An unusual case of nerve root compression by intradiscal gas pseudocyst of the lumbar spine

An Intradiscal gas collection, referred to as the vacuum disc phenomenon (VDP) is a relatively common finding on radiographic studies of the lumbar spine, whereas gas-containing lumbar disc hernia is rarely observed. We report a case of a patient with left leg pain, provoked by a radiographically and surgically documented L4-5 gas containing disc hernia.

Inverse relation between vertebral body deformity and intervertebral disk narrowing in lumbar spine of elderly women

To investigate the relation between vertebral body deformity and disk narrowing in the lumbar spine of elderly patients, a longitudinal radiographic study of 56 aged women was retrospectively performed. We measured disk areas and body heights on two lateral lumbar radiograph sets obtained with an average interval between examinations of 10 years. The absolute values of disk areas on first examination and the rates of change of area of disks adjacent to nondeformed bodies were smaller than the corresponding values for the deformed bodies. Conversely, deformed bodies tended to have normal or expanded disks regardless of the mode of deformity. Despite the small number of subjects studied, our findings suggested that an inverse relation may exist between vertebral body deformity and disk narrowing.

[Pull-out strength and bone tissue reaction of plasma-sprayed hydroxyapatite coatings with different thicknesses or substrates]

Synthetic hydroxyapatite has been reported to have good histocompatibility, while metal to have good mechanical properties in vivo. This author coated hydroxyapatite on SUS316L stainless steel and titanium rods, using plasma-spraying techniques. Then they were implanted into tubular bones of five dogs. The pull-out strength of hydroxyapatite-coated metals was found to be stronger than that of non-coated metals and increased with passage of the time. After four weeks postoperatively, the coating layer fractured between hydroxyapatite and the metal by the pull-out test. A numerous new bone in contact with hydroxyapatite was observed. Fifty microns is found to be an ideal thickness of the coating layer. The pull-out strength of hydroxyapatite-coated titanium was higher, comparing to that of hydroxyapatite-coated SUS316L stainless steel. These results suggested that perovskite and rutile existed at the interface between hydroxyapatite and titanium after plasma-spraying and made hydroxyapatite to bond tightly to the titanium. Synthetic perovskite showed no pathological reactions to canine bone tissue.