The effect of posterior compression of the facet joints for initial stability and sagittal profile in the treatment of thoracolumbar fractures: a biomechanical study

Purpose!#!Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile.!##!Methods!#!Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression.!##!Results!#!We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state.!##!Conclusion!#!Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies

Method for Carrying out an Automatic Braking Action

The present invention relates to a method for carrying out an automatie braking action, wherein at least one quantity representative of the application of the brake pedal is determined and an automatie braking action is triggered when at least one limit value (brake pedal application limit value) of the quantity representative of the application of the brake pedal is exceeded, wherein the brake pedal application limit value is modified or the quantity representative of the brake pedal is weighted according to at least one action of the driver, in particular adetected movement of the driver's foot, prior to an application of the brake pedal of the braking action considered or prior to the considered braking action