Spine
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This static, nondestructive, in vitro biomechanical study examines anterior solid rod construct stiffness following the addition of multilevel, threaded cortical bone dowels in a bovine model. A comparison is made with a clinically relevant posterior construct with and without an anterior release. ⋯ Disc space augmentation increased stiffness except in axial rotation, in which values were restored to the intact level. Stiffness was superior to a clinically relevant posterior instrumentation comparison group following anterior release, and was equivalent to a posterior construct without anterior release except in anterior flexion. In addition, the implants enhanced lordosis. Increased rigidity should improve rates of arthrodesis, while maintenance of sagittal alignment may prevent pathologic compensatory curves in adjacent spinal segments. Further research is required to determine the optimal method of achieving structural interspace support.
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An analysis of the vascular anatomy relative to the underlying discs in the lower lumbar spine performed by using radiologic studies. ⋯ The results of this study suggest that a laparoscopic approach to the L3-L4 intervertebral disc will seldom be accomplished without significant retraction of the aorta. Access to the L4-L5 space will be accomplished readily in approximately one third of the patients. In the others, it will require significant vascular dissection. The L5-S1 space, conversely, will be readily accessible by the authors' definitions without significant vessel dissection in the majority of patients.
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Data were collected prospectively on 38 patients who underwent anterior cervical discectomy and fusion for neck pain with no symptoms or signs of radiculopathy or myelopathy. ⋯ A significant decrease in pain, a significant increase in function, and a high degree of patient satisfaction were found with anterior cervical discectomy and fusion for neck pain. Improvements were not affected by worker's compensation status or gender.
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Measurement of changes in cerebrospinal fluid concentrations of nerve tissue markers, total proteins, and immunoglobulin after compression of nerve root or application of nucleus pulposus in a pig model. ⋯ The neurofilament protein and total protein concentrations in cerebrospinal fluid may have diagnostic importance in cases wherein clinical findings are not clearly related to the radiologic changes and vice versa. These protein markers also may be useful tools in different experimental models.