Spine
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Prospective trial. ⋯ The authors have developed a novel method of spinal stereotaxy using exact plastic copies of the spine manufactured using biomodeling technology. Biomodel spinal stereotaxy is a simple and accurate technique that may have advantages over frameless stereotaxy.
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Comparative Study
Effects of degeneration on the biphasic material properties of human nucleus pulposus in confined compression.
The biphasic compressive material properties of normal and degenerate human nucleus pulposus tissue were measured in confined compression. ⋯ Swelling is the primary load-bearing mechanism in both nondegenerate and degenerate nucleus pulposus. Knowledge of the biphasic material properties of the nucleus pulposus will aid the development of new treatment strategies for disc degeneration aimed at restoring mechanical function of the intervertebral disc.
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A finite-element study of posterior alone or anterior/posterior combined instrumentation following total spondylectomy and replacement with a titanium mesh cage used as an anterior strut. ⋯ This experiment shows that from the viewpoint of stress shielding, the reconstruction method, using additional anterior instrumentation with posterior pedicle screws (MPAI and SPAI), stress shields the cancellous bone inside the titanium mesh cage to a higher degree than does the system using posterior pedicle screw fixation alone (MPI). Thus, a reconstruction method with no anterior fixation should be better at allowing stress for remodeling of the bone graft inside the titanium mesh cage.
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Postoperative outcomes of cervical pedicle screw (CPS) placement were evaluated. The screws were inserted in degenerative vertebrae using anatomic landmarks. ⋯ The deviation rate of CPS placement using anatomic landmarks was higher than anticipated, although no serious complications were encountered. Refinement of the technique (e.g., using a computer-assisted navigation system) is strongly recommended.