Biomedical subjects
Publications and source records attributed to J Cummine.
The authors report a case of posterior fusion of the lumbar spine using Cotrel-Dubousset instrumentation in which the rods dislodged from the tulip-headed pedicle screws postoperatively. They recommend that, to avoid this complication, particular care be taken to ensure the locking washers are inserted tightly without cross threading and that an adequate length of rod is left protruding beyond the screw.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In order to study factors influencing osteogenesis after bone and bone marrow transplantation, we have caused guinea pigs to become scorbutic, and looked at the cell morphology at sites of bone formation. We had previously studied normal guinea pigs and found that autologous marrow in intermuscular implants was associated with bone production by the ninth day, regardless of the type of stored allogeneic bone transplanted with it. In subscorbutic guinea pigs, using identical implants, bone did not appear within the first 13 days, and the cell population around the implants was different. These experiments support the dominant role of bone marrow cells in osteogenesis and cast further doubt on the primary role of devitalised bone as an inducer of bone formation. Interference with cell function by deprivation of a single essential molecule, Vitamin C, produces great change in the ability of cells to synthesise bone, or pre-osseous matrix.
Explore the source record for details and available documents.
There has been conflicting evidence in the past regarding the contribution made to new bone formation by various components of a bone graft. This study in guinea pigs has compared cortical and cancellous bone allografts, both non-decalcified and hydrochloric acid decalcified, inserted into a muscular site for up to thirteen days, both alone and combined with autologous bone marrow. New bone formation was seen only if the implant contained fresh autologous marrow and it was not seen before the ninth day of implantation. There were no differences in the cell populations about cortical and cancellous grafts. Undecalcified bone evoked giant cell formation as well as new bone.