Object. Melatonin is a very effective antioxidant agent. This study was performed to investigate the effects of melatonin in experimental spinal cord injury (SCI). The authors also compared its effects with those of methylprednisolone, which also protects the spinal cord from secondary injury because of its antioxidant effect on membrane lipids. Methods. Adult male albino rats were used for the study, and paraplegia was produced using a previously described weight-drop technique. Melatonin and methylprednisolone were given intraperitoneally by bolus injections of 100 mg/kg and 30 mg/kg, respectively, immediately after induction of trauma. The animals were killed, and 1-cm samples of injured spinal cord were obtained at 1, 24, and 48 hours postinjury. Lipid peroxidation was estimated by thiobarbituric acid test. Electron microscopic studies were performed to determine the effects of melatonin on neurons, axons, and subcellular organelles after experimental SCI. A grading system was used for quantitative evaluation. Following SCI, there was significant increase in lipid peroxidation. In melatonin- and methylprednisolone-treated groups, lipid peroxidation was found to decrease to the baseline (preinjury) levels. There was a significant difference between trauma-alone and treatment groups, but no statistical difference was found between the melatonin- and methylprednisolone-treated groups. Electron microscopic findings showed that SCI produced by the weight-drop technique resulted in profound tissue damage. Conclusions. Both melatonin and methylprednisolone have been shown to protect neuron, axon, myelin, and intracellular organelles including mitochondrion and nucleus. However, this study provides quantitative evidence that this protection of neurons and subcellular organelles of spinal cord after secondary injury is much more obvious in melatonin-treated rats than those treated with methylprednisolone. In view of these data, melatonin has been shown to be very effective in protecting the injured spinal cord from secondary injury.

Study design: A case report of intraradicular disc herniation. Intraradicular disc herniation is a special type of intradural disc hernations. In this report, we present the tenth case of intraradicular lumbar disc herniation and suggest a new classi®cation for intradural disc herniations. Case report: A 32-year-old male was admitted to hospital having experienced pain in the lower back and right leg for 1 month prior to admission. Neurological examination revealed weakness of the extensor hallucis longus, positive Lase gue's sign, decreased ankle re¯ex in his right lower extremity, and bilateral paravertebral muscle spasm. Magnetic resonance imaging (MRI) revealed a disc herniation with a posterolateral extruded fragment on the right at the level of the L5-S1 space. He underwent L5 laminectomy. During the operation, the right S1 root was found to be swollen and immobile. A longitudinal incision was made in the dura of the right S1 root and an intradural free disc fragment was removed, and the S1 root was relieved. The patient was free of pain postoperatively. Conclusion: We suggest a new classi®cation for intradural disc herniations with this unusual case presentation and review the literature for pathogenesis, clinical picture, diagnosis and treatment. Spinal Cord (2001) 39, 545 ± 548

A 4-year-old girl presented with an intramedullary epidermoid cyst of the cervical spinal cord. The clinical, radiological, and surgical features and a brief critical review of the literature are included in this report. The cyst contents were removed totally in two operations. The child had a coexisting neuroenteric cyst in the posterior mediastinum. To our knowledge, this coexistence has not been previously reported. Contemporary imaging modes and prospects of the surgical treatment are discussed.

Arterial bleeding during transsphenoidal surgery for pituitary adenoma is known complication. This usually happens due to rupture of intracavernous carotid or delayed hemorrhage due to the carotico-cavernous fistula and/or pseudoaneurysm. There is also evidence that cavernous carotid aneurysms may occur with pituitary tumors, yet largest series failed to demonstrate any link between aneurysm formation and pituitary tumors. Usually such an aneurysm rupture results in formation of carotico-cavernous fistula. However, pituitary apoplexy and even epistaxis have been reported. In this paper we present a patient with recurrent pituitary adenoma and cavernous carotid artery aneurysm, which caused significant hemorrhage during the surgery. Although retrospective analysis of MRI disclosed that the patient had the aneurysm before the first surgery, it remained silent until the second operation. Therefore neurosurgeons should be very susceptive to any signal changes on preoperative MR images, especially in recurrent cases, where normal anatomical relations are disturbed by fibrotic tissue. Also, we reviewed the vascular complication of pituitary surgery based on the literature.

The authors present the case of a 20-year-old woman with right-sided temporal intraparenchymal meningioma originating from underlying meningioangiomatosis. The patient manifested temporal-type seizures as the initial symptom. She had no stigmata of neurofibromatosis Type 2. Neuroradiological studies revealed an intraaxial, contrast-enhancing lesion in the right temporal lobe. After gross-total removal of the tumor, histological examination revealed a transitional meningioma with surrounding neural parenchyma and features of meningioangiomatosis. Although there were no signs of anaplasia, necrosis, or increased mitosis, tumor islands were observed in the adjacent neuropil. The rare association of meningioangiomatosis and meningioma is discussed, along with radiological and surgical findings.