Short same-segment fixation of thoracolumbar burst fractures

Introduction: Minimizing the number of vertebral levels involved in fusion of a spine fracture is a common goal of internal fixation. This is achievable by utilizing traditional short-segment posterior fixation (SSPF). However, in SSPF there is reported up to a 54% incidence of instrument failure or unfavorable clinical outcome. Short-segment posterior fixation with pedicle fixation at the level of the fracture (short same-segment fixation) suggests biomechanical advantages toward maintenance of kyphosis correction and reducing failure rates. However its clinical efficacy is largely unknown.

Methods: The team conducted a retrospective review of 25 thoracolumbar burst fracture patients who were treated with short same-segment fixation between September 2005 and April 2009. The primary outcome measure was incidence of reoperation and loss of kyphosis correction within the follow-up period. Long-term functional status and pain was also assessed.

Results: Average duration of the most recent follow-up was 21.64 months (range 3 to 42 months). Two patients (8%) required reoperation due to either hardware failure or pseudoarthrosis. Mean pre-operative kyphosis was 14.49°. Average post-operative kyphosis was -0.74° (lordosis). Average follow-up kyphosis of all cases was 10.78°. Excluding failures, average follow-up kyphosis was 8.67°. A mean of 15.23° of kyphosis correction was attained from pre-operation to post-operation (P < 0.0001). Average loss of kyphosis correction from immediate post-operation to most recent follow-up was -11.51° and -9.51 excluding the two failures (P < 0.0001). Average pre-operative to most-recent follow-up kyphosis correction was 3.72° (P = 0.067) and 5.51° excluding failures (P = 0.0024). At initial one-month follow-up, average disability score was 52.63% (range 16% to 84%). At most recent follow-up, average disability score was 5.5% (range 0% to 16%). One patient was lost to long-term follow-up. Mean difference from one-month follow-up to most recent follow-up (excluding failures) was 47.27% (P < 0.0001).

Conclusions: Short same-segment fixation decreases implantation failure rate and reoperation rate compared to traditional SSPF, however long-term kyphosis correction was not maintained. Despite this loss of kyphosis correction, clinical pain and disability improved at long-term follow-up.