OBJECTIVESTo compare short-term and long-term change of paraspinal muscle between percutaneous and open pedicle screw fixation in the treatment of thoracolumbar fractures.

METHODSThirty-three patients were divided into four groups: short-term percutaneous pedicle screw fixation group, short-term open pedicle screw fixation group, long-term percutaneous pedicle screw fixation group, and long-term open pedicle screw fixation group. Paraspinal muscle were studied by needle electromyography and CT. Cross-sectional area and color grade information of paraspinal muscle were measured using CT image.

RESULTSThe area and color grade of paraspinal muscle changed significantly after surgery. The color grade of paraspinal muscle showed significant change while the muscle area observed no significant change in the two short-term groups; There was significant change in paraspinal muscle area, however no significant change was found in muscle color grade of the two long-term groups. In electromyography study the results showed that there was significant difference in the two short-term groups, however no significant difference existed in the long-term groups. There was no significant difference of patients treated by the two surgical technique in long-term function evaluation.

CONCLUSIONBoth percutaneous and open pedicle screw fixation damage paraspinal muscle, however the muscle showed less injury treated by percutaneous pedicle fixation.