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The prevalence of aneurysm formation in adults with Moyamoya disease (MMD) is higher than that in the general population. The treatment strategy is often individualized based on the patient’s disease characteristics. A 22-year-old man was diagnosed with MMD after presenting a small thalamic intracerebral and subarachnoid hemorrhage in the quadrigeminal cistern. Cerebral angiography revealed a small aneurysm (2.42 mm) in the left anterior choroidal artery. Since the hemodynamics in the left hemisphere was compromised, an indirect bypass surgery was performed. The patient’s condition deteriorated postoperatively because of poor perfusion of the internal carotid artery, and massive hydration was required. During neurocritical care, the aneurysm increased in size (5.33 mm). An observation strategy was adopted because of the distal aneurysmal location and the high risk involved. Subsequently, the patient recovered, and newly developed collateral flow appeared from the external carotid artery. Additionally, a dramatic size reduction of the aneurysm (1.51 mm) was noticed. Our case suggests that MMD-related dissecting aneurysms on a distal cerebral artery, which present a high risk of embolization, could be managed by indirectly reducing the hemodynamic burden. Massive hydration in such cases should be avoided or balanced to avoid the risk of rapid growth and aneurysm rupture.

OBJECTIVE One-fourth of cerebral cavernous malformation (CCM) patients are children, but studies on these patients are scarce. This study aimed to identify the clinical presentation of pediatric CCM patients and to investigate clinical outcomes according to the treatment modalities applied on the basis of our institution’s treatment strategy. METHODS The authors performed a retrospective analysis of 124 pediatric CCM patients with a follow-up of more than 1 year from 2000 to 2019. They performed resection (n = 62) on lesions causing intractable seizure, rebleeding, or mass effect and observed the clinical courses of patients with lesions in deep or eloquent areas without persistent symptoms (n = 52). Radiosurgery (n = 10) was performed when the patient refused resection or strongly desired radiosurgery. The authors investigated the clinical characteristics, performance status (modified Rankin Scale [mRS] score), and rebleeding rate at the 1-year and last follow-up examinations and compared these among 3 groups classified on the basis of treatment applied. The authors evaluated seizure outcomes at the 1-year and last follow-up examinations for the surgery (n = 32) and observation (n = 17) groups. Finally, the authors drew cumulative incidence curves for the discontinuation of antiepileptic drugs (AEDs) for patients in the surgery (n = 30) and observation (n = 9) groups. RESULTS The 3 groups showed slight differences in initial symptoms, lesion locations, and rates of recent hemorrhage. The proportion of patients with improved mRS score at the 1-year follow-up was significantly greater in the surgery group than in the other groups (67% of the surgery group, 52% observation group, and 40% radiosurgery group; p = 0.078), as well as at the last follow-up (73% surgery group, 54% observation group, and 60% radiosurgery group; p = 0.097). The surgery group also had the lowest rebleeding rate during the follow-up period (2% surgery group, 11% observation group, and 20% radiosurgery group; p = 0.021). At the 1-year follow-up, the proportion of seizure-free patients without AEDs was significantly higher in the surgery group than the observation group (88% surgery group vs 53% observation group, p < 0.001), and similar results were obtained at the last follow-up (91% surgery group vs 56% observation group, p = 0.05). The 5-year AED-free rates for the surgery and observation groups were 94% and 50%, respectively, on the cumulative incidence curve (p = 0.049). CONCLUSIONS The clinical presentation of pediatric CCM patients was not significantly different from that of adult patients. Lesionectomy may be acceptable for pediatric CCM patients with indications of persistent seizures despite AED medications, rebleeding, and mass effects.

Purpose We aimed to refine the radiotherapy (RT) volume and dose for intracranial germinoma considering recurrences and long-term toxicities.Materials and Methods Total 189 patients with intracranial germinoma were treated with RT alone (n=50) and RT with upfront chemotherapy (CRT) (n=139). All cases were confirmed histologically. RT fields comprised the extended-field and involved-field only for primary site. The extended-field, including craniospinal, whole brain (WB), and whole ventricle (WV) for cranial field, is followed by involved-field boost. The median follow-up duration was 115 months.Results The relapses developed in 13 patients (6.9%). For the extended-field, cranial RT dose down to 18 Gy exhibited no cranial recurrence in 34 patients. In CRT, 74 patients (56.5%) showed complete response to chemotherapy and no involved-field recurrence with low-dose RT of 30 Gy. WV RT with chemotherapy for the basal ganglia or thalamus germinoma showed no recurrence. Secondary malignancy developed in 10 patients (5.3%) with a latency of 20 years (range, 4 to 26 years) and caused mortalities in six. WB or craniospinal field rather than WV or involved-field significantly increased the rate of hormone deficiencies, and secondary malignancy. RT dose for extended-field correlated significantly with the rate of hormone deficiencies, secondary malignancy, and neurocognitive dysfunction.Conclusion De-intensifying extended-field rather than involved-field or total scheme of RT will be critical to decrease the late toxicities. Upfront chemotherapy could be beneficial for the patients with complete response to minimize the RT dose down to 30 Gy. Prospective trials focused on de-intensification of the extended-field RT are warranted.

Cervical spontaneous spinal epidural hematoma (CSSEH) is a rare condition that can be potentially fatal if not properly diagnosed and managed. While prompt surgical decompression and evacuation of the hematoma are generally considered as the first line of treatment, mild cases that were managed through observation and conservative treatment have been reported. Our patient was a 24-year-old man who experienced two CSSEH events 8 months apart, both of which were managed conservatively. This was a rare case of recurrent CSSEH in which recovery was achieved without surgical intervention. We believe conservative treatment with close observation may be effective in CSSEH patients presenting with mild neurologic symptoms who have a tendency towards spontaneous neurologic improvement.

Ossification of the posterior longitudinal ligament (OPLL) can progress even after cervical spine surgery and may cause neurological injury as a result of minor trauma. The purpose of this study was to investigate the preventive factors associated with OPLL progression after anterior cervical discectomy and fusion (ACDF), a procedure commonly performed in clinical practice.We retrospectively investigated 295 male soldiers who underwent ACDF surgery between 2012 and 2017. Patients who were followed up for12 months using dynamic radiography and computed tomography (CT) were included in the study. Radiological parameters investigated included OPLL progression, C2-C7 angles on dynamic radiography, segmental angles, C2-C7 cervical sagittal vertical axis (C2-C7 SVA), and the T1 slope. These parameters were measured preoperatively and 1 year postoperatively.A total of 49 patients were enrolled, and 10 patients were confirmed to have OPLL progression. Comparison between the OPLL progression and non-progression groups showed no statistically significant differences in pre- and postoperative cervical range of motion. However, statistically significant differences were observed in the postoperative neutral C2-C7 angle (progression -3.9°±6.4° vs. non-progression -13.4°±7.9°,Increased SVA (1.4 mm) and a small postoperative neutral C2-C7 angle (-8.01°) 1 year after ACDF were associated with OPLL progression. It is important to be mindful of these factors during follow-up after ACDF, because additional surgical treatment may be necessary for OPLL progression due to neurological injury caused by minor trauma.

Because of the rarity of the disease, paraspinal arteriovenous shunt (PAVS) is not well recognized, and therapeutic options remain controversial. To introduce a rare disease of PAVS and demonstrate its etiology, clinical features, treatment options, and outcomes, we presented a case report and conducted a systematic review and individual participants data (IPD) meta-analysis. Studies regarding on PAVS were integrated and IPD were obtained including patients’ demographics, disease etiology, clinical and radiologic features, clinical courses and outcomes. Clinical manifestation and treatment outcomes were reviewed, and comparison analysis (cervical versus thoracolumbar) were performed. Further, logistic regression analyses were conducted to identify the poor prognostic factors (incomplete obliteration). Fifty-two articles were selected, and 88 patients enrolled. General and location-specific characteristics of PAVSs were identified: ‘3/4 of the isolated and 1/4 of the associated etiology’, ‘bruit, thrill, or murmur (cervical) and weakness (thoracolumbar) as common symptoms’, ‘40% multiple feeders’, and ‘22% intradural venous involvement’. Endovascular treatment was usually preferred (75%). Of 88 enrolled patients, 18 patients showed incomplete obliteration (20.5%). In multivariate analysis, ‘etiologies of systematic genetic dysplasia (P = 0.031) and trauma (negatively, 0.038)’ were significantly associated with incomplete obliteration. The parameters of ‘multiple feeders (0.066)’ and ‘combined approach (negatively, 0.065)’ are verified only in univariate analysis. General as well as location-specific characteristics of PAVS is successfully demonstrated. Approximately 20% of the incomplete obliteration is noted, and three potential poor prognostic factors are identified, namely, ‘etiology of systematic genetic dysplasia (positive) and trauma (negative)’, ‘combined approach (negative), and ‘multiple feeders’.

OBJECTIVEThe surgical indications for some arachnoid cysts (ACs) are controversial. While surgical procedures can be effective when an AC is a definite cause of hydrocephalus or papilledema, most ACs do not cause any symptoms or signs. Some surgeons perform several procedures to treat ACs because of their large size. The purpose of this study was to compare the long-term outcomes of Galassi type III ACs between surgery and nonsurgery groups.METHODSThe medical records of 60 patients diagnosed with sylvian ACs (Galassi type III) who visited Seoul National University Children’s Hospital from July 1990 to March 2018 were analyzed. The authors compared the outcomes between those treated with surgery and those not treated with surgery.RESULTSOf the 60 patients, 27 patients had no symptoms, 19 patients had vague symptoms and signs associated with ACs, and the remaining 14 patients had definite AC-related symptoms and signs. Thirty-eight patients underwent surgery, and 22 patients underwent observation. Some operations were accompanied by complications. Among the 33 patients in the surgery group, excluding 5 with hydrocephalus or papilledema, 8 patients needed 18 additional operations. However, there were no patients in the nonsurgery group who needed surgical intervention during the follow-up period (mean 67.5 months), although the size of the AC increased in 2 patients. Changes in AC size were not correlated with symptom relief.CONCLUSIONSWhen patients with hydrocephalus or papilledema were excluded, there was no difference in the outcomes between the surgery and nonsurgery groups regardless of the size of the sylvian AC. Surgeons should be cautious when deciding whether to operate.

In recent automobile trends, the functions of opening and closing the vehicle door are accomplished by touch sensor and smart-phone NFC (Near Field Communication) systems. These convenience features are incorporated into the outdoor handle. However, this function can’t be used when chrome plating is applied to this part for design purposes. To solve the problem of chrome plating, we studied a metal sputtering deposition process technology, which can preserve the metal feeling without interfering with NFC and touch sensor operation. To achieve this interface communication and sensing performance, we developed a surface treatment that can generate micro-cracks in the thin film layer. We also investigated how the door handle manufacturing process affected the shape of the micro-cracks in the thin film. Results showed that the thickness of the thin film and the target power played a crucial role in controlling the residual tensile stress in the thin film, which was one of major factors responsible for generating micro-cracks in the thin film layer. The shape of the micro-cracks in the thin film was affected by the adjacent layers of the thin film, the primer paint and UV top coat. The surface energy of the primer paint and the shear stress produced by the hardening of the UV top coat were found to affect the shape of the micro-cracks. In addition, we found that there was no change in the shape of the micro-cracks with additional heat treatment, if the residual tensile stress was sufficiently relieved by the micro-cracks formed in the thin film. The slits between the micro-cracks in the outdoor handle cover allowed the Capacitance Sensor and NFC to perform.

Encephaloduroarteriosynangiosis (EDAS) is a commonly used indirect revascularization operation method to treat pediatric patients with Moyamoya disease (MMD). Arachnoid dissection frequently has been performed during the EDAS operation to promote better revascularization. However, no studies have yet proven its surgical benefits. In this study, we investigated the impact of arachnoid preservation on the surgical outcome and postoperative complication by comparing pediatric patients with MMD who had the arachnoid membrane preserved during EDAS operation with those who had it dissected.This was a retrospective cohort study based on a single surgeon's experience at a single institution. A total of 206 pediatric patients with MMD who underwent EDAS operation at Seoul National University Children's Hospital were recruited for the study. We compared the surgical outcome and the postoperation complication rate of these 2 groups. Furthermore, risk factors for postoperative complication were analyzed.The overall clinical outcome (P = 0.342) and the extent of revascularization of middle cerebral artery territories (P = 0.736) were not different between the arachnoid dissection group and the arachnoid preservation group. However, the postoperative infarction/hemorrhage rate was significantly greater in the arachnoid dissection group (P = 0.005). Arachnoid dissection (P = 0.011) and young age (3 years old, P = 0.012) were significantly associated with increased risk of postoperative complications.Arachnoid preservation may help to reduce postoperative complications without decreasing the surgical outcome of EDAS. Furthermore, factors such as the patient's age should be taken into account when treating pediatric patients with MMD.

Epilepsy has been known to humankind since antiquity. The surgical treatment of epilepsy began in the early days of neurosurgery and has developed greatly. Many surgical procedures have stood the test of time. However, clinicians treating epilepsy patients are now witnessing a huge tide of change. In 2017, the classification system for seizure and epilepsy types was revised nearly 36 years after the previous scheme was released. The actual difference between these systems may not be large, but there have been many conceptual changes, and clinicians must bid farewell to old terminology. Paradigms in drug discovery are changing, and novel antiseizure drugs have been introduced for clinical use. In particular, drugs that target genetic changes harbor greater therapeutic potential than previous screening-based compounds. The concept of focal epilepsy has been challenged, and now epilepsy is regarded as a network disorder. With this novel concept, stereotactic electroencephalography (SEEG) is becoming increasingly popular for the evaluation of dysfunctioning neuronal networks. Minimally invasive ablative therapies using SEEG electrodes and neuromodulatory therapies such as deep brain stimulation and vagus nerve stimulation are widely applied to remedy dysfunctional epilepsy networks. The use of responsive neurostimulation is currently off-label in children with intractable epilepsy.

Objective In complex lumbosacral lipomatous malformation or retethering, “crotch” dissection, an incision on the dura or lipoma at the site lateral to the lipoma-cord fusion line saving underlying roots, is often not easy. Attempts of this dissection in complex and obscured conditions may cause damage to the spinal cord or nerve roots. A method for caudal extension of untethering while positive areas on electrical stimulation were encountered during the crotch dissection of lumbosacral lipomatous malformation is described. Methods After thinning out the negative-response area just caudal to the positive-response area, a small perforation is made at the negative-response area skipping the positive-response area with probing the dissection direction through the subarachnoid space by an inside-out fashion. Subsequently, the procedure is continued caudally from the perforation site. Results Safe caudal extension of untethering is possible using this method. Illustrative operative photographs are shown. Conclusions By using this method, safe untethering can be achieved avoiding root injuries in complicated lipomas such as chaotic or retethering cases.

Purpose: For analyzing the epidemiology and treatment according to the KSPNO protocol results of germ cell tumor patients at our institution.Methods: From 2004 to 2019, of 6494 patients with intracranial neoplasms, 61 (0.9%) patients with iGCTs were enrolled. Pediatric patients underwent chemotherapy and radiotherapy according to the Korean Society for Pediatric Neuro-Oncology (KSPNO) protocol, and adult patients were treated with bleomycin, etoposide, and cisplatin (BEP) regimens. Survival rates, recurrence rates, and posttreatment morbidity were analyzed to identify risk factors. Results: The median age was 20.0 years (range: 1-42), and the follow-up duration was 77.7 months (range: 10.0-203.4 months). The tumors developed most frequently in the pineal gland (49.2%). There were no significant differences in outcomes between protocols, but the KSPNO protocol group had lower tumor recurrence (14.8% vs. 17.6%, p=0.524) and mortality rates (0% vs. 5.9%, p=0.307) than the other groups. According to the pathological subtype, the outcomes were significantly different between the germinoma and nongerminomatous germ cell tumor (NGGCT) groups. The 10-year progression-free survival rates were 93.2% and 67.1% in the germinoma and NGGCT groups, respectively (p = 0.009). The NGGCT pathological type (p=0.021) was a significant recurrence-associated factor in the multivariate analysis. Significant adverse occurred in 14 patients (7 patients in each group).Conclusions: Pure germinomas have a higher survival and lower recurrence rate than NGGCTs. A multidisciplinary approach is needed to select appropriate iGCT treatments, and reducing the radiation dose could minimize posttreatment morbidity.Clinical trial registrationNot applicable

BackgroundPhysicians can find it challenging to decide whether confirmative digital subtraction angiography (DSA) should be performed in patients who present with "suspicious small aneurysm-like structures" on magnetic resonance angiography (MRA). Factors associated with "false positive aneurysms on MRA" (FPAMs)," which are finally confirmed as negative on DSA, have rarely been reported. This study aimed to identify the clinical or radiologic clues indicative of FPAM on DSA.MethodsPatients who had undergone DSA between 2016 and 2019 for suspicious aneurysm-like structures < 5 mm in size on MRA were enrolled. Patient demographics and the details regarding the geometry of the structures were retrospectively reviewed. Univariate and multivariate logistic regression analyses were conducted to identify the associated factors. Receiver operating characteristic curve analysis was performed to assess the clinical implications.ResultsOf the 107 suspicious structures, 46 were indicated as being false positive on DSA (42.96%). Location (positive on C7 and negative on C5-6 ICA) and lower dome to neck ratio were found to be significant parameters in the multivariate analysis. The dome to neck ratio threshold value was 0.99.ConclusionSuspicious aneurysm-like structures located not on C5-6 but on C7 ICA and having wide neck morphologies (dome to neck ratio < 0.99) are highly likely to be negative on DSA.

Background Recently, modern technology such as diffusion tensor imaging (DTI), neuro-navigation and intraoperative neurophysiological monitoring (IOM) have been actively adopted for the treatment of thalamic tumors. We evaluated surgical outcomes and efficacy of the aforementioned technologies for the treatment of pediatric thalamic tumors. Methods We retrospectively reviewed clinical data from 37 children with thalamic tumors between 2004 and 2017. There were 44 operations (27 tumor resections, 17 biopsies). DTI was employed in 17 cases, neuro-navigation in 23 cases and IOM in 14 cases. All diagnoses were revised according to the 2016 World Health Organization Classification of Tumors of the Central Nervous System. Progression- free survival (PFS) and overall survival (OS) rates were calculated, and relevant prognostic factors were analyzed. The median follow-up duration was 19 months. Results Fifteen cases were gross total resections (GTR), 6 subtotal resections (STR), and 6 partial resections (PR). Neurological status did not worsen after 22 tumor resections. There were statistically significant differences in terms of the extent of resection between the groups with DTI, neuro-navigation and IOM (n=12, GTR or STR=12) and the group without at least one of the three techniques (n= 15, GTR or STR=9, p=0.020). The mean PFS was 87.2±38.0 months, and the mean OS 90.7±36.1 months. The 5-year PFS was 37%, and the 5-year OS 47%. The histological grade (p≤0.001) and adjuvant therapy (done vs. not done, p=0.016) were significantly related to longer PFS. The histological grade (p= 0.002) and the extent of removal (GTR/STR vs. PR/biopsy, p=0.047) were significantly related to longer OS. Conclusion Maximal surgical resection was achieved with acceptable morbidity in children with thalamic tumors by employing DTI, neuro-navigation and IOM. Maximal tumor resection was a relevant clinical factor affecting OS; therefore, it should be considered the initial therapeutic option for pediatric thalamic tumors.

Background and Purpose— In pediatric moyamoya disease, there are few reports on the efficacy of surgical intervention for stroke prevention. We evaluated the long-term outcomes of indirect bypass surgery on a relatively large number of children with moyamoya disease in a single center. Methods— From August 1988 to December 2012, 772 children underwent indirect bypass surgery. This study included 629 patients who were followed up for >5 years, excluding patients with moyamoya syndrome. The mean clinical follow-up duration was 12 years (range, 5–29 years). Cross-sectional analysis was performed based on either Karnofsky Performance Scale or Lansky Play Performance Scale to evaluate overall clinical outcomes and factors associated with unfavorable outcomes. To analyze the longitudinal effect of surgery, the annual risk of symptomatic infarction or hemorrhage on the operated hemisphere after indirect bypass surgery was calculated with a person-year method, and the event-free survival rate was evaluated using the Kaplan-Meier method. Results— The overall clinical outcome was favorable in 95% of the patients. The annual risks of symptomatic infarction and hemorrhage on the operated hemispheres were 0.08% and 0.04%, respectively. Furthermore, the 10-year event-free survival rates for symptomatic infarction and hemorrhage were 99.2% and 99.8%. Conclusions— Indirect bypass surgery could provide satisfactory long-term improvement in overall clinical outcome and prevention of recurrent stroke in children with moyamoya disease.

C2–3 disc herniation is rare and a definitive treatment of choice has not been established. The purpose of this case report is to suggest posterior approach as one of the best options. A 49-year-old man visited our clinic with a 7-year history of neck pain and occipital headache and a 2-month history of right arm pain. C2–3 intervertebral disc herniation of the central type was diagnosed on magnetic resonance imaging (MRI), and surgery was performed, including C1 laminectomy, C2–3 laminoplasty, and C2–3 posterior fixation. The posterior approach was used because the patient's neck was difficult to operate anteriorly. After 3 months postoperatively, MRI showed widened cerebrospinal fluid space at the C2–3 level. The visual analogue scale score for pain improved in the occipital area and right arm. However, the untouched protruded central disc, subjective weakness in right hand grasping, and numbness persisted. In conclusion, this case highlights posterior decompression and fixation as a good treatment of choice for decompression at the C2–3 level disc herniation, from where it is difficult to remove compressive lesions directly via the anterior corridor.

In general, intracranial germ cell tumors (GCT) are sensitive to chemotherapy, radiation therapy, and have favorable outcomes. However, a rare chemotherapeutic retro conversion phenomenon, known as intracranial growing teratoma syndrome (iGTS), shown a poorer prognosis. We analyze the diagnostic characteristics and the result of treatment response for the patients with iGTS treated in our institutes (SNUH and SNUBH, from 1997 to 2019). The electronic medical records and PACS were used for reviewing the clinical information, follow-up MRI images, tumor markers (alpha-fetoprotein, human chorionic gonadotropin, in serum or cerebrospinal fluids), and pathological findings. Out of 328 intracranial GCT patients, seventeen were finally identified as iGTS. Sixteen out of 17 patients were non-germinomatous GCTs, and 1 were germinomas. Initial pathology was common in order of immature teratoma (26.7%), other than immature teratoma (11.5%), and germinoma (0.5%). All of the tumors showed typical ‘honeycomb appearance’ in their follow-up MRI images. Sixteen out of 17 tumors were surgically resected as 2nd look surgery. Among them, 13 tumors were gross totally resected. Twelve were alive without evidence of recurrences during follow-up periods, and the other was dead from the progression of the disease. Among the other than the gross total resection group (n=4), two patients were dead, one recurred the tumor, and the other is following up with stable disease after adjuvant radiation therapy. Early detection and total resection of the tumor as possible might be meaningful for favor prognosis, especially in non-germinomatous GCTs patients.

Dandy-Walker malformation (DWM) is a congenital brain anomaly characterized by dysgenesis of the cerebellar vermis and the presence of a posterior fossa cyst. The association of syringomyelia with DWM is extremely rare. A 10-year-old patient who was diagnosed with DWM in infancy presented with progressive scoliosis and fecal incontinence. He had been treated with cystoventriculoperitoneal shunting with a Y-connection during infancy, which was followed by a revision 6 years later. During the revision surgery, intraventricular bleeding occurred and was managed conservatively. Imaging studies for the current visit revealed syringomyelia along the cervicothoracic spinal cord and a membranous structure around the cervicomedullary junction. Phase-contrast cine magnetic resonance imaging (MRI) revealed disturbed cerebrospinal fluid (CSF) flow across the membrane. We excised the arachnoid web that was tethering the brainstem and blocking CSF flow. Postoperatively, the patient experienced symptom relief, and the follow-up imaging study demonstrated a dramatic decrease in the size of the syringomyelia. We suggest that syrinx formation in this patient was possibly caused by disturbed CSF flow and tethering of the brainstem. We experienced an unusual case of DWM with syringomyelia which was caused by an arachnoid web blocking CSF flow and tethering the brainstem. The arachnoid web seems to be formed by previous bleeding which occurred at the time of shunt revision. After excision of the arachnoid web, the patient showed good outcome.

This case report showed a young soldier complained of low back pain during military training. Intramuscular hematoma accompanied by the lumbar compression fracture was observed in computed tomography. However, the possibility of intramuscular tumors could not be ruled out through additional examinations, and thus surgically removed, and was diagnosed as cavernous hemangioma. This report is a rare and instructive case in which a hemangioma mimicked bleeding with the lumbar fracture.

Treatment indications for arachnoid cysts are not clear. Some surgeons take improvement in neurocognitive function into account as a surgical indication for arachnoid cysts. However, only a few studies have evaluated the relationship between arachnoid cysts and neurocognitive function. Furthermore, studies that analyze neurocognitive function as an effect of arachnoid cyst surgery are even rarer. The purpose of this study was to analyze the neurocognitive function scores of children with arachnoid cysts before and after surgery and to examine whether surgical treatment led to improved neurocognitive function. From June 2009 to August 2012, data for 24 children diagnosed with arachnoid cysts who underwent surgery at Seoul National University Children’s Hospital were analyzed. Pre-operative and post-operative cyst volume was assessed and neurocognitive function was tested using the Korean version of the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Bender-Gestalt Test (BGT). Comparison of pre- and post-operative profiles by laterality of the arachnoid cyst was performed. Patients had age-appropriate full-scale intelligent quotients (FSIQ), verbal IQ (VIQ), and performance IQ (PIQ) pre-operatively, which were maintained after surgery. Of the subtests, Block Design showed significant improvement post-operatively (p = 0.021). This means that visuo-spatial integration and mental construction abilities were improved after surgery. Patients with left or right arachnoid cysts did not show statistically significant changes in FSIQ, VIQ, or PIQ after surgery (110.21 versus 113.95, p = 0.307; 108.92 versus 111.54, p = 0.368; 107.88 versus 111.04, p = 0.152, respectively). Subanalysis showed that the pre- and post-operation VIQ mean scores of the patients with right arachnoid cysts were significantly higher (p

BACKGROUND The existence of tethering tracts in spinal dysraphism, other than congenital dermal sinus (CDS), has been recognized and has been summated into an integrated concept of limited dorsal myeloschisis (LDM). OBJECTIVE To elucidate the underlying embryology of LDM in relation to CDS by focusing on the pathological features of special cases of tethering tracts. METHODS Out of 389 spinal dysraphism patients who were operated on from 2010 to 2016, 5 patients who had tethering tracts composed of both CDS and LDM (or "probable LDM" if only fibrous tissue was found) were identified. Their clinical presentation, radiological images, operative findings, and pathology were thoroughly reviewed. RESULTS Three nonsaccular-type patients harbored stalks in which the squamous epithelial lined sinus (CDS) was found in the distal portion, and fibroneural (LDM) or fibrous (probable LDM) tissue in the proximal part. Two patients had saccular lesions, and a stalk was found inside the sac, connecting a small pit on the skin to the spinal cord. The tracts were pathologically identical to a CDS. CONCLUSION This study reports the coexistence of CDS and LDM (or probable LDM) components. These unique cases support the hypothesis that the CDS and LDM are among a spectrum of an anomaly that is caused by failure of complete dysjunction between cutaneous and neural ectoderms. Neurosurgeons should be aware of the possibility of coexisting "CDS" components in cases suggestive of LDM. In such cases, not only untethering but also meticulous removal of the squamous epithelium is critical.

Background: Moyamoya disease (MMD) is the most common surgically treated paediatric cerebrovascular disease in East Asia. The rare incidence and variety of surgical techniques applied have limited the clinical research on MMD. In paediatric MMD, there are few reports on the efficacy of surgical intervention for stroke prevention. We evaluated the long-term outcomes of indirect bypass surgery on a relatively large number of children with MMD in a single centre. Methods: From August 1988 to December 2012, 772 children with MMD underwent indirect bypass surgery. This study included 629 patients who were followed up for more than 5 years, excluding patients with moyamoya syndrome. The mean clinical follow-up duration was 129 ± 60 months (range, 60-337 months). Cross-sectional analysis was performed to evaluate overall clinical outcomes and factors associated with unfavourable outcomes. To analyse the longitudinal effect of surgery, the annual risk of symptomatic infarction or haemorrhage after indirect bypass surgery was calculated with a person-year method, and the event-free survival rate was evaluated using the Kaplan-Meier method. Findings: The overall clinical outcome was excellent in 55%, good in 38%, fair in 6%, and poor in 1% of the patients. Therefore, 92% of the patients had a favourable clinical outcome (excellent and good). The annual risks of symptomatic infarction and haemorrhage ipsilateral to the operated vascular territory were 0.06% and 0.04%, respectively. Furthermore, the 10-year event-free survival rates for symptomatic infarction and haemorrhage in the operated hemispheres were 99.4% and 99.6%, respectively. Interpretation: Indirect bypass surgery resulted in satisfactory long-t:erm improvement in overall clinical outcome and prevention of recurrent stroke in children with MMD. Funding Statement: This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI12C0066). Declaration of Interests: There are no conflicts of interests. Ethics Approval Statement: This study was approved by the Seoul National University Hospital Institutional Review Board (No. 1808-050-964).

Background: Encephaloduroarteriosynangiosis (EDAS) is a commonly used indirect revascularization operation method to treat pediatric Moyamoya disease (MMD) patients. Arachnoid dissection has been frequently performed during the EDAS operation in an effort to promote better revascularization. However, no studies have yet proven its surgical benefits. In this study, we investigated the impact of arachnoid preservation on the surgical outcome and post-operative complication by comparing pediatric MMD patients who had the arachnoid membrane preserved during EDAS operation with those who had the arachnoid membrane dissected. Methods: This was a retrospective cohort study based on a single institution, single surgeon's experience. A total of 206 pediatric MMD patients who underwent EDAS operation at Seoul National University Children's Hospital were recruited for the study. We compared the surgical outcomes of these two groups, as well as, post-operation complication rate. Furthermore, risk factors for post-operative complication were analyzed. Findings: The overall clinical outcome (p = 0.342) and the extent of revascularization of MCA territories (p = 0.736) were not different between the arachnoid dissection group and the arachnoid preservation group. However, post-operative infarction/hemorrhage rate was significantly higher in the arachnoid dissection group (p = 0.005). Arachnoid dissection (p = 0.011) and young age (less than 3 years old, less than 3 years, p = 0.012) were significantly associated with increased risk of post-operative complication. Interpretation: Arachnoid preservation may help to reduce post-operative complication without decreasing the surgical outcomes of EDAS operation. Furthermore, patient factors such as the patient's age should be taken into account when treating pediatric MMD patients. Funding Statement: This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI12C0066). Declaration of Interests: The authors state: "There are no conflicts of interests." Ethics Approval Statement: The present study was a retrospective cohort study which was approved by the Seoul National University Hospital Institutional Review Board.

While molecular subgrouping has revolutionized medulloblastoma classification, the extent of heterogeneity within subgroups is unknown. Similarity network fusion (SNF) applied to genome-wide DNA methylation and gene expression data across 763 primary samples identifies very homogeneous clusters of patients, supporting the presence of medulloblastoma subtypes. After integration of somatic copy-number alterations, and clinical features specific to each cluster, we identify 12 different subtypes of medulloblastoma. Integrative analysis using SNF further delineates group 3 from group 4 medulloblastoma, which is not as readily apparent through analyses of individual data types. Two clear subtypes of infants with Sonic Hedgehog medulloblastoma with disparate outcomes and biology are identified. Medulloblastoma subtypes identified through integrative clustering have important implications for stratification of future clinical trials.

The optimal treatment for Chiari I malformation in children is still under debate. The aim of this study was to evaluate the surgical outcome of the pediatric Chiari I malformation, focusing on clinico-radiological factors and technical aspects. Fifty-six patients with Chiari I malformation who received surgery at Seoul National University Children’s Hospital were included. The mean age was 7.9 years. The patients were divided into three groups: group I (n = 8) with hydrocephalus, group II (n = 11) without syrinx, and group III (n = 37) with syrinx. Group I received shunting operation initially, and others received foramen magnum decompression (FMD). Group III was further subdivided: group IIIa (n = 9), minimal intradural manipulation, and group IIIb (n = 27), active intradural manipulation. The outcomes were compared between the groups. The mean follow-up period was 75.9 months. In group I, symptoms were resolved or had improved in most patients, with only one patient received additional FMD. Symptoms resolved or improved in 10 (91 %) and 25 cases (84 %) in groups II and III, respectively. Syrinx was markedly decreased in 31 cases (86 %) in group III. FMD was less effective for scoliosis (improved or stabilized in 57 %). The persistence of syrinx was related with an aggravation of scoliosis. The outcomes between group IIIa and IIIb showed no significant difference. In most pediatric Chiari I patients with hydrocephalus, a shunting operation was sufficient. FMD showed high efficacy in treating patients without hydrocephalus. The extent of the intradural procedure did not have a significant effect on the clinical outcome.

Object Postoperative epidural hematoma (EDH), a blood collection between the inserted galeal flap and the overlying skull flap (epigaleal flap hematoma), is a frustrating complication of the surgical treatment of moyamoya disease (MMD) in pediatric patients. The symptoms of postoperative EDH are often similar to those of postoperative cerebral ischemia, and may cause confusion during clinical decision making. The authors designed this study to evaluate the incidence, clinical presentation, risk factors, and treatment outcomes of postoperative EDH in pediatric patients with MMD. Methods A retrospective review of 148 pediatric patients with 250 craniotomies who underwent indirect bypass revascularization surgery between January 2002 and December 2006 was performed. This group consisted of 60 male and 88 female patients, and the mean age at surgery was 7.5 years (range 1–18 years). Results Of the 250 craniotomies, postoperative EDH was detected in 32 cases. In 12 cases of EDH, surgical treatment was necessary (4.8% of 250 craniotomies). During the same period, 743 non-MMD craniotomy operations were performed. In 6 of these 743 operations, patients developed postoperative EDH that required surgical treatment, significantly less than the percentage of EDH requiring postoperative treatment in patients with MMD (0.8%, p < 0.001). The average interval between craniotomy surgery and the detection of EDH was 1.8 days (range 0–5 days) in patients with MMD and 0.5 days (range 0–2 days; p = 0.018) in the non-MMD craniotomy group. Postoperative EDH was observed in significantly fewer cases (17 of 191) when a subcutaneous drain (SCD) was inserted over the bone flap than in cases in which an SCD was not inserted (14 of 55; p = 0.001). The mean international normalized ratio of prothrombin time in the immediate postoperative blood test was 1.27 ± 0.17 in the EDH group and 1.20 ± 0.11 in the non-EDH group (values are expressed as the mean ± SD; p = 0.008). Central galeal flap tenting suture and immediate postoperative platelet count were not related to the incidence of postoperative EDH following pediatric MMD surgery. Conclusions Postoperative EDH is more likely to be found following craniotomy in patients with MMD than in those without MMD, and may occur in a delayed fashion. Insertion of an SCD and immediate correction of an abnormal value for international normalized ratio of prothrombin time can decrease the incidence of postoperative EDH following surgery for pediatric MMD.

Choroid plexus tumor is a rare brain tumor with variable clinical features according to the histological grade. We reviewed the treatment outcome of 23 children, focusing on the biological behavior of the atypical choroid plexus papilloma (ACPP) and the current therapeutic strategy in choroid plexus carcinoma (CPC). The demographics, clinical features, surgical treatments, adjuvant therapies, and survival were reviewed. The median age at diagnosis was 18 months—55 months for choroid plexus papilloma (CPP), 8 months for ACPP, and 15 months for CPC. Gross total resections were achieved in seven of eight patients with CPP, seven of seven with ACPP, and three of eight with CPC. Seven patients with CPC received chemotherapy. Four patients received high-dose chemotherapy (HDCT) and autologous peripheral blood stem cell transplantation (aPBSCT), and three among them have survived. Four patients with CPC received radiotherapy. One CPP patient and one CPC patient underwent radiosurgery. All CPP and ACPP patients have survived. The overall survival rate of the CPC patients was 62.5 % in the first year and 42.9 % in the second year. The progression-free survival rate of the CPC patients was 50 % in the first year and 0 % in the second year. Seven patients underwent permanent cerebrospinal fluid diversion surgery because of hydrocephalus or subdural effusion. CPP and ACPP were surgically curable. Multi-modal treatments are necessary in the management of CPC with poor prognosis. HDCT and aPBSCT may be important to treat infants for whom radiotherapy is limited. Hydrocephalus and subdural effusion should be resolved with appropriate management.

Moyamoya disease (MMD) is a chronic cerebrovascular occlusive disease, and progressive involvement of the posterior cerebral artery (PCA) has been reported. However, majority of MMD articles are presenting classic anterior circulation related issues. This study investigates the preoperative factors related to the long-term outcome of posterior circulation in MMD. Retrospective review of 88 MMD patients (166 PCAs in either hemisphere) without symptomatic disease involvement of PCA at initial diagnosis was done. Data at initial diagnosis regarding age, presence of infarction, status of the PCA, type of posterior communicating artery, and the angle between PCA and basilar artery were reviewed. Progressive stenosis of PCA was evaluated by symptom or radiological imaging during follow up. During an average follow up of 8.3 years, 29 out of 166 (18 %) evaluated PCAs showed progressive disease involvement. The average time of progression from the initial operation was 4.9 years, with the latest onset at 10.8 years. The patients who showed progressive stenosis of the PCA tended to be younger, present with infarction, have smaller angle between PCA and basilar artery, and have asymptomatic stenosis of the PCA at initial presentation. However, multivariate analysis confirmed only the presence of initial infarction and a smaller angle between PCA and basilar artery to be significantly associated with progressive stenosis of PCA. Involvement of PCA in MMD may occur in a delayed fashion, years after the completion of revascularization of anterior circulation. Persistent long-term follow-up regarding the posterior circulation is recommended.

Cerebellopontine angle (CPA) tumors are uncommon in children, and the pathological spectrum is different from that of adults. In this study, we reviewed the pathological diagnosis of pediatric patients with a CPA tumor to determine the pattern in this age group. In a cohort of 267 patients with posterior fossa tumor, tumor locations were determined with preoperative magnetic resonance imaging (MRI). The pathological diagnosis, imaging characteristic, and treatment outcomes of patients with CPA tumors was reviewed and analyzed. Twenty-six patients (9.7 %) had a tumor in the CPA. The pathological spectrum was wide, from malignant intrinsic brain tumors to benign extra-axial tumors and sarcomatous lesions. Eighteen patients (69 %) had malignant tumors. The pathological nature was strongly linked to patient age. The mean age of malignant tumor group was significantly younger than that of benign tumor group. MRI findings that favored malignant histology included a plastic feature of the tumor, multiple signal voids, encasement of major arteries, widening of lateral recess, focal cerebellar edema, and hydrocephalus. The presence of seeding in the neuraxis also indicated malignant pathology. Especially, increased density on precontrast computed tomography was a strong predictor of malignant pathology. Malignant CPA tumors showed high surgical morbidity rate and grim long-term prognosis. Patient age and tumor location are the two most important clues for the diagnosis of any brain tumor. Unlike in adult patients, clinicians should expect a high probability of malignant histology for pediatric CPA tumors, especially in infants and young children.

NAND flash memory is widely used as a cost-effective storage with high performance [1–2]. This paper presents a 128Gb multi-level cell (MLC) NAND flash memory with a 150 cells/string structure in 14nm CMOS that can be used as a cost-effective storage device. This paper also introduces several approaches to compensate for reliability and performance degradations caused by the 14nm transistors and the 150 cells/string structure. A technique was developed to suppress the background pattern dependency (BPD) by applying a low voltage to upper word lines (WLs) - the drain side(SSL side) WLs with respect to the location of the selected WL - during the verify sequence. Two techniques are also used to improve the program performance: equilibrium pulse scheme and smart start bias control scheme (SBC) in the MSB page. In addition, the first cycle recovery (FCR) of read enable (RE) and the bi-directional data strobe (DQS) is used to achieve a high speed I/O rate. As a result, a 640µs program time and a 800MB/s I/O rate is achieved.

Background There has been controversy regarding the management of syringomyelia associated with tethered spinal cord. Previous reports on the topic have included only a small number of patients, considered open/closed spinal dysraphism together, or had a short follow-up. Objective To review a uniform group of patients with syringomyelia associated with tethered cord and treated mainly by untethering alone. Methods Of the 135 patients operated on for closed spinal dysraphism between 2003 and 2008, 33 patients with preoperative syringomyelia were identified. The preoperative/postoperative clinical data and syrinx index (ratio of the syrinx area and the cord area) were retrospectively reviewed. The syrinx index of each patient was plotted as an individual graph to outline the temporal change of the syrinx before and after untethering surgery. Results Five patients showed symptom progression during the preoperative period, and 4 of the 5 had an additional magnetic resonance imaging before the operation that showed progression of the syringomyelia. Postoperatively, 31 of 32 patients (97%) who underwent postoperative follow-up imaging showed long-term stability or a decrease in the syrinx index. Four symptomatically stable patients showed a transient increase in the syrinx index during the initial postoperative 6 months, which later decreased spontaneously. In 1 patient with retethering, the syrinx index increased 6 months before the onset of new urinary symptoms. Conclusion Untethering alone may be sufficient for the management of syringomyelia associated with tethered cord. A transient increase in the syrinx index during the initial postoperative period may be observed without additional surgery if patients are symptomatically stable.

Despite active and aggressive therapeutic measures, atypical teratoid/rhabdoid tumors (AT/RTs) are without doubt one of the most malignant brain tumors that occur during childhood. These tumors are more prevalent in children less than 3 years of age, and the prognosis is worse in these young children. Medical records of 14 patients diagnosed at our institution were reviewed. Patients diagnosed with AT/RT at our institution between 1997 and 2009 were identified. Clinical data for those patients with pathologic confirmation of AT/RTs were reviewed regarding surgery, adjuvant treatment, and survival. A total of 14 patients were identified. One patient who died 3 days after initial surgery was excluded, and 13 patients were recruited. Of the 13 patients, 7 were less than 1 year of age, and only 2 were over 3 years of age. Nine patients showed dissemination at diagnosis. Four patients were treated with radiation therapy (RTx), and 2 of these were less than 3 years of age. Ten patients had chemotherapy (CTx), and 3 of these underwent high dose chemotherapy and autologous peripheral blood stem cell transplantation. The median progression-free survival (PFS) was 4 months, and the median overall survival (OS) was 9 months. Univariable analysis revealed age more than 1 year, CTx, and RTx to be significant factors for better PFS and OS. None of the variables were significant in multivariable analysis. Young patients with AT/RT have a bad prognosis. An aggressive therapeutic strategy needs to be profiled for this age group.

Pediatric medulloblastoma is considered a highly heterogeneous disease and a new strategy of risk stratification to optimize therapeutic outcomes is required. We aimed to investigate a new risk-stratification approach based on expression profiles of medulloblastoma cohorts. We analyzed gene expression profiles of 30 primary medulloblastomas and detected strong evidence that poor survival outcome was significantly associated with mRNA expression profiles of 17p loss. However, it was not supported in independent cohorts from previously published data (n = 100). We speculated that this discrepancy might come from complex conditions of two important prognostic determinants: loss of tumor suppressors (chromosome 17p) and high expression of oncogenes c-myc (MYCC) or N-myc (MYCN). When patients were stratified into 5 or 7 subgroups based on simultaneous consideration of these 2 factors while defining the Wnt group as independent, obviously different survival expectancies were detected between the subgroups. For instance, predicted 5-year survival probabilities ranged from 19% to 81% in the 5 subgroups. We also found that age became a significant prognostic marker after adjusting for 17p, MYCC, and MYCN status. Diminished survival in age

Object Although the reported surgical outcome is favorable, there is little information regarding the long-term quality of life in pediatric patients with moyamoya disease (MMD) when they grow to adulthood. The authors conducted a survey to provide details of social adaptation and satisfaction in adults who underwent revascularization surgery for MMD during childhood. Methods One hundred twenty-three patients with MMD who had undergone surgery during childhood and were older than 18 years of age were recruited for this study. The authors mailed self-administered questionnaires regarding each patient's education, employment, marriage, driver's license, physical condition, and satisfaction. Sixty-five patients (53%) responded. Results Compared with the general population, the patients showed a similar rate of attaining a higher education. Forty-nine (80%) of 61 patients who were not currently high school students had entered college or university. However, the presence of neurological deficits on preoperative examination was a negative predictor of entrance into a college or university, as well as employment. Some patients had difficulty in planning marriage because of physical handicaps, and the rate of acquiring a driver's license and actual driving were relatively low. Approximately 80% of the responders were satisfied with their treatment outcomes, but more than one-half reported subjectively assessed neurological problems. Conclusions In this study, pediatric patients with MMD showed favorable social adaptation in adulthood. The findings also indicated that early diagnosis and intervention before the establishment of neurological deficits are essential to children with MMD in becoming better socially adapted. Further, more thorough clinical examinations are required during follow-up in patients with MMD.

The phenomenon of cyst enlargement in terminal myelocystocele (TMC) patients has been mentioned in the literature. However, its clinical significance has not been clarified in depth. We reviewed TMC patients who had experienced cyst enlargement during the preoperative period to determine the correlation with symptomatic progression. We sought to determine the optimal surgical strategy for such patients. Of eight patients who were operated on for TMC from 1991 to 2009, four patients that showed cyst enlargement before the operation were reviewed. A retrospective review of medical recordings, radiological imaging, and other evaluations for neurologic status was done, focusing on the temporal neurological changes that correlated with the cyst enlargement. Each of the four patients with cyst enlargement showed concurrent progression of neurologic symptoms, two by motor weakness and two by neurogenic bladder. In only one case, early detection and prompt surgery were possible, and this patient showed dramatic improvement in muscle strength after the surgery. The progression of neurologic deterioration was arrested postoperatively for the other three patients. Hence, cyst enlargement in a TMC patient should be considered as a warning for neurologic deterioration, and the operation should be performed expediently to prevent impairment in neurologic function.

Medulloblastoma (MBL), the most common malignant pediatric brain tumor, is incurable in about one-third of patients and can lead to long-term disabilities despite current multimodal treatments. The purpose of this study was to demonstrate in vitro biological effects of neurotrophins-3 (NT-3) on MBL cells and to evaluate the growth-inhibitory effect of neurotrophin-3 (NT-3)-secreting stem cells on tumor cells. We confirmed by western blotting that D283-MED cells express tyrosine kinase C, a specific receptor for NT-3. Analyzing the biological effects of NT-3 on MBL cells, we evaluated autophagy, apoptosis, senescence, and differentiation of tumor cells with NT-3. The NT-3 induced a concentration-dependent increase in apoptosis in the tumor cell line (P < 0.001). The high concentrations of NT-3 increased the expression of class III β-tubulin (P < 0.001) and decreased the expression of Nestin (P < 0.05). NT-3-secreting stem cells were produced by nucleofecting pIRES2.EGFP-NT3 into human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and their tropic property toward MBL cells was confirmed by migration assay. Double-layered co-culture experiments with the NT-3-secreting hAT-MSCs and D283-MED MBL cells were performed, and NT-3-induced cell death was studied by 3-(4,5-dimethylathiazol-2-yl)-2,5-dephenyl-tetrazolium bromide (MTT) assay. Consequently, the high concentrations of NT-3-secreting hAT-MSCs significantly (P < 0.05) increased the death of D283-MED cells in vitro. The present study demonstrated that both apoptotic cell death and neuronal differentiation of tumor cells were the mechanisms of growth-inhibitory effect of NT-3-secreting hAT-MSCs on MBL cell line.