The spine journal : official journal of the North American Spine Society
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The intervertebral disc (IVD) possesses a minimal capability for self-repair and regeneration. Changes in the differentiation of resident progenitor cells can represent diminished tissue regeneration and a loss of homeostasis. We previously showed that progenitor cells reside in the nucleus pulposus (NP). The effect of the degenerative process on these cells remains unclear. ⋯ Based on these findings, we conclude that IVD degeneration has a meaningful effect on the cells in the NP. D-NP cells clearly go through the regenerative process; however, this process is not powerful enough to facilitate full regeneration of the disc and reverse the degenerative course. These findings facilitate deeper understanding of the IVD degeneration process and trigger further studies that will contribute to development of novel therapies for IVD degeneration.
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Few studies exist for magnetic resonance imaging (MRI) issues and ballistics, and there are no studies addressing movement, heating, and artifacts associated with ballistics at 3-tesla (T). Movement because of magnetic field interactions and radiofrequency (RF)-induced heating of retained bullets may injure nearby critical structures. Artifacts may also interfere with the diagnostic use of MRI. ⋯ Ballistics made of lead with copper or alloy jackets appear to be safe with respect to MRI-related movement at 1.5-, 3-, and 7-T static magnetic fields, whereas ballistics containing steel may pose a danger if near critical body structures because of strong magnetic field interactions. Temperature increases of selected ballistics during 3-T MRI was not clinically significant, even for the ferromagnetic projectiles. Finally, ballistics containing steel generated larger artifacts when compared with ballistics made of lead with copper and alloy jackets and may impair the diagnostic use of MRI.
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Review Practice Guideline
An evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spinal stenosis (update).
The evidence-based clinical guideline on the diagnosis and treatment of degenerative lumbar spinal stenosis by the North American Spine Society (NASS) provides evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of degenerative lumbar spinal stenosis. The guideline is intended to reflect contemporary treatment concepts for symptomatic degenerative lumbar spinal stenosis as reflected in the highest quality clinical literature available on this subject as of July 2010. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder. ⋯ A clinical guideline for degenerative lumbar spinal stenosis has been updated using the techniques of evidence-based medicine and using the best available clinical evidence to aid both practitioners and patients involved with the care of this condition. The entire guideline document, including the evidentiary tables, suggestions for future research, and all references, will be available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.
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To our knowledge, no large series comparing the risk of vertebral artery injury by C1-C2 transarticular screw versus C2 pedicle screw have been published. In addition, no comparative studies have been performed on those with a high-riding vertebral artery and/or a narrow pedicle who are thought to be at higher risk than those with normal anatomy. ⋯ Overall, neither technique has more inherent anatomic risk of vertebral artery injury. However, in the presence of a high-riding vertebral artery, placement of a pedicle screw is significantly safer than the placement of a transarticular screw. Narrow pedicles, which might be anticipated to lead to higher risk for a pedicle screw than a transarticular screw, did not result in a significant difference because most patients (82%) with narrow pedicles had a concurrent high-riding vertebral artery that also increased the risk with a transarticular screw. Except in case of a high-riding vertebral artery, our results suggest that the surgeon can opt for either technique and expect similar anatomic risks of vertebral artery injury.