The Role of Magnetic Resonance Imaging and Computed Tomography in Spinal Cord Injury.

Traumatic injuries of the spine are associated with long-term morbidity and mortality. Timely diagnosis and appropriate management of mechanical instability and spinal cord injury are important to prevent further neurologic deterioration. Spine surgeons require an understanding of the essential imaging techniques concerning the diagnosis, management, and prognosis of spinal cord injury. We present a review in the role of computed tomography (CT) including advancements in multidetector CT (MDCT), dual energy CT (DECT), and photon counting CT, and how it relates to spinal trauma. We also review magnetic resonance imaging (MRI) and some of the developed MRI based classifications for prognosticating the severity and outcome of spinal cord injury, such as diffusion weighted imaging (DWI), diffusion tractography (DTI), functional MRI (fMRI), and perfusion MRI.

The Role of Magnetic Resonance Imaging to Inform Clinical Decision-Making in Acute Spinal Cord Injury: A Systematic Review and Meta-Analysis.

The clinical indications and added value of obtaining MRI in the acute phase of spinal cord injury (SCI) remain controversial. This review aims to critically evaluate evidence regarding the role of MRI to influence decision-making and outcomes in acute SCI. A systematic review and meta-analysis were performed according to PRISMA methodology to identify studies that address six key questions (KQs) regarding diagnostic accuracy, frequency of abnormal findings, frequency of altered decision-making, optimal timing, and differences in outcomes related to obtaining an MRI in acute SCI. A total of 32 studies were identified that addressed one or more KQs. MRI showed no adverse events in 156 patients (five studies) and frequently identified cord compression (70%, 12 studies), disc herniation (43%, 16 studies), ligamentous injury (39%, 13 studies), and epidural hematoma (10%, two studies), with good diagnostic accuracy (seven comparative studies) except for fracture detection. MRI findings often altered management, including timing of surgery (78%, three studies), decision to operate (36%, 15 studies), and surgical approach (29%, nine studies). MRI may also be useful to determine the need for instrumentation (100%, one study), which levels to decompress (100%, one study), and if reoperation is needed (34%, two studies). The available literature consistently concluded that MRI was useful prior to surgical treatment (13 studies) and after surgery to assess decompression (two studies), but utility before/after closed reduction of cervical dislocations was unclear (three studies). One study showed improved outcomes with an MRI-based protocol but had a high risk of bias. Heterogeneity was high for most findings (I2 > 0.75). MRI is safe and frequently identifies findings alter clinical management in acute SCI, although direct evidence of its impact on outcomes is lacking. MRI should be performed before and after surgery, when feasible, to facilitate improved clinical decision-making. However, further research is needed to determine its optimal timing, effect on outcomes, cost-effectiveness, and utility before and after closed reduction.

Diagnosis, Management, and Clinical Outcomes of Tandem Thoracic and Lumbar Stenosis: A Systematic Literature Review and Case Series.

BACKGROUND: A scarcity of data has been reported on tandem thoracic lumbar stenosis, which might be related to either the rarity or underdiagnosis of the condition. We have presented a systematic review of the clinical presentation, diagnosis, and treatment patterns for patients with symptomatic tandem thoracic and lumbar stenosis. METHODS: A PubMed/MEDLINE search was performed to find reports of patients with symptomatic tandem thoracic and lumbar stenosis. RESULTS: The review identified 10 studies with a total of 48 patients with tandem thoracic and lumbar stenosis. Most patients (n = 41; 85%) had had tandem stenosis diagnosed at the initial investigation, with 71% of the reports citing ossification of the ligamentum flavum as a contributing etiology. A few patients (n = 7; 15%) had had thoracic lesions diagnosed after neurologic deterioration that had occurred after lumbar surgery for previously suspected isolated lumbar stenosis. Surgical management varied from isolated thoracic decompression, staged decompression, and simultaneous decompression. Most patients (n = 41; 87%) showed improved neurologic status after surgery. CONCLUSION: Ossification of the ligamentum flavum might play a key role in the pathogenesis of the condition. Most patients with tandem thoracic and lumbar stenosis will show improvement after surgical decompression. Although the limited evidence available has raised concerns regarding neurologic deterioration after initial lumbar decompression in patients with coexisting thoracic stenosis, the data are insufficient to definitively determine an optimal surgical strategy. Further research is needed to identify the optimal diagnostic and management criteria for patients with symptomatic tandem thoracic and lumbar stenosis.

Diffusion tensor imaging in cervical spondylotic myelopathy: a review.

Degenerative spondylotic myelopathy is the most common cause of spinal dysfunction, as well as nontraumatic spastic paraparesis and quadriparesis. Although conventional MRI is the gold standard for radiographic evaluation of the spinal cord, it has limited application for determining prognosis and recovery. In the last decade, diffusion tensor imaging (DTI), which is based on the property of preferential diffusion of water molecules, has gained popularity in evaluating patients with cervical spondylotic myelopathy (CSM). The use of DTI allows for evaluation of microstructural changes in the spinal cord not otherwise detected on routine conventional MRI. In this review, the authors describe the application of DTI in CSM evaluation and its role as an imaging biomarker to predict disease severity and prognosis.

The Use of Magnetic Resonance Imaging by Spine Surgeons in Management of Spinal Trauma Across AO Regions-Results of AO Spine Survey.

OBJECTIVE: To determine use of magnetic resonance imaging (MRI) for management of spinal trauma as a function of the availability of an MRI scanner across AO regions. METHODS: A survey regarding MRI availability and/or accessibility was conducted across 6 global AO regions. Questions were formulated to 1) evaluate availability of an MRI scanner and 2) whether the availability of an MRI scanner influenced time taken to image patients with spinal trauma. Pairwise comparison of responses among AO regions was performed. RESULTS: The survey was sent to 5.813 AO Spine members and 561 completed surveys were obtained (Africa, 3%; Asia Pacific, 22.1%; Europe, 30.8%; Latin America, 25.7%; Middle East, 9.4%; and North America, 8.9%). On availability of MRI for spinal trauma, 31.9% reported that MRI was readily available at all times, 51.3% noted 24-hour availability, but more difficult to obtain during nighttime, and 8.7% reported not having an MRI at their hospital. On time taken to obtain scans if MRI is readily available, 32.4% responded that imaging was obtained within 1 hour, whereas 39.9% stated between 1 and 4 hours. On time taken to obtain scans when MRI is least available, 7% responded that imaging was completed within 1 hour whereas 31.4% stated between 1 and 4 hours. Responses from Latin America significantly differed (P < 0.05) from all other AO regions except Africa. CONCLUSIONS: MRI use varies across AO regions, with clinical decision making on obtaining MRI in spinal trauma being influenced heavily by the availability of an MRI scanner.

Intracranial Extraskeletal Mesenchymal Chondrosarcoma: Case Report and Review of the Literature of Reported Cases in Adults and Children.

BACKGROUND: Intracranial extraskeletal mesenchymal chondrosarcoma is a rare, malignant variant of chondrosarcoma that is characterized by undifferentiated mesenchymal cells interspersed with pockets of mature hyaline cartilage. CASE DESCRIPTION: In this study, we report a 23-year-old female patient who underwent multiple craniotomies for tumor resection, as well as adjuvant radiotherapy and chemotherapy. We review the literature for reported cases and discuss the histopathologic features, radiologic findings, therapeutic approaches, and outcomes associated with this rare tumor. CONCLUSIONS: Intracranial extra-skeletal mesenchymal chondrosarcomas are very aggressive tumors, and their management should emphasize attempting gross total resection followed by adjuvant treatment modalities, including radiation therapy and/or chemotherapy.

Comparison between quantitative measurements of diffusion tensor imaging and T2 signal intensity in a large series of cervical spondylotic myelopathy patients for assessment of disease severity and prognostication of recovery.

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is a common cause of spinal cord dysfunction. Recently, it has been shown that diffusion tensor imaging (DTI) may be a better biomarker than T2-weighted signal intensity (T2SI) on MRI for CSM. However, there is very little literature on a comparison between the quantitative measurements of DTI and T2SI in the CSM patient population to determine disease severity and recovery. METHODS: A prospective analysis of 46 patients with both preoperative DTI and T2-weighted MRI was undertaken. Normalized T2SI (NT2SI), regardless of the presence or absence of T2SI at the level of maximum compression (LMC), was determined by calculating the T2SI at the LMC/T2SI at the level of the foramen magnum. Regression analysis was performed to determine the relationship of fractional anisotropy (FA), a quantitative measure derived from DTI, and NT2SI individually as well their combination with baseline preoperative modified Japanese Orthopaedic Association (mJOA) score and ∆mJOA score at the 3-, 6-, 12-, and 24-month follow-ups. Goodness-of-fit analysis was done using residual diagnostics. In addition, mixed-effects regression analysis was used to evaluate the impact of FA and NT2SI individually. A p value < 0.05 was selected to indicate statistical significance. RESULTS: Regression analysis showed a significant positive correlation between FA at the LMC and preoperative mJOA score (p = 0.041) but a significant negative correlation between FA at the LMC and the ΔmJOA score at the 12-month follow-up (p = 0.010). All other relationships between FA at the LMC and the baseline preoperative mJOA score or ∆mJOA score at the 3-, 6-, and 24-month follow-ups were not statistically significant. For NT2SI and the combination of FA and NT2SI, no significant relationships with preoperative mJOA score or ∆mJOA at 3, 6, and 24 months were seen on regression analysis. However, there was a significant correlation of combined FA and NT2SI with ∆mJOA score at the 12-month follow-up. Mixed-effects regression revealed that FA measured at the LMC was the only significant predictor of ΔmJOA score (p = 0.03), whereas NT2SI and time were not. Goodness-of-fit analysis did not show any evidence of lack of fit. CONCLUSIONS: In this large prospective study of CSM patients, FA at LMC appears to be a better biomarker for determining long-term outcomes following surgery in CSM patients than NT2SI or the combination values at LMC.

Cerebral Trypanosomiasis in an Immunocompromised Patient: Case Report and Review of the Literature.

BACKGROUND: We document a case of central nervous system infection with Trypanosoma cruzi. CASE DESCRIPTION: An 88-year-old woman presented with altered mental status, right-sided weakness, and slurred speech. Her medical history was significant for methotrexate intake for rheumatoid arthritis, and she tested negative for human immunodeficiency virus. Magnetic resonance imaging of the brain showed bilateral thick and peripherally enhancing white matter lesions in the frontoparietal region with extensive surrounding vasogenic edema. A lumbar puncture revealed increased protein and lymphocytic pleocytosis, and needle biopsy highlighted brain necrosis, chronic inflammation, and numerous intracellular organisms suggestive of T. cruzi amastigotes. Despite treatment with benznidazole, the patient expired soon after presentation. CONCLUSION: Chagas disease should be included in the differential diagnosis of an immunocompromised patient presenting with a central nervous system mass, meningoencephalitis, or focal neurologic signs.

AOSpine Global Survey: International Trends in Utilization of Magnetic Resonance Imaging/Computed Tomography for Spinal Trauma and Spinal Cord Injury across AO Regions.

The aim of this study was to determine the current trends in magnetic resonance imaging (MRI)/computed tomography (CT) utilization for spine trauma in various clinical scenarios. We conducted a survey across six AO regions and preformed pair-wise comparisons between responses obtained from different AO regions. The survey was sent to 5813 surgeons and had a 9.6% response rate with the majority being orthopedic followed by neurosurgeons. In a neurologically intact patient, the predominant imaging modality for all AO regions was CT. For patients with spinal cord injury (SCI), the predominant choice for all AO regions was CT + MRI + x-ray except North America, which was CT + MRI; pair-wise comparisons revealed significant differences involving LATAM (Latin America) versus (Asia-Pacific [APAC], Europe [EU], and Middle East [MEA]) and APAC versus (LATAM and North America [NA]). In a patient with incomplete SCI (ISCI) who presented within 4 h and had CT, the predominant choice for all AO regions was "forgo MRI and proceed to operating room (OR)." Similar to ISCI, in a patient with complete SCI, the predominant option for all AO regions was the same as ISCI, but the range was lower. Pair-wise comparisons noted significant differences between MEA and APAC, with both exhibiting differences compare to NA, LATAM, and EU for complete and ISCI. Most AO regions obtained post-operative MRI only if there was a new deficit. In summary, decisions about the use of a particular imaging modality across AO regions appears to be influenced by the neurological status of the patient upon admission and the presence of neurological deficits post-surgery. Type of residency training and fellowship training did not have an influence on choosing the appropriate imaging modality for both intact and impaired patients. Further study is needed to determine whether accessibility to MRI would change surgeons' attitude toward obtaining MRI in patients with SCI.

Diffusion Tensor Imaging in Acute Spinal Cord Injury: A Review of Animal and Human Studies.

Diffusion tensor imaging (DTI), based on the property of preferential diffusion of water molecules in biological tissue, is seeing increasing clinical application in the pathologies of the central nervous system. Spinal cord injury (SCI) is one such area where the use of DTI allows for the evaluation of changes to microstructure of the spinal cord not detected on routine conventional magnetic resonance imaging. The insights obtained from pre-clinical models of SCI indicate correlation of quantitative DTI indices with histology and function, which points to the potential of DTI as a non-invasive, viable biomarker for integrity of white matter tracts in the spinal cord. In this review, we describe DTI alterations in the acute phase of SCI in both animal models and human subjects and explore the underlying pathophysiology behind these changes.

Correlation of magnetic resonance diffusion tensor imaging parameters with American Spinal Injury Association score for prognostication and long-term outcomes.

OBJECTIVEConventional MRI is routinely used to demonstrate the anatomical site of spinal cord injury (SCI). However, quantitative and qualitative imaging parameters have limited use in predicting neurological outcomes. Currently, there are no reliable neuroimaging biomarkers to predict short- and long-term outcome after SCI.METHODSA prospective cohort of 23 patients with SCI (19 with cervical SCI [CSCI] and 4 with thoracic SCI [TSCI]) treated between 2007 and 2014 was included in the study. The American Spinal Injury Association (ASIA) score was determined at the time of arrival and at 1-year follow-up. Only 15 patients (12 with CSCI and 3 with TSCI) had 1-year follow-up. Whole-cord fractional anisotropy (FA) was determined at C1-2, following which C1-2 was divided into upper, middle, and lower segments and the corresponding FA value at each of these segments was calculated. Correlation analysis was performed between FA and ASIA score at time of arrival and 1-year follow-up.RESULTSCorrelation analysis showed a positive but nonsignificant correlation (p = 0.095) between FA and ASIA score for all patients (CSCI and TCSI) at the time of arrival. Additional regression analysis consisting of only patients with CSCI showed a significant correlation (p = 0.008) between FA and ASIA score at time of arrival as well as at 1-year follow-up (p = 0.025). Furthermore, in case of patients with CSCI, a significant correlation between FA value at each of the segments (upper, middle, and lower) of C1-2 and ASIA score at time of arrival was found (p = 0.017, p = 0.015, and p = 0.002, respectively).CONCLUSIONSIn patients with CSCI, the measurement of diffusion anisotropy of the high cervical cord (C1-2) correlates significantly with injury severity and long-term follow-up. However, this correlation is not seen in patients with TSCI. Therefore, FA can be used as an imaging biomarker for evaluating neural injury and monitoring recovery in patients with CSCI.

Management and survival trends for adult patients with malignant gliomas in the setting of multiple primary tumors: a population based analysis.

INTRODUCTION: The impact of multiple primary tumors, in the setting of malignant glioma (MG), has not been heavily explored. METHODS: We extracted demographics and clinical data from the SEER-18 registry for adult patients with MGs. The cases were separated based on the sequence of MG diagnosis relative to the other primary tumors: Group (A) One primary only or first primary of multiple primaries and Group (B) second primary or subsequent primary tumor. Incidences, frequencies, and glioma-related survivals were analyzed. RESULTS: Group B constituted 12.8% of new MG. The incidences of group B, relative to those of all new MG, range from 0.14 to 0.18. Compared to group A, group B exhibited an older age. Moreover, group B exhibited a higher proportion of females, Caucasians, smaller tumors, non-operative cases, and those receiving radiation (p < 0.05); the proportion with GTR remained comparable. Multiple groupings (oral cavity, digestive system, respiratory system, skin, breast, genital systems, urinary system, lymphoma) exhibited lower glioma-related observed survival (p < 0.05) compared to Group A. An active diagnosis of "leukemia" appears to confer longer glioma-related survival while a history of "breast" or "digestive system" malignancies portends a shorter glioma-related survival. CONCLUSION: For newly diagnosed MG, a high proportion does have history of extra-CNS primary tumors. Generally, these patients appear to have worse glioma-related observed survival compare to those with malignant glioma as the only primary or the first of multiple primary tumors. Knowledge regarding epidemiology, clinical factors, and observed survival can help guide clinical management/consultation for this subset of patients.

Resting-state functional connectivity after concussion is associated with clinical recovery.

There has been a recent call for longitudinal imaging studies to better characterize the time course of physiological recovery following sport-related concussion (SRC) and its relationship with clinical recovery. To address this, we evaluated changes to resting-state functional connectivity (rs-FC) of the whole-brain network following SRC and explored associations between rs-FC and measures of clinical outcome. High school and collegiate football athletes were enrolled during preseason. Athletes that suffered SRC (N = 62) were assessed across the acute (within 48 hr) and sub-acute (days 8, 15, and 45) phases. Matched football athletes without concussion served as controls (N = 60) and participated in similar visits. Multi-band resting-state fMRI was used to assess whole-brain rs-FC at each visit using network-based statistic and average nodal strength from regions of interest defined using a common whole-brain parcellation. Concussed athletes had elevated symptoms, psychological distress, and oculomotor, balance, and memory deficits at 48 hr postconcussion relative to controls, with diminished yet significant elevations in symptoms and psychological distress at 8 days. Both rs-FC analyses showed that concussed athletes had a global increase in connectivity at 8 days postconcussion relative to controls, with no differences at the 48-hr, 15-day, or 45-day visits. Further analysis revealed the group effect at the 8-day visit was driven by the large minority of concussed athletes still symptomatic at their visit; asymptomatic concussed athletes did not differ from controls. Findings from this large-scale, prospective study suggest whole-brain rs-FC alterations following SRC are delayed in onset but associated with the presence of self-reported symptoms.

Glioblastoma in the setting of prior lower grade gliomas - insights from SEER database.

INTRODUCTION: Secondary glioblastomas (GBs) constitute a small subset of all GBs and tend to arise after a lower grade glioma. Though knowledge regarding this subset has gained traction in recent years, its definition continues to evolve, complicating its clinical management. Investigation of epidemiology and survival patterns may help provide needed insights. RESULTS: The age at GB diagnosis is significantly lower (46.22 vs 60.25 years) for group B. The distribution among type of GB (glioblastoma, giant cell glioblastoma, or gliosarcoma) was significantly different, with no diagnosis of giant cell GB in Group B. Compared to Group A, Group B exhibited a higher proportion of females, not married, smaller tumors, no GTR, and no radiation (all p < 0.05). GB-related observed survivals were comparable. Cox regression with inclusion of co-variates reveal no significant influence of GB group on observed survival. Regarding group B, mean age was 40.197 for diagnosis of initial lower grade glioma. The most common initial ICD-O-3 pathology was oligodendroglioma, NOS; astrocytoma, NOS; astrocytoma, anaplastic; and mixed glioma. METHODS: The SEER-18 registry was queried for patients with GBs. Patients were further classified into two GB groups: Group A - those with GB as the only primary tumor, and Group B - those with GB as a 2nd primary or subsequent tumor and with history of lower grade gliomas. Demographics and clinical factors were compared between group A and B. Appropriate statistics were employed to calculate incidences and differences among factors and GB-related survivals between the groups. CONCLUSIONS: Overall, Group B develops GBs at an earlier age, but observed survival remains similar to those with GBs as the only primary. Moreover, this subset also exhibit different proportions of the types of GBs, and well as differences in other key clinical factors (namely, gender and tumor size at presentation). Prior treatments for lower grade gliomas likely explain some of the differences noted regarding management course after diagnosis of GB.

Irradiation of pediatric glioblastoma cells promotes radioresistance and enhances glioma malignancy via genome-wide transcriptome changes.

Pediatric glioblastoma (GBM) is a relatively rare brain tumor in children that has a dismal prognosis. Surgery followed by radiotherapy is the main treatment protocol used for older patients. The benefit of adjuvant chemotherapy is still limited due to a poor understanding of the underlying molecular and genetic changes that occur with irradiation of the tumor. In this study, we performed total RNA sequencing on an established stable radioresistant pediatric GBM cell line to identify mRNA expression changes following radiation. The expression of many genes was altered in the radioresistant pediatric GBM model. These genes have never before been reported to be associated with the development of radioresistant GBM. In addition to exhibiting an accelerated growth rate, radioresistant GBM cells also have overexpression of the DNA synthesis-rate-limiting enzyme ribonucleotide reductase, and pro-cathepsin B. These newly identified genes should be concertedly studied to better understand their role in pediatric GBM recurrence and progression after radiation. It was observed that the changes in multiple biological pathways protected GBM cells against radiation and transformed them to a more malignant form. These changes emphasize the importance of developing a treatment regimen that consists of a multiple-agent cocktail that acts on multiple implicated pathways to effectively target irradiated pediatric GBM. An alternative to radiation or a novel therapy that targets differentially expressed genes, such as metalloproteases, growth factors, and oncogenes and aim to minimize oncogenic changes following radiation is necessary to improve recurrent GBM survival.

Advanced biomarkers of pediatric mild traumatic brain injury: Progress and perils.

There is growing public concern about neurodegenerative changes (e.g., Chronic Traumatic Encephalopathy) that may occur chronically following clinically apparent and clinically silent (i.e., sub-concussive blows) pediatric mild traumatic brain injury (pmTBI). However, there are currently no biomarkers that clinicians can use to objectively diagnose patients or predict those who may struggle to recover. Non-invasive neuroimaging, electrophysiological and neuromodulation biomarkers have promise for providing evidence of the so-called "invisible wounds" of pmTBI. Our systematic review, however, belies that notion, identifying a relative paucity of high-quality, clinically impactful, diagnostic or prognostic biomarker studies in the sub-acute injury phase (36 studies on unique samples in 28 years), with the majority focusing on adolescent pmTBI. Ultimately, well-powered longitudinal studies with appropriate control groups, as well as standardized and clearly-defined inclusion criteria (time post-injury, injury severity and past history) are needed to truly understand the complex pathophysiology that is hypothesized (i.e., still needs to be determined) to exist during the acute and sub-acute stages of pmTBI and may underlie post-concussive symptoms.

Intracranial hemangioblastoma - A SEER-based analysis 2004-2013.

INTRODUCTION: Intracranial hemangioblastoma (HB) is a rare pathology. Limited data exist regarding its epidemiology. METHODS: With the SEER-18 registry database, information from all patients diagnosed with intracranial HB from 2004 to 2013 were extracted, including age, gender, race, marital status, presence of surgery, extent of surgery, receipt of radiation, tumor size, tumor location, and follow-up data. Age-adjusted incidence rates and overall survival (OS). Cox proportional hazards model was employed for both univariate and multivariate analyses. RESULTS: A total of 1307 cases were identified. The overall incidence of intracranial hemangioblastoma is 0.153 per 100,000 person-years [95% confidence interval (CI)=0.145-0.162]. Through univariate analysis, age < 40 [hazard ratio (HR)=0.277, p<0.001], no radiation [HR=0.56, p=0.047], and presence of surgery [HR=0.576, p=0.012] are significant positive prognostic factors. Caucasian race [HR=1.42, p=0.071] and female gender [HR=0.744, p=0.087] exhibit noticeable trends towards positive prognosis. Through multivariate analysis, younger age [HR=1.053, p < 0.01], race [HR=1.916, p<0.01], and presence of surgery [HR=0.463, p<0.01 were significant independent prognostic factors. CONCLUSION: Clinical factors such as younger age, Caucasian race, and presence of surgery are significant independent factors for overall survival in patients with HBs. Though analysis regarding extent of surgery did not produce a meaningful relationship, this may be related to surgical bias / expertise. Moreover, no validation for radiation therapy was identified, but this may be related to short follow up intervals and the variable growth patterns of HBs.

Subependymal Giant Cell Astrocytoma: A Surveillance, Epidemiology, and End Results Program-Based Analysis from 2004 to 2013.

BACKGROUND: Subependymal giant cell astrocytoma (SEGA) is a rare, benign neoplasm predominantly associated with tuberous sclerosis complex. Clinical outcomes have largely been conveyed via small- and medium-sized case series. METHODS: With the Surveillance, Epidemiology, and End Results Program (SEER)-18 registry database, information from all patients diagnosed with SEGA from 2004 to 2013 was obtained (age, sex, race, marital status, tumor size, tumor location, occurrence of surgery, receipt of radiation, and follow-up data). Age-adjusted incidence rates and overall survival (OS) were determined. Cox proportional hazards model was used for both univariate and multivariate analyses. RESULTS: The overall incidence of SEGA within the SEER-18 database is 0.027 per 100,000 person-years (95% confidence interval, 0.024-0.031). A total of 226 cases were identified. For OS, univariate analysis revealed age younger than 18 years (hazard ratio [HR], 0.214; P = 0.004) and occurrence of surgery (HR, 0.328; P = 0.039) were significant positive prognostic factors. Sex, marital status, race, tumor size, tumor location, and receipt of radiation did not exhibit significant relationships. Interestingly, subanalysis for extent of resection to gross total resection did not show benefit. Multivariate analysis revealed that both age younger than 18 years (HR, 0.193; P = 0.002) and occurrence of surgery (HR, 0.286; P = 0.021) remained significant. CONCLUSIONS: Based on our analysis, younger age and occurrence of surgery are significant independent factors associated with better OS. There was no support for radiation.