 47 months. Seventy-one of the 75 patients were white. The majority had bilateral disease (n = 49). Perioperative ischemic events occurred in 5 patients (4.5%). The 5- and 10-year event rates were 5.8% and 9.9%. Significant associations were found with a history of thyroid disease (P = .05) and recurrent stroke. A trend was also found between hypertension and autoimmune disease with recurrent stroke. CONCLUSION: Outcomes were favorable with revascularization in this subset with moyamoya. A significant association between a history of thyroid disease and recurrent stroke was found. Additionally, high prevalences of autoimmune disease, hypertension, and thyroid disease were found in our cohort, suggesting that they may play a role in the pathophysiology and progression of moyamoya disease in this population. A new classification for moyamoya is proposed based on these data.

a b s t r a c t Objective: To evaluate nocturnal polysomnogram findings in children with suspected symptomatic Chiari type I malformation, correlate them with clinical and magnetic resonance imaging data and to determine if this information has value in clinical decision making process. Methods: A retrospective review identified 24 children with type I Chiari malformation, presumed symp- tomatic who had undergone neurological assessment, cranial magnetic resonance imaging and nocturnal polysomnography. Perimedullary subarachnoid space effacement on the magnetic resonance studies and the magnitude of cerebellar tonsillar descent in relation to the McRae line were correlated with frequency of obstructive or central sleep apnea, number of cortical arousals and evidence of impaired vocal mobility on laryngoscopy. The Wilcoxon rank sum test was applied for continuous variables and the Fisher exact test for categorical variables. Results: The median age of the subjects was 6 years. The findings from 16/24 subjects with perimedullary subarachnoid space effacement (effaced group) were compared with those of 8/24 in the non-effaced group. The central apnea index (1.5 (IQR 1-3.5) versus 0.5 (IQR 0-1.5)) and cortical arousal index (12 (IQR 10-19) versus 8 (IQR 6.5-9)) were significantly higher in the effaced group than in the non-effaced group (p = 0.0376 and 0.0036 respectively). Greater descent of tonsils as measured by distance from the McRae line to the tonsil tip was associated with significantly higher central apnea index, total arousal index and respiratory event related arousals. Measurements of clivus-canal angle, Klauss index and pB-C2 line did not correlate with abnormalities on polysomnography. Conclusion: The central apnea and arousal indices derived from the nocturnal polysomnogram correlate well with magnetic resonance imaging findings of subarachnoid space effacement and degree of ton- sillar herniation. In children with Chiari type I malformation, the nocturnal polysomnogram findings provides important information that aids in the decision making process about proceeding with surgical decompression.

Identification of a single epileptogenic focus in patients with tuberous sclerosis complex is a challenge. Noninvasive imaging modalities, including subtraction ictal single-photon emission computed tomography coregistered to magnetic resonance imaging (SISCOM), have been used to determine the dominant epileptogenic focus for surgical resection. We assessed whether complete resection of SISCOM hyperperfusion abnormality correlates with seizure-free outcome in 6 children with tuberous sclerosis complex-related epilepsy. The median seizure onset age was 4 months (range 1 day to 16 months). The age at surgery ranged from 8 months to 13 years. A dominant SISCOM hyperperfusion focus was identified in 5 patients with multiple tubers. SISCOM provided additional localizing information for epilepsy surgery in 3 patients with nonlocalizing or discordant electrophysiologic and neuroimaging findings. At a minimum of 2 years' follow-up, 3 patients were free of seizures overall. Freedom from seizures was associated with complete resection of SISCOM abnormality in 2 patients. These findings demonstrate that SISCOM can be useful in identifying the epileptogenic zone and in guiding the location and extent of epilepsy surgery in children with tuberous sclerosis complex and multifocal abnormalities. In children with tuberous sclerosis complex and intractable epilepsy, complete resection of the SISCOM hyperperfusion abnormality is associated with freedom from seizures.

Object To better understand syrinx pathophysiology, the authors performed a prospective study in which they used findings from serial clinical and magnetic resonance (MR) imaging examinations performed before and after craniocervical decompression to establish the time course of syrinx narrowing. Methods Serial clinical examinations and cervical MR imaging were performed in 29 consecutive patients with Chiari malformation Type I (CM-I) and syringomyelia before surgery, 1 week, and 3–6 months after surgery, and then annually. Time to narrowing of the syrinx (> 50% decrease in maximal anteroposterior diameter) following surgery was calculated using the Kaplan–Meier method. Results All syringes decreased in diameter and length (number of segments) on MR images at 3–6 months, 1 year, and 2 years or later. The syrinx diameter decreased from 6.9 ± 2.1 mm (mean ± standard deviation) preoperatively to < 1.5 mm at last evaluation (p < 0.0001). The median time to syrinx narrowing was 3.6 months following CM-I decompression (95% confidence interval 3.0–6.5 months). After surgery 94% of patients had improved symptoms, but symptoms resolved incompletely in 68% of patients; 52 and 59% of patients had residual dysesthesias and sensory loss, respectively. Clinical improvement occurred before partial or complete disappearance of the syrinx on MR images. Patient age, duration of symptoms, sex, preoperative syrinx diameter, and length of syrinx were unrelated to time to syrinx narrowing. Conclusions Most patients improve after decompression for CM-I, but many have residual symptoms. Syringes may continue to diminish for months to years after surgical decompression. A collapsed syrinx (absence of distention of the spinal cord) indicates that the pathophysiology has been reversed by treatment regardless of the completeness of elimination of the cavity on MR images.

This report reviews a series of 3 patients who developed superficial siderosis following posterior fossa operations in which dural closure was incomplete. In all 3 patients, revision surgery and complete duraplasty was performed to halt the progression of superficial siderosis. Following surgery, 2 patients experienced resolution of their CSF xanthochromia while 1 patient had reduced CSF xanthochromia. In this paper the authors also review the etiology, pathophysiology, diagnosis, and treatment of this condition. The authors suggest that posterior fossa dural patency and pseudomeningocele are risk factors for the latent development of superficial siderosis and recommend that revision duraplasty be performed in patients with posterior fossa pseudomeningoceles and superficial siderosis to prevent progression of the disease.

The aim of this study was to identify preadmission variables that are prognostic of epilepsy surgical candidacy for children admitted into an epilepsy-monitoring unit.This study is a retrospective review of patients 0-18 years who were admitted into the pediatric epilepsy-monitoring unit at Mayo Clinic between November 2010 and December 2013 to assess for surgery candidacy for medically intractable epilepsy. Demographic data, epilepsy details, treatments, electroencephalograph and imaging results, and the consensus notes of the epilepsy surgery conferences were collected.One hundred and forty eight children underwent inpatient, prolonged video-electroencephalograph monitoring for presurgical evaluation, of which 136 had their typical events recorded. Five recommended for callosotomy alone were excluded and 131 composed the study group. Of these 131, the epilepsy surgery conference consensus deemed that 69 were surgical candidates, of which 45 (65%) underwent resective surgery. Chi-square analysis found seven preadmission predictors of surgical candidacy: single semiology at seizure onset (P 0.001), structural etiology (P 0.001), one or more interictal foci all in the same hemisphere (P 0.004), focal background electroencephalograph slowing (P 0.001), focal or hemispheric abnormality on magnetic resonance imaging (P 0.001), male sex (P = 0.02), and normal development (P = 0.04).The presence of fewer than four predictors was suggestive of low likelihood of candidacy (31%), whereas if more than four factors were present, 91% were found to be surgical candidates. These findings facilitate clinical decision-making for providers in a cost-effective manner and provide realistic expectations for families.

PURPOSE We aimed to determine the yield of revising intracranially implanted electrodes and the factors contributing to the yield. METHODS Patients were identified from the Mayo Clinic Epilepsy Surgery Database between 1997 and 2010. Twenty patients had revision of intracranial electrode placements because initial implantation did not localize seizure onset adequately. RESULTS Seizures were captured in 18 of 20 patients who underwent intracranial electrode revision, of which 10 (55.6%) showed localized seizure onset that led to a surgical resection. Seizures were improved in 9 of 10 patients who underwent resection; of these, five were seizure free. The only factors found to be statistically significant in localizing ictal onset zone after revised implantation were prior focal scalp interictal discharges and an initial intracranial EEG showing ictal onset at the edge of the electrode grid. No permanent complication was associated with revised implantation, but one patient had transient apraxia of the right foot. CONCLUSIONS Revised implantation could be useful in selected patients with inadequate seizure localization on initial intracranial EEG. Resective surgery was performed in 50% of patients who underwent revision of intracranial electrodes with the majority of these patients experiencing an improvement in seizure control.

BACKGROUND: Medically intractable epilepsy involving drop attacks can be difficult to manage and negatively affect quality of life. Most studies investigating the effect of corpus callosotomy (CC) on seizures have been limited, focusing on the pediatric population or drop seizures alone, with little attention to other factors influencing seizure outcome. OBJECTIVE: To assess seizure outcomes after CC in adults and children. METHODS: Retrospective analysis was performed on all patients who underwent CC (anterior two thirds, 1- or 2-stage complete) at our institution between 1990 and 2011. Change in frequency after CC was assessed for drop seizures and other seizure types. Multiple factors were evaluated for impact on seizure outcome. RESULTS: Fifty patients met inclusion criteria. The median age was 1.5 years at seizure onset and 17 years at time of surgery. Anterior two-thirds CC was performed in 28 patients, 1-stage complete in 17, and 2-stage complete in 5. All 3 groups experienced a significant decrease in drop seizures (P < .001, P < .001, and P = .020, respectively), with 40% experiencing complete resolution, and 64% dropping at least 1 frequency category. Other seizure types significantly decreased in anterior two-thirds CC and 1-stage complete (P = .0035, P = .001, respectively). Younger age at surgery correlated with better seizure outcomes (P = .043). CONCLUSION: CC for medically refractory generalizing epilepsy is effective for both drop seizures and other seizure types. CC should be considered soon after a patient has been deemed medically refractory because earlier age at surgery results in lower risk and better outcome.

Introduction To evaluate long-term overall survival (OS), progression-free survival (PFS), and outcomes in pathologically proven brainstem low-grade gliomas (BS-LGG) in children. Methods The Mayo Clinic tumor registry identified 48 consecutive children (≤20 y, 52% female) with biopsy-proven BS-LGG treated at Mayo Clinic between January 1971 and December 2004. Medical records were retrospectively reviewed. For analysis, patients were censored at the time of recurrence, death, or last follow-up. Results The median age at diagnosis was 12 years with a median follow-up of 6.0 years. The majority of tumors were grade I (69%) and pathology was consistent with an astrocytoma in the majority of patients (98%). Gross total resection was obtained in 4, subtotal in 17, and 27 patients were biopsied only. Postoperative radiotherapy (RT) was used in 29 patients. Median OS for the entire group was 14.8 years with a 1-, 5-, and 10-year OS of 85%, 67% and 59%, respectively. Median PFS for the entire group was 7.3 years. Improved survival was associated with undergoing resection versus biopsy-only with 5-year OS rates of 85% and 50% (P=0.002), respectively. A high proportion of patients (42%) had diffuse tumors and 13 patients (27%) had diffuse pontine gliomas (DPGs). DPGs had an OS of 1.8 years with a worse median PFS than non-DPGs (1.8 vs. 11.1 y; P=0.009). RT was used preferentially in patients with poor prognosis such as those who had a biopsy-only procedure (19/27) and DPGs (9/13). Conclusions OS in this single institution retrospective study in pathologically proven BS-LGG with extensive follow-up displayed favorable long-term outcomes. Improved outcomes were associated with nondiffuse classification.

This study reports changes in long-term survival after the introduction of modern imaging in pediatric patients with low-grade gliomas (LGGs).Records from 351 consecutive pediatric patients diagnosed with LGG between 1970 and 2009 at Mayo Clinic Rochester were reviewed and divided into diagnosis before (group I: 1970 to 1989) and after (group II: 1990 to 2009) postoperative magnetic resonance imaging became regularly used in pediatric LGG.Median progression-free survival (PFS) and overall survival (OS) were not reached. Overall, 10-year PFS was 62% and OS was 90%. On multivariate analysis, improved PFS was associated with gross total resection (GTR; P0.0001) and postoperative radiation therapy (RT; P0.0001). In those undergoing less than GTR, PFS was improved with RT, nearing rates of patients receiving GTR (P=0.12). On multivariate analysis, higher OS was associated with GTR (P0.0001) and pilocytic histology (P=0.03). Group II had fewer headaches, fewer sensory/motor symptoms, less postoperative RT, and more GTRs. OS and PFS were not different between the groups.This large series of pediatric LGG patients with long-term follow-up found no significant changes in OS or PFS over time. Overall, GTR was associated with improved OS and PFS. RT was associated with an improvement in PFS, with the greatest benefit seen in patients undergoing less than GTR.

Objective To determine the incidence of and risk factors for cerebrospinal fluid (CSF), wound, and hematoma-related complications following intradural spine surgery. Background Complications of intradural spinal surgery requiring a return to the operating room lengthen hospital stay and increase cost as well as patient risk. Here we present our experience with complications in intradural spinal surgery. Methods Between 1993 and 2010, a total of 528 pediatric and adult patients who underwent biopsy and/or resection of intramedullary or extramedullary spinal lesions at Mayo Clinic-Rochester were evaluated. Results The overall complication rate in this series was 4.9%. Complications, such as neurologic worsening due to an etiology not able to be treated surgically, or medical complications, such as deep venous thrombosis, were not included in this study. The overall complication rates that were CSF-related, wound-related, hematoma-related, and miscellaneous were 3.0%, 1.1%, 0.6%, and 0.2% respectively. Complication rates decreased with age from 15.4% in 0- to 10-year-olds to 4.1% in 61- to 90-year-olds. Tumors represented the majority of pathology at 90.5%. The complication rate for patients who had prior treatment was higher at 6.9% compared with 4.7% in those who had no prior treatment (P = 0.5). Intramedullary tumors had a complication rate of 7.1% vs. 3.6% for extramedullary tumors (P = 0.14). Some patients (5.7%) had coexisting intracranial tumors at the time of their surgery but none had complications with intradural spine surgery. Conclusions Complications of intradural spine surgery are most commonly CSF related, may decrease with increasing age of the patient, and are higher with intramedullary tumors.

Objective To report clinical findings of rare retrobulbar optic nerve hemangioblastomas associated with von Hippel–Lindau disease (VHL). Design Retrospective observational case series. Participants Nine patients with VHL. Methods The clinical course and magnetic resonance imaging findings of patients with VHL and hemangioblastomas affecting the anterior visual pathway from the intraorbital optic nerve to the optic chiasm are reviewed. Main Outcome Measure Clinical course of retrobulbar optic nerve hemangioblastomas. Results The mean age of VHL diagnosis was 24±14 years, and mean follow-up was 5±4 years. All had other CNS lesions and retinal hemangioblastomas. Approximately 50% (5/9) had a previous enucleation or had visual acuity loss (4/9), some due to other VHL ocular complications. Four patients underwent surgical resection of an intracranial hemangioblastoma. Growth patterns and pathology are similar to those of other hemangioblastomas in the CNS. Conclusions Although these lesions are rare, patients with VHL who present with signs of optic neuropathy should be evaluated for anterior visual pathway hemangioblastomas impinging on the optic nerve from the orbit to the chiasm. On neuroimaging, the hemangioblastomas may demonstrate chiasmal or optic tract edema, associated cysts, and T 2 flow voids. Lesions may remain radiologically and clinically stable, evolve radiographically with no visual or neurological progression, or progress clinically and radiographically. Patients at risk for visual loss should be considered for surgical resection. Close coordination among neuroradiology, neurosurgery, and ophthalmology patient care teams is advised for optimal management of these patients.

Object The aim of this study was to determine whether ictal single-photon emission computed tomography (SPECT) is useful in localizing the site of seizure onset in patients in whom surgery for intractable epilepsy failed and who are being considered for repeated surgery. Methods Subtraction ictal SPECT coregistered to magnetic resonance imaging (SISCOM) studies were retrospectively analyzed in 58 patients who were being evaluated for possible repeated resection for intractable partial epilepsy between January 1, 1996, and October 31, 1999. All patients had persistent seizures subsequent to an initial resection and underwent another excision. The SISCOM-demonstrated abnormalities were classified as concordant, discordant, or indeterminate, compared with the localization of the epileptogenic zone revealed on video electroencephalography monitoring. The ability of SISCOM to predict operative outcome was also determined in patients who had undergone repeated surgical procedures. The SISCOM studies revealed a localized hyperperfused alteration in 46 (79%) of 58 patients. Forty-one (89%) of these 46 patients had a SISCOM-demonstrated alteration in the hemisphere of the previous epilepsy surgery. Imaging changes in 33 (72%) of the 46 patients were at the site of the previous focal cortical resection. Eight (17%) of the 46 had SISCOM-demonstrated abnormalities remote from the lobe in which surgery had been performed but in the ipsilateral hemisphere. The hyperperfusion focus was in the contralateral hemisphere in the remaining five patients (11%). The site of the epileptogenic zone was concordant with the SISCOM focus in 32 (70%) of 46 patients. Twenty-six patients underwent repeated resection and were followed up for a mean of 44 months thereafter; 11 of these patients (42%) had a significant reduction in seizure tendency. Only five patients (19%) were seizure free. Ten (50%) of 20 patients with a concordant SISCOM focus compared with none (0%) of three patients with a discordant focus had a favorable surgical outcome (p = 0.23). Conclusions The SISCOM method might be useful in the evaluation of, and the surgical planning for, patients with intractable partial epilepsy in whom previous resective treatment has failed and who are being considered for reoperation.

Object 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. Methods 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. Conclusions 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.

A focal lesion detected by use of magnetic resonance imaging (MRI) is a favorable prognostic finding for epilepsy surgery. Patients with normal MRI findings and extratemporal lobe epilepsy have less favorable outcomes. Most studies investigating the outcomes of patients with normal MRI findings who underwent (nonlesional) extratemporal epilepsy surgery are confined to a highly select group of patients with limited follow-up.To evaluate noninvasive diagnostic test results and their association with excellent surgical outcomes (defined using Engel classes I-IIA of surgical outcomes) in a group of patients with medically resistant nonlesional extratemporal epilepsy.A retrospective study.Mayo Clinic, Rochester, Minnesota.From 1997 through 2002, we identified 85 patients with medically resistant extratemporal lobe epilepsy who had normal MRI findings. Based on a standardized presurgical evaluation and review at a multidisciplinary epilepsy surgery conference, some of these patients were selected for intracranial electroencephalographic (EEG) monitoring and epilepsy surgery.Nonlesional extratemporal lobe epilepsy surgery.The results of noninvasive diagnostic tests and the clinical variables potentially associated with excellent surgical outcome were examined in patients with a minimum follow-up of 1 year (mean follow-up, 9 years).Based on the noninvasive diagnostic test results, a clear hypothesis for seizure origin was possible for 47 of the 85 patients (55%), and 31 of these 47 patients (66%) proceeded to intracranial EEG monitoring. For 24 of these 31 patients undergoing long-term intracranial EEG (77%), a seizure focus was identified and surgically resected. Of these 24 patients, 9 (38%) had an excellent outcome after resective epilepsy surgery. All patients with an excellent surgical outcome had at least 10 years of follow-up. Univariate analysis showed that localized interictal epileptiform discharges on scalp EEGs were associated with an excellent surgical outcome.Scalp EEG was the most useful test for identifying patients with normal MRI findings and extratemporal lobe epilepsy who were likely to have excellent outcomes after epilepsy surgery. Extending outcome analysis beyond the resective surgery group to the entire group of patients who were evaluated further highlights the challenge that these patients pose. Although 9 of 24 patients undergoing resective surgery (38%) had excellent outcomes, only 9 of 31 patients undergoing intracranial EEG (29%) and only 9 of 85 patient with nonlesional extratemporal lobe epilepsy (11%) had long-term excellent outcomes.