Taek-Hyun Kwon

Facet fusion in the lumbosacral spine: a 2-year follow-up study.

OBJECTIVE A clinical and radiological follow-up study was undertaken to assess the safety, efficacy, and complication rate associated with instrumented facet fusion of the lumbar and lumbosacral spine. METHODS This study involved 99 patients with degenerative lumbar disorders who were treated surgically at the authors’ neurosurgical department and followed for more than 2 years. Eighty-two patients underwent one-level fusion for the treatment of Grade I or II degenerative spondylolisthesis and accompanying spinal canal stenosis (44 patients) or recurrent disc herniation (38 patients). Seventeen patients underwent two-level fusion for the treatment of either double instances of the above indications (seven patients) or concurrent stenosis at the adjacent level (10 patients). RESULTS There were no technique-related complications. The overall 2-year success rate of fusion was 96%; the success rates by fusion type were 99% in one-level fusions and 88% in two-level fusions. Degenerative spondylolisthesis had the highest success rate at 100%, whereas the success rate in patients who had not responded to previous discectomy was 93%. Patients with concurrent stenosis experienced the lowest success rate: 80%. Excellent or good clinical results were obtained for 85% of patients with one-level fusions and for 65% of patients with two-level fusions. CONCLUSION Instrumented facet fusion alone is a simple, safe, and effective surgical option for the treatment of patients with single-level disorders, especially patients with degenerative spondylolisthesis.

Influence of rabbit notochordal cells on symptomatic intervertebral disc degeneration: anti-angiogenic capacity on human endothelial cell proliferation under hypoxia

OBJECTIVES Symptomatic degenerative disc disease (DDD) is associated with neovascularization and nerve ingrowth into intervertebral discs (IVDs). Notochordal cells (NCs) are key cells that may lead to regeneration of IVDs. However, their activities under conditions of hypoxia, the real environment of IVD, are not well known. We hypothesized that NCs may inhibit neovascularization by interacting with endothelial cells (ECs) under hypoxia. DESIGN Human IVDs were isolated and cultured to produce nucleus pulposus (NP) cell conditioned medium (NPCM). Immortalized human microvascular ECs were cultured in NPCM with notochordal cell-rich rabbit nucleus pulposus cells (rNC) under hypoxia. Vascular endothelial growth factor (VEGF), vascular cell adhesion molecule (VCAM), and interleukin-8 (IL-8) were analyzed by ELISA. Focal adhesion kinase (FAK), filamentous actin (F-actin), and platelet-derived growth factor (PDGF) were evaluated to investigate EC activity. Wound-healing migration assays were performed to examine EC migration. RESULTS The VEGF level of EC cells cultured in NPCM was significantly higher under hypoxia compared to normoxia. VEGF expression was significantly decreased, and FAK, F-actin, PDGF expression were inhibited when ECs were cocultured with rNCs under hypoxia. ECs cocultured with rNC in NPCM showed significantly decreased migratory activity compared to those without rNC under hypoxia. CONCLUSIONS The angiogenic capacity of ECs was significantly inhibited by NCs under hypoxia via a VEGF-related pathway. Our results suggest that NCs may play a key role in the development of IVDs by inhibiting vascular growth within the disc, and this may be a promising novel therapeutic strategy for targeting vascular ingrowth in symptomatic DDD.

Primary glioblastoma multiforme of medulla oblongata: Case report and review of literature

Glioblastoma multiforme (GBM) is the most common glial tumor of the adult brain. However, the primary GBM of medulla oblongata is a rarity. To the best of our knowledge, only four cases of GBM of medulla oblongata have been reported so far in the literature, and this is the second report of conventional GBM of the medulla oblongata in adults. We describe a case of 51-year-old female, who presented with a heterogeneous mass with exophytic feature located in the caudal brain stem that was approached and a near total tumor removal was achieved by median suboccipital route. A literature review with emphasis on anatomical location, radiological and histopathological findings, extent of tumor resectibility, and outcome is included.

Efficacy of superficial temporal artery-middle cerebral artery bypass in cerebrovascular steno-occlusive diseases: Hemodynamics assessed by perfusion computed tomography

Objectives: Our purpose of this study was to assess the cerebral hemodynamic improvement with perfusion computed tomography (CT), before and after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery in patients with cerebrovascular steno-occlusive diseases including both moyamoya disease and nonmoyamoya steno-occlusions. Materials and Methods: Twenty-four STA-MCA bypasses were performed to 22 patients with symptomatic cerebrovascular steno-occlusive diseases, including both moyamoya disease and nonmoyamoya steno-occlusive diseases. Brain perfusion CT images were obtained before and after the bypass surgery. The relative parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) derived from the perfusion CT were collected and analyzed to assess the efficacy of STA-MCA bypass. Results: The CBF increased, and MTT decreased after the bypass surgery in both moyamoya group and nonmoyamoya group. The increase of CBF in nonmoyamoya group and the decrease of MTT delay in moyamoya group, overall group were statistically significant (P < 0.05). No significant postoperative change in CBV was noted. During the postoperative follow-up period, none of the 22 patients experienced any repeated ischemic/hemorrhagic attacks nor any newly developed neurologic deficits. Conclusion: The STA-MCA bypass is an effective surgical management for patients with cerebrovascular steno-occlusive diseases, such as moyamoya disease and internal carotid artery/MCA steno-occlusion. And perfusion CT can be used as an effective quantitative modality to assess the cerebral perfusion before and after the STA-MCA bypass surgery.