ongenital Intraspinal Epidermoid Cyst: Case Report

The epidermoid cyst is formed as the result of inclusion of epithelial elements at the time of closure of the neural tube. The incidence of this tumor is less than 3% of all spinal canal tumors in children, The authors have experienced a 6-year old child with intraspinal epidermoid cyst which presented with symptom of back and abdominal pain. The magnetic resonance imaging study showed intraspinal mass lesion from level of T12 to S1. The patient had no history of previous lumbar puncture. We have removed totally the pearly-like intradural mass with laminoplastic laminotomy from T12 to L5. The pathological findings were compatible with epidermoid cyst. The postoperative course was uneventful without any neurologic deficit. Characteristics of this lesion with a pertinent literature is reviewed.ope

Outcome of Surgical Treatment for Lipomeningomyelocele

Lipomeningomyelocele(LMMC) is one of the most common forms of occult spinal dysraphism seen in clinical practice. It is now widely accepted that prophylactic surgery is indicated in most cases, but areas of controversies were remained. From January 1986 to December 1996, long term data are available for 57 patients who underwent surgery for LMMC repair. The most common presenting symptom of these patients were mass on back which was followed by weakness of lower extremities and bladder-bowel symptoms. Transitional type was most common(53%) and followed by caudal(28%) and dorsal type(19%). Surgical repair was performed at age of 1 month to 40 years(mean age: 48months old, median 5 months old). Follow up for these patients ranged from 10 to 130 months(mean 50.3 months). None of the patients who underwent surgery before deficits had occured had ever developed new neurological deficits at the end of the follow up. However, 8 of 57 patients(14%) had aggravation of thier initial neurologic status by history preoperatively. Those progressive symptoms were somewhat reversed or stabilized in all of them postoperatively. In addition, surgical correction in infancy provides a degree of reversibility but do not in older children. We concluded that early diagnosis and treatment should be taken to prevent these progression and permanency of neurological changes.ope

Post-Traumatic Basal Gangliar Ischemia in Children

The authors reviewed the cases of 12 children with unilateral motor weakness after minor head injury who were treated between 1990 and 1996. Eight were boys and four were girls, and all were less than seven years old (range, 8 month to 6years) ; unilateral weakness developed immediately after an apparently minor head injury. Computed tomography and MR scanning disclosed an ischemic lesion at one side of the basal ganglia. Most children recovered. The mechanism by which this ischemic lesion develops at the basal ganglia is not known. In children, however the angle between the middle cerebral artery and lateral perforating vessels is more acute than in the adult, and we believe that after minor head injury, stretching and distorting the angle of these perforating branches may lead to'unknown vessel change', with a consequent decrease in local blood flow. The end result is an ischemic lesion in the basal ganglia.ope

Assessment of Flow Dynamics of Cerebrospinal Fluid with Phase-contrast Cine MR Image

Phase contrast magnetic resonance imaging techniques can be used to evaluate the to-and-fro motion of cerebrospinal fluid(CSF) throughout CSF pathways between the ventricles and subarachnoid space of the brain and spine. This CSF motion is due to transmitted cardiac pulsation from systolic expansion of the cerebral hemispheres. To cover the entire cardiac cycle, peripheral cardiac triggering was used. Using this technique, we analyzed quantitative CSF motion over a cardiac cycle to distinguish normal CSF flow from that seen in hydrocephalus. We tested the reproducibility of the aqueductal CSF signal intensity on a phase contrast cine MR sequence in 28 patients with normal ventricle. Sixteen patients with obstructive hydrocephalus and 11 patients with normal pressure hydrocephalus(NPH) were investigated with the sequence before and after CSF diversion. The peak CSF flow velocity in aqueduct was significantly increased in patients with NPH and significantly decreased in patients with obstructive hydrocephalus(NPH group：6.71cm/sec, control group：2.94cm/sec, obstructive group；less than 1.0cm/sec). After LP shunting in NPH group, retrograde flow signal curves were anterogradely converted and the peak flow velocities were somewhat decreased(mean：5.10cm/sec). The clinical diagnosis of NPH was well correlated with the results of cine MRI. After endoscopic third ventriculostomy in obstructive group, we could note increased CSF flow velocity both at prepontine cistern and precordal subarachnoid space with markedly increased flow at prepontine cistern. Phase contrast cine MRI is useful in evaluatng the CSF dynamics in patients with hyperdynamic aqueductal CSF(NPH) or aqueductal obstruction(obstructive hydrocephalus).ope

Permeability Changes of Capillary Endothelial Monolayer according to the Malignancy of Co-cultured Cell Lines

Even though many hypotheses have been derived from the anatomical and functional analysis of in vivo models of brain tumors, it is still impossible to explain the mechanism of peritumoral edema. To determine whether increased permeability in a blood-brain barrier model correlated with the malignancy of a co-cultured brain tumor, the authors established an in vitro brain capillary endothelial monolayer co-culture model. Water-soluble factors which might explain the pathogenetic mechanism of peritumoral edema in brain tumors were expected and observed. The benign cell co-culture model used co-cultured astrocytoma cell lines such as C6 and H683 in the second compartment of a brain capillary endothelial monolayer culture model circumscribed with a 0.4u sized porous membrane which permitted communication of the media but limited cell migration to another compartment, and the malignant cell co-culture model used co-cultured glioblastoma cell lines such as 87MG and 373MG. Permeability at molecular weight 373 increased in the astrocytoma and glioblastoma co-culture models to 150% and 240% respectively, of that in a normal astrocyte co-culture model. Permeability at this molecular weight also increased in the astrocytoma- and glioblastoma-conditioned medium culture models to 38% and 131%, respectively, of that in a normal astrocytoma-conditioned medium culture model. The observed result was that permeability of the endothelial monolayer increased in accordance with the malignancy of co-cultured cells in the system permitting-other than cell migration-media transfer only. The result suggested that some factor soluble in media secreted from co-cultured cells changes the permeability of the endothelial monolayer and could explain the pathogenetic mechanism of peritumoral edema in malignant brain tumors.ope

Long-Term Follow-Up Results of Gamma Knife Radiosurgery for Hypothalamic Hamartoma : How can we Improve the Results?

Objective: Hypothalamic hamartomas (HH) constitute rare developmental lesions associated with gelastic seizure, precocious puberty, and abnormal behavior. Treatment for this lesion is very complicated due to its location. Gamma Knife radiosurgery (GKS) may be an efficient and safe treatment option, which produces little morbidity. The authors evaluated the long-term results of GKS for the HH. Methods: Eights patients with HH-related intractable gelastic seizure and/or precocious puberty underwent GKS between 1992 and 1996, with a mean age of 8.3 years at the time of GKS (range, 3.5-17.7 years). Three patients were presented with intractable gelastic seizure, and 4 patients with precocious puberty. One patient had both intractable seizure and precocious puberty. The mean follow-up duration was 76.6 (28.9-141) months. Results: The mean marginal dose for the large sessile type HH with intractable gelastic seizure was 11.5Gy (range, 9-13Gy) and that for the small pedunculated type with precocious puberty was 27Gy (range, 20-34Gy). There was no lesion volume change on follow-up MRI. Intractable seizure disappeared in only 1 patient and was not improved in the other 3 patients. Precocious puberty was not resolved by GKS in all cases. Conclusion: The long-term results of GKS for HH were not satisfactory. As for the control of epilepsy, the radiation dose in our cases was not enough to suppress and block the epileptogenic focus of HH and its propagation to surrounding tissue. Precocious puberty caused by HH is not indicated for GKS. If we could get better treatment outcome with higher radiation dose and/ or new dose planning technique, GKS might be primary treatment option for HH.ope

In Vitro Blood-brain Barrier Model of Astrocyte and Endothelial Monolayer Co-culture Using Collagen-coated Microporous Membrane

There are three types of the in vitro blood-brain barrier models that are endothelial monolayer, astrocyte and endothelial monolayer co-culture, and benign glioma and endothelial monolayer co-culture. We made these three types of models and evaluated permeability ratio for four molecular weight(MW 373, 4400, 9300, 38900) and electrical resistance of endothelial monolayer in each type. Astrocyte and endothelial monolayer co-culture showed the lowest permeability ratio and highest electrical resistance among them and that suggested astrocyte and endothelial monolayer co-culture was best for the in-vitro blood-brain barrier model.ope

Cerebral Hemodynamic Analysis in Pediatric Moyamoya Patients using Perfusion Weighted MRI

Objective: Classically, single photon emission tomography is known to be the reference standard for evaluating the hemodynamic status of patients with moyamoya disease. Recently, T2-weighted perfusion magnetic resonance(MR) imaging has been found to be effective in estimating cerebral hemodynamics in moyamoya disease. We aim to assess the utility of perfusion-weighted MR imaging for evaluating hemodynamic status of moyamoya disease. Methods: The subjects were fourteen moyamoya patients(mean age : 7.21yrs) who were admitted at our hospital between Sep. 2001 to Sep 2003. Four normal children were used for control group. Perfusion MR imaging was performed before any treatment by using a T2-weighted contrast material-enhanced technique. Relative cerebral blood volume(rCBV) and time to peak enhancement(TTP) maps were calculated. Relative ratios of rCBV and TTP in the anterior cerebral artery(ACA), middle cerebral artery(MCA) and basal ganglia were measured and compared with those of the posterior cerebral artery(PCA) in each cerebral hemispheres. Using this data, we analysed the hemodynamic aspect of pediatric moyamoya disease patients in regarding to the age, Suzuki stage, signal change in FLAIR MR imaging, and hemispheres inducing symptoms. Results: The mean rCBV ratio of ACA, MCA did not differ between normal children and moyamoya patients. However the significant TTP delay was observed at ACA, MCA territories (mean = 2.3071 sec, 1.2089 sec, respectively, p < 0.0001). As the Suzuki stage of patients is advanced, rCBV ratio is decreased and TTP differences increased. Conclusion: Perfusion MR can be applied for evaluating preoperative cerebral hemodynamic status of moyamoya patients. Furthermore, perfusion MR imaging can be used for determine which hemisphere should be treated, first.ope

Change of Somatosensory Evoked Field Potential according to the Severity of Hydrocephalus in Kaolin-induced Hydrocephalus of Rats

Objective：Somatosensory evoked potential(SSEP) has been known to be a good method for evaluating brain stem function, but it is not sufficient to check the fine changes of cortical functions. A fine change of cortical function can be expressed with somatosensory evoked cortical field potential(SSEFP) rather than general SSEP. To confirm the usefulness of SSEFP for evaluating the cortical function, the authors simultaneously measured SSEFP and the intracranial pressure-volume index(PVI) in kaolin-induced hydrocephalic rats. Method：Hydrocephalus was induced with injection of 0.1ml kaolin-suspended solution into the cisterna magna in 60 Sprague-Dawley rats. The authors measured PVI and SSEFP 1 week after injection of kaolin-suspended solution. To evaluate the severity of induced hydrocephalus, we measured the transverse diameter of the lateral ventricle on the coronal slice of the rat brain 0.40mm posterior to the bregma. Result：The typical wave form of SSEFP in control rats showed a negative-positive complex wave at early latency. In SSEFP of normal rats, N0 is 10.0 msec, N1 15.3 msec, P1 31.2 msec and N1-P1 amplitude 15.4μV. As hydrocephalus progressed, the peak latency of N1 and P1 were delayed. In mild hydrocephalus, negative peak waves were split. The N1-P1 amplitude was decreased only in severe hydrocephalus. The changes of the characteristics of SSEFP according to the severity of hydrocephalus were well correlated with the changes of PVI. Shunting normalized the characteristics of SSEFP in relation to ventricular sizes and PVI in hydrocephalic rats. Conclusion：SSEFP may be useful for evaluating the impairment of cortical function in hydrocephalus.ope

Effects of Methylprednisolone on the Neural Conduction of the Motor Evoked Potentials in Spinal Cord Injured Rats

Methylprednisolone (MP), a glucocorticoid steroid, has an anti-inflammatory action and seems to inhibit the formation of oxygen free radicals produced during lipid peroxidation in a spinal cord injury (SCI). However, the effects of MP on the functional recovery after a SCI is controversial. The present study was conducted to determine the effects of MP on the recovery of neural conduction following a SCI. A SCI was produced using the NYU spinal cord impactor. A behavioral test was conducted to measure neurological disorders, and motor evoked potentials (MEPs) were recorded. According to the behavioral test, using BBB locomotor scaling, MP-treated animals showed improved functional recoveries when compared to salinetreated animals. MEP latencies in the MP-treated group were shortened when compared to those in the control group. Peak amplitudes of MEPs were larger in the MP-treated group than those in the control group. The thresholds of MEPs tended to be lower in the MP-treated group than those in the control group. These results suggest that MP may improve functional recovery after a SCI.ope