We review results on the dynamics of warped gaseous discs. We consider tidal perturbation of a Keplerian disc by a companion star orbiting in a plane inclined to the disc. The perturbation induces the precession of the disc, and thus of any jet it could drive. In some conditions the precession rate is uniform, and as a result the disc settles into a warp mode. The tidal torque also leads to the...

Biomechanical analyses on lumbar spine under compressive load and flexion torque were performed using a nonlinear three-dimensional finite element method to evaluate the stability of artificial disc replacement. We prepared a validated intact lumbar L4-L5 motion segment and artificial disc inserted motion segment by replacing intact disc with the artificial disc which is being developed. Effect...

Lumbar disc degeneration occurs because of a variety of factors and results in a multitude of conditions. Alterations in the vertebral endplate cause loss of disc nutrition and disc degeneration. Aging, apoptosis, abnormalities in collagen, vascular ingrowth, loads placed on the disc, and abnormal proteoglycan all contribute to disc degeneration. Some forms of disc degeneration lead to loss of ...

a 25-year old man presented with chronic low back pain for about 5 years due to mild congenital lumbar kyphosis (l1-l3 25° with congenital posterior wedge vertebra l2). preoperative neurologic examination was normal. after posterior spinal fusion and instrumentation with moderate curve correction, the patient gradually developed the symptoms and signs of cauda equina syndrome due to intraoperat...

BACKGROUND The progression of disc degeneration is generally believed to be associated with low back pain and/or degenerative lumbar diseases, especially in the elderly. The purpose of this study was to quantitatively evaluate changes in lumbar disc height using radiographic measurements and to investigate risk factors for development of disc height narrowing of the elderly. METHODS From 1997...

OBJECTIVE Disc edge veins of Kraupa are a rare anomaly of the retinal venous system in which the main trunk of the retinal vein disappeared into the margin of the optic disc instead of its centre. METHODS A 40-year-old woman was detected to have an anomaly in her left optic disc in a routine eye examination. The eyes had an anomaly of the retinal venous system in which all branches of the ret...