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Sung-Kyun Hwang

Publications and source records attributed to Sung-Kyun Hwang.

10 recordsLinked to original sources
PubMed2006

Feasibility and limitations of endovascular coil embolization of anterior communicating artery aneurysms: morphological considerations.

OBJECTIVE: The purpose of this study is to analyze anterior communicating artery (AComA) aneurysm morphology and its relationship to the limitations and feasibility of endovascular coil embolization. METHODS: One hundred twenty-three patients were treated with endovascular coil embolization for AComA aneurysms. Aneurysm morphology was classified into six categories according to the projection of the aneurysm (anterior, posterior/superior, or inferior) and neck size (< 4 mm or >or= 4 mm). The following categories were used: Class A1, anterior projection and neck of aneurysm less than 4 mm; Class A2, anterior projection and neck of aneurysm 4 mm or more; Class B1, posterior (superior) projection and neck of aneurysm less than 4 mm; Class B2, posterior (superior) projection and neck of aneurysm 4 mm or more; Class C1, inferior projection and neck of aneurysm less than 4 mm; and Class C2, inferior projection and neck of aneurysm 4 mm or more. Endovascular procedures were categorized as either successful or unsuccessful according to specific criteria. In addition, patients were followed for recanalization. Clinical follow-up data was obtained at discharge and after 6 months and was classified according to the Glasgow Outcome Scale. RESULTS: Complete or near complete aneurysm occlusion was observed in 108 (88%) patients, partial embolization was performed in three (2.4%) patients, and embolization was attempted in 12 (9.7%) patients. Successful embolization for AComA aneurysms was performed in 86 out of 123 (70%) patients or 77.5% (86 out of 111 patients) of those patients in whom embolization was possible. Statistical analysis demonstrated that anterior projecting aneurysms were more likely to be successfully coiled than either inferior or posterior/superior directed AComA aneurysms. In addition, inferiorly projecting AComA aneurysms and wide-neck aneurysms had a significantly higher rate of recanalization. CONCLUSION: Endovascular coil embolization of AComA aneurysms shows good outcome in our study. Despite advanced modern techniques, there are limitations in the endovascular approach to AComA aneurysms. Consideration of aneurysm morphology may be used to guide approaches in the treatment of AComA aneurysms.

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

Guidelines for the ligation of the sigmoid or transverse sinus during large petroclival meningioma surgery.

The authors present guidelines for the ligation of the transverse or sigmoid sinus during the surgical removal of petroclival meningiomas. The medical records and venograms of 14 patients with a petroclival meningioma requiring transverse or sigmoid sinus ligation treated in the Department of Neurosurgery, Seoul National University Hospital between 1986 and 1999 were reviewed. All patients successfully received a sinus trial clamping during the operation. The drainage pattern of the confluens of Herophili was classified into four types: Type A, confluens and equal on both transverse sinuses; Type B, confluens and nondominant transverse sinus on the tumor side; Type C, confluens and dominant transverse sinus on the tumor side; and Type D, unilateral transverse sinus only. Of the 14 cases, four were Type A, five were Type B, and two were Type C. There was no brain swelling after intraoperative test clamping of the sinus for more than 30 minutes. None of the cases developed postoperative complications related to the sinus ligation. Patients with Type A, B, or C drainage patterns were ideal candidates for sinus ligation, especially transverse sinus ligation, if the test clamping proved to be safe. The sinus was cut proximal to the superior petrosal sinus, distal to the vein of Labbé.

Journal Article↗
PubMed2003

Meningeal hemangiopericytomas: long-term outcome and biological behavior.

BACKGROUND: The authors present a retrospective clinical analysis of meningeal hemangiopericytomas. The long-term outcome and biologic behavior, including local recurrence and extraneural distant metastasis, are elucidated. METHOD: Clinical records and radiologic findings of 31 cases with meningeal hemangiopericytoma treated at Seoul National University Hospital and Asian Medical Center between 1982 and 1999 were carefully reviewed. The final outcome was determined by direct or phone contact and questionnaire by mail. The duration of follow-up was from 1 to 216 months (mean 77). All patients underwent craniotomy and Simpson Grade I or II resection was possible in 24 patients. Conventional radiotherapy was given in 11 patients (in 5 after total excision and in 6 for residual mass) and stereotactic radiosurgery was conducted in 6 cases. RESULTS: Intracranial recurrence was seen in 12 cases (38.7%) and the mean period before the first recurrence was 104 months. The recurrence was at the primary site in 11 cases and diffuse leptomeningeal seeding occurred in the remaining case. The 5-year recurrence free rate was 59.2% and the extent of excision was the significant factor (72.7% in total excision group and 20.8% in the incomplete excision group, p = 0.006). In four patients (12.9%), extraneural metastases developed at an average of 107 months. Six patients died during the follow-up period; however, 2 of these died of unrelated causes. CONCLUSIONS: Complete excision is the most important factor in reducing recurrence. However, recurrence may occur even after complete excision. Careful long-term follow-up is mandatory because of the long disease-free interval.

Adult↗
PubMed2003

Long-term outcome of trigeminal neurinomas with modified classification focusing on petrous erosion.

BACKGROUND: The authors present a retrospective analysis of 29 consecutive patients with trigeminal neurinomas. Modified classification based on the tumor distribution over petrous ridge is suggested to select the optimal surgical approach and to predict the outcome. METHODS: Preoperative computed tomography (CT) or magnetic resonance (MR) images were analyzed to measure a long diameter of tumor axis (LD), which divided into middle and posterior fossa and a width of the petrous erosion (PW) by the tumor on axial image. The tumors were classified into four groups (M, tumor confined to middle fossa; Mp, tumor mainly in middle fossa; M = P, tumor equally distributed into both middle and posterior fossa; Pm, tumor mainly in cisternal space of posterior fossa with slender, rarely round extension into Meckel's cave), and extent of removal was compared between the groups. Long-term outcomes were based on recurrence-free survival. RESULTS: Total removal was achieved in 16 patients including stage operation (55%). Excluding three tumors, which underwent gamma knife for residual tumor, 8 of 10 subtotally removed tumors recurred at 50 months on average. The LD and PW are significantly different among the tumor types. The M = P type is the largest in both parameter, while the M type is the smallest in LD; Pm type is the smallest in PW, respectively. The tumors with equal or lager posterior fossa component (M = P and Pm type) were more difficult to remove totally by single attempt than those with smaller or nil posterior fossa mass (Mp and M type). Also, the corrected PW (PW over the tumor diameter of minor portion) shows a tendency to influence the extent of removal as the relatively narrow PW hindered the total removal. CONCLUSIONS: Aggressive attempt for total removal using skull base approach is recommended, especially for those having dominant posterior fossa component and for those having relatively narrow PW.

Adolescent↗
PubMed2003

A case of recurrent subependymoma with subependymal seeding: case report.

Subependymoma is a rare, slow growing, rarely recurrent tumor. We report a case of re current subependymoma with subependymal seeding. An intraventricular tumor in the left temporal horn was detected in a 48-year-old female who presented with a 4-year history of dizziness and memory disturbance. Following near total surgical resection, a tumor diagnosis of subependymoma was confirmed by scattered clusters of isomorphic nuclei embedded in a dense fibrillary matrix of glial cell processes. Twenty-six months after surgery, follow-up (F/U) magnetic resonance (MR) imaging revealed tumor recurrence in the previous site which necessitated linear accelerator radiosurgery (LINAC). A further 21 months later, F/U MR imaging showed recurrent, multiple, enhanced, nodular lesions in the enlarged left lateral ventricle for which the patient underwent reoperation. Radiological and operative findings revealed local relapse with subependymal seeding. The pathological finding was similar to that of the previous tumor and compatible with subependymoma. The patient underwent radiation therapy for the residual tumor. This case history suggests that symptomatic residual tumors require close observation even though the clinical course of subependymoma is usually benign.

Brain Neoplasms↗
PubMed2002

Olfactory neuroblastomas: survival rate and prognostic factor.

Olfactory neuroblastomas are known to be rare and clinically malignant tumors. The authors analyzed the clinical features, long-term treatment outcomes, and prognostic factors related to 21 cases of olfactory neuroblastomas, treated between January 1979 and October 2000, retrospectively reviewed with medical records and radiologic findings. The mean follow-up period was 28.7 months (range 4-178). The extent of tumor was classified according to the UCLA staging system. Statistical analysis for survival was done using the Kaplan-Meier method and the log-rank test. The mean age was 27 years (13-62), the peak incidence occurred in the second decade (8/21, 38%), and the male to female ratio was 13:8. According to the UCLA staging system, there were 3 cases of T1, 5 of T2, 6 of T3, and 7 of T4. The 5-year survival rate was 21.3% and the average survival time was 28.9 months. The group (n = 14) undergoing radical surgical resection as the primary modality, registered a higher survival rate than the radiation and chemotherapy group (n = 7), with 2-year survival rates being 76.2% vs. 14.3%, respectively (p = 0.0274). The early stage (T1, T2) groups exhibited a better survival rate than the advanced (T3, T4) groups with 5-year survival rates being 38.1% vs. 9.1%, respectively (p = 0.0336). The mean recurrence free time was 7.8 months (range 1-25). From these findings we could conclude that tumor detection in the early stage, radical surgical resection as the primary treatment modality, and regular follow-up with radiologic evaluation for recurrence or metastasis, represent important factors for an improved outcome.

Adolescent↗
PubMed2002

The experience of ligation of transverse or sigmoid sinus in surgery of large petroclival meningiomas.

The authors present the experience of ligation of transverse or sigmoid sinus in the surgical removal of petroclival meningiomas. We reviewed the medical records and venograms of 14 patients with petroclival meningiomas, in whom the intraoperative ligation of transverse or sigmoid sinus had been done at our hospital between 1986 and 1999. All patients passed the intraoperative test clamping of the sinus. The drainage pattern of confluence of Herophili was classified into four types: type A, confluence and equal drainage on both transverse sinuses; type B, confluence and non-dominant transverse sinus on the tumor side; type C, confluence and dominant transverse sinus on the tumor side; and type D, unilateral transverse sinus only. Among the 14 cases, four cases were in type A, five cases in type B, and two were type C. There was no evidence of brain swelling after intraoperative test clamping of the sinus for more than 30 min. None of the patients experienced postoperative complications related with sinus ligation. Our observation suggests that the transverse or sigmoid sinus ligation is tolerable to patients who show the drainage patterns of type A, type B, and type C, if the test clamping proves to be safe.

Adolescent↗
PubMed2002

Aggressive vestibular schwannomas with postoperative rapid growth: clinicopathological analysis of 15 cases.

OBJECTIVE: Vestibular schwannomas (VSs) are known to be relatively slow-growing tumors. Some VSs, however, rapidly regrow or recur after surgical resection. Our objective was to investigate the clinicopathological characteristics of these tumors and to elucidate factors that can predict rapid regrowth or recurrence after surgical resection. METHODS: Between 1978 and 2000, 29 patients with VS underwent reoperation for regrowth or recurrence at the Department of Neurosurgery in Seoul National University Hospital. Among these patients, 15 experienced rapid VS regrowth or recurrence (annual growth rate, >15 mm/yr). The clinical, radiological, operative, and pathological findings were reviewed. For a comparison of the morphology and proliferative activity, 15 cases of VS were randomly selected as a control group from among the consecutive operative cases with tumor size larger than 4 cm treated between 1991 and 1999. Pathological parameters consisting of cellularity, pleomorphism, mitosis, necrosis, invasion to adjacent tissue, and microvascular proliferation were analyzed. Proliferative indices (e.g., Ki-67 index) also were evaluated. Statistical analyses were performed using Fisher's exact test and the analysis of variance test. RESULTS: The differences in clinical features between the aggressive VS group and the control VS group were nonspecific. The mean ages at diagnosis were 40.6 years (range, 21-63 yr) and 49.7 years (range, 35-67 yr) (P = 0.438), and the male-to-female ratios were 7:7 and 5:10 (P = 0.462), respectively. The clinical symptoms and signs were similar between the two groups. Radiologically, aggressive tumors at initial presentation had more lobulating contours than those in the control group (7 of 13 cases versus 3 of 15 cases; P = 0.001). In pathological findings, cellularity and pleomorphism were significantly higher than those in the control group (P = 0.001). However, mitosis, necrosis, invasion to adjacent tissue, and microvascular proliferation were not different between the two groups. The proliferative index (Ki-67 index) was higher in the aggressive group than in the control group (2.28 [range, 0.1-8.6] versus 0.59 [range, 0-1.5]; P = 0.034). CONCLUSION: VSs presenting with lobulating contour, high proliferative index (Ki-67 index), and high cellularity or pleomorphism require frequent radiological investigation during follow-up to facilitate early detection of regrowth or recurrence.

Adult↗