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Ependymomas encompass multiple clinically relevant tumor types based on localization and molecular profiles. Tumors of the methylation class "spinal ependymoma" (SP-EPN) represent the most common intramedullary neoplasms in children and adults. However, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical relevance have been described in a large, epigenetically defined series. Transcriptomic (n = 72), epigenetic (n = 225), genetic (n = 134), and clinical data (n = 112) were integrated for a detailed molecular overview on SP-EPN. Additionally, we mapped SP-EPN transcriptomes to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. The integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord revealed that SP-EPN display the highest similarities to mature adult ependymal cells. Unsupervised hierarchical clustering of transcriptomic data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype A tumors primarily carried previously known germline or sporadic NF2 mutations together with 22q loss (bi-allelic NF2 loss), resulting in decreased NF2 expression. Furthermore, they more often presented as multilocular disease and demonstrated a significantly reduced progression-free survival as compared to SP-EP subtype B. In contrast, subtype B predominantly contained samples without NF2 mutation detected in sequencing together with 22q loss (monoallelic NF2 loss). These tumors showed regular NF2 expression but more extensive global copy number alterations. Based on integrated molecular profiling of a large multi-center cohort, we identified two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities., (© 2024. The Author(s).)

Study Design: This was as clinical retrospective study., Objectives: We sought to evaluate the characteristics of Pediatric intramedullary spinal cord tumors (PISCTs) and to identify differences between pediatric and adult intramedullary spinal cord tumors., Summary of Background Data: PISCTs represent a rare clinical entity with limited evidence-base in the literature., Methods: This study is a subanalysis of the retrospective multicenter observational study authorized by the Neurospinal Society of Japan, including consecutive patients with spinal intramedullary tumors treated surgically at 58 institutions between 2009 and 2020. Data on 1080 intramedullary spinal cord tumors were obtained, consisting of 91 pediatric and 939 adult patients. Survival was compared using Cox hazard regression while clinical differences were evaluated using multivariable logistic regression that controlled for confounders., Results: Pediatric patients had a shorter overall, and progression-free, survival than adults. Pediatric patients with ISCTs were likely to have scoliosis [odds ratio (OR) = 6.49, 95% CI: 2.26-18.7], short preoperative symptom duration (OR = 0.99, 95% CI: 0.98-0.99), lower incidence of paresthesia (OR = 0.41, 95% CI: 0.22-0.77), higher incidence of paresis (OR = 2.10, 95% CI: 1.01-4.35), histopathology of astrocytoma (OR = 2.97, 95% CI: 1.19-7.43), and postoperative functional deterioration upon discharge (OR = 2.83, 95% CI: 1.43-5.58). Age was not a statistically significant prognostic factor of overall survival among the pediatric cohort., Conclusion: We found that the clinical characteristics of ISCTs differed between pediatric and adult patients. In terms of histopathological types, astrocytoma was most common in pediatric patients. ISCT occurring at an early age may not be an indicator for poor prognosis., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objectives: Ependymoma is the most common spinal intramedullary tumor. Although clinical outcomes have been described in the literature, most of the reports were based on limited numbers of cases or been confined to institutional experience. The objective of this study was to analyze more detailed characteristics of spinal intramedullary ependymoma (SIE) and provide clinical factors associated with progression-free survival (PFS)., Methods: This retrospective observational multicenter study included consecutive patients with SIE in the cervical or thoracic spine treated surgically at a total of 58 institutions between 2009 and 2020. The results of pathological diagnosis at each institute were confirmed, and patients with myxopapillary ependymoma, subependymoma, or unverified histopathology were strictly excluded from this study. Outcome measures included surgical data, surgery-related complications, postoperative systemic adverse events, postoperative adjuvant treatment, postoperative functional condition, and presence of recurrence., Results: This study included 324 cases of World Health Organization grade II (96.4%) and 12 cases of World Health Organization grade III (3.6%). Gross total resection (GTR) was achieved in 76.5% of cases. Radiation therapy (RT) was applied after surgery in 16 cases (4.8%), all of which received local RT and 5 of which underwent chemotherapy in combination. Functional outcomes were significantly affected by preoperative neurological symptoms, tumor location, extent of tumor resection, and recurrence. Multivariate regression analysis suggested that limited extent of tumor resection or recurrence resulted in poor functional outcomes. Multiple comparisons among the groups undergoing GTR, subtotal resection and biopsy, or partial resection of the tumor showed that the probability of PFS differed significantly between GTR and other extents of resection., Conclusion: When GTR can be safely obtained in the surgery for SIE, functional maintenance and longer PFS can be expected., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Anterior cervical disc replacement (ACDR) using cervical artificial disc (CAD) has the advantage of maintaining the range of motion (ROM) at the surgical level, subsequently reducing the postoperative risk of adjacent disc disease. Following the approval for the clinical use in Japan, a post-marketing surveillance (PMS) study was conducted for two different types of CAD, namely, Mobi-C (metal-on-plastic design) and Prestige LP (metal-on-metal design). The objective of this prospective observational multicenter study was to analyze the first 2-year surgical results of the PMS study of 1-level ACDR in Japan. A total of 54 patients were registered (Mobi-C, n = 24, MC group; Prestige LP, n = 30, PLP group). Preoperative neurological assessment revealed radiculopathy in 31 patients (57.4%) and myelopathy in 15 patients (27.8%). Preoperative radiological assessment classified the disease category as disc herniation in 15 patients (27.8%), osteophyte in 6 patients (11.1%), and both in 33 patients (61.1%). The postoperative follow-up rates at 6 weeks, 6 months, 1 year, and 2 years after ACDR were 92.6%, 87.0%, 83.3%, and 79.6%, respectively. In both groups, patients' neurological condition improved significantly after surgery. Radiographic assessment revealed loss of mobility at the surgical level in 9.5% of patients in the MC group and in 9.1% of patients in the PLP group. No secondary surgeries at the initial surgical level and no serious adverse events were observed in either group. The present results suggest that 1-level ACDR is safe, although medium- to long-term follow-up is mandatory to further verify the validity of ACDR for Japanese patients.

Each year, the Japan Neurosurgical Society (JNS) reports up-to-date statistics from the Japan Neurosurgical Database regarding case volume, patient demographics, and in-hospital outcomes of the overall cohort and neurosurgical subgroup according to the major classifications of main diagnosis. We hereby report patient demographics, in-hospital mortality, length of hospital stay, purpose of admission, number of medical management, direct surgery, endovascular treatment, and radiosurgery of the patients based on the major classifications and/or main diagnosis registered in 2018 and 2019 in the overall cohort (523283 and 571143 patients, respectively) and neurosurgical subgroup (177184 and 191595 patients, respectively). The patient demographics, disease severity, proportion of purpose of admission (e.g., operation, 33.9-33.5%) and emergent admission (68.4-67.8%), and in-hospital mortality (e.g., cerebrovascular diseases, 6.3-6.5%; brain tumor, 3.1-3%; and neurotrauma, 4.3%) in the overall cohort were comparable between 2018 and 2019. In total, 207783 and 225217 neurosurgical procedures were performed in the neurosurgical subgroup in 2018 and 2019, respectively, of which endovascular treatment comprised 19.1% and 20.3%, respectively. Neurosurgical management of chronic subdural hematoma (19.4-18.9%) and cerebral aneurysm (15.4-14.8%) was most common. Notably, the proportion of management of ischemic stroke/transient ischemic attack, including recombinant tissue plasminogen activator infusion and endovascular acute reperfusion therapy, increased from 7.5% in 2018 to 8.8% in 2019. The JNS statistical update represents a critical resource for the lay public, policy makers, media professionals, neurosurgeons, healthcare administrators, researchers, health advocates, and others seeking the best available data on neurosurgical practice.

Purpose: We previously reported that there was a subgroup of IDH-mutated astrocytomas harboring only 19q-loss showing oligodendroglioma-like morphology and significantly longer overall survival (OS) compared with 19q-intact astrocytomas. The aim of this study was to further explore the biological characteristics of this possible subgroup and obtain insight into the mechanism of their relatively benign clinical behavior., Methods: We compared gene expression pattern between five 19q-loss and five 19q-intact IDH-mutated astrocytomas by microarray analysis., Results: By comparing expression levels of genes of 19q-loss astrocytomas to those of 19q-intact astrocytomas, 102 up-regulated genes and 162 down-regulated genes were extracted. The down-regulated genes clustered heavily to 19q and 4p while the up-regulated genes clustered to 4q. It was noteworthy that fibroblast growth factor 1 associated with stem cell maintenance and multiple genes associated with glioma progression were down-regulated in 19q-loss astrocytomas, and these results were validated with the independent TCGA data set. On t-SNE analysis of the 19q-loss astrocytomas with other IDH-mutant glioma subgroups from the TCGA datasets, the expression pattern of the 19q-loss astrocytomas showed no shift toward oligodendrogliomas with 1p/19q codeletion but rather constituted a subgroup of astrocytoma., Conclusions: These findings suggested that 19q-loss in astrocytomas is more likely acquired event rather than an early event in oncogenesis like the 1p/19q-codeletion in oligodendrogliomas, and that the biological features of 19q-loss astrocytomas are possibly related to differentially expressed genes associated with stem cell maintenance and glioma progression., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: In cervical spondylotic myelopathy (CSM), compromise of blood flow to the compressed spinal cord has been postulated to contribute to the development of myelopathy. Although decompressive surgery has been considered to improve spinal cord blood flow, evidence to support this notion is scarce. To determine whether blood flow improves after decompressive surgery for CSM, regional blood flow was measured in a model of chronic cervical compression in rats by using a fluorescent microsphere technique., Methods: Thin polyurethane sheets, measuring precisely 3 × 5 × 0.7 mm, were implanted under the C5-6 laminae in 24 rats to induce continuous compression on the cervical spinal cord. These sheets expand gradually by absorbing tissue fluid. This animal model has been demonstrated to reproduce the clinical features and histological changes of CSM, including progressive motor weakness with delayed onset and insidious tissue damage prior to symptom onset. Twenty-four rats that underwent sham operation were allocated to a control group. To confirm the development of cervical myelopathy, motor functions were measured weekly over the study period. Nine weeks after implantation of the sublaminar expanding sheets, histological studies and C5-6 decompressive surgery were conducted. Regional blood flow in the brainstem and cervical spinal cord was measured sequentially until 120 minutes after decompression., Results: In the CSM group, bilateral forepaw grip strength deteriorated progressively from 5 weeks after implantation. In the compressed C5-6 segment of the spinal cord, significant flattening of the cord, a decreased number of motor neurons, and vacuolations of gray matter were demonstrated. In the control group, blood flow in the brainstem and cervical spinal cord was unchanged by the decompressive surgery. In the CSM group, however, diminished blood flow and continuous blood flow increments for 120 minutes after decompression were demonstrated in the compressed C5-6 spinal cord segment., Conclusions: Chronic mechanical compression induced regional spinal cord blood flow insufficiency concomitant with progressive neuronal loss and motor dysfunction in a chronic compression model in rats. Decompressive surgery increased spinal cord blood flow. These findings suggest that blood flow recovery may contribute to postoperative neurological improvement.

Background: The most common cause of intracranial subarachnoid hemorrhage (SAH) is an intracranial aneurysm or other vascular lesion; however, spinal lesions have also been implicated. Furthermore, vascular lesions rarely occur in the thoracolumbar region. We herein presented a case of intracranial SAH caused by an isolated aneurysm in the thoracic spinal artery. Case presentation: A 79-year-old woman developed the sudden onset of headaches in the parietal and occipital regions followed by vomiting. Head computed tomography (CT) scans showed SAH in the basal cistern and around the parietal lobe cortex. Cerebral angiography detected no aneurysm or vascular malformation. Spinal CT on day 1 showed extensive SAH at the posterior surface of the spinal cord, which was the most prominent at the level of T9/10, and spinal angiography subsequently revealed an aneurysm fed by the T10 radicular artery. The aneurysm was resected by T8-10 laminectomy, and the patient recovered with no long-term neurological deficit. Conclusions: A literature review revealed 17 cases of intracranial SAH from thoracolumbar vascular lesions. Most cases resulted in poor functional outcomes, which occurred in the later phase of the disease and may have been avoided with earlier diagnoses and interventions. We suggest whole spine CT as a useful tool for rapid screening of this rare lesion, and is recommended when an initial survey for intracranial lesions does not detect any likely lesions. Furthermore, ventricular reflux on head CT may lead to an accurate diagnosis in the absence of spinal symptoms.

Background: Middle meningeal artery (MMA) embolization can be a treatment option for selected cases of chronic subdural hematoma (CSDH) patients. However, appropriate timing of this procedure or the conditions to be considered are still not standardized., Methods: Between 2008 and 2018, 18 symptomatic CSDH patients underwent MMA embolization at our institution. The timing of embolization and the risk factors for recurrence of CSDH, the recurrence rate after an embolization, and the complication were thoroughly reviewed., Results: Of the 18 cases, 16 patients were male. The median age at MMA embolization was 78.5 years (range, 66-98 years). The median follow-up period were eight months (range, 2-53 months). Possible risk factors for CSDH recurrence harbored by those patients were age > 74 yrs (10), brain atrophy (4), separated hematoma (3), coagulopathy (3), anticoagulant administration (3), and thrombocytopenia (1). No recurrence or complication was observed in any of the patients after the embolization., Conclusions: MMA embolization is effective and safe in preventing recurrence of CSDH with high risk of recurrence, and could be a standard treatment for such cases., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The Japan Neurosurgical Database (JND) is a prospective observational study registry established in 2017 by the Japan Neurosurgical Society (JNS) to visualize real-world clinical practice, promote science, and improve the quality of care and neurosurgery board certification in Japan. We summarize JND's aims and methods, and describes the 2018 survey results. The JND registered in-hospital patients' clinical data mainly from JNS training institutions in 2018. Caseload, patient demographics, and in-hospital outcomes of the overall cohort and a neurosurgical subgroup were examined according to major classifications of main diagnosis. Neurosurgical caseload per neurosurgeon in training in core hospitals in 2018 was calculated as an indicator of neurosurgical training. Of 523,283 cases (male 55.3%) registered from 1360 participating institutions, the neurosurgical subgroup comprised of 33.9%. Among the major classifications, cerebrovascular diseases comprised the largest proportion overall and in the neurosurgical subgroup (53.1%, 41.0%, respectively), followed by neurotrauma (19.1%, 25.5%), and brain tumor (10.4%, 12.8%). Functional neurosurgery (6.4%, 3.7%), spinal and peripheral nerve disorders (5.1%, 10.1%), hydrocephalus/developmental anomalies (2.9%, 5.3%), and encephalitis/infection/inflammatory and miscellaneous diseases (2.9%, 1.6%) comprised smaller proportions. Most patients were aged 70-79 years in the overall cohort and neurosurgical subgroup (27.8%, 29.4%). Neurotrauma and cerebrovascular diseases in the neurosurgical subgroup comprised a higher and lower proportion, respectively, than in the overall cohort in elderly patients (e.g. 80 years, 46.9% vs. 33.5%, 26.8% vs. 54.4%). The 2018 median neurosurgical caseload per neurosurgeon in training was 80.7 (25-75th percentile 51.5-117.5). These initial results from 2018 reveal unique aspects of neurosurgical practice in Japan.

Objective: Erythropoietin (EPO) is a clinically available hematopoietic cytokine. EPO has shown beneficial effects in the context of spinal cord injury and other neurological conditions. The aim of this study was to evaluate the effect of EPO on a rat model of spinal cord compression-induced cervical myelopathy and to explore the possibility of its use as a pharmacological treatment., Methods: To develop the compression-induced cervical myelopathy model, an expandable polymer was implanted under the C5-C6 laminae of rats. EPO administration was started 8 weeks after implantation of a polymer. Motor function of rotarod performance and grip strength was measured after surgery, and motor neurons were evaluated with H-E, NeuN and choline acetyltransferase staining. Apoptotic cell death was assessed with TUNEL and Caspase-3 staining. The 5HT, GAP-43 and synaptophysin were evaluated to investigate the protection and plasticity of axons. Amyloid beta precursor protein (APP) was assessed to evaluate axonal injury. To assess transfer of EPO into spinal cord tissue, the EPO levels in spinal cord tissue were measured with an ELISA for each group after subcutaneous injection of EPO., Results: High-dose EPO maintained motor function in the compression groups. EPO significantly prevented the loss of motor neurons and significantly decreased neuronal apoptotic cells. Expression of 5HT and synaptophysin was significantly preserved in the EPO group. APP expression was partly reduced in the EPO group. The EPO levels in spinal cord tissue were significantly higher in the high-dose EPO group than other groups., Conclusion: EPO improved motor function in rats with compression-induced cervical myelopathy. EPO suppressed neuronal cell apoptosis, protected motor neurons, and induced axonal protection and plasticity. The neuroprotective effects were produced following transfer of EPO into the spinal cord tissue. These findings suggest that EPO has high potential as a treatment for degenerative cervical myelopathy., Competing Interests: The authors have declared that no competing interests exist.

IDH-mutant gliomas are classified into astrocytic or oligodendroglial tumors by 1p/19q status in the WHO 2016 classification, with the latter presenting with characteristic morphology and better prognosis in general. However, the morphological and genetic features within each category are varied, and there might be distinguishable subtypes. We analyzed 170 WHO grade II-IV gliomas resected in our institution. 1p/19q status was analyzed by microsatellite analysis, and genetic mutations were analyzed by next-generation sequencing and Sanger sequencing. For validation, the Brain Lower Grade Glioma dataset of The Cancer Genome Atlas was analyzed. Of the 42 grade III IDH-mutated gliomas, 12 were 1p-intact/19q-intact (anaplastic astrocytomas [AA]), 7 were 1p-intact/19q-loss (AA), and 23 showed 1p/19q-codeletion (anaplastic oligodendrogliomas). Of the 88 IDH-wild type glioblastomas (GBMs), 14 showed 1p-intact/19q-loss status. All of the seven 1p-intact/19q-loss AAs harbored TP53 mutation, but no TERT promotor mutation. All 19q-loss AAs had regions presenting oligodendroglioma-like morphology, and were associated with significantly longer overall survival compared to 19q-intact AAs (P = .001). This tendency was observed in The Cancer Genome Atlas Lower Grade Glioma dataset. In contrast, there was no difference in overall survival between the 19q-loss GBM and 19q-intact GBM (P = .4). In a case of 19q-loss AA, both oligodendroglial morphology and 19q-loss disappeared after recurrence, possibly indicating correlation between 19q-loss and oligodendroglial morphology. We showed that there was a subgroup, although small, of IDH-mutated astrocytomas harboring 19q-loss that present oligodendroglial morphology, and also were associated with significantly better prognosis compared to other 19q-intact astrocytomas., (© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Hemangioblastoma is usually amenable to total surgical resection, but indication for surgery can be hampered by its location, multiplicity, or repeated recurrences frequently observed in patients with von Hippel Lindau disease (VHLD). Stereotactic radiosurgery (SRS) has been administered for such cases as an alternative therapeutic option with generally favorable clinical response, but the effect of SRS has not been underscored by histological examination of the treated hemangioblastoma. Here we present histology of VHLD-associated hemangioblastoma tissue resected three months after SRS because of cyst enlargement. It confirmed that hemangioblastoma cells totally disappeared after SRS with a marginal dose of 20 Gy. Furthermore, Electron microscope revealed that endothelial cells of the vascular structure disappeared while maintaining the basement membranes, and leakage of intraluminal contents was observed around the structure. We showed the SRS was effective for hemangioblastoma pathologically at least with the marginal dose of 20 Gy. Leakage of intraluminal contents from the damaged vascular structure losing the endothelial cells is one possible mechanism for the cyst enlargement, and it may be a reason of poor control rate of SRS for the cystic hemangioblastoma., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Motor evoked potential (MEP) recording is used as a method to monitor integrity of the motor system during surgery for intramedullary tumors (IMTs). Reliable sensitivity of the monitoring in predicting functional deterioration has been reported. However, we observed false positives and false negatives in our experience of 250 surgeries of IMTs., Objective: To delineate specificity and sensitivity of MEP monitoring and to elucidate its limitations and usefulness., Methods: From 2008 to 2011, 58 patients underwent 62 surgeries for IMTs. MEP monitoring was performed in 59 operations using transcranial electrical stimulation. Correlation with changes in muscle strength and locomotion was analyzed. A group undergoing clipping for unruptured aneurysms was compared for elicitation of MEP., Results: Of 212 muscles monitored in the 59 operations, MEP was recorded in 150 (71%). Positive MEP warnings, defined as amplitude decrease below 20% of the initial level, occurred in 37 muscles, but 22 of these (59%) did not have postoperative weakness (false positive). Positive predictive value was limited to 0.41. Of 113 muscles with no MEP warnings, 8 muscles developed postoperative weakness (false negative, 7%). Negative predictive value was 0.93. MEP responses were not elicited in 58 muscles (27%). By contrast, during clipping for unruptured aneurysms, MEP was recorded in 216 of 222 muscles (96%)., Conclusion: MEP monitoring has a limitation in predicting postoperative weakness in surgery for IMTs. False-positive and false-negative indices were abundant, with sensitivity and specificity of 0.65 and 0.83 in predicting postoperative weakness.

Objective: When treating patients with cervical spondylotic myelopathy (CSM), we often note amelioration in concomitant hypertension after surgery. To assess the effects of surgery and the mechanisms thereof, blood pressure (BP) and parasympathetic nervous activity were monitored prospectively in CSM patients undergoing surgery., Methods: Sixty-eight consecutive CSM patients who underwent surgery with myoarchitectonic spinolaminoplasty were enrolled. BP and electrocardiography were recorded preoperatively and at 1, 3, and 6 months postoperatively. Forty-six patients completed the scheduled follow-ups and were analyzed. Preoperatively, 17 had a mean BP higher than 100 mmHg (the HT group) and 12 had hypertension despite taking medication (the HT-refractory group). To evaluate alterations in parasympathetic function, the coefficient of variation of the RR interval (CVRR) was evaluated., Results: A significant BP reduction was observed in the HT group 6 months after surgery, but not in the normotensive group (n=29). The effect was more remarkable in the HT-refractory group. A transient BP increase at 1 and 3 months after surgery was observed in all groups. Comparisons were made between groups classified by age (over 65 years or younger than 60 years) and the presence or absence of an intramedullary hyperintense T2 signal on magnetic resonance imaging, but no significant differences were detected. Measurements of CVRR did not significantly differ between the groups over the course of follow-up., Conclusion: Hypertension coexisting with CSM can be ameliorated after surgical treatment. The effect is likely to be mediated by moderation of sympathetic activity, rather than parasympathetic activation. We believe that a combination of adequate decompression of the spinal cord and relief from musculoskeletal stresses effectuate this moderation.

Intravascular lymphoma (IVL) has been characterized in many case reports by multiple white matter lesions reflecting ischemic changes. In contrast, there are very few case reports of cerebral or cerebellar hemorrhage resulting from IVL. A 56-year-old woman was referred to our department with two-week history of headache, nausea, and poor appetite. Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) showed dilated veins on the cerebellar surface. No ischemic lesions were detected on diffusion-weighted images. Three days after admission, the patient had a large cerebellar hemorrhage, prompting emergency surgery. Unfortunately, the patient died on the 11th postoperative day. Massive CD20-positive lymphoma cells were recognized in the cerebellar veins, but not in the arteries or the parenchyma of the brain. This is the rare case report of a cerebellar hemorrhage complication from IVL that might have been caused by venous congestion. The dilated veins on the cerebellar surface recognized from the Gd-enhanced T1-weighted images were specific clues in this case.

Study Design: Basic animal research., Objective: The effects of granulocyte colony-stimulating factor (G-CSF) were assessed in a rat chronic spinal cord compression model to explore the potential of G-CSF as a pharmacological treatment for cervical spondylotic myelopathy., Summary of Background Data: G-CSF is a hematopoietic cytokine used clinically to treat neutropenia. Recently, neuroprotective effects of G-CSF have been reported in spinal cord disorders., Methods: To introduce the chronic cervical cord compression, thin polyurethane sheets were implanted under C5-C6 laminae of rats and gradually expanded by absorbing water. This model reproduces delayed compressive myelopathy of the cervical spine. In sham operations, the sheets were immediately removed. G-CSF (15 μg/kg) or normal saline (NS) was administered subcutaneously 5 days a week. Experimental groups were sham operation given NS; cord compression given NS; and cord compression given G-CSF. To assess motor functions, rotarod performance, and grip strength were measured. Twenty-six weeks after surgery, cervical spinal cords were examined histopathologically. In the prevention experiment, G-CSF or NS administration was started immediately after surgery. In the treatment experiment, their administration was started 8 weeks after surgery. In another experiment, in three groups in the prevention experiment, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining was performed to assess apoptotic cell death at 8 weeks after surgery., Results: In the prevention experiment, administration of G-CSF preserved the motor functions and motor neurons throughout the 26 weeks, and significantly decreased the number of apoptotic cells at 8 weeks. In the treatment experiment, G-CSF administration from 8 weeks after surgery markedly restored the motor function temporarily to a level equal to the sham group., Conclusion: G-CSF prevents the decline in motor functions and preserves motor neurons in the rat chronic cord compression model. G-CSF also improves motor function in the progressive phase of compression myelopathy., Level of Evidence: N/A.

Object: Spinal digital subtraction angiography (DSA) is indispensable for the precise diagnosis of spinal vascular lesions and the assessment of blood supply to the spinal cord. However, comprehensive spinal DSA covering multiple segments requires repetition of selective catheterization into small segmental arteries, which is time consuming, sometimes difficult, and hazardous. The authors investigated the usefulness of CT angiography with intraarterial contrast injection (IA-CTA) as a preliminary study preceding spinal DSA. With the advent of multidetector CT, it is feasible to obtain images of the spinal cord vasculature instantaneously overa number of segments., Methods: A total of 56 patients with lesions involving the spinal vasculature underwent IA-CTA with 64- or 320-row detector CT in advance of comprehensive spinal DSA. Contrast material was injected via a pigtail catheter placed at the aorta in proximity to the segments of interest. Scanning was repeated twice to obtain arterial- and venous-phase images to differentiate between the arterial and venous components. The spinal arteries were identified by paging the various multiplanar reconstruction images and tracing the vessels from the aorta. Spinal DSA was subsequently performed by guiding selective catheterization to the feeding segments in reference to the IA-CTA findings. Visualization of the segmental arteries, normal spinal arteries, and abnormal vessels during IA-CTA was investigated and compared with that obtained during spinal DSA., Results: In all 56 patients, spinal IA-CTA successfully enabled visualization of the spinal vessels, including the radicular arteries and the anterior spinal artery. Below the aortic arch, all segmental arteries were identified clearly. The segmental arteries, radiculomedullary arteries, spinal arteries, and abnormal vessels were traced from the aorta, which would be the target of selective catheterization. In 3 (6.8%) patients, IA-CTA revealed severe aortic atherosclerosis and occlusion of some segmental arteries. The information obtained was useful for directing selective catheterization studies. The findings of IA-CTA corresponded well with those of spinal DSA., Conclusions: IA-CTA is a useful adjunct to spinal DSA for surveying the vasculature surrounding the spinal cord and for orienting selective catheterization. IA-CTA can complement spinal DSA, curtail unnecessary segmental injections, and thus reduce procedural complications.

Cervical laminoplasty was developed as an alternative to cervical laminectomy for treatment of cervical myelopathy, in which hinges are created to lift the lamina. Various techniques of laminoplasty have since been developed after two prototype techniques: Hirabayashi's open-door laminoplasty and Kurokawa's spinous process splitting (double-door) laminoplasty. Several in vitro studies report superior biomechanical stability of the cervical spine after laminoplasty compared with laminectomy. In clinical situation, randomized control studies are scarce and superiority of one procedure over another is not uniformly shown. Lack of hard evidence supporting the purported advantages of laminoplasty over laminectomy, that is, reduced rate of postoperative instability and kyphosis development, while preserving range of motion (ROM), has been a weak selling point. Currently, laminoplasty is performed by majority of spine surgeons in Japan, but is rarely performed in the United States and Europe. Recent development in laminoplasty is preservation of muscle attachment, which enabled dynamic stabilization of the cervical spine by neck extensor muscles. After treatment with new laminoplasty techniques with active postoperative neck ROM exercises, postoperative instability, kyphosis, axial neck pain, and loss of ROM seems minimal. Well-designed clinical trials to show the effectiveness and long-term outcome of this surgical procedure are warranted.

Object: Regional blood flow is decreased in experimental models of chronic spinal cord compression, and the alteration presumably contributes to the development of myelopathy. Cilostazol (Otsuka Pharmaceuticals Co.), a selective Type III phosphodiesterase inhibitor, has been shown to be neuroprotective in cerebral hypoperfusion animal models and clinically effective in preventing the recurrence of cerebral infarction. To investigate the neuroprotective effect of cilostazol on cervical spondylotic myelopathy, the preventive effect against progressive motor dysfunction and the loss of anterior horn motor neurons were assessed using a chronic cord compression model in rats., Methods: To produce chronic cervical cord compression in male Wistar rats, thin polyurethane sheets (3 × 5 × 0.7 mm) that gradually expand over 48-72 hours by absorbing water were implanted under the C5-6 laminae. In sham operations, the sheets were momentarily placed and then immediately removed. This model has been shown to reproduce characteristic features of clinical cervical myelopathy, with progressive motor disturbances after a latency period and insidious neuronal loss preceding the onset of symptoms. In the treatment group, cilostazol (30 mg/kg/day) was orally administered to the rats once a day, starting the day after surgery and continuing through the entire observation period of 25 weeks. In the control group, vehicle solution was administered under the same protocol. Changes in motor function were monitored by measuring bilateral forepaw grip strength and the duration of forced running on a treadmill. Twenty-five weeks after surgery, cervical spinal cords were examined histopathologically., Results: Cilostazol preserved both forepaw grip strength and forced running capability. The drug also preserved anterior horn motor neurons in the C5-6 spinal cord segment, which diminished in number in the untreated chronic compression group. The drug decreased the number of TUNEL-positive apoptotic cells., Conclusions: These results indicate that cilostazol is neuroprotective in the chronically compressed cervical cord and is potentially useful in the treatment of cervical spondylotic myelopathy.

Background: Drill-induced heat has been suspected as a cause of tissue injury, and there are ample experimental data to substantiate the implication. However, no clinical results have been presented with measurement of temperature in the vicinity of neural structures during the actual spinal procedures., Methods: Using a thermocouple, temperature in the gutters drilled in the midline and the lateral margins of the lamina was monitored closely in 61 patients, who underwent the French-door style of cervical spino-laminoplasty. The drilling was performed intermittently for a duration of 5 or 10 seconds, using 3- or 5-mm diamond burrs with sufficient continuous cooling irrigation. The correlations between bone temperature elevation and postoperative sensorimotor symptoms were then analyzed., Results: In the lateral gutters at the most cephalad level (typically C3), where the drilling was performed underneath an overlying bundle of muscle attached to C2's spinous process, the temperature rose significantly. This occurred even with 5-second drilling sessions. The average peak temperature was 44 °C at this level. At all other sites, the temperature was maintained below 40 °C. In three patients, transient neurological deficit developed postoperatively, which did not correlate with the incidence of bone temperature elevation., Conclusions: Intermittent drilling with sufficient irrigation can prevent thermal neuronal damage generated by high-speed drills. Drilling with small diamond burrs in deep and narrow spaces covered by overlying muscles predisposes to inadequate irrigation and thermal elevation. Continuous, protracted drilling without frequent irrigation may result in excessive heat generation and nerve injury.

Thyroid cancer is not a common primary cancer causing intracranial metastasis. Here we report a 74-year-old woman with magnetic resonance imaging (MRI) demonstrating a 4 cm round, heterogeneously enhancing mass in the trigone of the right lateral ventricle. Systemic screening by computed tomography (CT) examination detected a 20 mm nodule with calcification in the thyroid, multiple well circumscribed nodules in bilateral lung filed, and a bone metastasis to the right dorsal rib. Cerebral angiography demonstrated a hypervascular mass fed from anterior and posterior choroidal arteries. Tumor biopsy via parietal transcortical approach confirmed a thyroid carcinoma metastasis to the choroid plexus. Of the 33 reported cases of choroid plexus metastasis, 14 (42%) are from kidney and 3 (9%) from thyroid cancer, which appears to be overrepresented considering their prevalence among all brain metastasis. There may be seed-and-soil relationship between thyroid cancer and choroid plexus.

Neurocutaneous melanosis (NCM) is a rare condition characterized by central nervous system melanocytic tumors associated with congenital melanocytic nevi. Phacomatosis pigmentovascularis (PPV) is an association of vascular nevus with pigmentary nevus. Aberrant maturation of neural crest-derived cells is considered to be related to pathogenesis in both conditions. However, association of NCM and PPV has not been reported to the best of our knowledge. Melanocytoma, which usually involves the leptomeninges or spinal cord, is extremely rare in the retroperitoneum. We present here a case of a patient with NCM, PPV, and melanocytic tumors in the spinal cord and retroperitoneum, which were treated surgically. A 40-year-old woman had a 2-year history of dysesthesia and weakness in the left leg. History included congenital giant blue nevus-like lesion in the trunk, a port-wine stain in the sacral area, and Caesarean section performed 8 years before, when diffuse pigmentation in the peritoneum was noted. Magnetic resonance (MR) imaging of the spine revealed an intramedullary tumor at T10 level with paramagnetic signal characteristics. The spinal cord tumor was totally removed, and the histological diagnosis was melanocytoma. Three months later, a left retroperitoneal mass with histological features of melanocytic tumor was removed. Neither tumors recurred and the patient stays ambulatory 4 years after the surgery. Multiple subtypes of melanocytic tumors with distinctive features of NCM and PPV can develop simultaneously, mimicking malignant melanoma. Gross total resection of each tumor, when indicated, is beneficial.

Object: Gamma Knife surgery (GKS) has gained increasing relevance in the treatment of metastatic brain tumors, but many metastatic tumors contain a large cystic component and often exceed the size limit for GKS. For such lesions, the authors adopted a procedure in which stereotactic aspiration is first performed and followed immediately by GKS on the same day. In this paper, the authors describe this 1-day combined procedure and evaluate its efficacy., Methods: Between 2005 and 2010, 25 cystic metastases in 25 patients were treated at Dokkyo Medical University. The patients first underwent MRI and stereotactic aspiration of the cyst while stationary in a Leksell stereotactic frame; immediately afterward, the patients underwent a second MR imaging session and Gamma Knife treatment. Tumor volume reduction, tumor control rate, and overall survival were examined., Results: Tumor volume, including the cystic component, decreased from 8.0-64.2 cm(3) (mean 20.3 cm(3)) to 3.0-36.2 cm(3) (mean 10.3 cm(3)) following aspiration, and the volume of 24 of 25 lesions decreased to less than 16.6 cm(3), which is equivalent to the volume of a 3.16-cm sphere. At least 20 Gy was delivered to the entire lesion in 24 of 25 cases. Good tumor control was obtained in 16 of 21 cases that could be evaluated during a median follow-up period of 11 months (range 1-27 months); however, reaccumulation of cyst contents was observed in 2 patients who required Ommaya reservoir placement., Conclusions: The 1-day aspiration plus GKS procedure is an effective and time-efficient treatment for large cystic brain metastases.

Background: Fluorescence angiography with indocyanine green (ICG) provides real-time information regarding the patency of vessels. To enhance the capability to delineate flow direction, flow velocity and sequence of dye filling in different components of complex spinal vascular lesions such as perimedullary arteriovenous fistulas (AVFs), we tried selective intraarterial injection of ICG with catheterization in the proximity of the AVFs., Method: Prior to taking the position for surgery, a metallic introducer sheath was placed into the femoral artery, and placed over the patient's lateral buttock. After the exposure of the AVFs, a standard angiographic catheter was advanced into the proximal portion of the feeding artery and a small volume of diluted ICG (0.06 mg in 5 ml saline for one examination) injected repeatedly. To avoid the thromboembolism, heparinized saline was perfused continuously thorough the catheter and sheath., Findings: The small injection volume and the close proximity of the injection site to the lesions resulted in quick rise and fall of the fluorescence without any background. Time and spatial resolution of analysis were enhanced; flow dynamics such as direction, velocity and alteration after temporary occlusion were well visualized. The feeders and drainers were clearly distinguished, and the shunts could be precisely identified., Conclusions: Selective intraarterial injection ICG fluorescence angiography was very useful for perimedullary AVFs. Albeit that it requires intraoperative selective catheterization, this repeatable technique has an advantage to improve temporary resolution and provides accurate information of the flow dynamics through the complex anatomy of vascular lesions.

Here we report a metastatic brain carcinosarcoma from the uterus that posed a problem on diagnosis by containing an extensive gliomatous component. A 56-year woman developed motor aphasia 3 months after hysterectomy for a uterine tumor. Magnetic resonance imaging (MRI) demonstrated a left frontal cystic tumor, which was treated by stereotactic radiosurgery. The lesion recurred 5 months later and was resected. Histological examination demonstrated neoplastic cells that were positive for glial fibrillary acidic protein (GFAP), leading to the diagnosis of high-grade glioma. This lesion recurred again after 9 months, and was resected again. The tumor tissue mostly consisted of GFAP-positive gliomatous cells, but close examination identified a sarcomatous component compatible with the metastatic lesion from the uterine sarcoma. This sarcoma component contained GFAP-negative-CD10-positive cells and GFAP-positive-CD10-negative cells. There was no clear border between those components, and, therefore, the lesion was considered to be a metastatic tumor from the uterus showing extensive neural differentiation. Although rare, uterine tumors are known to show such neural differentiation, and the histological diagnosis in such cases can be challenging.

Study Design: Sham-operation-controlled animal study to assess alterations in blood flow in the spinal cord in a chronic compression model. Laboratory investigation., Objective: Cervical myelopathy is a common cause of disability in elderly patients. Hypothesis was made that ischemia subsequent to the spinal cord compression plays an important role in the pathogenesis of the spinal cord dysfunction. This study was undertaken to assess alterations in the blood flow of the spinal cord under chronic compression in a rat model., Summary of Background Data: Histologic study of spinal cord from patients with spondylotic myelopathy showed ischemic tissue changes. Experimentally, spinal cord hypoperfusion in combination with chronic spinal cord compression induced myelopathy in dogs. We previously showed that chronic compression of the spinal cord in rats produces gradual deterioration of mobility of the animals accompanied by cord tissue degeneration compatible with ischemic changes., Methods: Chronic compression of the cervical spinal cord was implemented by implantation of a thin urethane polymer sheet under the C5-C6 laminae, which expands by absorbing tissue water over 48-72 hours. The control group underwent sham operation. Twelve weeks later, blood flow to the C3-C4 and C5-C6 spinal cord segments were measured by fluorescent microsphere methods., Results: In the control group, the blood flow in the C5-C6 segment was larger than C3-C4 segment. In the compression group, the blood flow in the C5-C6 was significantly reduced compared to the C3-C4 segment., Conclusion: Under chronic focal spinal cord compression, there was a decrease of the blood flow in the compressed segment in comparison to the rostral segment. Our data are compatible with the hypothesis that alteration in the spinal cord blood flow contributes to pathogenesis of myelopathy.

Study Design: Basic animal research., Objective: Cervical spondylotic myelopathy is a common condition among elderly and often treated by surgery. To explore possibility of pharmacologic treatment, limaprost alfadex, a prostaglandin E1 derivative with vasodilatory and antiplatelet action, was tried in a rat chronic spinal cord compression model., Summary of Background Data: Limaprost increased the blood flow of cauda equina and improved motor functions in animal models of lumbar stenosis. The drug is clinically used to treat neurogenic intermittent claudication., Methods: : Forty-two rats were allocated to four groups: (A) sham operation without permanent cord compression, given 5 mL/kg of distilled water twice a day (n = 6); (B) sham operation, receiving 300 μg/kg limaprost twice a day (n = 6); (C) cord compression, receiving the vehicle (n = 15); and (D) cord compression receiving the drug (n = 15). A thin polyurethane sheet that expands by absorbing water was implanted under the C5-C6 laminae to produce cord compression. For sham operation, the sheet was immediately removed. Exercise tests were repeated on a rotating treadmill until 26 weeks after surgery, and then the animals were killed and the spinal cord harvested for motor neurons counts. RESULTS.: Treadmill endurance (seconds, mean ± standard error of mean) 2 weeks after surgery was 497.7 ± 2.3, 434.5 ± 65.5, 423.1 ± 33.0, and 480.5 ± 19.5 in groups A, B, C, and D, respectively. At 26th week, the duration was 497.7 ± 2.3, 421.2 ± 78.8, 21.3 ± 11.7, and 441.3 ± 40.4 (P < 0.0001 for the decrease in C group, multivariate analysis of variance with correction for multiple measures.) The motor neuron counts were 38.3 ± 3.6, 38.2 ± 2.6, 32.6 ± 1.9, and 36.2 ± 2.3 in groups A, B, C, and D (P = 0.34), respectively., Conclusion: Limaprost alfadex prevented decline of forced locomotion capability in rats with chronic compression of the cervical cord.

Spine surgery has made radical advancements in the last two decades and provision has expanded a great deal. The history of the technical development is briefly reviewed. To analyze trends in utilization and to assess the macroeconomic demand for spine surgery, the incidence of all spine surgery per capita is estimated referring to diverse statistical data from the USA, Korea and Japan. When compared internationally, there is a great disparity in the utilization of spine surgery, especially for fusion/instrumentation. Medico-socioeconomic conditions underlying the variations are discussed. Adequate surgeon training has to be supplied in a matched volume, and the number of surgeons to balance the need is estimated.

Objective: Magnification by surgical loupes has the distinct merits of agility and nimbleness in observation, a wide stereo base effectuating superior depth sensation, and light augmentation by an objective lens that is larger than the pupil. However, continuous use of these loupes causes neck strain for surgeons as a result of flexion posture and fatigue. To minimize the strain and fatigue and maximize the advantages and performance of binocular telescopes, we have developed a novel optical design., Methods: To allow observation of the operative field with the surgeon's neck and eye in a straight position, the light path of the telescopes was angulated downward with roof prisms. For maximum image quality, Keplerian real-image optics were adopted., Results: The optics, finishing of the lens, and assembly were perfected through practical trials of more than 500 procedures over a period of 3 years., Conclusion: The new ergonomically designed optics provide excellent image quality comparable to standing microscopes in the low to medium range of magnification, while effectively reducing the neck flexion of surgeons working in the operative field below and relieving the surgeon's fatigue during hours of continuous use.

Object: Laminoplasty has been used to expand the cervical spinal canal, based on the belief that reconstruction of the laminae preserves musculoskeletal function. The true efficacy of laminoplasty for maintaining spinal alignment, stability, and flexibility, however, remains to be proven. The authors have developed a new method, myoarchitectonic spinolaminoplasty (MSLP), which preserves all of the nuchal muscles and reconstitutes all of the musculoskeletal couplings to the posterior elements of the vertebrae. The details of this technique are described, and the efficacy of the technique in conserving muscle volume, alignment, and motion, as well as in preventing postoperative musculoskeletal discomfort, is assessed., Methods: The authors' previous midline-splitting laminoplasty procedure, which utilized a hydroxyapatite (HA) implant as a substitute for the spinous process, was improved. Detachment of the muscles is avoided with this new technique by cutting inside the spinous process. The bone-muscle flaps are affixed to the HA spinous process. Radiographs, computed tomography scans, and neurological evaluations obtained at the 1-year follow-up in the groups of consecutive patients assessed immediately prior to and after the modification of the previous technique (the control and the MSLP groups, respectively) were analyzed and compared., Results: The HA bone constructs became integrated due to osteoconduction. The cross-sectional area of the semispinalis capitis, semispinalis cervicis, and multifidus muscles remained significantly larger in the MSLP group. Slight attenuation in lordosis was observed in the control group, but was prevented in the MSLP group. Range of motion was somewhat restricted in the MSLP group, but the incidence of neck pain and shoulder strain was significantly reduced., Conclusions: The new MSLP method was effective in preserving the volume and functions of the nuchal musculature and helping to minimize postoperative musculoskeletal complaints.

Dermcidin (DCD) is a gene for an antimicrobial peptide DCD-1 in human sweat glands. It has become evident that the gene products of DCD exhibit a wide range of biological functions. In addition to its antimicrobial function, it is reported to be a neuronal survival factor, a putative oncogene in breast cancer and a proteolysis-inducing factor (PIF) that induces skeletal muscle proteolysis to cause cancer cachexia. Here we identified DCD in human placental tissue and determined its previously uncharacterized proteolytic activity. We also show that recombinant DCD induced an invasive phenotype in a human choriocarcinoma cell line JAR in vitro. This work suggests that DCD might participate in the regulation of placental function by means of modulating the proteolytic cascades on the trophoblastic cell surface, and might be involved in the pathophysiology of pregnancy-related disorders, as well as cancer and neuronal diseases.

Objective: Neuromuscular choristomas (NMC) are rare benign tumors of the peripheral nerves. We report an NMC affecting the oculomotor nerve., Clinical Presentation: An 18-year-old girl presented with long-standing intermittent retro-orbital pain and oculomotor paresis. Magnetic resonance imaging scans demonstrated a small nodular lesion on the left oculomotor nerve, similar to the findings for a schwannoma., Intervention: The tumor was resected with the parental oculomotor nerve, which was reconstructed using a peroneal nerve graft. Postoperatively, the patient became pain-free, and her oculomotor function partially recovered. Histologically, the lesion consisted of well-differentiated smooth muscle fibers intermingled with mature nerve elements consistent with the diagnosis of an NMC, although the possibility of leiomyoma in this rare location was not excluded completely., Conclusion: NMC may need histological confirmation for diagnosis if they occur in the intracranial space. The resection is feasible, and the function of the affected nerve can be at least partially restored with the nerve reconstruction.

Surgery with following chemoradiotherapy is the mainstream glioma treatment. In the course of postradiation events, however, it is sometimes difficult for neurosurgeons, radiologists, and pathologists to discriminate tumor recurrence from radiation necrosis. The epidermal growth factor receptor (EGFR) gene, on chromosome 7, is known to gain in copy number frequently in high-grade gliomas. The authors applied the fluorescence in situ hybridization (FISH) method to observe the gene's numerical status in pre- and postradiation glioma samples to elucidate whether this technique is useful in the discrimination of glioma recurrence from radiation necrosis. When 15 postradiation glioma samples and 4 postradiation nonglioma samples were tested, all the recurrent glioma tissue harbored numerical aberrations of the gene, whereas no abnormality could be observed in necrosis or in nonglioma gliosis. FISH could even prove a residual glioma cell in a gliotic tissue taken by needle biopsy after gamma-knife radiosurgery, which had been executed on a supposed metastatic brain tumor. FISH is considered to be of help in accurate diagnosis, especially when the usual histopathological diagnosis is difficult because of radiation effects or small sample size.

Cervical myelopathy is a common cause of neurological disability among the elderly; however, the exact mechanism for the insidious and progressive deterioration remains to be elucidated. To study the pathophysiology, we developed a simple experimental model reproducing the course. In rats, a thin sheet of expanding polymer was implanted microsurgically underneath the C5-C6 laminae. In the control group, the polymer sheet was removed immediately. Changes in motor functions were monitored for 25 weeks after the operation, with voluntary exercise activity measured by odometer attached to revolving cages, and forced running capability measured by duration of exercise on a rotating treadmill. Motor neurons were counted stereologically in continuous sections. In the compression group, the forced running capability deteriorated after a latent period of 17 weeks and progressively thereafter. In the control group, it stayed unchanged throughout 25 weeks. Course of the voluntary exercise was comparable between the groups. Motor neuron density in the compression group decreased significantly in 9 weeks (-20.3%) and 25 weeks (-35.5%), but not in 1 or 3 weeks. This practical model properly reproduces characteristic features of the clinical cervical myelopathy, with progressive motor disturbance after a latency and insidious neuronal loss preceding the symptoms.

A case of a dural arteriovenous fistula (DAVF) that developed at the site of nerve root sleeve damage as a result of lumbar disc extrusion is reported. A 60-year-old man who had undergone lumbar discectomy 3 years previously for severe left-sided sciatica and L5-S1 disc herniation presented with progressive gait disturbance. After the initial surgery, the symptoms resolved. Fourteen months after the operation, however, he started to experience dysesthesias in both legs and progressive gait and urinary disturbances. Physical examination revealed a weakness of the anterior tibialis and the gastrocnemius muscles, as well as decreased contractility of the anal sphincter and marked sacral hypesthesia. Magnetic resonance (MR) imaging revealed swelling and a T2 signal elongation in the conus medullaris; angiography demonstrated arteriovenous dural shunting between the left lateral sacral artery and the left S-1 radicular vein at the site of the previous operation. Surgery was conducted to excise the DAVF on the S-1 nerve root sleeve and an arterialized intradural vein on the root. The procedure resulted in resolution of the symptoms and disappearance of the abnormal angiographically and MR imaging-documented anomalies. This is the first report of a DAVF in which progressive conus myelopathy developed after a lumbar discectomy.