Journal of neurosurgery
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Journal of neurosurgery · Oct 2003
Comparative StudyOne-level one-sided lumbar disc surgery with and without microscopic assistance: 1-year outcome in 114 consecutive patients.
The aim of this study was to compare the outcomes following macrodiscectomy and microsurgery for one-level one-sided lumbar disc excision. ⋯ Microdiscectomy allows the surgeon good visualization and is less traumatic to the involved tissues. Interestingly, the results of this study indicated that microsurgery does not reduce hospitalization time, nor does it improve the overall surgery-related outcome. The main differences between the two procedures were length of the incision and operative time. The author found that lumbar microdiscectomy allows patients earlier return to work and/or normal life with less reliance on postoperative narcotic analgesic agents.
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Journal of neurosurgery · Oct 2003
Inhibition of proteoglycan and type II collagen synthesis of disc nucleus cells by nicotine.
Systemic nicotine has been hypothesized to cause degeneration of the intervertebral disc which in turn decreases vascular supply to the disc through a cholinergic receptor-mediated process. Another possible mechanism may be through direct regulatory effects on disc cells. In this study, the authors tested the hypothesis that nicotine adversely affects nucleus pulposus cells by directly inhibiting proteoglycan synthesis and gene expression of type II collagen (Phase I study). They also assessed the hypothesis that nicotine inhibits the bone morphogenetic protein (BMP)-2-induced upregulation of extracellular matrix (Phase II study). ⋯ The results of this study raise the possibility that nicotine may contribute to the process of disc degeneration by a direct effect on the nucleus pulposus cells, possibly by antagonizing the effect of BMP-2.
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Journal of neurosurgery · Oct 2003
Effect of ipsilateral subthalamic nucleus lesioning in a rat parkinsonian model: study of behavior correlated with neuronal activity in the pedunculopontine nucleus.
The purpose of this study was to investigate the spontaneous behavioral changes and the alteration of neuronal activities in the pedunculopontine nucleus (PPN) after ipsilateral subthalamic nucleus (STN) lesioning by kainic acid in a rat parkinsonian model created by lesioning with 6-hydroxydopamine (6-OHDA). ⋯ The results demonstrated that STN lesioning induced behavioral improvement in rat parkinsonian models. This result, which confirms previously held assumptions, may account for the therapeutic effect of STN stimulation in Parkinson disease. The alteration of the neuronal activities in the PPN units also indicates that the PPN units are responsible for the improvement in motor symptoms observed after STN lesioning in rat parkinsonian models.
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Journal of neurosurgery · Oct 2003
Spinal blood flow in 24-hour megadose glucocorticoid treatment in awake pigs.
Because of the controversy regarding the benefits of 24-hour administration of methylprednisolone in patients with spinal cord injury (SCI), it is important to investigate its mechanism of action and side effects. This study was conducted to determine if high-dose methylprednisolone modulates neural and vertebral blood flow in an awake large-sized animal model without SCI. ⋯ In the awake pig model, 24-hour methylprednisolone treatment does not modulate cerebral or SCBF, nor does it increase the risk for vertebral osteonecrosis by producing vertebral ischemia.
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Journal of neurosurgery · Oct 2003
Mechanism of the spinal cord injury and the cervical spondylotic myelopathy: new approach based on the mechanical features of the spinal cord white and gray matter.
The authors have previously investigated the mechanical properties of the white and gray matter in the bovine cervical spinal cord, demonstrating that the gray matter is more rigid, although more fragile, than the white matter. In the present study they conducted additional tensile tests on the bovine cervical spinal cord by changing strain levels and strain rates applied to the white and gray matter. ⋯ These differences in mechanical properties between the white and gray matter constitute different mechanisms contributing to the development of tissue damage and clinical symptoms.