Biomedical subjects

Young-Seob Chung

Publications and source records attributed to Young-Seob Chung.

4 recordsLinked to original sources

PubMed2006

Optimal extent of resection in vestibular schwannoma surgery: relationship to recurrence and facial nerve preservation.

Surgical treatment of vestibular schwannoma is targeted at complete removal with preserved neurological function. Complete removal may cause significant deficits, whereas subtotal tumor removal is associated with a high recurrence rate. The present study assessed the risk of tumor recurrence and postoperative facial nerve function in relation to the extent of surgical resection by reviewing the clinical records and radiological findings of 116 patients with vestibular schwannoma treated between 1990 and 1999. The extent of resection was classified as follows: gross total resection (GTR), near total resection (NTR), and subtotal resection (STR). Facial nerve function was graded using the modified House-Brackmann grade, and patients grouped into good (grades 1-2) and intermediate or poor (grades 3-6). Of the 116 patients, 26 (22%) underwent GTR, 32 (28%) NTR, and 58 (50%) STR. The recurrence rates were 3.8% (1/26 cases), 9.4% (3/32), and 27.6% (16/58) for GTR, NTR, and STR, respectively. GTR and NTR showed no statistically significant difference in terms of recurrence rate (p=0.620). However, recurrence was significantly less after NTR than STR (p=0.043). Immediately postoperative facial nerve function was good in 15.4% of patients after GTR, 40.6% after NTR, and 46.6% after STR. The STR and NTR carried a lower risk of facial nerve palsy than GTR in the immediately postoperative stage (p=0.006 and 0.036, respectively). Nevertheless, no statistical significance was observed in extent of resection and postoperative facial nerve outcome between the groups at last follow up (p=0.227). GTR is the ideal surgical treatment for vestibular schwannoma, but NTR is a good option, with better facial nerve function preservation than GTR without significantly increasing the risk of recurrence.

Adult↗

PubMed2005

Aggressive vestibular schwannomas showing postoperative rapid growth - their association with decreased p27 expression.

Vestibular schwannomas (VSs) are relatively slow growing tumors. However, some rapidly regrow or recur after surgical resection. The objective of this study was to identify those molecular characteristics predicting rapid recurrence after surgical resection. Immunohistochemically determined expressions of several cell cycle regulators and apoptosis-associated proteins in 12 cases of aggressive VS (AVS) and in 15 control cases of usual VS (UVS) cases were compared. The expressions of p53 and Bax (pro-apoptotic protein), Bcl-2 (anti-apoptotic protein), Fas, and Fas-L (apoptotic death receptor and ligand), caspase 3 (apoptotic effector caspase proteins), and p27 and p21 (cyclin-dependent kinase inhibitors) were analyzed using tissue array blocks. Loss of p27 expression was observed in 8 of 12 AVS cases (67%) and in 3 UVS cases (20%); p21 was expressed in all cases. Loss of Bax was observed in 3 AVS and 3 UVS cases. The anti-apoptotic protein, Bcl-2, was expressed in 9 AVS (75%) and 11 UVS (73%), and p53, Fas-L, and caspase 3 were negative and Fas was positive in all AVS and UVS cases. Of these, only the loss of p27 was statistically significant (P = 0.02). The loss of p27 in AVS may explain the unusually high proliferative potential of AVS versus UVS, and p27 may be a predictor of VS aggressiveness. The expressions of other apoptosis associated proteins were not significantly different in the two groups. This may be the first report to identify a molecular entity associated with aggressive VS. However, further studies are required.

Cell Proliferation↗

PubMed2004

Involuntary movement induced by cerebral ischemia: pathogenesis and surgical outcome.

OBJECT: Involuntary movement is an uncommon manifestation of a transient ischemic attack. It may be induced by cerebral hemodynamic insufficiency, which is associated with several cerebral ischemic diseases. The authors present three cases of limb shaking due to moyamoya disease (MMD) or radiation-induced middle cerebral artery stenosis, and three additional cases of choreic movement due to MMD. Neuroimaging studies and surgical outcomes in these patients were retrospectively analyzed to investigate the pathological mechanism underlying the symptoms and to provide guidance for the management of involuntary movement disorders in cases of ischemic cerebral disease. METHODS: The patient population included two children and four adults with ages at presentation ranging between 7 and 50 years. The initial presenting symptoms were involuntary movements in all six cases. A magnetic resonance imaging finding common in all cases was a small infarct in the frontal corona radiata, which did not extend to the cortex or basal ganglia. A perfusion defect in the frontoparietal cortical and subcortical regions was demonstrated by single-photon emission computerized tomography in all patients. Improved hemodynamic circulation in the frontoparietal cortical and subcortical regions occurred in parallel with clinical improvement following indirect or direct bypass surgery. CONCLUSIONS: Ischemic dysfunction of the frontal cortical and subcortical motor pathways rather than that of the basal ganglia was suspected to be the cause of the observed contralateral involuntary movements. Direct and indirect bypass surgery can be used effectively to treat involuntary movements in patients with cerebral ischemic diseases such as MMD and in those with stenosis of an intracranial major artery.

Adolescent↗

PubMed2002

Vertebrobasilar dissection: a possible role of whiplash injury in its pathogenesis.

We reviewed 29 patients with vertebrobasilar dissections (VBD) to investigate the correlation between minor trauma and VBD and the clinical features of this trauma-related condition. Mean age was 43 years, with a male predominance (male/female ratio was 25/4). Seventeen patients presented with subarachnoid hemorrhage (SAH), and 12 with ischemic symptoms. Two patients presenting with ischemia had extracranial VBD (V3 segment). Angiographically, aneurysmal dilatation was observed in most SAH patients (13 patients) in contrast to narrowing or occlusion in most ischemic patients (10 patients). Among the 12 SAH patients treated with coil embolization or conservatively, five died, whereas all ischemic patients recovered well with anticoagulation and/or antiplatelet therapy. Seven patients had received minor or trivial head/cervical trauma, due to whiplash injury, minor fall, or during exercise, which were identified to precede with the lapse of some time (a few minutes or days) the onset of symptoms. All of these patients presented with ischemic symptoms, and they were younger than the other ischemic or SAH patients. The site of vertebral artery dissection was intracranial in four cases, extracranial in one case, and combined in two cases at the level of the V3 segment and the origin of the posterior inferior cerebellar artery. However, no SAH occurred. These clinicopathological findings, i.e. ischemia and angiographic narrowing/occlusion, suggest that dissections were subintimal. Therefore, it is believed that this minor or trivial trauma may primarily cause subintimal dissection with luminal compromise, leading to ischemic symptoms, rather than subadventitial or transmural dissection with aneurysmal dilatation, leading to SAH. This lesion may also occur in younger patients with a favorable outcome. Careful note should be made of patient for the early recognition of this disorder.

Adolescent↗