European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Because the disc and facets work together to constrain spinal kinematics, changes in the instant axis of rotation associated with disc degeneration or disc replacement may adversely influence risk for facet overloading and arthritis. The relationships between L5/S1 segmental kinematics and facet forces are not well defined, since previous studies have separated investigations of spinal motion and facet force. The goal of this cadaveric biomechanical study was to report and correlate a measure of intervertebral kinematics (the centrode, or the path of the instant axis of rotation) and the facet forces at the L5/S1 motion segment while under a physiologic combination of compression and anterior shear loading. ⋯ Overall, the facet force was increased on the ipsilateral side of bending (P=0.002). The IAR positions demonstrate that the L5 vertebral body primarily rotates forward during flexion (IAR close to vertebral body center) and rotates/translates backward during extension (IAR at or below the L5/S1 intervertebral disc). In lateral bending, the IAR obliquity demonstrated coupling with axial torsion due to resistance of the ipsilateral facet.
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Comparative Study
Complications of transpedicular screw fixation in the cervical spine.
Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. ⋯ Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.
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Randomized Controlled Trial
The effectiveness of calcitonin on chronic back pain and daily activities in postmenopausal women with osteoporosis.
The aim of this study was to investigate the effect of nasal calcitonin on chronic back pain and disability attributed to osteoporosis. The study design involved three groups of osteoporotic postmenopausal women suffering from chronic back pain. Group I consisted of 40 women with vertebral fractures, group II of 30 women with degenerative disorders and group III of 40 patients with non specific chronic back pain and without abnormality on plain X-rays. ⋯ Repeated measures ANOVA showed that there were no significant time, group or interaction effects for pain intensity and disability in any of the groups studied. Mean Oswestry and NRS scores were reduced during the follow-up period in the groups IA, IIIA, but the differences between the two time points were not statistically significant. Intranasal calcitonin has no effect on chronic back pain intensity and functional capacity of osteoporotic women regardless of the presence of fractures, degenerative disorders or chronic back pain of non-specific etiology.
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Comparative Study
Detailed pathological changes of human lumbar facet joints L1-L5 in elderly individuals.
Facet joints play an important role in intervertebral load transmission and are crucial for rotational kinematics. Clinically, the role of facet joints as a possible source of low back pain is seen as controversial and at present is not sufficiently investigated. In this study, human lumbar facet (zygapopyhysial) joints from donors with advanced age were analyzed macroscopically, for degenerative changes. ⋯ In conclusion, most margins of the articular facets are subject to degenerative changes in the lumbar spine of elderly persons, the topographical pattern being different in superior and inferior facets. This observation can be explained by the segmental motion patterns during extension/flexion movements of the facets. Sometimes, due to the marginal extension, it is obvious that not all changes can be assessed by CT or MRI.
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Comparative Study
The borders of the odontoid process of C2 in adults and in children including the estimation of odontoid/body ratio.
The odontoid process of C2 projects upward from the superior roof of the body of C2. There is a confusion about the inferior border of the odontoid. The aims of this clinical study were to describe the inferior border of the odontoid process based on the remnant of dentocentral synchondrosis in adults, and the estimation of the odontoid/body ratio in pediatric and adult ages. ⋯ This study demonstrated that the neck of the odontoid segment at the level of superior articulating facets is not the synchondrosis between the odontoid process and the body of C2. The synchondrosis is located well below the level of superior articulating facets. It can be demonstrated with sagittal and coronal images of MR in both of pediatric and adult individuals.