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Dong Gyu Kim, Chul-Kee Park and Sun Ha Paek

✓ Bo Sung Sim (1924–2001) stands as a prominent figure in the history of Korean neurosurgery. His devoted contributions have led to the fruitful development of modern neurosurgery in Korea. Sim practiced advanced neurosurgical techniques, undertook basic research, was passionate about education in the early years of neurosurgery in Korea, and played an essential role in founding the Korean Neurosurgical Society. Sim was a true neurosurgeon—a teacher, a scientist, and a superb pioneer in Korean neurosurgery.

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Kyu-Won Shim, Sun-Young Joo, Se-Hoon Kim, Joong-Uhn Choi and Dong-Seok Kim

Object

Medulloblastoma is the most common malignant neuroepithelial tumor found in children. Several reports have described efforts to identify the prognostic significance of various patterns of pathological and immunohistochemical features in medulloblastoma, but the published data appear to be controversial. The authors therefore attempted to demonstrate these prognostic factors convincingly in a retrospective study performed in patients with medulloblastoma.

Methods

The data used were obtained in 58 patients with medulloblastoma who were > 3 years of age and in whom > 1 year of follow-up was available after the maximal resection, craniospinal irradiation, and chemotherapy treatments. These assessments were performed to compare the immunohistochemical features to cellular differentiation, the proliferation index (PI), the apoptotic index (AI), and oncogenesis revealed by TrkC and c-erbB-3. In addition, the authors tried to determine the prognostic utility of these results in this tumor category.

Results

There was no statistically significant correlation between the prognosis and the degree of cell differentiation, but a positive correlation was noted between the PI and the AI in a tumor mass. The number of cases with a PI > 10% was significantly greater in the group of tumors in patients with recurrent medulloblastoma. A close association between the PI as a continuous variable and the progression-free and overall survival was also found. Most importantly, the PI is the only significant prognostic factor for the overall survival of patients with medulloblastoma.

Conclusions

Therefore, the authors suggest that the PI is directly linked to the prognostic factor for medulloblastoma and that immunohistochemical staining is a potentially powerful tool for predicting the prognosis of patients with medulloblastoma.

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Xiao-Fei Hou, Dong-Wei Fan, Chui-Guo Sun and Zhong-Qiang Chen

Object

The primary object of this investigation was to study recombinant human bone morphogenetic protein–2 (rhBMP-2)–induced ossification of the ligamentum flavum and associated histone H3 modification in a rat model. In an additional set of studies the authors investigated spinal cord and behavioral changes in the same model.

Methods

The authors report on 2 separate sets of studies. A total of 90 rats were used for the 2 sets of studies (45 each); in each study, a lyophilized rhBMP-2 and collagen mixture (20 μg rhBMP-2 and 200 μl collagen) was implanted in the lumbar extradural space in 18 rats; another 18 animals were used for a sham-operation control group and underwent implantation of lyophilized collagen without rhBMP-2 at the same level; an additional 9 animals were used as untreated controls. Lumbar spinal samples were harvested from the rhBMP-2 groups and the shamoperation control groups at 1 week, 3 weeks, and 9 weeks after the operation. Samples were also obtained from untreated controls at the same time points. All samples were scanned using micro-CT and then made into paraffinembedded sections. The sections from the first set of 45 rats were stained using elastica van Gieson and toluidine blue, and the expression of histone modifications (H3K9ac, H3K18ac, H3K4me3, and H3K36me3) and osteogenic transcription factors (osterix, Runx2) was detected by immunohistochemistry. In the second set of studies, hindlimb motor function was assessed at 1 week, 3 weeks, and 9 weeks after surgery. After behavioral evaluation, samples were harvested, scanned using micro-CT, and then made into paraffin-embedded sections. The sections were stained using Luxol fast blue. The expression of NeuN was also detected using immunohistochemistry.

Results

Ossification was seen in the rhBMP-2 group from 1 week after insertion, and the volume of ossified mass increased at 3 and 9 weeks. There was no ossification seen in the sham-surgery and normal controls. The pathological changes of ossification involved ligament degeneration, cartilage formation, and, finally, bone replacement. Spinal cord evaluation showed a significant decrease in white matter content and number of neurons at 9 weeks after operation in the rhBMP-2–treated group (compared with findings in the sham-surgery and control groups as well as findings at the earlier time points in the rhBMP-2 group).

Using immunohistochemical staining, histone modifications (H3K9ac, H3K18ac, H3K4me3, and H3K36me3) and osteogenic transcription factors (osterix, Runx2) all were found to be expressed in the fibrocartilage area of the rat ossified ligamentum flavum samples (rhBMP2 group).

Conclusions

This rhBMP-2–induced OLF is a typical endochondral ossification, which is similar to clinical OLF. The compressed spinal cord around the ossification site showed signs of a chronic degenerative process. Histone H3 modifications (H3K9ac, H3K18ac, H3K4me3, and H3K36me3) may play an important role in OLF.

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Wilson P. Daugherty, Joseph E. Levasseur, Dong Sun, Gaylan L. Rockswold and M. Ross Bullock

Object. In the current study, the authors examined the effects of hyperbaric O2 (HBO) following fluid-percussion brain injury and its implications on brain tissue oxygenation (PO2) and O2 consumption (VO2) and mitochondrial function (redox potential).

Methods. Cerebral tissue PO2 was measured following induction of a lateral fluid-percussion brain injury in rats. Hyperbaric O2 treatment (100% O2 at 1.5 ata) significantly increased brain tissue PO2 in both injured and sham-injured animals. For VO2 and redox potential experiments, animals were treated using 30% O2 or HBO therapy for 1 or 4 hours (that is, 4 hours 30% O2 or 1 hour HBO and 3 hours 100% O2). Microrespirometer measurements of VO2 demonstrated significant increases following HBO treatment in both injured and sham-injured animals when compared with animals that underwent 30% O2 treatment. Mitochondrial redox potential, as measured by Alamar blue fluorescence, demonstrated injury-induced reductions at 1 hour postinjury. These reductions were partially reversed at 4 hours postinjury in animals treated with 30% O2 and completely reversed at 4 hours postinjury in animals on HBO therapy when compared with animals treated for only 1 hour.

Conclusions. Analysis of data in the current study demonstrates that HBO significantly increases brain tissue PO2 after injury. Nonetheless, treatment with HBO was insufficient to overcome injury-induced reductions in mitochondrial redox potential at 1 hour postinjury but was able to restore redox potential by 4 hours postinjury. Furthermore, HBO induced an increase in VO2 in both injured and sham-injured animals. Taken together, these data demonstrate that mitochondrial function is depressed by injury and that the recovery of aerobic metabolic function may be enhanced by treatment with HBO.

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Sang-Hoon Yoon, Sun Ha Paek, Sung-Hye Park, Dong Gyu Kim and Hee-Won Jung

✓Primary skeletal non-Hodgkin lymphoma is rare. The authors report a case of a small lymphocytic B-cell lymphoma of the skull occurring in a 53-year-old man who presented with right-hand apraxia. Initial computed tomography and magnetic resonance imaging revealed a hematoma-mimicking lesion in the left frontoparietal subdural area. A frontotemporoparietal craniectomy and biopsy procedure yielded a diagnosis of small lymphocytic B-cell lymphoma, with a metastatic nodule in the retrobulbar area. Three years after undergoing radiation therapy and surgery, the patient has shown neurological improvement without systemic dissemination of the malignancy. The lesion in this case was misdiagnosed as a subdural hematoma, and shows the importance of including lymphoma in the differential diagnosis of subdural mass lesions.

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Dong-Hun Kang, Duck-Ho Goh, Seung-Kug Baik, Jaechan Park and Yong-Sun Kim

Object

This study aimed to investigate morphological predictors of intraprocedural rupture (IPR) during coil embolization of ruptured cerebral aneurysms.

Methods

A retrospective analysis was conducted in 322 consecutive patients with ruptured cerebral aneurysms who were treated with coil embolization over an 8-year period from January 2005 to December 2012. The authors analyzed all available data with emphasis on morphological characteristics of the aneurysm as shown on baseline angiography in relation to IPR. Regarding aneurysm morphology, the authors classified patients according to multilobulation, presence of a daughter sac, and presence of a small basal outpouching (SBO).

Results

The incidence of IPR was 4.8% (16 of 332). In terms of aneurysm configuration, the presence of multilobulation (100.0% [16 of 16] in the IPR group vs 89.2% [282 of 316] in the non-IPR group, p = 0.388) and daughter sac (75.0% [12 of 16] in the IPR group vs 59.2% [187 of 316] in the non-IPR group, p = 0.208) were not significantly associated with IPR. However, SBO, found in 9% (30 of 332) of the study population, was significantly associated with IPR (56.3% [9 of 16] in the IPR group vs 6.7% [21 of 316] in the non-IPR group, OR 18.06, p < 0.0001).

Conclusions

Based on the authors' data, the more general groups of multilobulation and daughter sac were not significantly associated with IPR, although the more specific subgroup with an SBO was. More confirmation studies on these results are required, but they point to the possibility that SBO (with its possible connection to basal rupture) is an important morphological risk factor for IPR during coiling. In addition, future comparison of coiling and clipping treatment for ruptured aneurysms associated with an SBO seems necessary.

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Taek Hyun Kwon, Dong Sun, Wilson P. Daugherty, Bruce D. Spiess and M. Ross Bullock

Object. This study was conducted to determine whether perfluorocarbons (PFCs) improve brain oxygenation and reduce ischemic brain damage in an acute subdural hematoma (SDH) model in rats.

Methods. Forty adult male Sprague—Dawley rats were allocated to four groups: 1) controls, acute SDH treated with saline and 30% O2; 2) 30-PFC group, acute SDH treated with PFC infusion in 30% O2; 3) 100-O2 group, acute SDH treated with 100% O2; and 4) 100-PFC group, acute SDH treated with PFC plus 100% O2. Ten minutes after the induction of acute SDH, a single dose of PFC was infused and 30% or 100% O2 was administered simultaneously. Four hours later, half of the rats were killed by perfusion for histological study to assess the extent of ischemic brain damage. The other half were used to measure brain tissue oxygen tension (PO2). The volume of ischemic brain damage was 162.4 ± 7.6 mm3 in controls, 165.3 ± 11.3 mm3 in the 30-PFC group, 153.4 ± 17.3 mm3 in the 100-O2 group, and 95.9 ± 12.8 mm3 in the 100-PFC group (41% reduction compared with controls, p = 0.002). Baseline brain tissue PO2 values were approximately 20 mm Hg, and after induction of acute SDH, PO2 rapidly decreased and remained at 1 to 2 mm Hg. Treatment with either PFC or 100% O2 improved brain tissue PO2, with final values of 5.14 and 7.02 mm Hg, respectively. Infusion of PFC with 100% O2 improved brain tissue PO2 the most, with a final value of 15.16 mm Hg.

Conclusions. Data from the current study demonstrated that PFC infusion along with 100% O2 can significantly improve brain oxygenation and reduce ischemic brain damage in acute SDH.

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Chul-Kee Park, Dong-Chul Kim, Sung-Hye Park, Jeong Eun Kim, Sun Ha Paek, Dong Gyu Kim and Hee-Won Jung

Object

Cystic vestibular schwannoma (VS) is a unique subgroup of VSs characterized by unpredictable expansion of the cyst component. Little is known, however, about the mechanism of cyst formation. In this study the authors compared neuroimaging and histological characteristics of cystic with solid VS to determine the pathogenesis of the cystic subgroup.

Methods

Two cohorts, one comprising 10 patients with cystic VS and the other comprising 10 patients with solid VS, were studied. Surgery was chosen as the primary treatment in all patients, with no other modality applied. Preoperative magnetic resonance images and histological characteristics of the tumor in patients with cystic VSs were evaluated and compared with those in the group with solid VSs. Differences between the two groups were assessed using the chi-square test. Neuroimaging findings revealed that either fluid-fluid level or hemosiderin deposit was present in all cystic VSs. Histological evidence of microhemorrhage, such as hemosiderinladen macrophages (p = 0.069), hemosiderin deposits (p = 0.019), thrombotic vessels (p = 0.008), and abnormal vessel proliferation (p = 0.006) were more prominent in cystic VSs compared with solid ones. There was no difference in Antoni type dominance and Ki-67 proliferative index between the two groups.

Conclusions

Intratumoral microhemorrhage is a possible mechanism of pathogenesis in cystic VS.

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Dae Kyu Lee, Hee-Won Jung, Dong Gyu Kim, Sun Ha Paek, Ho-Shin Gwak and Gheeyoung Choe

✓ The authors present a case of postoperative spinal seeding of papillary craniopharyngioma. This 27-year-old man who had previously undergone subtotal removal of a suprasellar craniopharyngioma was admitted because of low-back and right leg pain. Results of neurological examination showed a limitation in straight-leg raising in the right side with no sensorimotor changes. Magnetic resonance imaging of the lumbar spine demonstrated multiple enhanced intradural extramedullary masses causing spinal cord compression. Pathological examination of the tumor tissue obtained via laminectomy revealed papillary craniopharyngioma, which had the same histological features as those of the previous suprasellar tumor. Several ectopic recurrences of craniopharyngioma have been reported; however, the authors believe that this is the first published report of the spinal seeding of craniopharyngioma.