| 摘要 |
A nested closure plug and set screw arrangement with break-off heads for securing a spinal fixation rod within to a bone screw includes a closure plug advanceable into an open channel of a bone screw and having a central threaded bore to receive a threaded set screw. The set screw is provided with a centrally positioned set point and a V-ring for cutting engagement with the surface of a clamped rod. The closure plug may be provided with a V-ring for the same purpose. The set screw V-ring is positioned and adapted to deform into engagement with the closure plug by engagement with the rod surface. By this means, the set screw and closure plug may be removed simultaneously. The closure plug and set screw have break-off installations which separate from their fasteners when pre-selected installation torques are exceeded. |
