Vertebral motion measured using biplanar radiography before and after Harrington rod removal for unstable thoracolumbar fractures of the spine.

The use of Harrington distraction rods for stabilization of fracture dislocation of the thoracolumbar spine is well established. For better initial stabilization and later return of flexibility we routinely use a long rod but fuse over a short segment and then remove the rods at 1 year. A biplanar radiographic technique was used to assess vertebral motion both before and after removal of Harrington rods in five patients. The investigation showed the rod acted to restrict movement and relieved loads on the spine that they spanned. Although all the patients regained considerable spinal flexibility once the rods were removed, none of the intervertebral joints measured could be considered solidly fused. However, the pattern of movement remained abnormal 6 months after rod removal with many intervertebral joints exhibiting lateral flexion and axial rotation during voluntary flexion extension. Despite this, a long rod/short fuse stabilization with routine rod removal after 1 year combines the initial advantage of operative stabilization and is shown to allow a return of spinal flexibility subsequently.