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Biomedical subjects

S J Lipson

Publications and source records attributed to S J Lipson.

34 records · Page 2Linked to original sources
PubMed1988

Metaplastic proliferative fibrocartilage as an alternative concept to herniated intervertebral disc.

It is hypothesized on the basis of experimental intervertebral disc degeneration that herniated disc is actually newly synthesized proliferative metaplastic fibrocartilage and not herniation of pre-existing disc tissue, particularly that of the nucleus pulposus. Human material in selected surgical tissues was examined to test this concept. Histology revealed evidence for proliferative fronts of fibroblastic cells in herniated discs with hypocellular interiors. Hydroxypyridinium cross-link assay was used to determine the maturity of the collagen. Results indicated, with statistical significance, that herniated disc is a younger tissue than in situ annulus fibrosis, and that herniated disc is not from the nucleus pulposus, thus supporting the hypothesis.

Adult↗
PubMed1988

Spinal stenosis.

Degenerative spinal stenosis is the most common type of stenosis encountered, often presenting with neurogenic claudication. History and physical examination indicate its presence and radiologic imaging is used to demonstrate the spatial reduction in the lumbar canals. Nonoperative therapy can be effective while surgical decompression offers the most reliable and definitive therapeutic intervention.

Humans↗
PubMed1985

Cervical myelopathy and posterior atlanto-axial subluxation in patients with rheumatoid arthritis.

Posterior atlanto-axial subluxation, which is uncommon and usually is considered a benign condition, was associated with cervical myelopathy in four patients with rheumatoid arthritis. The cause of the myelopathy appeared to be posterior kinking of the spinal cord without demonstrable compression. Contrast-enhanced sagittal imaging or computerized tomographic sagittal reconstruction provided the best means of demonstrating the abnormal configuration of the spinal cord. Halo traction and occipitocervical fusion yielded satisfactory results in all four patients after follow-up of one to two years. We developed a method to provide rigid fixation of an occipitocervical fusion in which a corticocancellous iliac-bone graft was backed with metal mesh, wired in place, and reinforced with methacrylate.

Aged↗
PubMed1984

Computed tomography of aneurysmal bone cyst of the L1 vertebral body.

A 31-year-old woman with an aneurysmal bone cyst of the L1 vertebral body proved by biopsy and studied by plain lumbar spine roentgenography, radionuclide studies, myelography, and CT is presented. The unusual location of involvement of the vertebral body alone and the difficulty in differential diagnosis between aneurysmal bone cyst and benign giant cell tumor are discussed.

Adult↗
PubMed1981

Experimental intervertebral disc degeneration: morphologic and proteoglycan changes over time.

An animal model of intervertebral disc degeneration produced by surgical ventral disc herniation in the rabbit is described. Histologic studies showed proliferation of cells on the inner third of the annular wound, with metaplasia into fibrocartilage in the first 2 weeks following injury. Progressive fibrocartilaginous change occurred, reproducing the morphologic changes of disc degeneration over the first 6 weeks involving nearly the entire disc. Proteoglycans (total and newly synthesized) were studied qualitatively and quantitatively for periods of 1 to 200 days after herniation. There were two periods of time during the early course of degeneration when the ability of the proteoglycans to aggregate by interaction with hyaluronic acid was recovered, but this decreases progressively after 6-7 weeks. There was an immediate loss of water content from the injured disc which was restored only transiently during the first 2 days after herniation. Thereafter the water content progressively decreased. The uronic acid content of the disc changed in parallel with the changes in water content. The hyaluronic acid content decreased rapidly after herniation. However, the size of the proteoglycan monomers did not change with degeneration. The biochemical and morphologic changes are correlated, and an early repair mechanism is postulated to exist after injury.

Animals↗
PubMed1980

Vertebral osteophyte formation in experimental disc degeneration. Morphologic and proteoglycan changes over time.

Experimental intervertebral disc degeneration produced in rabbits by ventral nuclear herniation reliably produces vertebral osteophytes. Osteophytes arise from proliferating inner annular fibers which undergo metaplasia into cartilage, calcify, and proceed through an endochondral ossification sequence. Proteoglycans extracted from the osteophytes reveal that the degree of aggregation, molecular size of the monomer, and the chondroitin sulfate/keratin sulfate ratio are directly related to the cartilage state of the tissue.

Animals↗
PubMed1977

Dysplasia of the odontoid process in Morquio's syndrome causing quadriparesis.

Eleven patients with documented Morquio's syndrome who had dysplasia of the odontoid process and resulting atlanto-axial instability were reviewed. They were found to be at risk for acute traumatic quadriparesis, chronic myelopathy of a variable and often rapid rate of progression, and sudden death by respiratory arrest. The evidence suggests that early prophylactic posterior cervical fusion is indicated for patients with this malformation and that once quadriparesis is established, recovery of function is limited.

Adult↗
PubMedDate not supplied

1980 Volvo award in basic science. Proteoglycans in experimental intervertebral disc degeneration.

An animal model of intervertebral disc degeneration induced surgically by ventral nuclear herniation in the rabbit produces morphologic changes of disc degeneration. Histologic characteristics and proteoglycan changes have been studied at various times after herniation. After injury, there was metaplasia into fibrocartilage originating from the cells along the margins of the annular wound, with proliferation of cells changing almost the entire disc space into fibrocartilage. A vertebral osteophyte occurred through an endochondral ossification sequence. Aggregating proteoglycans had two periods of repletion in the early course of degeneration. The water content of the disc was rapidly but only transiently restored in the first two days after herniation, whilst the changes in the total proteoglycan content of the disc paralleled these changes. Hyaluronic acid content decreased rapidly after herniation, but the size of the proteoglycan monomers did not change with degeneration. It is suggested that loss of confined fluid mechanics signals an abortive repair attempt rather than that of biochemical changes in proteoglycans initiate disc degeneration.

Animals↗
PubMedDate not supplied

Atlantoaxial arthrodesis in the presence of posterior spondyloschisis (bifid arch) of the atlas. A report of three cases and an evaluation of alternative wiring techniques by computerized tomography.

The presence of a bifid posterior arch of the atlas has been regarded as a contraindication to the wiring of C1-2 for atlantoaxial arthrodesis. Three cases with C1 posterior spondyloschisis are presented with successful atlantoaxial arthrodesis using laterally placed wires to avoid the midline defect of the atlas. An experimental study of the efficacy of three different wiring constructs by computerized tomography showed that there is little difference between midline versus lateral wiring in restricting rotation of C1-2.

Adult↗
PubMedDate not supplied

Rheumatoid arthritis of the cervical spine.

The synovitis of rheumatoid arthritis (RA) injures structures in the cervical spine, allowing atlantoaxial subluxation, atlantoaxial impaction, and subaxial subluxation. Spinal cord and vertebral artery injury can ensue. Subluxations are common, but neurologic abnormalities are less so. Patients with RA can die from subluxations but usually do not, although many become worse with time. Nonsurgical management is supportive and designed to lessen pain. Neurologic abnormality is the major indication for surgery. Preoperative skeletal traction is often needed. Posterior fusion is most commonly done for stabilization.

Arthritis, Rheumatoid↗