[Seat-belt and chance fractures of the thoracolumbar spine].

INTRODUCTION The authors have attempted to elucidate the differences between Chance, seat-belt, and flexion distraction fractures. Chance and seat-belt fractures have more common features, while flexion distraction fractures differ, in particular, due to the mechanism of injury. A difficult diagnosis is sometimes a common characteristic, while therapy is always the same. PATIENTS AND METHODS During the period from 1997 to 2005, the authors treated 23 seat-belt fractures, and only three "genuine" Chance fractures. All patients had normal neurological findings. The mechanisms of injury were a car crash in 20 cases, and a fall associated with flexion in 6 cases, such as a rolling fall while skiing. According to the localisation, Chance fractures were found at the L 1 level twice and at the L 2 level once. Seat-belt injury was found once each in the areas of T 7, L 4, L 5, -twice at L 2 and L 3, and 16 times at the T / L spine transition, respectively. All patients were operated on using instrumented posterolateral spondylodesis. RESULTS All fractures healed by spondylodesis as confirmed by X-ray images. All patients returned to their original job or school. 14 patients were evaluated 6 months after removal of the metallic implants. The mean subsequent kyphotisation was 1.4 degrees with the largest deviation of 4 degrees in a patient with a pure ligamentous variant of a seat-belt fracture. CONCLUSION The objective of this work is to illustrate the various types of spinal distraction injuries of a seat-belt character and Chance fracture, when the vertebral body is not compressed. X-rays and often also CT scans show a "benign" character. Interpretation of the findings is very important for the development of further chronic instability of the spine and all consequences. If the diagnosis of a distraction injury is made the operative stabilisation is essential. That is why all our patients were tretaed by operation.