A 59-year-old man presented with both leg radiating pain and paresthesia for 4 years. Other physical findings were not remarkable. MRI showed a large, elongated posterior extradural cyst from T12 to L3 with surrounding bony erosion (Fig. 1A, B).Thinned overlying laminas were found on operative field and the cyst was ruptured during laminectomy. There was a hole-like dural defect near to right L1 root sleeve and we performed primary closure of the defect. Some part of cyst wall was also removed.The patient's symptoms were gradually subsided and follow up image taken 1 month after the operation showed complete disappearance of the cyst (Fig. 1C). Case 2A 51-year-old female patient visited our clinic with left buttock pain and paresthesia for 3 years. Her pain was aggravated on coughing and she also complained of gait disturbance with both sole numbness on walking.MRI showed a large extradural cyst located posterior to the INTRODUCTIONSpinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. SEAC is more commonly found among male patients and during the second decade of their life. SEACs can be found in any location, although mostly reported to be located at mid thoracic to the thoraco-lumbar junction, commonly in a posterior position 1,3,4,6,10,12) . SEAC is an outpouching herniation of arachnoid membrane through a dural defect that may communicate to intradural subarachnoid space 5) . The etiology of this herniation is still unclear and can be either congenital or acquired 6) . These cysts can result in fluctuating symptoms associated with cord or root compression. It is assumed that they can be enlarged by subsequent pressure change in the cerebrospinal fluid (CSF) during exercise and Valsalva maneuvers as there is micro-communication between the cysts and subarachnoid space 2,6) . Despite the rarity of SEACs, they are important in neurosurgical view because they are surgically curable disease. Diverse surgical techniques have been introduced and many reports reviewed favorable outcome of SEACs with surgical treatment. We experienced 2 cases of SEACs and performed cyst fenestration and primary repair of dural defects for all of them. The aim of this article Department of Neurosurgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, KoreaSpinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. The etiology remains still unclear. We experienced 2 cases of SEACs and reviewed the cases and previous literatures. A 59-year-old man complained of both leg radiating pain and paresthesia for 4 years. His MRI showed an extradural cyst from T12 to L3 and we performed cyst fenestration and repaired the dural defect with tailored laminectomy. Another 51-year-old female patient visited our clinical with left buttock pain and paresthesia for 3 years. A large extradural cyst was found at T1-L2 level on MRI and a communication between the cyst and subarachnoid space was illustrated by CT-myelography. We performed cys...

Spinal intradural extramedullary teratoma is a rare condition that develops more commonly in children than in adults and may be associated with spinal dysraphism. We report a rare case of adult-onset intradural extramedullary teratoma in the thoracolumbar spinal cord with no evidence of spinal dysraphism and without the history of prior spinal surgery. The patient was a 38-year-old male whose chief complaint was urinary incontinence. X-ray images of the thoracolumbar spine showed the widening of the interpedicular distance and posterior marginal erosion of the vertebral bodies and pedicles at the T11, T12, and L1 level. Magnetic resonance imagings of the lumbar spine showed a lobulated inhomogeneous high signal intradural mass (87x29x20 mm) between T11 and L1 and a high signal fluid collection at the T11 level. Laminectomy of the T11-L1 region was performed, and the mass was subtotally excised. The resected tumor was histopathologically diagnosed as a mature cystic teratoma. The patient's symptom of urinary incontinence was improved following the surgery.

No abstract

Epoxy was blended with benzoxazine resin and aluminum trihydrate (ATH) additive to render flame retardancy while maintaining mechanical properties. The ATH was modified using three different silane coupling agents and then added to 60/40 epoxy/benzoxazine mixtures. The effect of blend compositions and surface modification on flame retardant and mechanical properties of the composites was investigated by UL94, tensile, and shear tests. Resin mixtures containing more than 40 wt% benzoxazine revealed a UL94 V-1 rating with enhanced tensile and shear strength. Upon addition of 20 wt% ATH to 60/40 epoxy/benzoxazine, a V-0 rating was achieved. The lowered tensile and adhesive properties of the composites in the presence of ATH were improved by modifying the ATH surface using silane coupling agents.

Epoxy resin was mixed with benzoxazine resin and an aluminum trihydrate (ATH) additive to provide flame retardancy and good mechanical properties. The ATH was modified using three different silane coupling agents and then incorporated into a 60/40 epoxy/benzoxazine mixture. The effect of blending compositions and surface modification on the flame-retardant and mechanical properties of the composites was investigated by performing UL94, tensile, and single-lap shear tests. Additional measurements were conducted including thermal stability, storage modulus, and coefficient of thermal expansion (CTE) assessments. The mixtures containing more than 40 wt% benzoxazine revealed a UL94 V-1 rating with high thermal stability and low CTE. Mechanical properties including storage modulus, and tensile and shear strength, also increased in proportion to the benzoxazine content. Upon the addition of ATH to the 60/40 epoxy/benzoxazine mixture, a V-0 rating was achieved at 20 wt% ATH. The pure epoxy passed a V-0 rating by the addition of 50 wt% ATH. The lower mechanical properties at high ATH loading could have been improved by introducing a silane coupling agent to the ATH surface. The composites containing surface-modified ATH with epoxy silane revealed about three times higher tensile strength and one and a half times higher shear strength compared to the untreated ATH. The enhanced compatibility between the surface-modified ATH and the resin was confirmed by observing the fracture surface of the composites.