Short segment pedicle screw fixation for unstable T11-L2 fractures: with or without fusion? A three-year follow-up study.

In unstable thoracolumbar fractures T11-L2, exaggerated kyphosis at the end of treatment may predispose to late back pain and poor functional outcome. Short-segment (SS) (3 vertebrae) pedicle instrumentation has become a popular method of treatment. However the question to add a fusion or not is still under debate. The authors retrospectively evaluated the radiological and functional results in 74 patients who had undergone an SS pedicle screw fixation. They were divided into two groups: group 1 (39 patients) was the non-fusion group; group 2 (35 patients) was the fusion group. In the non-fusion group the mean preoperative, immediate postoperative and final kyphosis angles at the fracture site were respectively 20.8 degrees +/- 6.4, 8.2 degrees +/- 4.8, and 15.2 degrees +/- 6.0. In the fusion group the corresponding angles were 26.6 degrees +/- 4.1, 7.9 degrees +/- 2.1, and 8.4 degrees +/- 2.4, which demonstrated a distinctly better final result (p < 0.0001). In the non-fusion group the preoperative, immediate postoperative and final follow-up visual analog scores (VAS) for back pain were respectively 7.3 +/- 0.8, 3.9 +/- 0.8, and 3.4 +/- 0.9. In the fusion group the corresponding scores were 7.5 +/- 1.0, 3.9 +/- 1.1, and 1.6 +/- 0.7; the final result pleaded again in favour of fusion (p < 0.0001). Moreover, there were significantly more implant-related complications (screw loosening and breakage) in the non-fusion group (p < 0.0001). The authors conclude that fusion is advisable to obtain a better final outcome with respect to kyphosis and pain, and to avoid implant-related complications. However, at least one other study has led to the opposite conclusion: the issue remains controversial.