[Significance of ligamentotaxis for internal fixator osteosynthesis in fractures of thoracic and lumbar vertebrae].

Between 1985 and 1990 104 operations on the lower thoracic and lumbar spine using the AO-internal spinal fixation system were performed. The preoperative computed tomography (CT) scans as well as either the postoperative CT scans or the CT scans taken after implant removal of 41 cases were available for evaluation of the narrowing of the spinal canal and the subsequent fracture reduction by means of computer-aided planimetry. It is shown that a near normal reduction of the spinal canal through ligamentotaxis is achieved for a fracture between T 12 and L 2, whereas for fractures between L 3 and L 5 an incomplete reduction is observed. A correlation between the neurologic deficit and the degree of narrowing of the spinal canal could not be established. Obviously, the damage to the spinal cord is determined primarily through the dynamic forces of the impact. Also no statistical correlation could be demonstrated in our cases of the time interval between accident and operation to the degree of reduction of the fracture achieved.