The spine journal : official journal of the North American Spine Society
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The currently accepted surgical treatments for compressive cervical myelopathy include both anterior and posterior decompression. Anterior approaches including multilevel discectomy with fusion or vertebral corpectomy with strut grafting, both with and without instrumentation, have enjoyed successful outcomes, but have been associated with select postoperative complications. Laminoplasty has been developed to decompress the spine posteriorly while avoiding the spinal destabilization seen after laminectomy. ⋯ Cervical laminoplasty remains a reliable procedure for posterior decompression of the spine, but the optimal approach to cervical myelopathy must take into account both patient and disease characteristics, as well as the capabilities and experience of the surgeon.
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Current well regarded thoracic and lumbar spine injury classifications use mechanistic and anatomical categories, which do not directly rely on quantifiable management parameters. Their clinical usefulness is not optimal. ⋯ A clinically useful thoracic and lumbar spine injury classification should be based on parameters that are the primary indications for management decisions. The same parameters should be injury severity quantifiable as to guide treatment. In this study we introduced spinal canal deformity and column biomechanical functions as quantifiable parameters in thoracic and lumbar injury severity classification. Validation of this method is beyond the scope of this preliminary study.
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Lumbar fusion has been associated with inconsistent clinical outcomes and significant complications. Posterior dynamic devices have been developed to stabilize painful diseased lumbar motion segments while avoiding fusion. The Device for Intervertebral Assisted Motion (DIAM) is a silicone interspinous process "bumper" that is being clinically implanted for varied indications. ⋯ The DIAM device is effective in stabilizing the unstable segment, reducing the increased segmental flexion-extension and lateral bending motions observed after discectomy. In flexion-extension the DIAM restored postdiscectomy motion to below the intact values (p<.05). Interestingly, the DIAM device did not reduce the increased axial rotation motion observed after discectomy. These biomechanical effects must be considered when evaluating the clinical applications of the DIAM.
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Comparative Study
Biomechanics of two-level Charité artificial disc placement in comparison to fusion plus single-level disc placement combination.
Biomechanical studies of artificial discs that quantify parameters such as load sharing and stresses have been reported in literature for single-level disc placements. However, literature on the effects of using the Charité artificial disc (ChD) at two levels (2LChD) as compared with one-level fusion (using a cage [CG] and a pedicle screw system) plus one-level artificial disc combination (CGChD) is sparse. ⋯ The changes at L3-L4 level for both of the cases were of similar magnitude (approximately 25%), although in the CGChD model it increased and in the 2LChD model it decreased. The changes in motion at the L4-L5 level were large for the CGChD model as compared with the 2LChD model predictions (approximately 70% increase vs. 10% increase). It is difficult to speculate if an increase in motion across a segment, as compared with the intact case, is more harmful than a decrease in motion.