Seung-Yeob Yang

Dongguk University, Seoul, Seoul, South Korea

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Publications (11)31.32 Total impact

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    Kwang-Moo Woo, Seung-Yeob Yang, Keun-Tae Cho
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    ABSTRACT: In patients with spontaneous intracerebral hemorrhage (ICH), the risk factors for seizure and the effect of prophylactic anticonvulsants are not well known. This study aimed to determine the risk factor for seizures and the role for prophylactic anticonvulsants after spontaneous ICH. Between 2005 and 2010, 263 consecutive patients with spontaneous ICH were retrospectively assessed with a mean follow-up of 19.5 months using medical records, updated clinical information and, when necessary, direct patient contact. The seizures were classified as early (within 1 week of ICH) or late (more than 1 week after ICH). The outcomes were measured with the Glasgow Outcome Scale at discharge and the modified Rankin Scale (mRS) at both 2 weeks and discharge. Twenty-two patients (8.4%; 9 patients with early seizures and 13 patients with late seizures) developed seizures after spontaneous ICH. Out of 263 patients, prophylactic anticonvulsants were administered in 216 patients. The prophylactic anticonvulsants were not associated with a reduced risk of early (p=0.094) or late seizures (p=0.326). Instead, the factors associated with early seizure were cortical involvement (p<0.001) and younger age (60 years or less) (p=0.046). The risk of late seizure was increased by cortical involvement (p<0.001) and communicating hydrocephalus (p=0.004). The prophylactic anticonvulsants were associated with a worse mRS at 2 weeks (p=0.024) and at last follow-up (p=0.034). Cortical involvement may be a factor for provoked seizures. Although the incidence of early seizures tended to decrease in patients prescribed prophylactic anticonvulsants, no statistical difference was found.
    Journal of Korean Neurosurgical Society 10/2012; 52(4):312-9. · 0.60 Impact Factor
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    ABSTRACT: Objectives: We investigated the radiosurgical outcomes of patients with nonbenign meningiomas retrospectively and sought to identify prognostic factors for local tumor control after radiosurgery with an emphasis on histopathology. Methods: Between 1998 and 2010, 35 patients with 49 atypical or anaplastic meningiomas were treated with radiosurgery. The mean tumor volume and marginal irradiation dose were 3.5 cm(3) (range 0.3-25.3) and 16 Gy (range 12-21), respectively. Results: The actuarial local tumor control rates for patients with atypical meningiomas at 1, 2 and 3 years after radiosurgery were 78, 53 and 36%, respectively, whereas those for anaplastic meningiomas were 35% at 1 year and 10% at 2 years. Multivariate analysis revealed that the mitotic count (≤8 per 10 high-power fields; HPF) and the MIB-1 proliferation marker labeling index (LI; ≤8%) were significant favorable prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas (p = 0.014 and p = 0.012, respectively). Conclusions: Radiosurgery could be a treatment option for patients with atypical meningiomas, but more aggressive treatments are needed for those with anaplastic meningiomas. Histopathological factors such as mitotic count and MIB-1 LI are significant prognostic factors for the radiosurgical outcomes of patients with nonbenign meningiomas and should be considered before radiosurgery.
    Stereotactic and Functional Neurosurgery 07/2012; 90(5):316-324. · 1.46 Impact Factor
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    ABSTRACT: To date, seizures in relation to arteriovenous malformations (AVM) have been a secondary target of most studies. The insufficient evaluation, in conjunction with the lack of consistent seizure outcome assessment, has made it been difficult to draw conclusions about seizure outcome after radiosurgery for AVM. This study aimed to determine the effect of radiosurgery on seizure outcome depending on AVM obliteration and on the development of new seizure in patients with AVM. Between 1997 and 2006, 161 consecutive patients underwent radiosurgery for unruptured AVM and were retrospectively assessed with a mean follow-up of 89.8 months by their medical records, updated clinical information, and, when necessary, direct patient contact. Seizure outcome was assessed using the Engel seizure frequency scoring system. Of the 86 patients with a history of seizure before radiosurgery, 76.7% (66/86) were seizure-free and 58.1% (50/86) were medication-free at the last follow-up visit. Of the patients who achieved AVM obliteration, 96.7% (58/60) were seizure-free while 30.8% (8/26) of those patients who did not achieve AVM obliteration were seizure-free (p = 0.001). The proportion of patients who were medication-free was 81.7% (49/60) of the patients with obliteration and 3.8% (1/26) of patients without obliteration (p < 0.001). Of the 75 patients with no history of seizure before radiosurgery, 10 had provoked seizures due to the direct and indirect radiosurgical influences after radiosurgery. Although radiosurgery tends to cause seizures temporarily, the radiosurgery may improve seizure outcomes in patients with AVM-related seizures, especially in patients with AVM obliteration.
    Neurology 03/2012; 78(17):1292-8. · 8.30 Impact Factor
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    ABSTRACT: Occipital neuralgia (ON) is a condition characterized by a paroxysmal stabbing pain in the area of the greater or lesser occipital nerves; it is usually regarded by clinicians as idiopathic. Some have suggested that ON can be induced by trauma or injury of the occipital nerves or their roots, but tumor has rarely been reported as a cause of ON. We report herein a case of foramen magnum meningioma in a 55-year-old woman who presented with ON triggered by head motion as the only symptom without any signs of myelopathy. This case indicates that it is important to consider the underlying causes of ON. Precise neurologic and radiological evaluations such as cervical spine magnetic resonance imaging are needed.
    Journal of Clinical Neurology 12/2009; 5(4):198-200. · 1.81 Impact Factor
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    ABSTRACT: Radiosurgery is an effective treatment option for patients with small to medium sized arteriovenous malformations. However, it is not generally accepted as an effective tool for larger (>14 cm(3)) arteriovenous malformations because of low obliteration rates. The authors assessed the applicability and effectiveness of radiosurgery for large arteriovenous malformations. We performed a retrospective study of 46 consecutive patients with more than 14 ml of arteriovenous malformations who were treated with radiosurgery using a linear accelerator and gamma knife (GK). They were grouped according to their initial clinical presentation-17 presented with and 29 without haemorrhage. To assess the effect of embolization, these 46 patients were also regrouped into two subgroups-25 with and 21 without preradiosurgical embolization. Arteriovenous malformations found to have been incompletely obliterated after 3-year follow-up neuroimaging studies were re-treated using a GK. The mean treatment volume was 29.5 ml (range, 14.0-65.0) and the mean marginal dose was 14.1 Gy (range, 10.0-20.0). The mean clinical follow-up periods after initial radiosurgery was 78.1 months (range, 34.0-166.4). Depending on the results of the angiography, 11 of 33 patients after the first radiosurgery and three of four patients after the second radiosurgery showed complete obliteration. Twenty patients received the second radiosurgery and their mean volume was significantly smaller than their initial volume (P = 0.017). The annual haemorrhage rate after radiosurgery was 2.9% in the haemorrhage group (mean follow-up 73.3 months) and 3.1% in the nonhaemorrhage group (mean follow-up 66.5 months) (P = 0.941). Preradiosurgical embolization increased the risk of haemorrhage for the nonhaemorrhage group (HR, 28.03; 95% CI, 1.08-6,759.64; P = 0.039), whereas it had no effect on the haemorrhage group. Latency period haemorrhage occurred in eight patients in the embolization group, but in no patient in the nonembolization group (P = 0.004). Radiosurgery may be a safe and effective arteriovenous malformation treatment method that is worth considering as an alternative treatment option for a large arteriovenous malformation.
    Acta Neurochirurgica 02/2009; 151(2):113-24. · 1.79 Impact Factor
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    ABSTRACT: The aim of the current study was to determine whether a pulmonary resection and gamma-knife radiosurgery (GKRS) protocol is superior to GKRS alone in selected patients with stage IV nonsmall-cell lung cancer (NSCLC). The authors performed a retrospective case-control study of 232 consecutive patients with newly diagnosed NSCLC from January 1998 to December 2005 and screened them to identify a study cohort in which all patients had thoracic stage I or II, Karnofsky performance status >or= 70, no extracranial metastases, and 1-3 synchronous brain metastases of less than 3 cm, and were treated with GKRS (n=31). The study cohort was divided into 2 groups, those with and without concomitant pulmonary resection. Sixteen patients with pulmonary resection were assigned to the treatment group and 15 without pulmonary resection were assigned to the control group. Median follow-up was 27.3 months (range, 4.4 months to 90.9 months). Mean survivals for the treatment group and the control group were 64.9 and 18.1 months, respectively (P< .001). There was a statistically significant association between pulmonary resection and better survival (OR=78.408). One-year and 5-year local brain tumor control rates were 97.1% and 93.5%, respectively. The pulmonary resection and GKRS protocol could prolong survival in patients with thoracic stage I or II NSCLC, no extracranial metastases, and a limited number of small synchronous brain metastases.
    Cancer 05/2008; 112(8):1780-6. · 4.90 Impact Factor
  • Seung-Yeob Yang, Dong Gyu Kim, Hyun-Tai Chung
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    ABSTRACT: Stereotactic radiosurgery offers a broad spectrum armamentarium for the safe treatment of various lesions within the central nervous system. Radiosurgery uses stereotactic targeting methods to precisely deliver highly focused, large doses of radiation to small intracranial tumors and arteriovenous malformations (AVMs). It is widely used for the treatment of metastatic brain tumors, non-resectable tumors, residual or recurrent benign and malignant tumors as well as for the treatment of AVMs, functional diseases, and pain disorders. Although radiosurgery has the potential to produce complications, the majority of patients experience clinical improvement with less morbidity and mortality than those occur in surgical resection.
    Journal of the Korean Medical Association 01/2008; 51(1):27. · 0.18 Impact Factor
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    ABSTRACT: The authors describe a modified technique of encephaloduroarteriosynangiosis (EDAS) with bifrontal encephalogaleoperiosteal synangiosis (EGPS) and present the preliminary results of the procedure. Between January 2004 and June 2005 the authors performed modified EDAS with bifrontal EGPS in 17 patients with moyamoya disease. Surgical results were evaluated in terms of clinical outcomes, changes visible on neuroimages, extent of revascularization noted on angiograms, and hemodynamic changes demonstrated on single-photon emission computed tomography (SPECT) scans. The follow-up period ranged from 6 to 21 months (mean 11.5 months). The overall clinical outcomes were excellent or good in 15 patients (88.2%) and poor in two (11.8%). The overall morbidity rate was 5.9% (one of 17 patients). Based on changes in the anterior cerebral artery (ACA) and middle cerebral artery (MCA) territories after surgery, as shown on SPECT scans following administration of acetazolamide, 14 patients (82.4%) exhibited an improved vascular reserve capacity in both the ACA and MCA territories. It is the authors' opinion that wide covering of the cortex is necessary for sufficient revascularization. In the present study they demonstrate that modified EDAS with bifrontal EGPS is a safe and efficient surgical approach that covers not only the MCA territory but also the ACA territory.
    Journal of Neurosurgery 04/2007; 106(3 Suppl):237-42. · 3.23 Impact Factor
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    ABSTRACT: The visual outcome in patients with tuberculum and diaphragm sellae meningiomas treated with microsurgery was evaluated. Prognostic and diagnostic values of short- and long-term postoperative visual outcome and etiology for postoperative visual deterioration are discussed with special attention. Clinical data for 30 surgically treated patients with tuberculum and diaphragm sellae meningiomas were reviewed retrospectively. The mean duration of the follow-up period was 75.9 months (range, 12-151 mo). Mean tumor diameter and volume was 25.9 mm (range, 16.3-63.3 mm) and 12.4 cm (range, 2.3-125.6 cm). A visual impairment score was used to assess the short-term (< or =2 wk after surgery) and the long-term (>6 mo after surgery) postoperative visual outcome. Various predictive factors for visual outcome were tested statistically. Complete resection was achieved in 23 out of 30 (76.7%) patients. Average preoperative, short- and long-term visual impairment scores were 48.2, 43.4, and 40.9, respectively. Favorable visual outcome was achieved in 80% of patients in the short term and 70% in the long term. Short-term postoperative aggravation of visual function was an ominous sign of further aggravation or at least of little hope for recovery, whereas there was a tendency to improve in the long term if short-term postoperative visual function showed favorable outcome. Recurrence or regrowth of tumor fully was responsible for late deterioration of visual function. No significant prognostic factor for visual outcome could be found. Short-term postoperative visual outcome was a strong indicator of permanent visual outcome after surgery for tuberculum sellae and diaphragm sellae meningiomas.
    Neurosurgery 08/2006; 59(2):238-43; discussion 238-43. · 3.03 Impact Factor
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    ABSTRACT: Radiation-induced glioblastoma multiforme (GBM) is a rare complication of radiotherapy. The authors report such a case occurring 10 years after treatment of cerebellar medulloblastoma. The patient was a 15-year-old boy who had undergone a gross-total removal of a medulloblastoma and received radiation therapy at the age of 5 years. He had experienced no tumor recurrences for 10 years until a new enhancing mass was found at the original site of the medulloblastoma. Following its resection the new lesion was found to be a GBM and there was no evidence of a medulloblastoma. The second tumor developed at the same site as the previous one after a sufficient latent period and fulfilled the criteria for a radiation-induced neoplasm. The original tumor cells expressed synaptophysin without p53 overexpression, a characteristic feature of medulloblastomas. In contrast, cells from the later tumor expressed glial fibrillary acidic protein and p53 but not synaptophysin. A sequence analysis of the p53 gene showed deletion at codon 233 and a C to G transition at codon 278 in the GBM but no mutation in the medulloblastoma. A GBM specimen revealed no amplification of the epidermal growth factor receptor compared with a normal control specimen. In conclusion, the clinical features of a radiation-induced GBM are similar to that of the primary GBM, whereas its genetic alterations render it a secondary GBM. These findings indicate that radiation-induced GBM should be considered a distinct clinical entity.
    Journal of Neurosurgery 06/2005; 102(4 Suppl):417-22. · 3.23 Impact Factor
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    ABSTRACT: Paragangliomas of the cauda equina are rare neuroendocrine tumors. Four cases of nonsecreting paraganglioma of the cauda equina, preoperatively misdiagnosed as neurinoma, are presented with an emphasis on the correlation between magnetic resonance imaging findings and pathological features. Although it is difficult to correctly diagnose paraganglioma preoperatively for intradural extramedullary tumors, especially in the cauda equina, paraganglioma should be included in differential diagnoses.
    Journal of Neuro-Oncology 04/2005; 72(1):49-55. · 2.79 Impact Factor