The effect of postoperative immobilization on short-segment fixation without bone grafting for unstable fractures of thoracolumbar spine

BACKGROUND: Controversy regarding the fixation level for the management of unstable thoracolumbar spine fractures exists. Often poor results are reported with short-segment fixation. The present study is undertaken to compare the effect of fixation level and variable duration of postoperative immobilization on the outcome of unstable thoracolumbar burst fractures treated by posterior stabilization without bone grafting. PATIENTS AND METHODS: A randomized, prospective, and consecutive series was conducted at a tertiary level medical center. Thirty-six neurologically intact (Frankel type E) thoracolumbar burst fracture patients admitted at our institute between February 2003 and December 2005 were randomly divided into three groups. Group I (n = 15) and II (n = 11) patients were treated by short-segment fixation, while Group III (n = 10) patients were treated by long-segment fixation. In Group I ambulation was delayed to 10th-14th postoperative day, while group II and III patients were mobilized on third postoperative day. Anterior body height loss (ABHL) percentage and increase in kyphosis as measured by Cobb's angle were calculated preoperatively, postoperatively, and at follow-up. Denis Pain Scale and Work Scales were obtained during follow-up. RESULTS: Mean follow-up was 13.7 months (range 3-27 months). At the final follow-up the mean ABHL was 4.73% in group I compared with 16.2% in group II and 6.20% in group III. The mean Cobb's angle loss was 1.8° in group I compared with 5.91° in group II and 2.3° in group III. The ABHL difference between groups I and II was significant (P = 0.0002), while between groups I and III was not significant (P = 0.49). CONCLUSION: The short-segment fixation with amenable delayed ambulation is a valid option for the management of thoracolumbar burst fractures, as radiological results are comparable to that of long-segment fixation with the advantage of preserving maximum number of motion segments.