OBJECTIVETo study the influence of different age and short or long segments of pedicle screw fixation to the clinical efficacy of early single thoracolumbar fracture.

METHODSFrom June 2005 to June 2008, 27 patients of early single thoracolumbar fracture were treated using short or long segments pedicle screw instrumentation, fracture vertebral (AO classification: type A1 or A2) was between T11 or L2. All patients were divided into A or B group according to age. A group: 12 cases mean age (32.6+/-10.7) years old (range, 16-55 years old). B group: 15 cases mean age (66.8+/-9.2) years old (range, 56-78 years old). All patients were treated with bony autograft by transpedicular of fracture vertebral and internal fixation by pedicle instrumentation. Pedicle screws were inserted in the pedicles of above and lower adjacent vertebral body of fracture vertebral, and others were inserted in the pedicles of above and lower two vertebral bodies of injured vertebral. Recorded operation time, blood loss and occurrence of complications. All patients took X radiograph plane examination (anterior-posterior position and lateral position) before operation and during 1 week of post operation and more than 1 year of follow up. Measured percentage of anterior compression vertebral high and kyphosis angle of the fracture vertebral by the same one group doctors.

RESULTSMean follow up time was (29.6+/-9.1) months (range, 10 - 34 months). The patients using short segments pedicle screw fixation in A and B group, mean operation time were (102+/-16) min and (118+/-24) min (P=0.072), mean volume of loss blood were (315+/-87) ml and (331+/-87) ml (P=0.064) respectively. The patients using long segments pedicle screw fixation in A and B group, Mean operation time were (138+/-22) min and (159+/-31) min (P=0.052), Mean volume of loss blood were (446+/-102) ml and (482+/-148) ml (P=0.055) respectively. There was no statistic different significantly between A and B group. The patients using short segments fixation, preoperative, during one week of post operation, one year of follow up, in A group the percentage of anterior compression vertebral high were 41.3+/-14.0, 5.4+/-1.0, 13.6+/-1.1, and 38.5+/-11.2, 8.3+/-2.1, 21.4+/-5.2 in B group. The patients using long segments fixation, at some time of preoperative, during one week of post operation and one year of follow up the percentage of anterior compression vertebral high were 40.8+/-11.5, 4.6+/-1.2, 8.3+/-1.0 in group A, and 44.3+/-10.2, 9.7+/-2.1, 11.2+/-3.0 in group B. In group A and B the kyphosis angle of fracture segment was 17.5 degrees+/-1.0 degrees and 16.3 degrees+/-3.1 degrees before operation, 4.2 degrees+/-1.0 degrees and 6.0 degrees+/-1.1 degrees in one week of postoperation and 11.5 degrees+/-1.0 degrees, 13.4 degrees+/-3.0 degrees in one year later postoperation. All the compression vertebral high was recovered and kyphosis was corrected significantly during one week and one year after operation (P<0.05), but there was some loss of kyphosis correction rate in follow up.

CONCLUSIONThere is better clinical efficacy of short segments pedicle instrumentation for treating early thoracolumbar fracture in the young group, but long segments fixation of pedicle instrumentation is more suitable for the older group.