Reduction of bone retropulsed into the spinal canal in thoracolumbar vertebral body compression burst fractures : a prospective randomized comparative study between Harrington rods and two transpedicular devices

This was a prospective, randomized study. To compare the ability of three methods of internal fixation (Harrington rods, AO internal fixator, posterior segmental fixator) to obtain reduction of intracanal fragments in thoracolumbar vertebral compression burst fractures. Sixty-seven acute thoracolumbar compression burst fractures of T12 or L1 were randomized into three groups that were treated using one of the three methods. Reduction was accomplished indirectly by distraction applied using the fixation device. The spinal canal encroachment was calculated as a percentage of the estimated pre-injury value from serial transverse computed tomographic scans obtained on admission and immediately after surgery. The median preoperative sagittal encroachment of the spinal canal was 37% (range, 0-90%) of the normal diameter. All three methods of internal fixation produced a spinal canal clearance provided that the patient was operated on within 4 days after trauma. The median postoperative encroachment varied from 13% (range, 0-37%) to 22% (range, 0-37%), the best reduction being attained using Harrington rods and the poorest with the posterior segmental fixator. There was a suggestive statistical significance between these two. The differences in postoperative spinal canal encroachment and ability to obtain spinal canal clearance observed between the devices studied were small. There seems to be no reason to base the choice of the operative method in thoracolumbar fractures on any hypothetical differences in reductive power between Harrington rods and the AO internal fixator.