| 摘要 |
An instrument for adjusting a spinal rod relative to a bone anchor includes a handle connecting a set screw driver with a reduction collar. The handle includes an inner shaft engageable with the set screw driver, an outer shaft engageable with the reduction collar, and a clutch connecting the inner shaft to the outer shaft and permitting selective rotation of the inner shaft relative to the outer shaft, and thus, selective rotation of the set screw driver relative to the reduction collar. The handle clutch may include a spring and a plurality of disc clutch members positioned about the outer shaft. The spring biases the disc clutch members into contact with one another and at least one disc clutch member may rotate relative to an adjacent disc clutch member upon application of a torque to the reduction collar and the outer shaft greater than a preselected torque value. |
