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Biomedical subjects

M Tile

Publications and source records attributed to M Tile.

40 records · Page 3Linked to original sources
PubMedDate not supplied

Determination of a locus of instantaneous centers of rotation of the lumbar disc by moiré fringes. A new technique.

The aim of this study was to define the motion of the L4-5 spinal segment moving from full extension to full flexion. A new technique using moiré fringes was applied to measure angles of 3-degree change, a technique proven to be highly accurate for small angular changes. This investigation has identified a locus of centers of rotation (centrode) that is located in the posterior half of the intervertebral disc. The direction of the locus passes from posterior to anterior and back to posterior. The technique can be adapted for evaluation of in vivo radiographs. This technique may prove useful in identifying aberrations in movement associated with spinal segment instability in its earliest stages.

Biomechanical Phenomena↗
PubMedDate not supplied

Centrode patterns in the lumbar spine. Baseline studies in normal subjects.

Segmental spinal instability is a known cause of back pain, but no method of accurately quantifying instability exists. The movement of complex joints with rotational and translational components (such as the lumbar motion segment) is tracked by a pathway of instantaneous centers of rotation, or a centrode. Instability, ie, excessive and/or erratic movement, is reflected by increased centrode length in cadaver studies. This study describes an in vivo method that precisely determines the centrode pattern and reports the results for 21 normal male volunteers who were studied at the L4-5 and L5-S1 levels. Each volunteer underwent lateral radiographs of the lumbar spine. High speed films were used and six positions, from full extension to full flexion, were recorded. Acetate tracings and contour matching techniques recorded the relative positions of the vertebral bodies on each film. Multiple tracings of each radiograph, combined with a digitizer and computer, were used to improve precision in the calculated centrode patterns. Centrode lengths measured 43.7 mm and 55.9 mm, respectively, for the L4-5 and L5-S1 levels. This study demonstrates that precise centrode pattern analysis for sagittal plane motion of the lumbar spine is possible in vivo. Studies are under way to determine whether this technique will be useful as a clinical test in diagnosing early segmental instability of the lumbar spine in patients with low-back pain.

Adult↗
PubMedDate not supplied

Spinal stenosis. Results of treatment.

Seventy patients with spinal stenosis are reported according to the new international classifications. Cases where the stenosis was caused mainly by interluminar lesions such as disk protrusion are excluded. The treatment of patients with segmental disease and adequate technical decompression was generally successful while the patients with more generalized disease had less predictable end results. In spite of wide decompression of the lateral gutter of the spinal canal, there was little tendency to further olisthesis except in the degenerative spondylolisthesis group. Spinal fusion did not appear to be necessary except in this latter group of patients. Technetium polyphosphate scanning techniques have shown an active process in the facet joints of the spondylolisthesis group with degenerative disease.

Constriction, Pathologic↗