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ABSTRACT: The seizure network may be different between temporal lobe epilepsy with hippocampal sclerosis (TLE+HS) and without HS (TLE-HS). Chronic seizure activity may alter the diffusion properties of a seizure network. The thalamus is known to have an anatomical connection to the medial temporal area and to play a role in seizure modulation. This study aimed to evaluate differences in thalamic changes between TLE+HS and TLE-HS with diffusion tensor imaging (DTI).
Nine patients with TLE+HS and nine patients with TLE-HS were included in the study. All patients underwent surgery with good seizure outcomes. Hippocampal sclerosis was verified pathologically. Sixteen right-handed, normal subjects were enrolled as controls. DTI was acquired using 3.0 T MRI. The mean diffusivity (MD) and fractional anisotropy (FA) were calculated in the center of the bilateral thalamus with the DTIstudio program.
The MD of bilateral thalami increased in both TLE groups compared to controls (p<0.05), while FA values did not differ from controls. The MD of the thalamus ipsilateral to the epileptogenic side was higher in the TLE+HS group than in the TLE-HS group (p=0.007). Onset age, seizure duration, seizure frequency and total seizure number were not correlated with FA and MD changes (p>0.05).
Bilateral thalamic diffusion properties are altered in temporal lobe epilepsy. The presence of hippocampal sclerosis enhances the change ipsilaterally.
Epilepsy research 03/2010; 90(1-2):21-7. · 2.48 Impact Factor
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ABSTRACT: The aim of this study was to describe a novel technique for laminoplasty in which translaminar screws are used in the thoracic and lumbar spine.
The authors first performed a morphometric study in 20 control individuals using 3D reconstructed CT scans and spine simulation software to measure the lengths and diameters of the spaces available for translaminar screw placement from the T-1 to S-1. Based on the results of the morphometric study, the authors then attempted translaminar screw fixation in 5 patients (April 2007-July 2007) after en bloc laminectomy in the thoracic and lumbar regions. All patients had intradural lesions: 3 schwannomas, 1 cavernoma, and 1 arachnoid cyst.
The morphometric study in control individuals revealed that the safe trajectories for simulated screws measured 25-30 mm in length and 8-11 mm in diameter in the thoracic region (T1-12) and 26-34 mm in length and 6-7 mm in diameter in the lumbosacral region (L1-S1). This morphometric and simulation study showed that translaminar screw placement would be possible in practice. Five patients underwent en bloc laminoplasty and translaminar screw fixation in which the screws measured 2.7 mm in diameter and 24 or 26 mm in length. Sixteen attempts at translaminar fixation were made in 8 vertebrae. Fourteen translaminar screws were successfully placed at the thoracic and lumbar levels. Two microplates had to be used because the laminae were too thin and narrow after further laminectomy with undercutting. There were no complications associated with the translaminar screws. The mean follow-up period was 14.5 months. There was no screw breakage or displacement. Solid osseous fusion was documented in 2 patients who underwent CT scanning 15 months postoperatively.
The authors found that the laminoplasty and translaminar screw technique is feasible in the thoracic and lumbar regions, but further studies are needed to analyze the biomechanical effects and long-term outcomes in a large number of patients.
Journal of Neurosurgery Spine 07/2009; 10(6):603-9. · 1.53 Impact Factor
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ABSTRACT: Functional magnetic resonance imaging (fMRI) is frequently used to localize language areas in a non-invasive manner. Various paradigms for presurgical localization of language areas have been developed, but a systematic quantitative evaluation of the efficiency of those paradigms has not been performed. In the present study, the authors analyzed different language paradigms to see which paradigm is most efficient in localizing frontal language areas.
Five men and five women with no neurological deficits participated (mean age, 24 years) in this study. All volunteers were right-handed. Each subject performed 4 tasks, including fixation (Fix), sentence reading (SR), pseudoword reading (PR), and word generation (WG). Fixation and pseudoword reading were used as contrasts. The functional area was defined as the area(s) with a t-value of more than 3.92 in fMRI with different tasks. To apply an anatomical constraint, we used a brain atlas mapping system, which is available in AFNI, to define the anatomical frontal language area. The numbers of voxels in overlapped area between anatomical and functional area were individually counted in the frontal expressive language area.
Of the various combinations, the word generation task was most effective in delineating the frontal expressive language area when fixation was used as a contrast (p<0.05). The sensitivity of this test for localizing Broca's area was 81% and specificity was 70%.
Word generation versus fixation could effectively and reliably delineate the frontal language area. A customized effective paradigm should be analyzed in order to evaluate various language functions.
Journal of Korean Neurosurgical Society 05/2009; 45(4):219-23. · 0.60 Impact Factor
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ABSTRACT: Anterior cervical discectomy and fusion (ACDF) is currently the standard treatment for cervical disc disease. Some patients wish to be treated with a less invasive method, because of their social/physical situations. Here we present one method of treatments for socially/physically active patients. Three patients had triceps weakness and mild posterior neck pain. The offending lesions were at the C6-7 level. All were middle-aged soldiers with families. If conventional ACDF were performed, they would have to retire from the military according to the regulation. They had to be able to perform military drills after the treatment if they were going to be able to keep their jobs. Because of their social/physical situations, all wanted to choose method with that they could treat the disease and keep their jobs. For these reasons, the posterior cervical endoscopic discectomies were performed. Ruptured fragments were successfully removed in all. The arm pain improved by more than 90% in two patients by 7 days and in the other patient by 2 months, respectively (excellent outcome by Macnab's criteria). None of the operations caused instability. All of the patients are currently able to successfully perform their military drills without difficulty. The posterior cervical endoscopic discectomy may be a promising alternative for the physically/socially active patients.
Journal of Korean medical science 05/2009; 24(2):302-6. · 0.84 Impact Factor
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ABSTRACT: Recently, diffusion tensor (DT) imaging was introduced to demonstrate white matter tracts. However, research interest has focused on the anatomical rather than the functional aspects of this imaging modality. The authors undertook a functional analysis of DT imaging to determine the relationship between weakness and changes on DT images.
Diffusion tensor images were obtained in 23 patients with lesions located adjacent to the pyramidal tract. Patients were classified according to their motor deficit. Axial magnetic resonance image sections through the maximum tumor diameters were selected and the mean apparent diffusion coefficients (ADCs) and mean fractional anisotropies (FAs) were measured. One ovoid region of interest (ovROI) was placed in the center of the pyramidal tract and another was designed to include the whole pyramidal tract at the same axial level (wROI). To determine intraobserver variability, a single neurosurgeon measured mean ADCs and FAs four times by using these two different ROI types without knowledge of any clinical information. To determine interobserver variability, a second neurosurgeon who was also unaware of any clinical information measured the mean ADCs and FAs by using the wROI method. The five measurements produced the same results. The mean FA at the lesion side of the pyramidal tract was significantly lower in patients with weakness (p < 0.01). Little intraobserver measurement variability occurred using the ovROI method, and no interobserver variability occurred using the wROI method.
Motor weakness was significantly related to a low mean FA in the pyramidal tract on the lesion side. Designing an ROI that includes the whole pyramidal tract is an easier and more reproducible method than using an ovROI method.
Journal of Neurosurgery 02/2007; 106(1):111-8. · 2.96 Impact Factor
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ABSTRACT: 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.
Neurologia medico-chirurgica 05/2006; 46(4):176-80; discussion 180-1. · 0.61 Impact Factor
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ABSTRACT: Parietal lobe epilepsy (PLE) is neither common nor easily diagnosed because of its variable clinical features. To elucidate its characteristics and surgical outcome, the authors reviewed their surgical experiences.
Between September 1994 and August 2001, 38 patients with PLE received surgical treatment at the Seoul National University Hospital. All patients underwent resection, mainly involving the parietal lobe.
Preoperatively, over 60% of the cases were not considered to be PLE, even though PLE was the most common diagnosis (15/38, 39.8%). An invasive study was performed in 37 of the 38 patients. Awake operations under regional anesthesia were performed in 20 patients (52.6%). Seizure disappeared in 15 (Engel's classification I, 39.5%), and rare seizure remained in 5 (Engel II, 13.2%). Thirteen patients showed a worthwhile improvement (Engel III, 34.2%), whereas 5 exhibited no worthwhile improvement (Engel IV, 13.2%). Pathologies were diverse, the most common being cortical dysplasia (94.3%).
Since PLE is difficult to diagnose preoperatively, an invasive study covering the parietal lobe is mandatory, if PLE is suspected. Cortical dysplasia was the most common etiology, thus awake operation under regional anesthesia and intraoperative brain mapping is helpful during extensive resection in order to spare the eloquent cortex.
Stereotactic and Functional Neurosurgery 02/2004; 82(4):175-85. · 1.85 Impact Factor
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ABSTRACT: Case report.
To report three cases of spinal intramedullary lipoma seen in the last 10 years and present the clinical characteristics and surgical outcome of these cases.
Two patients were boys aged 12 years and 7 months, respectively. The other was a female patient aged 6 months. Chief complaints were hemiparesis, back swelling and thoracic scoliosis. All patients were diagnosed with magnetic resonance images. The lesion was located in the cervico-thoracic spine (foramen magnum to T1) in one case, thoracic spine (T9-T12) with the back swelling at L2-4 level in the second, and in the third, one mass extended from C6 to T11 and the other mass was located in the L1-2 level, separately.
All masses were removed subtotally and dysraphism was absent. Postoperatively, neurological status of the first and the second patient were unchanged, but in the third case weakness was transiently aggravated.
Intramedullary lipoma is a rare spinal lesion and multiple intramedullary lipoma is extremely rare. Treatment principle is surgical decompression before symptom progression. Laminoplastic laminotomy is an appropriate approach for decompression of an intramedullary lipoma.
Spinal Cord 06/2003; 41(5):310-5. · 1.80 Impact Factor
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ABSTRACT: The language pathways consist of ventral and dorsal systems connected via the uncinate fasciculus and arcuate fasciculus, respectively. Seizures in medial temporal lobe epilepsy (mTLE) affect both tracts. Previous studies, however, have focused on the arcuate fasciculus to explain the language disturbance in mTLE. In contrast, we compared changes in both the uncinate and arcuate fasciculi using diffusion tensor imaging.
Thirteen patients with left mTLE and 12 with right mTLE were studied. The Wada test showed left dominance for language in all these patients. Sixteen healthy right-handed subjects were also studied. The mean fractional anisotropy and mean apparent diffusion coefficient with their lateralization index of two fasciculi were compared between hemispheres and between subjects.
The mean apparent diffusion coefficient of the arcuate and uncinate fasciculi in both left- and right-mTLE patients increased bilaterally compared with that in healthy subjects. In left mTLE, the fractional anisotropy of the uncinate fasciculus was lower ipsilaterally (P = 0.002) and was significantly lateralized contralaterally (P < 0.001) compared with control subjects, whereas the fractional anisotropy of the arcuate fasciculus showed no lateralization (P = 0.577). In right mTLE, such a difference was not prominent.
The seizure network affects both arcuate and uncinate fasciculi bilaterally in both left- and right-mTLE patients. The change is most prominent in the left uncinate fasciculus in left mTLE.
World Neurosurgery 75(3-4):509-16. · 0.68 Impact Factor
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ABSTRACT: Established in 1957, the Department of Neurosurgery at Seoul National University College of Medicine is the one of the oldest neurosurgical departments in Korea. The seven past Chairmen (Bo Sung Sim, Kil Soo Choi, Dae Hee Han, Byung-Kyu Cho, Hyun Jib Kim, Hee-Won Jung, and Dong Gyu Kim) have devoted themselves to the development of the department. The current chair, Chun Kee Chung, assumed the position in July 2010. The current department comprises several clinical programs that encompass the entire spectrum of neurosurgical disorders, with 29 specialized faculty members and care teams in three hospitals: Seoul National University Hospital (SNUH), Boramae Medical Center (BMC), and Seoul National University Bundang Hospital (SNUBH). The remarkable growth of the department during the last half century made it possible to perform 5,666 operations (3,299 at SNUH, 411 at BMC and 1,860 at SNUBH) during 2009. A total of 1,201 articles authored by faculty members were published in scientific journals between 1958 and 2009, approximately 32% of which were published in international journals. The department is regarded as the "Mecca" of neurosurgery in Korea because of its outstanding achievement and the many distinguished alumni with leadership roles in the academic field. This article traces the clinical, academic, and scientific development of the department, its present activities, and its future direction.
World Neurosurgery 75(3-4):397-406. · 0.68 Impact Factor
